I have a 1992 B250 with the 3.9. It would not run when I got it, so I replaced the ECM with a rebuilt, and it ran pretty well. I took it on a couple of small trips, (3-10 miles) and it did fine.

I parked it and tried to start it after sitting for a day, and it turns over well, but no start. I ran the self diagnosis codes, and they came back crank position sensor and the idle valve. I replaced both of them and still no start. What next?

 

Find out what you are missing. Fuel, or spark.

 

It has fuel from a new pump amd sending unit. Not sure why it doesn't have spark. I changed the parts thst were listed on the codes. Do I need to now reset the ECM by unplugging it for a time?

 

Pull the center wire from the distributor cap and use that wire to test for spark. Doing this takes the distributor out of the equation. If you don't get spark from that center wire when cranking, then it's likely a bad ignition coil.

 

Does the fuel pump run while cranking?

 

fuel pump does run when cranking.

Hereś a brief summary of what Ive done so far:

It did not run when I got it, and I put a rebuilt (ebay) ECM in it when I got it to my home. It ran pretty well a couple of days on short trips, but now I have not been able to start it for over a week. It cranks, but will not spark.

I ran the self diagnosis codes, and they translated to the crank sensor and idle valve. I replaced them and still no start.

I then replaced the ignition coil, and did a spark test from the coil to the distributor-no spark.

What next? It could be the ECM, but it ran immediately when I hooked it up the first time. I've been told to replace the distributor pickup coil which is cheap, but I don't want to continue to dump new parts into this problem if not necessary.

Thanks for any help!

 

The 'pick up coil' in the distributor has nothing to do with ignition. It's for injector timing. That's it. The PCM needs it to start the engine, but, once running, it is essentially ignored.

If you aren't getting spark, and are still getting codes for the crank sensor, even after replacing it..... Verify you are getting 5 volts TO the sensor. Verify you are getting some signal FROM the sensor. Test at the coil connector, to see if it has voltage, and if the PCM is actually trying to control it.

 

How would I know if the PCM is trying to control the coil? Would there be a change in voltage from teh ECM to the coil?

 

You can use a test light, if you have one. A digital volt meter likely won't react fast enough.... (or, you can 'borrow' noid lights from your local big chain auto parts store) Put the test light across the pins of the coil connector. It should flash while cranking. If it doesn't, PCM is not controlling coil.