For the GT guys ... high idle?

[jjorgensen52]

When I fired up the new motor in the GT, runs beautifully and real smooth, but idles waay high (2K) and then starts to rev higher on its own (I shut it down when the RPM's passed 3000). The IAC, MAP, etc on this motor are the same ones that came off the old motor which idled just under 1k.

I did change the dist. plugs, and wires. The timing, although I have not pulled the timing connector yet, was set at roughly 4* of retard and I haven't advanced it yet (IIRC the spec is 8* advance or thereabouts?)

Things I can think of:
-EGR valve is off and not blocked, possible source of air (although I ran it once before like that, don't remember it revving but could be wrong)
-Possibly a vacuum leak on the intake
-IAC is screwed up now because of the engine being out for ~3 months

Thinking through it right now I'm putting money on the EGR, but you never know. If I just pull the EGR off and toss it, am I going to get an error code?

 

[dgoodhue]

Re: For the GT guys ... high idle?

If you have an air leak, you should see it on a vacuum gauge. An air leak will show up as low vacuum.

 

[jjorgensen52]

Re: For the GT guys ... high idle?

If you have an air leak, you should see it on a vacuum gauge. An air leak will show up as low vacuum.

I figured that would be the case but I have not had a chance to get a vacuum gauge on it yet. I hope that's not the case I don't want to have to pull the dang thing apart again

 

[KFC_Or_Bust]

Re: For the GT guys ... high idle?

Check the vac lines, there's one on the back of the intake manifold closer to the passengers side that immediately Tee's off into another line. That one is commonly overlooked since there are plug wires, breathers and all sorts of wires in that little nook there, give them a look and don't forget about the other two vac lines, the big one off the brake booster and the other one just under the TB. I think that's all the vac lines on the CPI but I could be mistaken.

 

[midnightbluS10]

Re: For the GT guys ... high idle?

So you ran it without an egr or an egr block off plate?

I'd say that's the problem.

 

[jjorgensen52]

Re: For the GT guys ... high idle?

So you ran it without an egr or an egr block off plate?

I'd say that's the problem.

Yeah ... I had plugged the system the last time I ran it, but forgot that I had removed it :roll: