91 Festiva Poor Idle

[WeDefyU]

My wife's Festiva, "Steve", is having an issue where letting off the gas it dies. I temporarily bypassed this by taking up some throttle cable and raising the idle. She still notices it because when putting through town it almost bucks when you're trying to maintain speed and feathering the throttle. Her car is fuel injected, has new plugs, wires, cap, rotor, air filter, tranny, and clutch. Thanks for the help all.

[georgeb]

That's not the way to turn up the idle. Readjust the cable so it has some slack. Remove the rubber plug on the throttle body and turn the large screw to the left to increase idle speed. It probably has an issue with the idle air control.

[RhodeStiva]

actually that screw is just for fuel air ratio, but yet it might change a little. i had the same problem the other day i bought a new air intake tube, the old one had a leak right at the throttle body.and i cleaned the IACV now my car works awesome.

[georgeb]

actually that screw is just for fuel air ratio, but yet it might change a little. i had the same problem the other day i bought a new air intake tube, the old one had a leak right at the throttle body.and i cleaned the IACV now my car works awesome.

i'm pretty sure there is no "mixture" adjustment on an EFI car.

[RhodeStiva]

I have a 82 and that is what mine does.

[georgeb]

I have a 82 and that is what mine does.

'82 what?

[FestYboy]

actually that screw is just for fuel air ratio, but yet it might change a little. i had the same problem the other day i bought a new air intake tube, the old one had a leak right at the throttle body.and i cleaned the IACV now my car works awesome.

no, it's an air bypass screw for base idle. once your festy warms up, the IAC becomes inactive and all idle control comes from the base idle screw.

[RhodeStiva]

92*. Lol

[FestYboy]

look for cracks or tears in the intake tube after the VAF and before the throttle body

[WeDefyU]

I will look for leaks in the intake tube. Thanks.

I was driving Steve Thursday morning and the car decided to share it's coolant with the truck and semi behind me. I thought I blew a head gasket because when I fixed the bypass hose that burst and filled the radiator, it puked coolant out the radiator when I tried to start it. Turns out, the head was .018" out of spec, got it machined, replaced the water pump, timing belt, cam oil seal, temp sender, thermostat, and coolant fan. Now I can get back to the idle problem.

[scitzz]

Check the TPS.

[FestYboy]

I will look for leaks in the intake tube. Thanks.

I was driving Steve Thursday morning and the car decided to share it's coolant with the truck and semi behind me. I thought I blew a head gasket because when I fixed the bypass hose that burst and filled the radiator, it puked coolant out the radiator when I tried to start it. Turns out, the head was .018" out of spec, got it machined, replaced the water pump, timing belt, cam oil seal, temp sender, thermostat, and coolant fan. Now I can get back to the idle problem.

i'd say you likely fixed the idle issue with all the work listed... a blown head gasket can easily make a hose burst instantly, especially at speed.

keep us updated reguardless

[WeDefyU]

I wish that was the case (that the top end rebuild fixed the idle), but sadly no, still dies when you let off the gas.

I got an eautorepair.net account and got some info on adjustments you can make and different sensor measurements. Friday I'll get on that, basically make sure all that stuff works. Thanks for the help.

[FestYboy]

make sure your throttle isn't snapping compleatly shut... this can easily choke an engine enough to cause a stall. there's a small solenoid on the passenger side of the TB that is supposed to catch the throttle before it slams shut and then ease it to the final few degrees of travel. it's called a dashpot. it should move every time you open the throttle.

[WeDefyU]

I checked the dashpot, it works perfect. Next I put a .020" feeler gauge between the throttle mechanism and throttle stop screw, then a .028" feeler gauge, I had continuity on the TL and IDL pins of the TPS with both, and shouldn't have continuity with the .028" feeler gauge, so I adjusted that. Then checked my coolant temp sensor, ohm reading seamed accurate to the low temp here. Then hooked up my dwell/rpm device, shorted the self test input to ground, and adjusted the idle speed. So far, all is well, I drove it about 30 miles last night, and didn't have even a hickup. I'm getting ready to put a few miles on it, I'll keep you updated.