2000 astro van 4.3 issue.Alternator seized up so I replaced it and also belt. After i beg your pardon fuel pump didn"t revolve on so replaced it. Tho doesn"t start. Replaced fuel pump relay, no joy. Replaced ignition switch, no joy.Here"s the monster thing. I deserve to jump the relay and also pump runs. Forgot the exact relay number yet I am acquire 2 12v readings ~ above the relay...with relay out and also multimeter testing. Acquiring 4 volts which i assume is sensor. This is all with crucial off. I thought I have to only have actually 1 12v reading with vital off however I"m obtaining 2.Haven"t checked fuel pressure or spark top top distributor.Should I check that or do I have actually other issues?
Tyler
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ModeratorYou don"t scare me, I solve CHRYSLERS
I think you"re looking at a prejudice voltage native the PCM? You"ve really likely collection a fuel pump relay code in the PCM, not that that"ll cause your problem.This video is what you want to watch if you want to recognize this better. I additionally attached the wiring diagram because that reference.

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You"re better off partially plugging the relay into the socket and carefully research the pins. This will finish the circuit, yet still provide you access to the terminals.Key on, with the relay partially installed, take back your readings. One of those 12V readings have to be gone. Let us know what you find, and also we can go native there.
cheryl hartkornPlatinum Member
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do you have a scanner that has actually bi directional controls? or just backprobe or choose tyler stated leave the relay partially out and also check pin 85 for manage from the pcm while cranking. Need to be strength side switched
matt.friedmanTopic AuthorNew Member
That video clip is awesome! I"ve been so confused why I have actually 12v on 2 pins. I have actually a meter and test light and will inspect this tomorrow morning and report back. Thank you really much!
matt.friedmanTopic AuthorNew Member
Tyler
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ModeratorYou don"t scare me, I solve CHRYSLERS
No worries, a check light and DMM will job-related perfectly. i forgot come ask - with the pump relay bypassed (and the pump running), does the start and run? If not, climate it"s possible that the pump control problem is a symptom the a bigger issue.
I couldn"t acquire it to run the various other day yet I"ll inspect again. Ns didn"t readjust the pigtail either yet it ran fine v this one ~ above it. I might drop the tank again to check lines and wiring.It sputtered however didn"t begin so pcm is alright I"m assuming simply not acquiring fuel. I"m no a mechanic through any way and renders me want to torch this vehicle haha
Ok so did the dam and also test light and also it did no zero out. Jumped the fuel pump and also attempted come start. It fired yet did not start. Miscellaneous is draining the battery and cannot number out what the is. There is fuel pressure yet do not know what psi. Checked the wires come the pump through poking thru them a d gained low voltage ~ above gray. Could be i didn"t have actually a good ground...had the dmm of a fuel line.How could transforming the alternator reason all these problems....is over there a circuit the the plug because that alternator runs on or something?Throw whatever u have at me and also I"ll shot it
I dunno that replacing the alternator would have caused these symptoms, unless the battery is weak (from acquiring discharged) and also causing other issues. Or, is it feasible that there"s a negative battery connection? How"s the cranking speed?I"m i m really sorry to nag, however it"s worth gift specific. Through the key on, relay partially installed, what space the voltages at all four fuel pump relay pins? and the very same readings during cranking. That"ll spell the end what"s happening at the relay.
Ok let"s ago up. I can not acquire 12v at the pump once I experiment the gray wires. I"m obtaining 4 come 5v. Have the right to u connect a wiring diagram to whereby these wires walk for Me? This may explain my battery drain as well. I"m going to begin at the pump and work ago instead the chasing ghosts.Do you have a video clip explaining what voltage in what cable for the pump.

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Sure, we can do that! Here"s a connect to the engine power diagram, and a shoot of the fuel pump wiring:www.rebab.net/media/kunena/attac...17/DownloadPdf27.pdf
The diagram mirrors C310, the key connector that goes native the vehicle to the tank and also pump itself. This connector is top top the vehicle drivers frame rail, just ahead the the tank, if i remember correctly. It consists of the fuel pump power and also ground, pin A grey and pin G black. I"m not sure where you"ve been testing before this, however C310 provides an idea experimentation location if you have the right to put your hands ~ above it. Grey should have 12V (or near to everything battery voltage is) anytime the relay is energized. Black should have less 보다 .5V at every times (relay off, relay on, whatever). 4-5V would indicate a voltage drop, or weak resource voltage, top top the grey wire. Paul has actually several good videos the end there on fuel pump diagnostics, but you might probably start out through these two:
Ok here"s what ns have.12v come pump.Ground an excellent to pump.60psi pump pressure0psi element pressureNo 2 sec prime on computer system side that relay.Jump relay and get 60psi and also car sputtered however didn"t start.Looks favor from the relay come pump is fine, but relay is no being commanded to close and also prime. Guessing it"s ecm?
Possible, however I think Cheryl is right, powers and grounds room a good place to start. I can"t choose them all out ideal now, but they"ll be in the PDF diagram ns posted earlier.Did you occur to watch the last video I posted? The symptoms sounds VERY similar to yours.