I have completed the installation of my Edelbrock intake manifold and runners on my 1985 Corvette. Forum members were a big help with vaccume line routing and distributor installation, thanks. I now have it running (kinda). My problem is it won't idle and it doesn't run just right under 2500 RPM. Other things I did were:

Install 160 deg thermostat (when driving temp did not go over 160)
Bypass coolant to the throttel body
Installed new EGR valve
Eliminated Air Pump and all assocciated lines and controls
Port Plenum and gaskets to match Runners
Ported front of plenum
Cleaned the Throttel Body

I tried setting the base idle speed using the instructions for a 1989 TPI and everything goes well until step 11 where you are to set idel speed to 425 RPM +/-25. When I get down to around 600 the engine stalls.

I took the car for a drive of about 40 miles. It would stall when I had to stop.

Pulled codes after test drive and got following:
12 EMC check
21 TPS voltage high
22 TPS voltage low
32 EGR fault
33 MAF voltage low
34 MAF voltage high
43 Electronic spark control fault
12 EMC check

Once I was home, after checking the codes, I attempted to check the timing. I undid the ESC wire, single wire behind drivers valve cover, and attempted to check the timing. I adjusted as best I could but it moved some as the idle went up and down (without distributor movement). I then cleared the codes and went for a 10 mile test drive and it ran about the same as the first drive (I may have caused some of the above codes while working on the car),

Pulled codes and got the following:
12 ECM check
33 MAF voltage low
12 ECM check

When I installed the manifold to the heads I used gold RTV aroung all 8 intake ports (the Right Stuff around water ports and the front and rear engine walls. I did not use any sealer on the intake to runner or runner to plenum gaskets, though I did consider using RTV on these gaskets should I have?

All vaccume lines are connected.

Any suggestions will be appreciated.

Once the car is running right I have new 1.5 roller rockers to install. I glad I didn't do both at the same time as now I can be sure the problem is with the intake.

 

Check to see if your connection to the MAF is tight - I got the same codes when I never even connected it after pulling the plenum one time. If not that, I'd say vacuum. Gotta watch those runner to base areas, sometimes the gaskets don't line up like they should. But if ya permatexed there, then you ruled that out....

 

Un plug MAF sensor and see how it idles. On my 89 I unplug my MAF first when Im having issues with ruff engine running. Good luck. I think MAF relays on 85 are inside ECM.

 

Sounds like you have a vaccum leak.why did you use sealer for the manifold gaskets?can you get gaskets for this manifold.check that all connections are good at the maf.why the 160 stat.if the car runs to cool, it will not go to closed loop mode.