3.8 V6 fuel inj (155,000 miles)
Runs/idles fine
(when it doesnt stall/shut off)
*does not use oil
*no head gasket leak/typical with this eng.
*Auto trans shift somtimes hesitation or just not smooth, not terrible just noticeable to me who works on cars but not my wife.
*power stering has some minor noise when turning,not squealing more like low on fluid and hesitating or fighting or rubbing noise,fighting against itself when turing??
Symptoms:
Van developed this problem which lasted about 3 weeks of Aug 07.Van taken for repairs, tech. could not identify any problem.Van ran fine for 5 months and now same problem reappeared?
*shuts off ramdom under 35mph city driving and short trips, nothing else seems to be consistant (weather/temp etc…)
*shuts off while driving/no warning signs.
*sometimes shuts off while stopped at light or stop sign and then after restarting hesitates/stalls when trying to accelarate, almost like not getting fuel.This usually clears up in under 1 minute and then runs fine.
* problem can last a few days and happen multipule times in a day then go away for a day or so and reappear or subside for a few months and then reappear again as it is doing now.
Problem related repair history:
* Problem developed Aug 07 about 3 days after a 1500 mile trip, drove car about 3 weeks before taking for repair.
* Took to Qualified mech.(not a dealer)who had the van approx. a month due to van not exihiting any problems. Tech used the in this period as if it was his own vehicle inorder to recreate problem, no stalling or shutting off occured?
*Diagnostic performed/no codes showed.
*Tech said he used some type of diagnostic equipment to monitor while he was using van personnally that would indicate any problems/no codes showed.
* Chected timing etc… all was good.
Need some advise of which direction or areas to check??
Tks in advance for responses!!!
Two things to check for this problem. These are crankshaft position sensor and the ignition module.
The crankshaft position sensor provides a signal to the ECU. From this the ECU determines when to fire the ignition module for which cylinder, and when to fire an injector for which cylinder. If the signal is lost from the crankshaft position sensor the engine will shut down.
The ignition module operates in two modes. These are the start and run modes. When the engine is started, the ignition module allows full battery voltage to the secondary ignition system. This ensures that the spark is hot enough to start a cold engine. Once the engine starts, and the ignition switch is allowed to move to the run position, the ignition module switches to the run mode. The ignition module then reduces the voltage to secondary ignition system. This done because it allows the secondary ignition system components to last longer. Much like how ballast resistors/wires operated on the old point type ignition systems. It could be that run mode of the ignition module is beginning to fail. And this of course will cause the engine to stall.
The difficulty with diagnosing if either of these components are the source of the problem is, the problem has to occuring to determine which one it is.
Tester
Since no codes are showing up with this I would suspect something is acting up in fuel system. The fuel pump relay may be intermittent and this would be easy to replace. The fuel pump could also be the trouble but that isn’t so easy to replace. I would try to prove the pump is bad before replacing it.
I would agree with both Tester and Cougar. I would almost bet it is ignition module. I pulled one off before because the car had a lack of performance under a load and had it tested. Checked out fine but problem presisted. Went ahead and took a gamble after elimanating everything else and repalced the ignition module and problem fixed.
Thanks all, will advise out come.
When you have given up on everything else, replace the fuel pressure regulator. The valve seat is known to wear on just one side causing it to stick open. Stalling at stop lights is a symptom when the manifold vacuum is highest. In the initial stages this can disappear for weeks and pressure tests will be normal. It can be detected by a drop in fuel pump current going from about 4A to 2A.
Thanks all, turns out it was the fuel pump relay which is located in the CCRM module. Went to junk yard and for around 15 bucks picked-up component parts that were mentioned above and changed one by one (except for the fuel pump that was last resort) natually last part changed was the one. After 1 year I finally feel confident this was the problem!!!
AGAIN THANKS FOR THE GREAT INFO!!!