VERY High Idle! HELP!

[Stee420aT]

So what once was a turbo 420a Turbo car has now been transferred to a stock 420a that ran beautiful in its donor car. I removed the safc and the wideband, wired everything back up to stock. Car still has 4g63 injectors and walbro 255 fuel pump, has resister pack on it of course. Started it up and it won't come down from 3200 RPM. I think it could be the injectors and fuel pump but that doesn't make much sense to me. Or somewhere along the way the front o2 sensor isn't properly wired. Any ideas greatly appreciated!

 

[stubull05]

Take out those injectors for one, fuel pump should be fine. Also double check your vacuum lines. If they had a wideband on is it still the same o2 or did you get a narrowband to replace it?

Also with the SAFC did you *solder the wires back to stock?

 

[jayson427]

for one a stock 420a has 190-210cc injectors and depending on the 4g63's you have in there its way to much fuel especially with a wally 255. unless you have your fpr still hooked up? for the high idle its usually your iac,tps or map sensor. i would make sure your iac is clean and your wires are good. if the sensors are good then you have a massive vac leak which you can narrow down with carb cleaner. just a few guesses

 

[dsmspickdad]

First off remove those injectors they larger than needed. Check your ISC or vacuum lines. Sounds like you are sucking air in somewhere. Would need more information to correctly diagnosis the issue. Check throttle cable.

 

[Stee420aT]

I completely understand that the injectors and rail are way too much but the only way to fix that problem is to remove the walbro, it has a fuel return line and the stock rail doesnt, plus my fuel line doesnt fit onto the stock rail as it was modified so i had no choice as of now. It does have a stock FPR and it is hooked up to manifold vacuum line. The map sensor is hooked up to a FCD as well, my next stop is to remove the FCD and wire it back up stock. Also, it has a narrow band o2 sensor that is hooked back up to the original harness.

One more think, the stock rail does not have a FPR, does that mean its at the stock fuel pump?

 

[johnmel]

Terry's Talon Troubleshooting Tips #3 - Fast Idle (aka. Idle Surge) this may help

 

[Stee420aT]

Interesting and potentially useful although it didn't seem to apply to how my car is set up so there are some things missing. Thank you. I'm going to mess with the MAP first then check the O2 wiring.

 

[jayson427]

taking the fcd off will help. your stock fpr is by the tank it opens at 47psi i believe so unless you have a aftermarket one you will need to find smaller injectors which you know. im confused when you say the vac line is hooked up to it. only 95's had the fpr on the firewall all other years are by the tank so im not sure what you have going on there it doesnt sound right tho. you should have 4 vac lines 3 of them go to the intake manifold the other one goes to the throttle body.

 

[Stee420aT]

The fuel rail is off of somthing else, i'd imagine its also off of a 4g63, it has the FPR on the end of the rail with a return and vacuum line nipple.

Also for some reason the wire colors are completely different than the one coming off my map sensor, anyone know where i can find a diagram to correctly disconnect the FCD and reconnect it stock?

 

[jayson427]

alright well you might be able to make it work but not easily. do you have the 420a rail still or any of that stuff? does it have the 420a throttle body or is it something else?

 

[Stee420aT]

i have everything else other than stock fuel line connector (one on current fuel line is too big for stock rail) and i have stock rail and injectors but there is a fuel return line as well.

safc was just spliced into the harness which i just snipped off so connections are stock, all wires except for one which i soldered back to where it needed to go. easy. car actually runs really good, just the idle giving me a big problem.

 

[dsmaz]

I would put the 420a rail on it. It sounds like u have the 95 rail. The 95 rail should also have a fpr on the side of it. Since your car is a 97 u dnt have the return line in the engine bay. I would just block off the rerurn line on the 420a rail and use that one until u get an appropriate rail for your year.