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Posted by Gordon Maney [208.126.206.67] on Thursday, December 24, 2009 at 09:23:21 :
In Reply to: No voltage at lift pump lead posted by Gordon Maney [208.126.206.67] on Wednesday, December 23, 2009 at 21:59:32 :
My circumstances or symptoms are these:
No start.
No voltage at the end of the lead for the lift pump when bumping the starter.
Using the Bluechip Diesel site’s diagnostic information you get this reference:
“....the best way to be sure the VP 44 is getting battery voltage, is to verify that there is battery voltage to the removable plug on the injection pump. Remove plug and hold it so it looks like a smiley face. The bottom right pin is #7, batter voltage. The bottom left pin is#6, ground. Be sure to verify voltage during the “start” function of the ignition switch as well as the “run” position.”
I do not get a voltage at pins 7 and 6 when in a key on mode. At this time I do not have a helper to do the cranking mode test. I could figure out a way to attach my VOM leads to the connector but I am not willing to risk damage of those connection points. I will make that measurement as soon as possible, to be thorough.
Bluechip provides this:
“If you don’t hear the lift pump, check fuse number 9 in the fuse box on the left side if the dash AND the “ASD” relay in the “ECM” (fuse box under the hood). Don’t assume the injection pump is getting battery voltage if you hear the lift pump running when you bump the key, just because the lift pump and injection pump BOTH run off the same ASD relay in the PDC. The lift pump needs 12 volt power from the ASD circuit AND the PCM to run.”
I have examined fuse 9 [checking it with an ohmmeter] in the left end of the dash board and have substituted a known good relay for the ASD relay in the PCM. I tested the relay by using it to power the wiper motor.
I have a suspicion that the lift pump had not been powered for some time. That because over a period of years, whenever changing a fuel filter, I could never hear the lift pump run if I bumped the starter. I always filled the filter canister manually, as bumping the starter caused no effect. The odd thing is that if the injection pump had never been getting a voltage.... It never would have been able to run. So.... what then?
In summary, I don’t seem to have a voltage at the injection pump or at the lift pump power lead. Using half of a proper Deutsch connector set, I made up a jumper lead allowing me to power the lift pump directly off the battery.
I will mention here that I also installed a Raptor pump and big line kit. My jumper lead is actually powering the Raptor harness. The pump works fine when powered that way and at my test gauge installed at the VP44 inlet fitting I am getting 15 psi. The pump did a beautiful job of rapidly filling the filter canister and I used to to bleed out at the VP44 inlet fitting gauge port. I crank and get fuel from loosened injector fittings.
I have the gnawing feeling I am not seeing something here. I have been poring over my official Dodge truck manuals and fail to find diagnostic information for injection system as a whole. They offer diagnostic info for some components.
A guess suggests that the ECM is not getting a voltage, or the ECM is bad. I don’t know how to pursue that further.
Regarding Spence's manual related comment. I am uncertain if I have the very same manual here, but find under engine startup mode that the PCM monitors the crankshaft position sensor. If the PCM does not receive a crankshaft sensor signal within 3 seconds it shuts down the fuel injection system.
The truck sets no codes other than PCM 1694, No CCD Messages Received From ECM. It sets no ECM code.
I realize it is Christmas and all of you are wrapping presents and baking pies. I am about to start doing the same. I do hope to do this voltage test [with helper] a bit later, to verify there is no voltage present at the VP44 even under cranking. Otherwise, the really serious work will not resume until the 26th.
Merry Christmas to you, and don't get eggnog on your sweater....
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