Stalling issue - EGR?

302GTS

If you need herpes, I'm your man!
Apr 20, 2009
481
2
18
Largo, FL
So my car still likes to stall when warm. Base idle reset didn't work, full tune-up didn't work, new distributor didn't work (although it fixed my misfire! :nice:). I was talking to a local shop owner today and he suggested my EGR could be at fault. When I bought the car and had a local tuner dump the codes, it popped out the EGR code, so he disconnected the lines coming from it, and capped them off. Could this be causing the stalling issue? If it is, what can I do to test/fix it?
 
If the vac line is divorced from the valve: if the EGR itself sticks open, that could cause rough idling. The main cause would be a piece of carbon sitting on the seat.

You can remove the EGR valve and clean it. There are a couple of fasteners that hold it on, and then the feed pipe (soak the threads in PB for a bit before trying to break it loose).

I use a bore brush to clean the EGR passageway. Don't get carb cleaner near the diaphragm.

With the EGR disabled, you might get part throttle pinging.

I kinda doubt this is your issue. It's never a bad idea to clean the EGR valve however.
 
If the vac line is divorced from the valve: if the EGR itself sticks open, that could cause rough idling. The main cause would be a piece of carbon sitting on the seat.

You can remove the EGR valve and clean it. There are a couple of fasteners that hold it on, and then the feed pipe (soak the threads in PB for a bit before trying to break it loose).

I use a bore brush to clean the EGR passageway. Don't get carb cleaner near the diaphragm.

With the EGR disabled, you might get part throttle pinging.

I kinda doubt this is your issue. It's never a bad idea to clean the EGR valve however.
Thanks. I'll try doing this over the next week or so, along with just collecting ideas for other things. Picking up a code scanner this weekend probably, so I'm gonna try dumping codes to see if it'll give me any hints.
 
Did you reset your TPS after adjusting the idle?
No, I didn't. I only have an analog multimeter which, if you've never seen, I think is impossible to reach .98 volts with, haha. I only have a slight hanging idle. Idle's set at around 750 or so, and when it hangs it only hangs at around 1,000 rpms. Would a mis-set TPS cause stalling issues? It's real on-and-off, and only happens when the cars been driven a good amount in a day.
 
yes it definitely would cause stalling especially when the car gets hot. A friend of mine chased this issue (hot stalling) for months after doing a TFS HCI with a new throttle body. He never set the TPS on the new T-body. As soon as I had him reset his idle and TPS the car was fine. Try this procedure:

Begin with a cold vehicle. The idea here is to get the car to a firm cold idle with enough air bleed capacity left in the idle circuit for IAC adjustment.

The idle stop should be set first. Back out the idle stop screw, away from the bell crank arm, until about 1/2 turn past the point where it no longer makes contact (blade fully closed). Using a 0.010" feeler gauge, tighten until gauge just drags between screw and bell crank arm. Remove feeler gauge. Tighten screw exactly 1 1/2 turns. If the screw is very loose, put a drop of loc-tite or silicone on it, so it doesn't work out of adjustment.

Now remove the connector to the Idle Air Controller (IAC) just on the other side of the throttle body. Start the car and allow vehicle to warm for 2 minutes. Give a small "blip" to let it settle. If it is having a hard time staying running you may have to get an assistant until you can get to the front of the car. Now open or close the air bleed screw (CCW opens) next to the IAC until the car idles at 575 to 600 rpm. For guys with aftermarket cams and an EEC tuner, you might want to idle a bit more briskly, say 650 to 675.

Obviously, this rpm range is by what the car and driver wants...IE, no set idle speed, whatever works for YOU.

Turn off the car. Now count the number of turns clockwise to close on the idle air bleed screw. If it falls between 1/2 and 2, it's okay, now reverse it out the same number of turns. Log the number somewhere in case you need it for the future. Reconnect the IAC. You are done.

If the air bleed screw is above 2 turns, it's a good idea to tighten the idle stop screw another 1/2 turn, and then repeat the idle setting. If it is below 1/2 turn, then loosen the idle stop screw by 1/4 to 1/2 a turn, and repeat the idle setting. Be sure to put another drop of silicone RTV on the stop screw if it was disturbed. Reconnect the IAC.

Now remember we adjusted the set screw on the throttle body. That means that the voltage reading from the TPS sensor has changed. It should read between .96 and .99 volts. Anything outside of that range will cause all sorts of issues including misfires and rough idle.

you will have to back probe the TPS connector. With the connector attached to the TPS stick a paper clip into the rubber boot on the connector where the top and middle wires go into the connector. The rubber is very flexible the paper clip will slide in between the rubber and the wire.

Set your multimeter to volts. Turn ignition to ON. Then place your multimeter leads on the metal pins. If it comes up as a negative that is okay as long as you are -.96 to -.99. If you get this reading then great you are done and hopefully your issues are gone. If not proceed to step 9

This is where and extra pair of hands come in handy. Using a large screw driver you will need to loosen the bolts that hold the TPS. DO NOT USE A SCREWDRIVER THAT IS TOO SMALL BECAUSE YOU WILL STRIP THE BOLTS. They probably will be really tight so you have to really lean on the screwdriver and use some finesse.

Once the bolts are loose you will need to move the TPS up or down and continue to read the voltage. Once you get it to the desired setting you can retighten the bolts. What I do is I find .97 and then as carefully as possible I tighten the TPS down. what will happen is the voltage will change usually to .96 or .98 but that it okay. Once you are done with this manually open the throttle body a few times and close it then reread the voltage and make sure it is still within our desired range.

Depending upon how loose your set screw was you might want to cover it in RTV to hold your setting. At this point you have CORRECTLY reset you idle.
 
I appreciate the tip, RJ. I'm gonna set the TPS today after a nice dose of fresh oil. I'm really thinking this may be the issue, and I'm definitely hoping it is. Thanks a lot! :nice:
 
updates? i've been reading your threads regarding your problems. hope you got it all fixed up
Sorry, been meaning to update since earlier in the evening but the girlfriend had other plans. I went to set the TPS today after work, digital multimeter and paper clip in hand... I have NO idea how to backprobe the TPS. :shrug: I'm going to look for some decent information on how to do that.

I'm definitely hoping this TPS solves my stalling issue, although I've found something that seems to prevent it, incase it'll help anyone else. If I start my car it'll idle at around 1,000 rpms for around 15-20 seconds at first. If I wait sitting in one spot until the idle drops down to around 700 or so, it'll run smooth as silk after doing that. That's just a band aid until I get it fixed for real though.