idle prob

[maitai69691]

first off i just swaped a used 7mgte. Used my old harnes and intake manifold. Well it starts right up an idles at like 2k for about 10sec then it bonces between 1500-2000 rpm like its got a vac leak but i cant find it. also theres no egr its a jspec. so far i tryed spray brake cleaner looking for the vac line leak no luck. thought i might be the IAC it ohmed out good so i pinched off the IAC vac line and the PCV line going in to the TB no change. Theres no codes. if i brin up the idle above 2k it revs fine its just at idle.

 

[maitai69691]

also could i just cap off the two vac lines on the TB sinc theres no egr stuff

 

[subjug4tor]

heres my thread about a similar problem I had: http://www.supramania.com/forums/showthread.php?t=76434


Try what JJ suggested that I do, it helped me figure out my issue.

 

[maitai69691]

so if i block off the iac and the pcv system the car should boog and die if not then i theres eather air passing the Tb or vac leak some where after the TB

 

[maitai69691]

found out why the brake clean didnt find any vac leaks its nonflamible so im going to try some thing else.but any other ideas would help

 

[jdub]

When you blocked off the PCV and ISCV, was the TB plate fully closed?

New gaskets for the lower intake manifold (x2)? How about the TB and ISCV gasket?

 

[maitai69691]

from what i can tell the TB is looks fully closed isac and TB where never removed i only undid the upper half of the intk manifold and the gasket looked good so i left it. im going to try some carb cleaner to look for a leak.
But would avac leak cause my idle to b so high. And if i hold the throtel highter if dosent bounce around maby CPS or TPS?

 

[jdub]

You don't want to re-use gaskets :3d_frown:

If you blocked off the ISCV and PCV, the engine should have died (assuming the TB plate is closed). This tells me you have a pretty big air leak somewhere.

Have you pulled ECU codes yet?
Should be the 1st thing to do...that is unless you like chasing your tail

 

[maitai69691]

the only code i got was HAC but thats because i forgot to plug it in but as for now theres no codes. I thinking of pulling the intk manifold putinga new gasket and replaceing all the vac lines near there.but if it is a vac leak would it rev fine.

 

[subjug4tor]

so if i block off the iac and the pcv system the car should boog and die if not then i theres eather air passing the Tb or vac leak some where after the TB

thats right. in my case the throttle was stuck a tiny bit open, and I had a little vacuum leak as well.

 

[jdub]

the only code i got was HAC but thats because i forgot to plug it in but as for now theres no codes. I thinking of pulling the intk manifold putinga new gasket and replaceing all the vac lines near there.but if it is a vac leak would it rev fine.

Of course it will rev with a vac leak. Also, make sure the vac line to the EGR VSV is blocked off since you do not have an EGR.


BTW - In the future do not make multiple threads for the same problem in different sections. I merged the threads and deleted the other one.
Consider this a warning

 

[maitai69691]

thanks for the help im going to go cheack things out and ill let you guys know whats up