420a (turbo) car stalls when stopped and bucks when taking off in 1st and 2nd

gsgoingturbo · 08-30-2009, 11:19 PM

Ok, I did the search and didn't find anything quite what I'm looking for.

I have a 420a and it's been turbo for almost a year. Recently I ran through some water on a rainy night (made the belts squeal) and since then the car has wanted to stall at stops. It has improved slightly, but now instead of stalling at stops, it bucks when taking off. I'll take off and it will buck hard, shift into 2nd and it'll continue, 3rd is fine. When I'm slowing down I can also hear my exhaust popping. I get some smoke from under the hood at times, don't really know why that is... I haven't really had time to check it, thought I'd ask for help.

What I have checked
:fuel pressure - 55psi
:no water in intake piping
:checked battery connections

Car has ran fine with no problems till the rainy night... any help would be greatly appreciated

LD25Delta9 · 09-03-2009, 10:42 AM

First off, do you have a CEL on? If so, scan it. If not, check your terminals on the alternator and also check for the resistance of your sensors on the back. Something could be cracked but not throwing a code. Not likely, but possible. Also, since you have a 99 fuel system and you may have mounted your FMU in the back, check your vaccum reference line for any cracks that may have sucked up water. I'd be pointing my finger hardcore at that being a possibilty.

95'RS-T · 09-13-2009, 06:13 AM

what do you mean your "exhaust pops" Do you mean Like a back fire?

gsgoingturbo · 09-18-2009, 09:21 AM

No, not backfiring... like when I'm drifting down a hill letting the car hold itself back, my exhaust sounds real throat. I have noticed that when I push my brake pedal hard my rpms will drop from around 700-800 to something like 300-400. This problem has gotten better since it started but still not fixed. Vacuum lines are ok, doesn't seem to be anything else noticeable that is wrong. Do have a CEL but haven't found time to get it read

GofaST4life · 09-18-2009, 03:18 PM

Go to your local auto store and get that CEL checked, it should take not even 5 minutes.

95'RS-T · 09-23-2009, 06:28 AM

the backfire from the compression when going down hill kinda sounds like your either running rich or bad down stream o2 sensor im leaning more towards the o2 sensor because of the CEL like stated above get it checked at your local autozone EDIT is it a 5 speed or automatic?

rstare · 09-23-2009, 10:35 AM

That "real throat" sound you're talking about, when you let your foot off the gas while it's still in gear is because the AFR is really lean. When you let your foot off the throttle in gear you get a really high vacuum and that spot in the table the ecu knows to run the AFR much leaner. Basically, the ecu knows you want to decelerate. That's what produces the "throat" sound.

gsgoingturbo · 10-03-2009, 07:54 PM

Quote:

Originally Posted by 95'RS-T

the backfire from the compression when going down hill kinda sounds like your either running rich or bad down stream o2 sensor im leaning more towards the o2 sensor because of the CEL like stated above get it checked at your local autozone EDIT is it a 5 speed or automatic?

manual

96TurboGS · 10-04-2009, 10:40 PM

Try cleaning the crankshaft connector harness by the oil filter on the back side of the oil pan. It may have picked up some water while passing though the puddle. Its famous for getting debris and water in them creating a intermittent signal to the PCM.