stalling problems

[vintagemuscle]

i bought my car last year (bone stock, 75,000 miles) with a bad idle surge and stalling problem. after fixing boost leaks i discovered my valve seals were leaking. so i had decided to freshen up the head with bronze guides, valve springs and new seals. i have also added a bunch of other aftermarket parts (check my profile). now the idle surge is gone but the stalling has gotten even worse. i cannot come to a stop without the car stalling. i have replaced the isc with a good used one and the maf. i also blocked the egr off. today i set the biss by grounding the two points and it didn't help at all. i am only reading 10in vacuum at idle, although i have 272's this still seems very low. i do not have any boost leaks! could the fiav or a bad ecm be causing my stalling problem. i am running out of options here and need some help. thanks.



Jim

 

[theSicKness]

are you sure about the boost leaks that seems very low on the vacume...id check to make suer everything is blocked off..and injector o rings/intake main

Jesse

 

[vintagemuscle]

i've done multiple boost leaks and came up with nothing. it has new injector seals, all new fmic piping with t-bolt clamps on extra tight and it will hold as much psi as i give it with the compressor. i'm baffled. it acts the exact same way as it did when it was stock.

 

[talon212]

Did you get a chance to compression test your cylinders? and if so what is your readings?

 

[vintagemuscle]

before i started it after i put the head on i did a compression test and my readings were between 140 and 120. i will check again but the engine sat all winter and that is why i think the compression was so low (all the oil came off of the cylinder walls causing the low compression).

 

[vintagemuscle]

update: performed another boost leak test today and now will not hold pressure. i don't know what is going on. i blocked the fiav off, but didn't help at all. all of the pressure is leaking out of the crankcase, under the valve cover. i have good compression (i think, about to go test this now), and new guides and valve stem seals. that leads me to believe it is the turbo seals ( i hope!)? it is the original 14b with 75k and has little to no shaft play. is there a definate way to confirm this?

 

[vintagemuscle]

just did compression test: 137, 130, 130, 130. low but it shouldn't cause my car to not run at idle. car runs and boosts perfect off idle. all timing marks look to be lined up correctly as i must have checked them 10 times while installing the timing belt. car runs super lean on the datalogger registering almost no volts on th o2 sensor ( which is new). any suggestions as what to do next?

 

[napkinthief]

my car has developed the same problem. I have changed the fuel pump, battery, all belts, and spark plugs and wires. Not solved yet. I do not have boost leaks because I do not have boost

 

[vintagemuscle]

my car has developed the same problem. I have changed the fuel pump, battery, all belts, and spark plugs and wires. Not solved yet. I do not have boost leaks because I do not have boost

you may have a vacuum leak. check all hoses coming off of the intake manifold. i still haven't solved my problem but i'm going to pull the ecu right now and see if that is part of the problem. i know the ecu doesn't have control of vacuum but it may be causing me to stall everytime i come to a stop? could the speed sensor on the trans also cause a stalling problem?

 

[toybreaker]

It sounds like you're doing all the right steps to narrow it down.

On the transmission speed sensor question, I believe the speed sensor is actually in the instrument cluster. It's on the speedo drive mechanism, inside the speedo itself.

The fact that it runs good off idle makes this problem a little confusing, and harder to find.

Did the ignition timing get set correctly? It's kind of a pain in the tookas, but it would be a good idea to verify that it's on the money.

There's a closed throttle switch on the throttle linkage. The rubber boot on the harness connector deteriorates, and it makes it hard to tell if it's really plugged in. I would look at that, and possibly the tps, to be sure that the ecu knows you want it to idle.

I found some cool v-facs and how to's when I was looking for something else, including a really nice description of how to check for idle hunting/surging/stalling. Maybe a run thru the v-fac/how to section might shed some light on things.

I am curious about the lean o2 readings. Lean doesn't idle well, especially with bumpier cammage. Do the 02 readings stay lean accross the board, or is only at idle?

Keep us posted, I'm curious, and want to know what fixes this problem.

 

[vintagemuscle]

well, the ecu looks perfect but i am still sending it in to get looked and and have it socketed. the o2 readings are only lean at idle. when at part throttle the o2 volts fluctuate and at wot they stay pretty rich as they are supposed to. now for some reason when i do a boost leak test off of the turbo i can hear a massive leak somewhere around the turbo but cannot feel any air. when the boost leak test is done off of the licp the leak is not there. i can only build 8-9 psi when testing off of the turbo but can build well over 20psi off of the licp. one of my problems has to be my turbo seal is bad. i don't think a bad turbo seal would cause such an erratic idle along with stalling.