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Richard M
Richard M, ASE Certified Technician
Category: Dodge
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Experience:  ASE Master Certified with L1
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1993 Dodge caravan: getting fuel..test lamp on the fuel pump harness

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1993 Dodge Caravan 3.3. No Start, not getting fuel. I've put a test lamp on the fuel pump harness and when I turn the key on it lights up for a moment, then goes out. I'm suspecting the ASD relay (circuit). Wondering what triggers the ASD relay to tell it to shut down? Other thoughts on why voltage to the fuel pump would come on then immediately shut off?
Hello BD,
When you turn the key on only the fuel pump will only momentarily turn on, then go off, until the ECM (computer) sees the engine cranking. This operation is normal.
Use the same procedure with the test light, but check it while cranking and you will see the test light stays lit.
While you are underneath check to see if the fuel pump runs, (listen for it) You will probably not hear it run.
Get a hammer, and while cranking, hit the bottom of the fuel tank and the van will likely start up.
If it does run, or if the test light stays lit while cranking you likely have a faulty fuel pump.
If you hear the fuel pump running and the van won't run you possibly have a clogged fuel filter.
Let me know.
Customer: replied 7 years ago.
It appears the fuel pump was bad. Have replaced the pump and filter. Can now clearly hear the pump running when the key is turned on, and while cranking, The engine fires sometimes, but will not run. A couple of times it has run roughly for about a minute, then died. Prior the start of this problem (cranks but would not start) the vehicle was running fine. Planning to see if I can put a fuel pressure gauge on it tomorrow. Thanks for your input.
Hi Bd,
I'd appreciate it if you would consider my time by clicking the "accept" button.

Now, check for consistant spark at the plug (see below) and to check for fuel; remove a fuel line at the engine, put the hose in a bottle while cranking, see if you are getting fuel.

Checking for spark; Remove a plug wire, stick a screwdriver in the end, hold the metal shaft of the screwdriver 1/4 inch away from metal on the engine. Have someone crank it while you watch for spark. (try to not touch the vehicle while you are doing this, and you won't get shocked)
Also, check codes; cycle the key ON - OFF - ON - OFF - ON ending in the run (ON) position, then look at the check engine light. You should see it flash as follows: on-off, pause, on-off, on-off (which is a code 12)
See if there are other codes. For example: a code 24 would be on-off, on-off, pause, then on-off 4 times. Each code will flash in a succession of 3 times
Richard M and other Dodge Specialists are ready to help you
Customer: replied 7 years ago.

I'm away from the vehicle this morning. We confirmed good spark yesterday. We get fuel at the schrader valve on the fuel rail, but it seems weak. We are a lttle suspicious of the new fuel pump we have installed. It is definitely louder than the original pump. Planning to try testing the fuel pressure later today.

Codes are 12 21 55.

 

Thanks

Yes, check the pressure. Did you replace the fuel filter?

Trouble code 21:

21** Oxygen sensor signalNeither rich nor lean condition is detected from the oxygen sensor input.

or

02 sensor shorted highOxygen sensor input voltage maintained above normal operating range

 

I doubt it would cause a no start condition though.

Customer: replied 7 years ago.

The NEW fuel pump we had installed was bad. Apparently it was pumping fuel, but not putting out even enough to even show up on the fuel pressure gauge. Installed the second fuel pump and it is running great now.

 

Thanks for your help along the way.

Thanks much for accepting the answer(s). Glad you got it running.

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