Car shuts off when A/C turned on...

[Howster]

Hi,

My fiance owns a 2007 Yaris 4-door. It has been a perfect car since she purchased it new at the end of 2006. However recently she purchased a Mini Cooper and the Yaris was being driven part-time by her 17 year old son.

The car stopped running one day a month or so ago. We had the car towed to our home and I began troubleshooting as I am an avionics and European car technician by trade. What I found first was the fuel gauge said it had two dashes left, however when I removed the fuel pump, the fuel tank was absolutely dry. I ordered a new sending unit and that was corrected. However it seemed the fuel pump was intermittent. I used my fluke meter, but found the fuel pump seemed to be fine.

I did find out she had not replaced plugs, or had a tune-up pretty much since new. I replaced plugs, oil, air filter, PCV valve, fuel injector o-rings and caps.
I cleaned the MAF with cleaner and checked or leaks in the vacuum system. I sprayed the throttle body and removed as much carbon as i could. After replacing all of these parts and doing the cleaning steps mentioned below, the car would drive ok for a number of miles, but then start running rough at low rpm or at idle. When the A/C is turned on, it pretty much dies. Then the car is very difficult to start unless I spray starting fluid into the air intake. Then it starts fine and idles perfectly. But when I give it a little throttle, it hesitates and wants to shut off. Once I get it past this point it will run fine. But this is all null and void when the A/C is turned on. Then all bets are off. I am stumped here.

I connected my OBD II and began getting P171 codes, which show a lean bank. This to me made sense that the fuel pump could be defective, but to not troubleshoot further and then spend the $250-300 for the pump and find out that isn't the problem was not an option just yet. I have also gotten P301-P304 codes, but these have not returned once they were cleared.

I wanted to test the fuel pressure but can't locate the test port to do this. Normally it is on the fuel injector rail, but not on the Yaris. I just replaced the battery and at least I can now get the car started without jumping it.

Can ANYONE please help me with this? I am a pretty intelligent person and can troubleshoot almost anything, but this Yaris has me going cookoo. Any help would be greatly appreciated.

A six pack will go to anyone who can help me sort this out. Understand that it is illegal to ship alcoholic beverages through the USPS system, so I will of course have to drink them for you. But a toast will be made during each new beer bottle cap being popped and we will mention your name numerous times. I won't chug it, and I won't drive while I am drinking your beer. I won't even drive afterwards. This beer would be for you. So can you/anyone give me some hints? Car has been sitting for about three weeks because of my work shift. Thanks so much to everyone for reading this really long and boring post. It is greatly appreciated.

Cheers,

Howie

P.S. Howie, Alma, and Max thank you.

[KTS]

since the fuel tank was dry and you are getting a lean code i would suggest cleaning the injectors incase some contaminant passed thru the filter and lodged itself in the injector rail or injector itself this mite explain the code P0171 and for P0301-304 check the coil packs. just my 2cents but hoping you can have the car workin soon.

[CTScott]

There is not a test port for the fuel pressure, but the quick release connector between the flexible fuel line and the fuel rail provide an easy point to connect to.

Aeromotive makes a nice inline fitting for connecting a pressure gauge. It has an 1/8" NPT gauge port and a 6AN port. If you purchase one, you will also need a 6AN plug for that port.
http://www.jegs.com/i/Aeromotive/027/15120/10002/-1

If you want to just bite the bullet and swap the fuel pump, I have an extra fully-tested one on hand that I use on my test bench when experimenting with modifying fuel pressure regulators for boosted applications. I could do $100 shipped on it.

[peewee1]

Perhaps the fuel filter is PLUGGED!!!!(if it has one)

[Howster]

Hi and thanks for the replies. I have totally cleaned the injectors, replaced the o-rings and caps, replaced the plugs, and so much other stuff I can't remember it all. However it was all done via troubleshooting and not just a way to replace things for the heck of it.

Everything needed to be done as it had not ever been done. I am still concerned as to why the car shuts off when the a/c is turned on. Once I figure that out the rest should fall into place. Thanks.

Howie

[CTScott]

Hi and thanks for the replies. I have totally cleaned the injectors, replaced the o-rings and caps, replaced the plugs, and so much other stuff I can't remember it all. However it was all done via troubleshooting and not just a way to replace things for the heck of it.

Everything needed to be done as it had not ever been done. I am still concerned as to why the car shuts off when the a/c is turned on. Once I figure that out the rest should fall into place. Thanks.

Howie

The AC obviously puts a large load on the engine. The Yaris ECM does not compensate as much for this at idle as most other cars' ECMs do. So, if you are having fuel delivery issues they will be amplified with the AC. You may wan to try pulling the coil connectors and disconnecting the fuel rail and turning the engine over while letting the fuel hose squirt into a container to see what the flow looks like.

[YarisSedan]

Have you tried resetting the fuel trim. After any repair if you dont reset it it will continue to run lean for a long while. Your long term fuel trim numbers are probably maxed already if its setting a system too lean code. The most common problem for system too lean is a vacuum leak. Reset your adaptive memory test drive the vehicle for awhile and watch your fuel trims, see if it goes back to lean and if its more so at idle or when your driving, more so when driving then id say its fuel related if its at idle its more than likely a vacuum leak.

[Howster]

How do I set this fuel trim you are talking about? I have checked for vacuum leaks, but only one suspect hose and it is repaired. I haven't messed with the TPS yet because I don't know the calibration to reset it.

Please tell me what I need to do for the trims you speak of. I have reset the coded on the OBD II but that is all. Also, I wanted to check the fuel pressure, however there is no port for checking that. I can borrow a fuel pressure tester from Auto Zone, but I again don't know the pressures. Any help would be greatly appreciated.

Cheers,

Howie

[Howster]

The beginning of all of this was when my stepson ran out of gas not knowing it was low. The gauge read 1/4 tank, but when I opened it up, it was drained totally dry. Sometimes I even have to spray with starting fluid or it will just run the battery dead. Also it always ran beautifully until this happened. The A/C always worked great and the car had great power. I always commented on how peppy this little engine is.

I have tried everything you guys have suggested except the fuel trim, which I don't know what that is. CTSCOTT, I have removed the fuel rail, cleaned and replaced fuel injector parts, cleaned MAF, and replaced plugs. Sprayed throttle body. Not sure what else to do. I suspect there might, just might be a vacuum leak, but looking at other things now.

I still think the fuel pump could be an issue, however once it starts with starting fluid it runs fine for the most part until I turn the A/C on. Still a hesitation as soon as I press the gas, but think it is all related.

Any other ideas and how to do the fuel trims would be swell.

Cheers,

Howie

[YarisSedan]

The computer has adaptive learning and can correct a lean or rich condition by adding or subtracting up to 30 percent fuel once its long term memory cant correct past that point it sets the check engine light. Depending on the scanner you are using simply resetting the check engine light may not reset the adaptive memory. A easy way to completely wipe the memory is disconnect both the negative and positive battery terminals from the battery and touch them together for 10 seconds and then reconnect them to the battery. This will discharge the capacitors in the ecu and completely whipe its memory back to zero.

Simply doing that you will be surprised how much different the car will run,

http://www.tooltopia.com/equus-3100.aspx

This is a real good diagnostic tool for the price It lets you look at all live data which includes fuel trim and 02 sensors as well as freeze frame data when your check engine light was triggered.

If the scanner you have lets you look at o2 voltage i would see if it is switching properly or is still indicating lean. If you watch your o2 voltage disconect a small vacuum line and spray a bit of brake clean or carb clean in the intake you should be able to watch your o2 signal spike rich.

[Howster]

Hey YarisSedan,

That sounds like a great idea. I will give that a shot and see what happens. I work aircraft avionics systems everyday, but don't seem to know about every type of ECM out there. I can do Ford stuff pretty well, but Yaris is new to me. I will let you know how it goes. I'm havin' a swig in your honor right this very second.

Cheers,

Howie

[Howster]

OK,

Here is the skinny on things as of now. Before I touched the battery posts, the car would not idle at all with the A/C on. It does now. However the engine will not go above say 1000 rpm with A/C on, but when I turn it on the engine will rev to well over 3000 rpm if I coax it. Meaning I have to burp the throttle lightly and sometimes rapidly to get that far.

Also there are now times when after getting the engine to rev up above 1ooo rpm, I can then turn the A/C on and let it go to idle and then burp the throttle. Sometimes it will go above 2-3000 rpm, but most times not.

One thing that seems to be consistent about 95% of the time is pressing the throttle and it stumbles and won't go above 1000 rpm. Confusing I know. Finally, and then probably has nothing to do with anything, but when I am starting the car and let go of the key, the starter keeps going until the car either starts finally, or well it doesn't start. This is 99% of the time since these problems started when my stepson ran out of gas.

What else can I check now? I don't really know where all of the vacuum lines are as I don't have a diagram. Are there a few behind the battery towards the bottom of the engine bay?

When I do burp the throttle hard, I can hear the intake really make a lot of noise. I have a new air filter and the box is secure, but I never heard it like that before. Makes me wonder if the hose from the throttle body to the air box has a leak in it. Will see what I can find. I am again a lost Yaris troubleshooter.

Thanks,

Howie

[nookandcrannycar]

The computer has adaptive learning and can correct a lean or rich condition by adding or subtracting up to 30 percent fuel once its long term memory cant correct past that point it sets the check engine light. Depending on the scanner you are using simply resetting the check engine light may not reset the adaptive memory. A easy way to completely wipe the memory is disconnect both the negative and positive battery terminals from the battery and touch them together for 10 seconds and then reconnect them to the battery. This will discharge the capacitors in the ecu and completely whipe its memory back to zero.

Simply doing that you will be surprised how much different the car will run,

http://www.tooltopia.com/equus-3100.aspx

This is a real good diagnostic tool for the price It lets you look at all live data which includes fuel trim and 02 sensors as well as freeze frame data when your check engine light was triggered.

If the scanner you have lets you look at o2 voltage i would see if it is switching properly or is still indicating lean. If you watch your o2 voltage disconect a small vacuum line and spray a bit of brake clean or carb clean in the intake you should be able to watch your o2 signal spike rich.

^^^^^ This. After changing my battery last year, my car was 'running rough'. I immediately posted here and CTScott replied that the situation should correct itself as the ECU needed to relearn the fuel trims. Sure enough, fewer than 24 hours later my Yaris was running just fine.

[Howster]

So I am assuming since the car was driving fine before it ran out of gas, these are just side effects of that. I did have to replace the battery, and I did some maintenance that needed to be performed long ago.

So is this what a dealership would do if this happened to a customer? He would tell the owner to drive it until it sorted itself out? I mean, as crappy as this car is running now, it would be difficult for most people to deal with for even 24 hours.

I will still give the vacuum lines a once-over, however I don't know where the main vacuum tree is located. Nothing apparent topside, so will remove the battery and go underneath. Thanks for all of your help everyone. If I have more issues I will post again. Wish me luck.

Cheers,

Howie

[AbsolutelyRed]

Fuel filter (or pump) would be my guess... sounds like it's starved for fuel. Not sure about the Yaris but on some cars when you run the tank dry you can get all the gunk from the bottom of the tank sucked in and it can clog the filter. The Yaris has a pre-filter screen as well as the fuel filter I believe.

Check the pressure, the Toyota service manual has troubleshooting info I would think.

[Howster]

I cleaned the in-tank fuel filter when I replaced the sending unit. From what everyone else has told me there is no true fuel filter per se. I would like to know what the fuel pressure is but there isn't a test port to do that.

I still think there may be a vacuum leak, but not sure. Will keep on keeping on until I sort it out. I think I will order a nice code scanner as my code readers don't really do what I feel I need to diagnose issues like this.

But please keep those cards and letters coming as something is sure to hit the spot sooner or later.

Cheers to everyone who has had input.

Howie

[CTScott]

I cleaned the in-tank fuel filter when I replaced the sending unit. From what everyone else has told me there is no true fuel filter per se. I would like to know what the fuel pressure is but there isn't a test port to do that.

I still think there may be a vacuum leak, but not sure. Will keep on keeping on until I sort it out. I think I will order a nice code scanner as my code readers don't really do what I feel I need to diagnose issues like this.

But please keep those cards and letters coming as something is sure to hit the spot sooner or later.

Cheers to everyone who has had input.

Howie


The fuel filter is actually the plastic can that surrounds the pump. The mesh piece that attaches to the bottom of the pump is just a large particle screen. The fuel filter runs about $40 for an aftermarket one.

[auxmike]

How about blowing out the fuel line with compressed air? Any chance the A/C compressor is starting to seize up and pull down the engine? Clogged CATS or exhaust?
Does the Yaris have an EGR valve? I've never spotted one during my adventures under the hood...

[Howster]

I haven't actually looked for the EGR valve yet, so not sure there is one. The A/C works fine and now after doing a procedure that CTScott had me do, it now idles with the A/C on. I could flush out the fuel lines but the car does run fine past the 1000 rpm range for the most part.

I am ordering a scanner which will do much more than just a reader. I am hoping that will save me in the long run.

Cheers,

[AbsolutelyRed]

There is a fuel filter, this is from another thread:

CT Scott is not entirely correct. The Part on the bottom of the Fuel pump/filter assembly is just the screen to keep big pieces out of the pump. The actual filter is above the screen and is the part that the pump is housed in. Here is the procedure for replacing this. I didn't change the screen, just the filter itself.
Change fuel filter 2007 Toyota Yaris
Posted 11-05-2012 at 02:02 PM by Microbuzz
There seems to be some confusion as to whether or not the fuel filter in a Yaris can be changed. I will clear this up right now. You CAN change your fuel filter and you CAN purchase just a fuel filter without the pump at a very reasonable price on line if you search a little. I live in Canada but purchased the filter from a U.S. supplier which only took about a week or so to arrive. The fuel filter is located INSIDE the gas tank and it is a little tricky to change it but it can be done in about 2 hours or so if you have any mechanical ability at all and the necessary tools. I will give a list of everything you need as well as step by step instructions. This procedure was for a 2007 Yaris purchased in Canada but it could be the same or close for most Yaris, Echo, possibly many Toyota models.

Tools/supplies required:
Pry bar (best) or large flat screwdiver. Air compresser with a high pressure air nozzle. A can of spray lubricant such as WD40. A tube of silicone seal. A universal fuel pump retainer ring removal tool (hard to find in parts stores in Canada but can be purchased on line). A 1/2 inch drive "J" bar or long torque wrench. A container such a large stainless steel mixing bowl. A CLEAN surface to work on in an open area (you will have gasoline spilling out of the old filter so don't do this in an enclosed area without ventilation). A couple of flat screwdrivers of various lengths and sizes, long needle nose pliers etc. A razor knife. A kettle (yes a kettle for boiling water but DON'T boil the water near your work station to avoid making a spark causing a fire) and an old cup to put the boiling water into.

Instructions:
First you need to access the cover over the fuel pump which is under the back seat cusion. In my vehicle I didn't need to remove the entire seat, just the cusion. First disconnect the shoulder belt from the lower buckle and set it out of the way. The back rests stay in place. To remove the cushion you can wedge the pry bar between the frame and the front of the seat and pry up. There is a U shaped part on the front/bottom of the seat cushion that clips into a nylon clip about 12 inches in on either side of the seat that will pop out when you pry on it. You can actually fold the edge of the seat up to see what you are doing. Once you have both clips disconnected lift the front of the seat up and it will disconnect from the hook at the back of the seat. Once you have removed the seat cushion, you will see the access cover for the fuel pump. Clean the area with compressed air then carefully pry up on it a bit at a time so you don't damage it. It is held down by a similar substance as a widshield and is very sticky. Try not to get dirt on it if you can. There is a covering over the electrical and a grommet going through the cover for the wiring. Remove the covering and grommet from the cover. Remove the cover then unclip the electrical connection and remove the cover from the vehicle. Set the wiring off to one side. The top of the fuel pump housing will likely be quite dirty (some little animal was nice enough to leave me sunflower seed shells) so blow it off as well as possible so dirt and debris doesn't fall into the tank. Now you will want to depressurize the fuel line so try to start the engine. It will sputter a few times then die. Once you have done this you can remove the fuel lines by disconnecting the clips and just pulling the fuel lines off. Careful not to lose the clips. Use a clean cloth to catch any drips and wrap the ends of the lines and wedge them up under the seat to keep them out of the way. You are now ready to remove the fuel pump assembly. Take the WD40 spray and squirt some around the top edge of the retainer ring. You may want to wait a while before attempting to undo the ring. Get your ring removal tool and adjust it so it fits snugly over the ribs on the retaining ring. DO NOT attempt to remove the ring without the tool, it won't happen. You may want to enlist the help of someone when you start to undo the ring. It may be very tight and hard to keep the tool from slipping off the ribs. Put your J bar or Torque wrench into the square in the removal tool, have your helper push down on the tool so it doesn't slip off the ribs and reef on the j bar. The ring should start to turn. Undo the ring until it comes off and place it to one side. Before you remove the pump assembly get your mixing bowl ready in the vehicle as gasoline will spill from the housing. Remove the entire assemly from the tank, being careful not to damage the float/fuel level sender unit attached to the housing. The hole is just big enough for the housing to come out. place the assembly in the bowl and remove it from the vehicle. Drain as much gas from the unit as posssible. More will come out as you work on it so you may want to work on a clean piece of cardboard to soak up what comes out. Make sure you are in a well venilated or open area. You can now start disassembling the pump assembly. It is all clipped together with nylon clips and very easy to disassemble. Be careful not to damage the fuel level float and sender while you work on the pump. Begin by disconnecting the elecrical connection from the bottom of the electical plug (don't attempt to remove the wire from the pump just yet) and remove the fuel line coming from the filter off the nipple on the housing. This fuel line is impossible to remove by pulling on it so take your razor knife and cut it lengthwise until it is cut through being careful not to cut the nipple itself. Be very gentle and make many light cuts until it's through and pull the line off. Undo the clip that holds the pump/filter assembly into the housing and remove the assembly from the housing. you will see a screen at the bottom of the pump that is part of the retainer that holds the pump into the middle of the filter. Gently pry the clips apart with a flat screwdriver to release the retainer and remove it from the bottom of the filter. You can now remove the pump from the centre of the filter. You may need to push gently on the electrical connecter to get the pump out of the filter. Once the pump is out unclip the electrical wire and remove it from the filter. Remove the check valve from the bottom of the filter being careful not to lose any "O" rings or spacers. There is also a small screen in the check valve. Make note of the position of all the O rings and spacers in case they come apart. check that there are no O rings or components remaining on the filter and discard it. Now you should clean all the parts. Use compressed air to blow out the pump, the screen (blow this out very well), the check valve and the entire housing. Make sure you blow out any and all the ports you can see. Check to make sure there is nothing obstructing the little flapper/one way valve at the bottom of the housing that allows gas into the housing (I had some hair and debris caught in mine). You may need a long thin screwdriver or some long thin needle nose pliers to get at it if theres something stuck there but try air first. Clean the rest of the housing as well as you can. You may need to scrape dirt away in a few places in the housing if you got some very dirty fuel. There is a little black tube (air bleeder I think) that you can unclip from the housing but DO NOT disconnect it from any of the nipples or you will damage it. Once you have everything clean you can start reassembly. Spray a little WD 40 on all the O rings and nipples as well as into the pump itself. Press the check valve into the the fuel filter, feed the electrical wire through the hole in the top of the filter, attach it to the pump and slide the pump into the filter making sure it seats on the nipple in the middle of the filter. Clip the retainer onto the bottom of the filter making sure everything fits together properly and all the clips are latched. Attach the other clip to the top of the filter and clip the pump/filter assembly into the housing. Check to make sure everything looks in place and there are no parts left over. Now, get your water boiling and have a cup of tea (HAHA, just kidding). You will notice the line coming from the filter is a hard plastic. This is very difficult to get onto the nipple so get your boiling hot water ready in a cup and dip the end of the line in it for 15 seconds or so to soften it up. then immediately press it onto the nipple as far up as you can. MAKE SURE it is running from the filter to the nipple the correct way because you won't get it off again. Connect your elecrical wire to the bottom of the plug and assembly is complete! Take the assembly and feed it back into the tank. You may want to enlist your helper again when reinstalling the unit. The housing is spring loaded so it's nice to have a second pair of hands to hold the assembly down while you tighten the retainer ring. You can also spray a little WD40 on the threads to make it easier to turn the retainer ring. Be careful to have the pump unit lined up properly and the O ring centred to avoid leakage. There is a little tab that holds the unit in place. Also be sure not to cross thread the retainer ring. If you cross thread it and damage the threads you may never get it on properly and it will leak. Use the tool to make sure it is tight, attach the fuel lines (make sure everything is clean) feed the electrical connector through the cover and attache to the assembly. Now you can test it before installing the cover. Turn on the key, wait a few seconds then crank the engine. It may take several attempts before it starts and it will likely sputter and/or stall some before it starts running. If it doesn't start you likely did something wrong or you need a pump, not just the filter but if it was running when you took it apart it should run again. If the filter was very dirty you will notice a substantial increase in performance. You can now replace the cover using silicone, replace the back seat cushion and you're done!

[Howster]

Hi Absolutely Red,

Thanks for the input, however I have had the pump assembly out a couple of times during all of this. I have replaced the sending unit and checked everything over. I do however want to order the fuel filter, but there seems to be quite a few on-line shops selling it.

I found the part at Rock Auto for $22.99. I hope it is the correct part. I am also still having the P171 codes, so haven't been able to clear them yet. The car is driving better, but still has hesitation when first pressing throttle pedal. It does run fine with the A/C on now so that is a big help.

Since the P171 code is a lean code, I am hoping the fuel filter will take care of that. But still also having some issues on engine start up where the starter keeps turning when I let go of the key. This doesn't seem to be a problem when the car starts normally.

So with that code there is still a chance of a fuel supply issue or a vacuum leak. Does anyone have a diagram of where all of the vacuum lines are located? Is there a vacuum tree where it all comes together? From topside I see nothing.

Everyone has been great with all of the information, and now I am hoping I am finally almost finished so this baby can be put back on the road as a daily driver. Thanks again.

Cheers,

Howster

[auxmike]

It's normal for the starter motor to do that. It's a little odd at first, but that's part of the Yaris' charm��

[Howster]

I was wondering if anyone has the specifications for fuel trims and O2 info for a 2007 Yaris? I am still having issues and purchased a Innova 3130C scanner. I just don't have a baseline for anything so don't have a starting point.

Now the only problem I am having is mainly hesitation on acceleration from a stop, but also sometimes at speed. Transmission seems to stumble when trying to go into passing gear.

It seemed to run better for a while when I put a new MAF sensor in it, and the hesitation was pretty much gone. However that lasted not very long. I now have the original back in. I have replaced the fuel filter, along with parts mentioned in earlier posts. Only thing I can think of now is vacuum lines and fuel pressure, although I don't know what the pressure should be. If anyone has an idea that would be sweet.

So many have helped with this and I am still dealing with this since I am not able to work on it except for the weekends. I would appreciate any info anyone can help with.

Thanks again,

Howster

[CTScott]

I was wondering if anyone has the specifications for fuel trims and O2 info for a 2007 Yaris? I am still having issues and purchased a Innova 3130C scanner. I just don't have a baseline for anything so don't have a starting point.

Now the only problem I am having is mainly hesitation on acceleration from a stop, but also sometimes at speed. Transmission seems to stumble when trying to go into passing gear.

It seemed to run better for a while when I put a new MAF sensor in it, and the hesitation was pretty much gone. However that lasted not very long. I now have the original back in. I have replaced the fuel filter, along with parts mentioned in earlier posts. Only thing I can think of now is vacuum lines and fuel pressure, although I don't know what the pressure should be. If anyone has an idea that would be sweet.

So many have helped with this and I am still dealing with this since I am not able to work on it except for the weekends. I would appreciate any info anyone can help with.

Thanks again,

Howster


Fuel pressure should be about 41 psi.

For a completely stock Yaris the fuel trims should stay pretty close to zero. On my red 08, they stay within the +/- 2 range.

[Howster]

Thanks for that CTScott. Do you happen to have any of the other baseline parameters I need to check things like STFT and LTFT? I am still trying to diagnose if I might have a faulty O2 sensor, but I don't know the parameters for any of this. I guess I can purchase a manual, however once I have this repaired we were going to sell it anyway.

I can't in good conscience sell a car or anything for that matter that is suspect. Never have and I won't start now. The 3130C is a very nice scanner, but if I don't have any parameters, as far as I am concerned it is just a glorified code reader, and I already have one of those.

I appreciate as always any assistance and am hoping to sort this out ASAP. BTW, is there a vacuum tree someone where all of the vacuum lines meet for all the various systems? I know my Fords always had that.

Here is what has been replaced on the Yaris to date.

BATTERY
Fuel Sending Unit
Fuel Filter and lower retainer ( I broke the retainer by accident).
Oil
Spark Plugs
O-rings and caps on all injectors.
PCV valve. and hose

I did purchase a new MAF sensor, but after a couple of days it didn't seem to correct any of the problems I was having. I reinstalled the original one. Also, I did as suggested and disconnected the battery terminals and touched them together for 10-20 seconds to reset the ECM. Once I did that, and I have done that twice since this all began, the car eventually was running pretty darn well. But I was still getting the P0171 codes and they are still coming back. This even when the new MAF was installed.

Sometimes I don't get the code for a full day of driving and sometimes it shows up in an hour. The car does not get driven regularly because we have other vehicles until this gets resolved. I will go ahead and check the vacuum lines more closely and replace anything that looks suspect.

I did read where the EVAP system can cause this problem, however I am not familiar with that system at all. What can anyone tell me as far as checking that out? Thanks again to all.

I anxiously await any information and once the car is up and running normally I promise I will drink a beer for each person that has assisted. So far I will be one drunk bastard.

Cheers to all.

Howster

[Howster]

I just took the 3130C out to the car again and noticed the STFT is within tolerance, which is well under 10. However the LTFT is at 36 and goes up to around 43 at times when I push the throttle. This is from what I have found out to be a for-sure problem. Any hints on what to check now? Maybe it is as simple as a vacuum leak and I just need to replace all of the lines. Couldn't hurt I guess. What say all?

Cheers,

Howster

[CTScott]

Here's a cap of a normal run. You can actually grab the service manual via the Micro Image forum: http://www.microimageonline.com/forums/showthread.php/4232-YARIS-FILES


51230

[CTScott]

I just took the 3130C out to the car again and noticed the STFT is within tolerance, which is well under 10. However the LTFT is at 36 and goes up to around 43 at times when I push the throttle. This is from what I have found out to be a for-sure problem. Any hints on what to check now? Maybe it is as simple as a vacuum leak and I just need to replace all of the lines. Couldn't hurt I guess. What say all?

Cheers,

Howster

Have you checked for exhaust leaks at the manifold or where it meets the mid-pipe?

[Howster]

Hi. No I haven't yet but I will check that this weekend. Thanks for the table as well. Would you look at vacuum leaks first or look at the exhaust manifold?

Cheers,

Howster

[Howster]

So CTScott,

What does that LTFT look like to you as opposed to the STFT? What other items on the chart you sent to me would I need to look at as priorities? This scanner is still new to me so still learning.

Cheers,

Howster

[CTScott]

So CTScott,

What does that LTFT look like to you as opposed to the STFT? What other items on the chart you sent to me would I need to look at as priorities? This scanner is still new to me so still learning.

Cheers,

Howster

Over +/-35 will trigger a DTC, so yours is definitely just over that range.

I would also watch the 02 sensor lambda and the injection volume.

The Yaris has very little as far as vacuum hoses go, so I would take a peek at them before the exhaust.

[Howster]

Will be checking for leaks this weekend. I am so over this as I have done all I have been taught and trained to do over the past 35 years. I guess I don't know as much as I thought about these cars. I repaired all of the obvious stuff, but just wasn't sure where all of the vacuum hoses were. I will take a look and see what happens. I will get some leak check and cross my fingers.

Thanks again CTScott

[Howster]

Hey CTScott,

One more thing I forgot to mention. The car is also very hard to start. If I use starting fluid, it will usually fire right up, however if it sits for a little while, I have to spray inside the filter box again to start it. Is this a problem also caused by a vacuum leak? I am kind of going around in circles now. I will be checking for leaks with leak detector fluid, but after that I am lost.

Thanks,

[Howster]

Hey CTScott,

Some things happened I had not tried before so updating you to see what I can do next. First, I did notate all of the fields that my scanner can see, and I will list them when I get home. I checked for leaks by spraying throttle body cleaner at the intake and exhaust where I could, as well as any vacuum lines I could find. I didn't find anything.

I decided to give it WOT with the scanner connected and what happens is well, pretty much nothing. Well nothing in a good way. The engine really kind of bogs down and if I keep it down it will start to sputter and pop, like it is backfiring. I don't let it get loud, but I did notice the scanner is all over the place. Initial acceleration is hesitant, and then if I keep it down it bogs and sputters and misses. If I get it gradual throttle then it revs pretty much ok.

There is also the problem of the car not wanting to start. I end up spraying starting fluid in the intake and it starts right up. Once warm it seems to start ok. This to me points to a fuel pump as maybe it just isn't putting enough pressure to start it up initially. I don't know how to check the fuel pressure because there isn't a place to check it with a gauge. My scanner doesn't read fuel pressure I don't think..

My next step I guess is to take it to the Toyota dealership and have them check out the damn thing. I think I have exhusted all options unless I chage an O2 sensor or something like that. My scanner says they are good, but what does it know? Any tips from what I have told you here would be great. Thanks again.

Howster