idle problems

scthunderbird

Registered User
I have a 1990 thunderbird sc that I just put an engine in the engine is a long rod 3.8, ported and polished heads and intake, mpx, mpfmic, comp cam, 60lb injectors, adj fpr set at 40psi, 85 mm tb, 85mm c and l maf. has a chip in it from david dalke. when it first starts it will rev to 300 rpm then idle at 1400 rpms, after about 2 min it will go down to 1100 rpm. ive tried adjusting throttle body but when i do it will have an irratic idle from 1100-1600 rpm. i set the voltage on the tps at .95 volts before starting. when i unplug the iac it will idle down and die. if i unplug the maf it will idle at 650-700 and then die after a couple min. I really need to get the bugs worked out so i can get it to dd for dyno time. i also would like to find a vaccum diagram if anyone has one. also like to know what vaccum lines that i can get rid of. thanks.
 
I have a 1990 thunderbird sc that I just put an engine in the engine is a long rod 3.8, ported and polished heads and intake, mpx, mpfmic, comp cam, 60lb injectors, adj fpr set at 40psi, 85 mm tb, 85mm c and l maf. has a chip in it from david dalke. when it first starts it will rev to 300 rpm then idle at 1400 rpms, after about 2 min it will go down to 1100 rpm. ive tried adjusting throttle body but when i do it will have an irratic idle from 1100-1600 rpm. i set the voltage on the tps at .95 volts before starting. when i unplug the iac it will idle down and die. if i unplug the maf it will idle at 650-700 and then die after a couple min. I really need to get the bugs worked out so i can get it to dd for dyno time. i also would like to find a vaccum diagram if anyone has one. also like to know what vaccum lines that i can get rid of. thanks.

You should get yourself an EVTM manual for this car. They are a huge help. If you have a vacuum leak teh best thign to do is to get a smoke test performed.
 
I have a 1990 thunderbird sc that I just put an engine in the engine is a long rod 3.8, ported and polished heads and intake, mpx, mpfmic, comp cam, 60lb injectors, adj fpr set at 40psi, 85 mm tb, 85mm c and l maf. has a chip in it from david dalke. when it first starts it will rev to 300 rpm then idle at 1400 rpms, after about 2 min it will go down to 1100 rpm. ive tried adjusting throttle body but when i do it will have an irratic idle from 1100-1600 rpm. i set the voltage on the tps at .95 volts before starting. when i unplug the iac it will idle down and die. if i unplug the maf it will idle at 650-700 and then die after a couple min. I really need to get the bugs worked out so i can get it to dd for dyno time. i also would like to find a vaccum diagram if anyone has one. also like to know what vaccum lines that i can get rid of. thanks.

There should be a basic vacuum diagram on a sticker on the radiator support.

I would bet money that you have one or more vacuum leaks. Definitely try a smoke test! Or at the least, use some propane to sniff them out.
 
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