DIY - 1.8L 1ZZ-FE TB Connector Chip Swap

[tk-421]

Originally Posted by MGargano

So I should turn it all the way in, then back out 1.5 turns? If not, what's the 'correct' procedure for adjusting the idle screw?

1. Turn engine off
2. Adjust the screw to your liking
3. Turn engine on and test for oscillation and high idle
4. If you need to modify the value, go to step 1
5. If you're satisfied with the setting, throw some epoxy in there and let dry (optional, but recommended)

FYI, I've read that it's better not to try adjusting the screw with the engine on, or else the ECU might need to be rebooted one last time to reset the values.

I had no idea which direction to turn to or anything like that... All I did was turn clockwise until I found the best setting after the second try. I guess I got lucky, because the damn screw got stripped at a very decent setting, so I didn't need to do any tweaking afterwards.

I also let the gasket maker do its thing for at least 4 hours IIRC, with the battery disconnected the whole time. I also did the coolant bypass, but didn't need to burp it afterwards.

No big oscillations, no CELs, and a pretty decent 2.5K idle... could've been a bit better, but I'm not complaining.

[Yoda]

I am gonna watch it over the week or so. My cold idle is 1.5k. and i didnt touch the screw. If it comes back the i will look into it but for right now its running great. I had to install the orignal TB back on to get the drill to drill out the rivets and forgot to reset the ecu when i replaced it with the 1zz. Then i drove it a bit not too hard. Then turned it off for 5 min or so. when i started it up again oscillation gone. Drove it again. Turned it off. Started up cel gone
Think my ECU went to college

[Yoda]

Originally Posted by tk-421

1. Turn engine off
2. Adjust the screw to your liking
3. Turn engine on and test for oscillation and high idle
4. If you need to modify the value, go to step 1
5. If you're satisfied with the setting, throw some epoxy in there and let dry (optional, but recommended)

FYI, I've read that it's better not to try adjusting the screw with the engine on, or else the ECU might need to be rebooted one last time to reset the values.

I had no idea which direction to turn to or anything like that... All I did was turn clockwise until I found the best setting after the second try. I guess I got lucky, because the damn screw got stripped at a very decent setting, so I didn't need to do any tweaking afterwards.

I also let the gasket maker do its thing for at least 4 hours IIRC, with the battery disconnected the whole time. I also did the coolant bypass, but didn't need to burp it afterwards.

No big oscillations, no CELs, and a pretty decent 2.5K idle... could've been a bit better, but I'm not complaining.

I thought you were suppose to do it while the engine is on. Look at it like a clock and turn buy 2 each time as you find the sweet spot(form 12 oclock to 2 or from 12 to 10 and so on) At each turn let the engine settle at the new position for 3 min if not the right idle turn it again. Not sure if its the same for our car tho.

[jkuchta]

Re-read post #78 in this thread.

If you adjust the idle screw while the car is running, then the ECU will compensate to run a preset idle speed, and you won't know if your adjustment worked or not.

[MGargano]

So after adjusting the idle screw I should be around 700-800rpm at warm idle? Will adjusting the screw have any effect on the high cold idle?

[tk-421]

Originally Posted by MGargano

So after adjusting the idle screw I should be around 700-800rpm at warm idle? Will adjusting the screw have any effect on the high cold idle?

It will, but it will always end up higher than stock. I settled on a 2.5K cold idle, which isn't too much I think.

[jkuchta]

Originally Posted by MGargano

So I should turn it all the way in, then back out 1.5 turns? If not, what's the 'correct' procedure for adjusting the idle screw?

No...turn it 1.5 turns counter-clockwise from the stock Corolla position (where it is when you first get the epoxy off).

[jkuchta]

Just thought I'd repost this:


Hey everyone:

I did this swap this last Sunday...and man what a differeance!

First off I installed the 1ZZ TB stock (no idle screw adjustment or chip swap). Cold idle was high (around 3K) and fluctuated, like everyone has mentioned, though my warm idle was around 850-900rpm, with a pretty bitchin' roughness (think bigger cam). There were definate problems though.

1) CEL: came on intermittantly with P0171 (iirc) lean condition, especially while transitioning from idle to part throttle, though once cleared, this CEL would not come back while driving or coming back to a stop, which makes me want to rule out any sort of air leak.

2) Throttle response was lacking, and pretty disconnected..i.e. while shifting the engine would over-rev 500-1000rpm, and the car seemed to lack any real grunt anywhere in the powerband. I have a scangauge, and could see I was getting full throttle operation.

3) When the car went into DFCO it would feel like I had just released the 'chuts! With the OEM TB DFCO is almost inperceptable, but with the unadjusted 1ZZ TB it was pretty uncomfortable feeling.

4) Heel-toe downshifting was pretty much impossible as well due to lack of fine rev control, and a wierd over-rev/under-rev (the car stalled itself twice) on deceleration.

These symptoms were consistant over more than 3 hours of driving.



On Monday afternoon, I removed the 1ZZ TB and swapped out the chip with the OEM 1NZ chip. I did this without disconnecting the battery, as I wanted to see how big a difference this swap would make, all other things being equal.

BIG DIFFERENCE!

1) High Cold idle lasts about half as long. Also, there is no ocillation. The rpms just go straight to 2500-2700, and then slowly taper back down.

2) The idle is also much more stable (like stock), with no (albeit cool) roughness.



Now I got to work setting the correct idle speed. For some reason, the epoxy over the idle set screw on my 1ZZ TB came off nice and easy, an in one piece. After a few minutes idleing, the engine settled to about 1K rpm, which set off a CEL (I think P0220 iirc(TB stuck open)). I adjusted the screw to the point of killing the engine (which triggered another CEL (P0505...bad idle)). I then screwed the idle set screw back in about half way, which when the engine was turned back on, gave me an idle of about 850 rpm. I then shut the engine back off and adjusted the screw back out about a turn, which (when the engine was turned back on) gave me a nice stable (and smooth) 720-750rpm.

Note: The idle speed in the last 1500+ miles has settled down to 600-700 rpm, which I would attribute to ECU trimming.

Based on the manual, this is as high as you can go without running the risk of getting a "bad idle" CEL. This idle rpm also makes leaving stoplights a little better in that the engine doesn't bog quite as much.



A note on setting the idle:

Adjustments should be made with the engine and ignition off, as doing the adjustment with the engine running will only cause the ECU to compensate to maintain the idle speed, almost regardless of the idle set screw position (took me 10 min. to figure that out).


Driving impressions:


1) Throttle response is better than stock, and the car pulls like a motha' (well....way more than with the stock TB) above 2200 rpms.

2) Heel-toe downshifting is better than stock (rpms come up a little faster, and with a little more "control" (i.e. a little tap gives a few hundred rpm (great for the 5th-4th shift), and a bigger dab gives about 1000 rpm (great for 4th-3rd, and 3rd-2nd shifts).

Once the idle was set there have been no CELs of any kind, and the car is a riot to drive!

As far as I'm concerned...this is a must-do mod for anyone with the stomach to do the chip swap (drilling out that first rivet is mentally the hard part), though the idle adjustment is pretty much a requirment to make this thing feel right.




A big THANK YOU to T-sport for the diy (and having the nuts to do this in the first place)!




Side note:

I also did the TB coolent bypass. My other mods are as follows : Simota Carbon SRI (the big box), WR header, Thermal axle-back, and nology hotwires, running Shell V-Power and Motul 300V 5W-30.

[MGargano]

Originally Posted by jkuchta

No...turn it 1.5 turns counter-clockwise from the stock Corolla position (where it is when you first get the epoxy off).

I got the epoxy off, but stripped the head of the screw trying to turn it. No matter which allen I tried, none seemed to fit correctly and I ended up rounding the edges of the hex off. Ideas for removal/replacement?

[jkuchta]

http://www.qvc.com/qic/qvcapp.aspx/v...&cm_ite=V28297

I have a set of these, and they work pretty well. I got them at ACE Hardware.

[MGargano]

Thanks... will try that on my next day off.

[MGargano]

Now that the head is totally shot, should I replace the original screw with something else?

[jkuchta]

Yes...take it to ACE and get a standard metric allen socket head cap screw (I think it's an M3 diameter with .5mm thread pitch...but I'm not 100% sure). I think you'll want something about 40-50mm long.

[marcus]

remind people thats gonna do this to play around with that screw before to put it on!!

[eii]

Originally Posted by jkuchta

And eii, if you want to go for a ride in a yaris with the 1zz tb install that was done correctly, PM me.

Oh I was just kidding, hehe . I based my install on the guide post you made earlier in this thread (thanks btw) so I'm sure I did it correct. I just get that < 1 minute 2.5k-ish cold idle start. Other than that it works great, I was just wondering what happened to demon. I just did the coolant bypass this morning, its more responsive and I definitely feel some more power. Cool stuff

[jkuchta]

Right on!

[MGargano]

I finally adjusted the idle screw and haven't got thrown a CEL yet and the start-up oscillation appears to be gone, but now the engine does a weird thing at idle. The RPMs drop very low (around 400) and the car starts to shudder like it's gonna stall out, then the engine revs itself up to about 1,500 RPM for a second. It keeps doing this over and over until I finally turn the car off for fear it's gonna stall. It's even worse when I'm idling with the A/C on. Also getting some jerkiness in the pedal when it enters DFCO.

[jkuchta]

turn the screw clockwise a half turn with the engine off. That should make it better. Also, if a half turn isnt enough, keep turning in half turn increments (with the engine off).