here's the scoop

89 GTU 174k miles, stock, meticulously maintained.

this car has run very well for me, plenty of power still for the miles it has and always held idle around 700-800, until now.....

problem started as a hesitation when i got on the throttle, in any gear. it has now escalated to extremely irratic throttle response, most times ending in a stalled engine. will always start right back up but will die at almost any stop.

the weird part is that it is kinda an on/off problem.....when it works the car runs and drives just as it always did, when starts the above mentioned problem the exhaust sounds like......pop pop crackle pop crackle pop pop on deceleration then die.
when its good it will go through the whole powerband without any issue for a few miles then it will go bad for a while. makes it hard to reliably drive

Things i've done:
1. searched for everything i can think of.
2. downloaded and reveiwed the FSM
3. put in new air filter(K&N drop in)
4. installed new fuel filter
5. gutted(reluctantly) glogged and gross cat
6. tested and adjusted TPS

i know this is a high mileage engine and i have yet to get a compression test done(kinda scared of the results) but i would like to extend its life just a little more before being forced to purchase an engine.

i usually try to search and find all my asnwers but i just had to ask on this one.

sorry for being soooo long. so, tell me what you think fellers.

thanks in advance.

 

Doesn't sound like a blown engine... I'm no specialist on blown engines but

Have you checked the timing?


Clean the BAC valve. That might be the Idle Issue.
The Bac is located on the back of the intake manifold (I think) its around there. But clean it with brake cleaner. And then let it dry, lube it up with Wd40. And reinstall.

And for the bucking i thought it would be the TPS. But adjust it. Drive it or whatever and then come back. See if the TPS is still within specs. Or wait a few days. Might need a replaced TPS (at idle it should be .95 volts) on the multimeter. Hope that helps

Evan

 

TPS checks out fine, i have followed all rightups on that one and i have checked checked and rechecked it.

i have NOT checked timing.....can timing become ...intermittant?

what exactly is the job of the BAC? and get it be intermittant? i will clean it tho.

Thanks man.

anyone else?

 

can it realy be the BAC valve??? i thought that you didn't need the bac valve, i took mine off...

 

I think it is hard to pinpoint the exact problem,
but here are a few ideas:

stalls at stop lights:
could be BAC valve, bad ECU to BAC connection, bad compression, bad charging system (check alt + battery)
Do the standard FSM test for the BAC

crackle pop in exhaust:
probably car is running rich
probably needs a good tune-up, maybe leaking injectors
if popping during deceleration, then it's the ACV valve. Again, do the standard FSM check for ACV valve, or search posts by HAILERS about ACV valve for quick check

Just to be on safe side,
do a compression check or at least check your vacuum reading at idle (if it's low, I would start to worry, otherwise it should be easily fixable somewhat)

hope this helps somewhat,
Hugues -

 

May want to also check and/or clean your injector connectors. They may have vibrated loose.

Rat

 

thanks a lot guys.

i know this engine is due and its put in its time but i just can't sit by a believe it dead after how good its been to me

thanks again.

wayne

 

it's probably not dead. If you can get it to idle at 750, it's probably still strong enough. I think it's something else. Now, if it has problem idling (lot of shaking or sounds like a chainsaw and can not keep a steady rpm), then you may have a problem.

Just do a compression check with a standard gauge (that can release pressure) and look for 3 even bounces.

Hugues -

 

yeah, i just need to aquire a guage.

when it will idle, and many times it will, it will still stay at around 750 like it used too. then, after it runs for a bit it was just make this god-awful po/fizzle\crack/pop pop(sorry, its hard to describe, but its groooooss) on deceleration and die.

 

crackle/pop on decelation means problem at the ACV valve. That may narrow your troubleshooting. Basically, the popping comes from fuel exploding in the exhaust.

The ACV's job is to inject a lot of air upon deceleration. When you decelerate, you are shuttiing the throttle plates closed, thus reducing the air coming to the engine via the intake. When this happens, the engine runs very very rich. So, the ACV injects air to burn all that fuel before it reaches the exhaust.

Actually, I should be more precise. It's the Anti Afterburn Valve that does that. It is part of the ACV valve though.

Get FSM (factory service manual, fuel section) from www.fc3s.org. There's a very good picture that explains it all.

Hugues -

 

Vacum leaks can do those simptoms. Use some carb cleaner or starting fluid to find them.

 

update,

i will be pulling the injectors on sunday to have them cleaned but in the mean time.......

i removed intake up to the TB looking for leaks but found none(didn't have any carp cleaner)

put everything back together, started it up and it was still acting the same way. tried to start it today but would not fire, pulled plugs and they were soaked with gas, unflooded and grounded initial set to disable BACm car fired up but was lopey and would barely hold idle and was smoking even at idle. i got the check angine light so i decided to go check my error codes.

dig this, i got 28, 2, 3, 7, 8
thats EGR valve, crank position NE sensor, crank position G sensor, unable to find what "7" is, and AFM.

can this much **** actually go bad at once? anybody know what 7 is?