My old truck won't crank. Checked for spark from coil and had none. Replaced it and pick up in dist.,no change. When I "release" pressure on fuel log it's just a dribble. Pump replaced 12 months ago.

Questions
Is there an interlock to keep it from firing if the fuel pressure is too low?
Should I be able to get a spark from the coil lead whenI turn it over?
What to look at next?

Been a good truck, now has 230,000 miles and motor is still good, but I can't just throw money at it and fuel pump and control modules are both expensive (relatively speaking) a little help please. Need my fishing truck back on the road.

Thanks, Mike

 

Swap out the ASD relay with the AC clutch relay. They are the same and that will let you troubleshoot a little. Fuel pump should use the same one as well. On my 92 I had an ASD go bad, it would crank forever but had no spark. New relay solved the problem. The original lasted 190k miles.

 

Tried this with no success. Thanks for posting, Mike

 

Ck on the right side of the engine and see if you you have a crank sensor. If you do unplug it and ck your fuel pressure, What happens is the crank sensor gets a 5v signal over the PCI bus system. If the sensor is shorting out the bus system which is for,Ignition and fuel pressure.

 

Looked around the front of the motor, each side and did not see a crank sensor. Around the flywheel(flex plate) maybe? I did try a different tool to push plunger on fuel log "test port?" and there is a pretty good gush of fuel, diameter of pencil and maybe 8" high when first relieved. There is voltage at the connector that plugs into the coil. I also replaced the pick up in dist. Anyway to test control module? Other thoughts?

Thanks, Mike

 

The crank sensor would be on the right (passenger) side, rear, of the engine, in between the engine and transmission (its not big, and is held on with two bolts or screws)
Since you have fuel pressure (so, obviously, voltage to the pump)and voltage at the coil, the relays are not at fault.
I would definitly agree with master tech in suspecting a crankshaft sensor problem. If the engine doesn't get a reading from the crank sensor within a short period of the engine turning over, it simply stops providing power to the fuel pump and coil by taking away the ground it provides to the ASD relay, and fuel pump relay (depending on model year).
Also, the camshaft sensor (aka hall effect sensor), which is located under the distributor cap, can cause similar problems.
Do a search, you'll find many other topics where this has been discussed.

 

I'll get a crank sensor today. If the one installed has continuity is there any thing else I can check on it?

Thanks for the replies hope to get my fishin' buddy running soon.

Mike

 

Oh I meant to mention this. I got fuel pressure when I turnrd the key on 5 seconds or so, turned it off and cycled it like this 3 or 4 times then jumped out and relieved the pressure/test port. Maybe I "tricked" it into building up pressure.

Mike

 

OK new crank trigger installed, still no fire !!!

Mike

 

Check out this posting/thread - sound like you may have the same problem - note that it is the power feed for the computer - computer will be dead if it happens to be the first wire that corrodes off the splice. My Dakota got taken out by a suicidal deer last week, but I can't stop reading the Dakota forum :-( https://dodgeforum.com/m_822901/tm.htm