Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
Van stalls when driving, then no start.No bus appears on odometer. replaced pickup coil in distributor &
engine computer. Sometimes it will run for days. I found that when it stalls I open the hood & push on the
connector on the drivers side going into computer. Thought it was a loose connection so I tightened it up
with zip ties. It stalled again the other day.
Do you think the engine computer could be losing power or ground? What happens when you wiggle on the connector when the engine is running? How long before you are able to start the engine again? What are you missing when the car is not starting(spark, injection pulse, 5v reference)
Sorry it took so long. I just got the wiring diagrams today,haven't had a chance to check anything yet.
When I wiggle connector with engine running it doesn't affect it. It stalled again today opened hood
when I wiggled connector I heard a click in the power distribution center sounded like a relay, I got back
in & it started right up. It ran for the rest of the day.
Hey laird! The clicking relay when you wiggle the computer connectors kinda suggests an ASD relay problem to me. The ASD relay controls power for the injectors, coil, and fuel pump, which definitely explains the stall. You could verify this by checking for power at any of the injectors (which are kinda hard to get to, I know) or the ignition coil during the crank no start.
The next time you get it to stall, see if you can wiggle individual wires at that connector. Let us know which one gets a response, and we can look it up on a wiring diagram, and see where it takes us.
The relay clicking in the power distribution box could be the ASD relay or the Fuel Pump relay, both of which are ground-side switched by the engine computer. It give us some direction. It would be helpful to know what you are missing when the car does not start. You want to do all of your testing only when the car doesn't start.
Is there power getting to the injectors when cranking?
Is there power getting to the ignition coil pack when cranking?
Is there power getting to the fuel pump when you are cranking?
Do you have an intact 5v reference circuit? This video will help you if you're unsure
the no bus to me sounds like your losing a power feed to the computer, when it happens next time check for a 5 volt ref at the tps. you may have a sensor that is intermittently shorting and pulling the reference voltage down. when no bus appears im pretty sure its going to be a no communication with a scanner
I tested the tps with the key on , (not running) by back probing I had 5 v ref in. .66v out. on wot I had
3.67 out. It's difficult to test when stalled as I would have to take the dog house out on the side of the road
or at a red light........next?????
Does your 3500 have a 5.2 or a 5.9L? Just want to know for diagram purposes.
Yeah, the dog house will be too much work to take off at a moments notice... How about this? I did some digging, and I found the fuse that the ASD relay feeds to power the ignition coil, injectors, O2's and PCM. It's listed as fuse 19/20 in the Power Distribution Center. Here's a partial wiring diagram:
The next time the van acts up, jump out and check for power at this fuse during cranking. If there's no power, then we're going in the right direction with the ASD relay. If there IS power, then we need to go in a different direction.
I replaced the tps. No such luck, it stalled 3 times today. Took it to mechanic, he said nothing he could do
unless it stalled while I was there.......Next??????
laird wrote: I replaced the tps. No such luck, it stalled 3 times today. Took it to mechanic, he said nothing he could do
unless it stalled while I was there.......Next??????
Any luck checking that fuse when the engine stalled?
I still think you were on the right track with that connector under the hood, near the computer. If you can find a way to consistently manipulate that connector to produce a stall, then we need to dig into that connector.
Its seems to me that you might have a bad connection, when it runs wiggle the wires, carefully. Strip back the loom as far back as you can and wiggle tug each wire if you can I think you will find one bad or more. Also you might unplug and check the connectors for (the green crud) both ends. Re seat the plug (don’t force or bend the pins)
I decided to go for it. I remove all of the wires from the connector, I saw some of the wires were frayed & some connections loose on the pins. I squeezed all connections and reinstalled wires on pins. Then I sprayed entire
connection with liquid rubber. Not very professional, but it worked. I will try & find a new wiring harness & connector.
Meanwhile it"s purring like a kitten.
