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Pulled DIC and now car won't start

S

sparty

New member
I pulled the DIC to replace the light bulbs.. I tried to start w/o the DIC in and it wouldn't start.. If I game the the throttle by pressing it I can keep it running, but as so as I let off the throttle it won't go to idle - it just dies and then I have a hard time starting.

I have a new fuel pump - check pressure with key on / engine off and it's 45 PSI - looks good to me.

Not sure what's going on - I think the DIC (driver information center) is just coincidence.. But I'm baffled why I can't start it and get it to idle. There are NO DTC's - and I can communicate to the ECM just fine. I tried to start with MAF disconnected but that didn't help!

Any suggestions - why would pressing the throttle after sensing engine firing and keeping the RPM's up work by using throttle, but won't idle or start without playing/pressing throttle?

1998 Pontiac Grand Prix Gt - 3.8L - 267000 miles

Thanks!
 


Try giving the throttle body a cleaning. If it's dirty, it won't allow the proper amount of airflow to keep the engine running.
 
Thanks - just disconnect the air filter and spray carb cleaner in the throttle body? Or other recommendations to clean throttle body?
 
sparty said:
Thanks - just disconnect the air filter and spray carb cleaner in the throttle body? Or other recommendations to clean throttle body?
Click to expand...

You're gonna need to pull it off to really get it clean. All the carbon builds up on the backside.

And with your amount of miles, chances are your TB is caked with carbon.
 
Subway guy thanks! I pulled the throttle body off, it definetely had carbon build up but I don't see how that would cause it not to start.. Anyways I cleaned it very very good...Looks brand new.. Then I took the IAC off (was a Autozone duralast) and the penile was extended all the way out - the spring looked stretched - didn't look in good shape. So since AutoZone has lifetime warranty I just replaced it. Put it all back together and fired it up - started right up - very very smoooth.. so thanks!

Now I just need to figure out why my 3 bulbs on the DIC aren't working. I ohm'd them out and they are ok.. I switched them to the two on the trac and they work.. so I will put some fly wires on the V rails and see what I got.. I'm thinking a CAP may have went bad that supplies the rails.. If this is the case I have no schematic so I will just get another DIC.. I did shine light against the display and I can see the computer is working just fine.. just the bulbs are not on.. Hopefully it's just the socket wings on the bulb not making contact.. Some fly wires and readings will tell for sure..

Again - thanks - strange the IAC and/or dirty throttle body would happen at the same time I am working in the DIC.. 267,000 orginal owners miles and now onwards to 300,000!
 
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