Hi guys
I have just put tpi into my 1991 RS Camaro ,new loom, ECM,intake etc when I start it the motor revs up tp 3200rpm I have checked for vac leaks and can not find any, i have checked TPS and MAP voltages and they both are what they should be when I disconnect the vac line from the MAP sensor the revs drop to 1200 but the the motor starts to overfuel (probably because the voltage has risen in the MAP sensor) where can I go from here any help would be great

 

What about baseline timing and idle air?

 

listen: at 3200 rpm you are not going to find a vac leak. you are only pulling a few inches at that rpm. I bet you have the lower runner gaskets reversed. There is a left and right gasket. but, they fit either side. If they are reversed its an automatic 3000 rpm idle. I hope its that.

 

im 100% sure its a vacuum leak....i know a guy that had a LB9 that did this...


turned out when he put his runners together he didnt do something right and it never sealed to the plenum

 

Thanks I will take the runners off and have a look, I just put them on the as they fitted I didn't know about left and right application ,how do you tell?

 

if you dont tighten the bolts up in a certain order the runners wont seal to the base and or plenum. But yes if you look at the runners the driver side if i remember correctly has the egr passage tube that lines up on both the base abd plenum.

 

Thanks I will check it out tonight

 

I pulled my runners, checked the gaskets the gaskets are fine and sealing ok, I put everything back together checking everything for leaks but when I started it it went streight to 3000rpm I rechecked all my base timing and its fine any thoughts?

 

you check the throttle body if its in good condtion?

ive heard about bad throttle shaft bushings causing issues...

also maybe the IAC on bottom of throttle body is bad allowing too much air in and idling to high?

try unplugging the iac and see what she does

i called up friend who had probems with his tpi and hes telling me all these things hes done before. HE also mentioned about a bad intake to head seal and that would cause extreme high idle.

have you tried the WD40 or carb cleaner trick bty spraying around certain parts of intake to find a vacuum leak?

id try to partially block off the TB entrance and see how it run with restricted air

 

is the egr valve stuck open, did you hook up the egr right. the vac line comes from the solonoid not the intake. otherwise it will open at idle..

 

I will try the IAC tonight , I have tried spraying starting fluid around the intake manifold and the runners but there was no rise in RPM the throttle body is a used one
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Yes I initially thought of the EGR and I pulled it out and checked the operation of it , it is sealing fine.

 

bad or sticking egr will causing stalling and bad performance

tpi is new to me...but gm in general isnt lol...

ive grown up under gm's all my life

 

hello im having similar problems with high idle and rough running TPI. Had a scan done this past weekend. They told me my egr valve is stuck and the line is actually removed from the person that had the car before me. Scan was good overall except it had a code 38.Im getting ready to remove all the mess to replace the egr valve. But i have NO IDEA where to plug the vac line to from the egr valve. can someone help me out? are there pictures on here showing me where it goes? thank you!!