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One of my brothers just bought a '88 Buick Park Avenue. The car has a LOT of miles on it but runs very well (and still has 40psi oil pressure at idle) other than 1 issue. When you come to a stop, the engine either dies as soon as you stop, or else the idle speed will gradually fall to the point where the engine stalls. Its fairly consistant too. It immediately starts right back up and will then idle fine in gear :confused:
I went over today to change the fuel filter on it. The filter that was on it was almost completely plugged up...you could just barely blow thru it. The new filter made no difference, but what I found something kinda weird. I know on my Lumina that you can disconnect the connector to the fuel pump, and then start the car and let it run itself out of fuel to take the pressure off the fuel line. I went all over underneath this thing and couldn't see any wiring to the fuel pump, nor find a fuse or relay for the fuel pump. It was getting dark (and it was getting cold fast) so I just cracked the fuel lines to bleed off the fuel pressure before opening it up completely. There was no pressure on the line at all...all that came out was a little stream of what was already in the line and filter. Shouldn't the fuel line be pressurized at all times? It has the 3800 series engine in it (Buick V6) if that makes any difference. It makes me wonder if the injectors are leaking, yet the engine starts super easy, idles perfectly, and seems to run just fine.
My other thought is the timing chain. I haven't ever worked on any of the Buick V6's that was this new...the newest one was an '84 model I believe that the timing chain let go on after something like 170K miles. I assume these things still use a timing chain?
 

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take a look at the fuel pressure regulator. a bad one might bleed off pressure like that back to the tank, and will cause low fuel pressure when it's running.
hook up a fuel pressure gauge to the test port on the fuel rail (which is also where you are supposed to release pressure before unhooking any fuel lines).
with the key on, but engine off, it should be around 42 psi i think. at idle, it should have a little less than that.
if that checks out, shut the engine off and see if it holds any pressure. it should stay pressurized pretty much forever if the regulator is good, but if it's bad, the gauge will drop quickly and steadily down.
if you don't have a fuel pressure test gauge, tell your brother to buy you one for working on his car. a decent one will be in the $30 range.
i've done many odd jobs like that for friend in exchange for oddball tools i'll need down the road.
 

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Isn't the fuel pressure check/bleed-off a tire valve stem?? Schrader valve type deal on the end of the fuel rail??

pdq67
 

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yeah.. it's supposed to have a plastic cover on it.
 

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also the regulator has a vacuum line going to it...if the diaphram is bad, fuel will leak into the vacuum line causing a rich condition that could make the car stall...in addition, check the idle air control motor...its in the throttle plate area...it has a square plug on it and threads into the butterfly plate...the pintle can get covered with crud, and not allow air into the idle port...
 

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Is the car an Automatic ???
If so, try putting the car in neutral as you slow down and are coming to a stop - if the engine keeps running and doesn't stall, it's the Torque Converter Lock-up solenoid that has failed and does not unlock the vehicle as the speed decreases.
It's a fairly easy fix, the solenoid is located inside the transmission side cover on that vehicle and you can get to it by removing the drivers side wheel and the plastic cover.
The part is @$40~60 depending on where you get it and you will need a new gasket or can silicone the pan back in place.

Hope this helps ...
John
 

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great point...does it shudder as you come to a stop...gm had problems with several trannys doing this...
 
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