btibbs70
10-14-2009, 08:54 AM
3 weeks on son's car and husband can't figure out what's wrong.
The engine on the '85/ 6cylindar/ automatic slowly dies.
What he's done so far:
replaced fuel pump
replaced transmission (it wouldn't shift out of 1st)
ran a code check for emmissions - no codes showed up
replaced gas
replaced fuel filter in the gas tank and the one on the rail
It starts beautifully, runs smoothly, then slowly dies. If he depresses the accellerator the engine revs, but then slowly starts dieing again when he removes his foot.
We are both out of work, and son has been without his car for work for 3 weeks. Please help my husband keep his sanity!
old_coot
10-14-2009, 09:47 AM
Sounds very much like the catalytic converter might be plugged up---either that or the idle jets are clogged and the choke is keeping it running initially until it starts to warm up................Dan
dougs85
10-14-2009, 12:54 PM
Dan could be right, but I think this is more likely. The following is from my 85 shop manual concerning The EGR valve on the Fuel injected V6.
"Results of Incorrect EGR System Operation
Too much EGR flow tends to weaken combustion, causing the engine to run roughly or stop. With too much EGR flow at idle, cruise. or cold operation, any of the following conditions may happen:
* Engine stops after cold start.
* Engine stops at idle after deceleration.
* Car surges during cruise.
* Rough idle.
If the EGR valve should stay open all of the time, the engine may not idle."
Doug
464elky
10-14-2009, 05:02 PM
Sounds very much like the catalytic converter might be plugged up---either that or the idle jets are clogged and the choke is keeping it running initially until it starts to warm up................Dan
X2 I'm going with the converter.
dougs85
10-14-2009, 06:56 PM
btibbs70 states this is an 85 V6. I'm assuming then it has TBI fuel injection. If this is correct there will be no idle jets or choke. There is an Idle Air Control (IAC) valve that is screwed into the throttle body. It is electronically controlled by the computer (ECM). It would probably NOT cause the stalling problem. A restricted exhaust can be tested by hooking up a pressure gage to the air injection manifold tree, (A.I.R.) pipe and running the engine at 2500 RPM. If the back pressure exceeds 2-3/4 psi then the cat, the muffler or a collapsed pipe is involved.
Doug
steelybill
10-16-2009, 10:16 PM
If the exhaust coming out the tail pipe seems extra quiet when the engine and converter are hot, it likely IS the converter. At idle there's barely a whisper coming out the pipe if the converter is clogging when it's hot. Had it happen on a new Camaro with only 2K miles.
Also, there is sometimes "carburetor" noise noise from the intake, even though it's a throttle body or port injection, which is reversion from the exhaust pressure.
btibbs70
10-21-2009, 12:30 PM
The correct EGR valve finally came in.
Kept our fingers crossed, but still have the poor thing slowly dieing.
Will try other suggestions. (sigh)
Dan could be right, but I think this is more likely. The following is from my 85 shop manual concerning The EGR valve on the Fuel injected V6.
"Results of Incorrect EGR System Operation
Too much EGR flow tends to weaken combustion, causing the engine to run roughly or stop. With too much EGR flow at idle, cruise. or cold operation, any of the following conditions may happen:
* Engine stops after cold start.
* Engine stops at idle after deceleration.
* Car surges during cruise.
* Rough idle.
If the EGR valve should stay open all of the time, the engine may not idle."
Doug