Stalling Issues

[87Ltd]

Hello,

This is gonna be kind've a long post so be prepared!

I haven't driven the car much (~150 mi) since last smog 2 years ago. So I started up the car again to get new tires mounted and see if all's fine prior to facing an upcoming smog test. I've noticed the car stalls every once in awhile (in no particular order) when shifting to Drive (sometimes), from hitting the brakes hard from ~20 mph (a lot), while at a stop sign just before taking off (sometimes), as I'm making a slow right turn, and finally when shifting into Reverse (sometimes).

I've done some searches and it seems this problem is usually IAC related. So I took apart and cleaned out the TB, vaccum block, upper phlenum, and IAC valve with "gunk fuel inj/air intake cleaner" and replaced all the gaskets. Pretty oilly, so I figure I've the problem licked.

I first reset the IAC via the "ALDL connector way" and checked the TPS. Stalling still there! So next I reset the IAC to the 10-20 range with my scan master like most recommend. This is with the stock Buick chip I last used for last smog test (if it matters). Scan tool results AF 05, L8 35, BAT 12.2-13.0, INT 126-135, BL 143, CLE 192, AES 138, RPM 750-775, TPS 0.44, TPS 0.44, IAC 15

So next I bump the IAC to above the 10-20 range to see if things get better. Seems better, less frequent stalling but still happens. Scan results AF 05, L8 35, BAT 12.2-13.0, INT 126-135, BL 140-142, CLE 175, AES 130, R 750-800, TPS 0.40, IAC 32

Once the AES also said hot. This is with a 160* stat and original chip.

Next day I put in my Caspers 8 position chip in the stock setting and my cat back on with no change in stalling. Scan results show IAC went down on its own though. Scan results AF 04, L8 32, BAT 12.5-13.5, INT 124-132, BL 143-147, CLE 189, ATS 126, RPM 725-775, TPS 0.40, IAC 18

I've checked for vacuum leaks around the TB and intake with propane (kinda hesitant since first time with the stuff). I assume the valve's OK since the IAC # go up a little when I shift into Drive and a lot while driving. Should I just replace the thing or is there something else I should look for?

Sorry for the long post.

(i'm gonna try to figure out how to put car info in post)

 

[granatl]

Could it just be old gas? The 150 mi in 2 years makes me wonder if you mean that you're on the same tankful. If so, get rid of it. After changing it, check the idle fuel pressure. You might need to change the fuel filter too.

 

[87Ltd]

I probably put in a full tank last year. I do have to confirm my records, but I most likely put in new plugs and fuel filter before last smog. I did run some Seafoam thru a vacuum line and then an oil change before the last chip change. Dealer doesn't carry TEC in the big cans anymore! Just little 1 oz? bottles. But I can put in a new fuel filter this weekend and drive a lot more so I can fillup with fresh gas.

Keep the ideas coming...

 

[87Ltd]

Here's a follow up. I passed smog (barely). That's the reason for running the car again. New gas, even replaced the fuel sock and pump over the weekend. Stalling is better now that I've replaced the old charcoal cannister and purge solenoid (they were clogged from loose charcoal). Actually, the BLM's right around 128 now. However, the stalling is now only when leaving from a stop. If I give the gas a quick "jab" it doesn't happen. Only when slowly easing into the gas pedal. My buddy who works on a lot of turbo buicks double checked for vacuum leaks (none), he reset my minimum idle again (IAC # within 10-25 range) with a new IAC valve, I've got the Tran+ (and reinstalled the orig and a spare OEM MAF). When he heard that the stalling is from a stop, he thought it could be the TPS. Luckily I had a new one that I tried out, no luck. He now thinks that it could be the ECM as he's seen this happen before. What do you guys think?

 

[87Ltd]

Stalling problem is solved!:smile:

My buddy was right. He lent me an ECM and all is good. He had checked my IAC's (he likes setting the minimum idle) while I go by IAC #. No vacuum leaks. My MAF was good. He's seen this happen before. Thinks my kill switch to the ECM (I'll have to redo that one) may have had something to do with it's demise.