Odd sputtering and rough idle Options

[Malek]

I know the 3SGTEs are notorious for destroying distributor caps and rotors and plugs, etc. but from what I read on here and other forums about this issue doesn't seem to quite match up to my issue.

Symptoms:
-Cold start: idles high normally
-Once warm: idles rough (misfire) and fluctuates 750 - 1000 rpm
-When driving: Major hesitation up to about 3k. Sounds of misfire.
-Above 3k at steady throttle, seems to run fine
-When giving good amount of throttle, doesn't pass 5-7psi and replicates video (below)
-Wideband reads 15ish when above is happening

A comment in the video said they changed their spark plug wires on their GST and it went away..however, this Evo is boosting pass 20psi and I can't get past 7..


Evo 8 Boost


Any suggestions before I jump into dizzy, wires, plugs..? Thanks!

[lagos]

Check for boost leaks or any disconnected hoses, especially your map sensor hose.
After that I would pull the plugs, mostly just to see if any of them haven't worked themselves loose out of the head.
If all that checks out, look at your mechanical timing (that the cams and the crank are EXACTLY at TDC), and check your ignition timing with a timing light and TE and E1 bridged.

Are your plugs, wires, cap and rotor all original, or did you change them with your swap? People talk about ignition issues, but the reality is that you should be able to get at least 3 years out of a new set of wires, cap and rotor, and at least a year out of copper plugs. So unless you are still using old ignition components that came with your clip, I doubt thats your issue.

[Box]

IACV perhaps?

[Malek]

Art, that is the most comprehensive check list I've seen through all of my searching!

Before I did anything this morning, I took it out for a drive. It started and idled fine. I let it warm up for about 30 seconds and drove it (I know you're supposed to let it warm up longer). Anyways, in it's cold state, it boosted normally to 13psi and AFRs were normal.

It started it's sputtering issue when it was warm. AFR reads high 14-15 when I try and step on the gas. This tells me it might have something to do with fuel.

I just replaced the fuel filter. The old one was nasty inside but it did not change anything.

[Malek]

Update:

Changed the spark plugs.

All better.

SN: I didn't bother changing any of the ignition stuff for the swap because I figured it'd last me to the summer when the engine would be taken out again anyways haha apparently not!

[Box]

Yay for easy fixes!

[lagos]

Update:

Changed the spark plugs.

All better.

SN: I didn't bother changing any of the ignition stuff for the swap because I figured it'd last me to the summer when the engine would be taken out again anyways haha apparently not!

Ignition components normally last a while under normal use (you dont have to replace them as often as people claim), but they do go bad quickly on imported engines/clips. You never know their fully history or how long they sat in warehouse somewhere with all kinds of corrosion going on. You pretty much have to replace to plugs, wires, cap and rotor when doing a swap.

My car used to buck a surge like crazy under boost, because my timing belt wasn't exactly perfect. It caused all kinds of uneven idle issues too. So the checklist comes from issues I've had to troubleshoot with my own car over the years.

This post has been edited by lagos: Apr 6, 2013 - 12:33 AM

[BonzaiCelica]

ok so bump. i'm pretty sure its the Idle Air Control valve. but just to make sure. here are my symptoms for the 3sge beams redtop motor

Upon Cold Start up: sometimes it will idle/sputter from 1,000-1300 rpm range.(normal idle for all celica's upon cold start is 1300 rpm for the first 30 sec). if it does sputter and have hard time staying at 1300 rpm all i have to do is drive it for 7-10 sec and then put it back into nuetral while the engine is running and the sputtering will go away.

I give it full throttle up to 7,000 rpm for anywhere up to 5-7 sec and then suddenly drop it into nuetral it will idle down to 500rpm and then the idle will die out after 3 sec.

if i'm slowly downshift from 5th to 2nd gear while coming to a complete stop. the idle will fluctuate from 500-700 rpm two times and then go up too its normal 800 rpm idle.

i know you can replace IAC or clean them. i replaced my spark plugs 15,000 miles ago with ngk iridiums...

This post has been edited by BonzaiCelica: May 28, 2013 - 2:00 PM