Im new to this forum but have read similar postings about this same problem and hope to get some assistance as well. Truck is manual tranny and has 150k miles it started running rough then it just would not start - replaced fuel filter, cap rotor, plugs and did not notice spark from leads or coil. replaced and still would not start. then sent ecm to avpro who indicated it ran in their truck so they kept my 160 $ and sent it back. fuel delivery seems fine but i have not checked pressure. when cranking engine over no fuel is visible on plugs - have not tryed truck since i got the ecm back but when i reinstall the ecm and it still does not start what do i change next/? any help is appreciated.

< Message edited by dwb -- 4/27/2006 9:12:41 PM >

 

What year truck is the 2600i dwb? You mentioned that you did not notice any spark from plug wires or coil so that would be the best place to start. Check to make sure that you have 12 volts to the positive side of the coil (Black w/ white stripe wire). Negative side of the coil ( White wire )should cause test light to flash while cranking over engine. If no power at all to coil then will have to backtrack the wiring to find out where it is lost. Power should be coming straight off of the igntion switch (At least in the 91 manual). If no flash on negative side then might be looking at a bad pickup coil/ignitor in the distributor. The distributor is turning???

 

Truch is a 91. has 12v on positive side nothing on negative. Rotor is turning when engine cranks. how do i check the ignitor? thanks,

 

Took distributor apart and removed ignitor. Haynes manual does not indicate how to test the ignitor. does anyone have the specs to test this thing
Thanks. dwb

 

There is no way of testing unfortunetly. An igniter is a solid state unit and its inputs and outputs can only be tested, ie. power is going to it for input, and coil is receiving trigger for output. The only thing the ignitor does is trigger the coil and run the tach if equipped. An ignitor is not that uncommon of a part to replace.

 

bkey is right on testing the ignitor. There is an old SST for dealer that you could install in place of the ignitor and if it would manually spark the coil then ignitor was deemed bad. If you have a buddy at the dealer then see if you could borrow the ignitor tester..#49-F018-002 and adapter harness..#49-N018-001. Otherwise just get another pickup coil/ignitor and you will probably be good to go.
One question though. You stated that you had 12v on positive side of coil and nothing on negative. By nothing you mean no flashing or just 0 volts all of the time? If is 0 volts all of the time try disconnecting the ignitor and see if you now have solid 12 volts at negative side as well.

 

Sorry for the delay i caught the antispylab virus and couldnt shake it. Anyway we left off with 12v on the positive side and nothing on the negative side of the coil connector. i disconnected the connector (ignitor) from the distributor and still no volts on the negative side. I also swapped out the ignitor with a used one and no luck. What is my next step? thanks for any advice. dwb

 

have you tested the main fuse and relay that supplies power to the ecm/injecters/crankshaftsensor/mass airflow
or have you tested the crankshaft sensor
if the ecm doesn't see a signal that the engine is turning over i don't think the coil will fire
i'm only going by the diagram i got from autozone
if i can help i got a 91 2600i as well maybe test something here and compare the results

 

Thanks for the schematic. If the 80A fuse looks unbroken can i assume it is ok or how do i test it? The haynes manual i have doesnt talk about the main relay or crank shaft sensor where are they located. I have the same 4x4 pictured in your reply.
Thanks dwb

 

went and took pics for the relay and mass air sensor but could not find the crank sensor?
the main relayis near the fuse block and should be powered by the fuse marked 30 amp fuel inj this will power up the injecters and mass air idle air control and crank sensor(were ever it is)
to test the fuse if unsure remove the fuse and use an ohm's meter just to check the fuse element is good should read 0 ohm's across the fuse