Hello! So i have a problem once again... I have a b2500 5.9 and I can't get it to turn over. It has been having trouble starting for the last couple weeks. It cranks strong but just won't turn over. After playing with it for a while sometimes it will start.

Yesterday was my first day i had to get a tow truck ride home. Tinkering with it did not lead to an eventual start. It has a new fuel pump, new cap and roter, new coil... After replacing all that stuff like an idiot i pulled the plug from the coil and tested it on crank. It's not getting any power. I'm leaning towards ym computer being bad but am not sure. This computer is one i got from a junk yard because my old one was having problems. It has been in my van for about 3 months and had no problems till the last 2 weeks. Anyone have any other ideas or experiences with something like this?

 

Try the crank sensor.

In my experience I've only had one ECM die on me (randomly), and the way I could tell it was bad is by the check engine light - it wouldn't come on right away when the key was turned to "on". I had to start leaving the ignition in the "on" position for several minutes until the ECM and check engine light came on. Then I could start my van up and it'd run.

The problem I had sounds simaller to yours. New ECM ran me about $400 unfortunately.

-Spenser

 

i already replaced the crank sensor with the cap and roter

 

Oh OK. Then I might lean towards the ECM too... If you had a friend with the same kind of van it'd be cool if you could swap computers to check.... Doubt that'd be the case though.

It sucks cause ECMs aren't too cheap. Maybe try ebay? Mine had a V6 and finding one was a little harder than the V8's.

-Spenser

 

Besides the PCM not working, a bad ASD relay will prevent power from reaching the coil, as well as the fuel injectors.

Is the fuel pump relay working, is power coming out of the contact?

 

Hi there, sorry to barge in on the thread, but I have a similar issue with my van (5.2 1995) - ever since I got the van, and the previous owner also had the same problem, it never fires first time even if I crank for a few seconds, but 95% of the time will fire up instantly on the second turn of the key.
I can hear the fuel pump come on each time, but I don't know what would be the best step to proceed to fault find this problem. Presumably I should check to see if I am getting spark output from the coil during the first crank, but whats the recommended way to do this without frying anything?

Thanks,
Ben

 

swappedthe relay with the ac relay and nada :-/ 2 computers in 4 months?? gimme a break!

 

I don't know the year of your vehicle.

Got Rockauto.com and under electronics click on ECM
and click the I nfo tab.

Or just click this:
http://www.cardone.com/english/club/...%2077-0005.pdf

Basically it says that ECMs fail due to a solenoid or sensor's resistance is out of whack.
Replacing the ECM without checking every possible culprit, is foolhardy.

Good luck.

 

well the first time the computer died it was because some pack rats had gotten into some fuel injector wiring and stuff. The computer hadn't completely gone out then but it was throwing out all kinds of weird error codes. I got this one from a junk yard and put it in and everything was normal again. These symptoms are all different then the problems i had before. I guess i could just bite the bullet and buy another one but this is ym work truck and i need it to work!

What would a mechanic be doing that i'm not?

 

A few years ago My van, on occasion, would start, but run horribly with all the relays clicking on an off. After 30 to 45 seconds of burping/farting and clicking, it would run perfect as if a switch were thrown. It started happening more often and in more severity.

I started throwing sensors at it.
Hall effect sensor (similar to CPS)
Map sensor because I was getting that code.

Then I started suspecting the ECM, and researched them, and found that Cardone was saying it is very rare for an ECM to fail on it's own. Something causes it to fail. A sensor out of whack or a sensor wire touching ground.

I wound up unravelling the tape surrounding the engine wiring harness and following each and every wire from each sensor to the ECM, cleaning and inspecting, and untangling everything. I checked for continuity on each wire from both ends.

I found a couple suspect things which I fixed but the problem continued to get worse.

I rerouted the wires leading to the fuel pump, and then realized I had not checked the wires leading to the transmission. So I checked them, and one which goes to the Lock up solenoid was burnt with bare wire touching the tranny's bell housing. So I fixed that, and not surprisingly the burp, fart, clicking syndrome continued.

By the laws of physics it is always the last thing you check. In my case is was the last possible thing I could have checked.

Then I knew, for sure, it was the ECM, Because I had checked the resistance on each and every sensor, and followed every single wire.

I then replaced the ECM, and have no more ECM issues in 4 or 5 years now.

When looking for the Cardone link I posted in the earlier post, I was a little surprised to find that they narrowed down the most likely cause of ECM failure to be the nearly the same exact cause of my ECM failure. They say check the Torque converter solenoid. The wires leading to my TCS were grounding out.

Start there with an ohm meter, and a Chilton or Haynes manual which show procedures for checking the resistance on sensors, and work your way through all the sensors. When You find some sensor reading way outside the parameters, replace that, then get a new ECM.

Let us know what you find.