7M-GTE; Won't idle longer than 20 sec.

[iskrem]

So I just got my 7M-GTE together after a rebuild. It starts nicely on first try, no holding key in etc. etc.

However, when it starts, it idles for about 20-30 sec then slowly loosing RPM and dies. When I start it up again it repeats.

I have tried to check for leaks by spraying "quick start" to see/hear any difference, but no luck. I have checked the CPS and timing aswell etc. Nothing wrong there. :\

Any suggestions? Fuel VSV wrong way? Fuel filter broken? AFM broken? ISC valve broken?

 

[zachm611]

have you checked your codes yet? http://www.cygnusx1.net/Supra/TechTips/engine_error_codes.aspx

 

[iskrem]

have you checked your codes yet? http://www.cygnusx1.net/Supra/TechTips/engine_error_codes.aspx

I did. No error codes, just fast blinking.

 

[NTRA08]

HUH weird...Fuel maybe.

 

[iskrem]

If I hold the gas pedal at 1200-1300 RPM it stays there, as soon as I take foot off it runs down and dies. So definitly not a fuel issue?

 

[jdub]

Check the ISCV for proper operation...you should hear/feel it step full open when the motor is shut down. I suspect the ISCV air path is blocked. The valve itself need to be cleaned (requires disassembly) or the check valve under it is clogged (requires replacement).

 

[iskrem]

I'll check the ISCV tomorrow. I drove the car around the block (200metres around), and now it won't idle. It starts, straight up to 1200 RPM and straight down to hell. God damn it!

 

[iskrem]

So I checked the ISCV. I think there is something missing here?! Haha.

 

[jdub]

I guess a clogged check valve is not the issue

 

[jetjock]

The problem is I don't see how a missing one could be either

 

[jdub]

Me either...definately not the no-idle problem! LOL!

 

[iskrem]

The engine won't idle when it's warm, but it idles 20-30 sec and dies when cold. A friend of mine suggested that I should tighten the idle wire since the car runs when I hit the pedal.

 

[jdub]

Idle is controlled by the ISVC....you do not want to adjust any "idle" screw on the TB. Your friend doesn't know how the idle system on the 7M works. The TB bypass screw found on the top of the early TB's is set full closed from the factory and should not be moved. The throttle stop screw on the linkage should be set per the TSRM...TB plate full closed at stop.

The likely reason it idles when 1st started is the ISCV steps full open at shut down. The ISCV then closes to set target idle. If yours has a bunch of crud inside where the valve seat meets the housing, it will block the air flow. That's why I told to to disassemble it and clean

 

[Mk3runner]

Can you drive it without it dying if you keep the rpms up? Like around the block a few times. Mine did same thing your talking about when I first built my motor and cranked it over.. Got cocky I drove it a while. Runs fine ever since

 

[iskrem]

Yea I can drive it fine if I keep RPM up, but as soon as I let go it dies when the engine is hot. Did 10minutes lap around the block, problem still persists.

 

[jetjock]

What is the idle if you unplug the ISCV before doing a cold start?

 

[iskrem]

What is the idle if you unplug the ISCV before doing a cold start?

I unplugged the ISCV when the engine is warm. And it idles like this, 1200 RPM to 1700 RPM, then down to 1200 RPM to 1700 RPM. Up and down, up and down. *REPEAT*

So it "idles".

EDIT:
If the ISCV is plugged in while engine is warm, it goes up to 1200 RPM and dies.

 

[jetjock]

That's nice. How about answering the question?

 

[iskrem]

That's nice. How about answering the question?

I will as soon as the engine cools down.

 

[jetjock]

OK. It has to be cold though. Maybe not overnight Norway cold (although that's OK too) but cold...