QuestionQUESTION: My 1993 Dodge Spirit has no current showing on my test light for the two-second duration at the fuel pump, when the key is turned to on. The car is 4 cyl. 2.5L "K" version. I examined the fuel pump relay (actually all the relays under the hood by the left shock tower). The relays showed no burnt or loose poles, and each relay showed similar continuity. I looked high and low for a separate fuse for the fuel system, under the dash and under the hood, but couldn't find any. Also, the fusible links look okay. Also, I have spark, based on my timing light working in sync with spark plug wires. Also, the only trouble code I get is 55, the ending code. I even disconnected the neg battery terminal for two minutes, to try to get the recent disconnect code. That didn't change the trouble codes. I still only get the 55 code. I haven't checked any of the fuel lines. Should I do this, or do I have another more likely problem? Thanks.
ANSWER: Hi John,
I would suggest that if the fuel pump relay has the same part number as any of the other relays on the inner fender that you try switching them around to see if substituting one for the other will get the fuel pump to run for a couple of seconds. Check whether or not you see 12V on the dark green/black wire at the relay for a couple of seconds, because the relay could be good but not the fuel pump. Also check that when you turn the ignition switch to the run position you see 12V on the dark blue wire (that comes from the ignition switch and is the voltage necessary to activate the relay).
Then let me know what you found
Please don't use the "Private" option when you follow up question as there is no need to keep this discussion from other viewers of the site.
Roland
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QUESTION: Hi Roland,
The relay I've been checking is the innermost one on the left shock tower. The blue terminal is hot when the key is turned to run. The dark green terminal shows no voltage for any duration, when the key is turned to run.
ANSWER: Hi John,
That is the fuel pump relay.
Make sure you have 12V on the red/white wire of the that relay, just in case. It comes direct from the battery but if it isn't present then there is a problem with a splice along the way. The fact that you have spark suggest that you have that voltage supply already because it is also needed by the ASD for supply to the coil. The
dark blue showing voltage means there is power to activate the fuel pump relay, and the fact that you have spark suggests that the dark blue/yellow wire of the relay is being grounded by the PCM while you are cranking over the engine and that should cause the fuel pump relay to close and send 12V from the red/white wire to the dark green/black wire that goes to the fuel pump. So unless there is a bad splice it would suggest to me that your fuel pump relay is not conducting across its internal points or its activation coil isn't closing the points. So, again, try substituting the second or third relay on the left fender (A/C clutch, fan relay, respectively) for the fuel pump relay (if either has the same part number) to check if it is the relay itself that is bad. You could also jump between the red/white and the dark green/black after removing the fuel pump relay to see if that causes the fuel pump to run, as a test that the wiring is ok and the problem is the relay itself. If you don't hear the relay click when the ignition is switch to the run position, that would suggest the relay is not activating for a couple of seconds as it should which would also implicat the relay, given that the rest of the wiring is good and you are still getting spark when you crank.
Roland
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QUESTION: Hi Roland,
I do have 12V at the red/white wire. I jumped the red/white wire to the dark green/black wire that goes to the fuel pump. Then I checked the fuel pump plug, and it showed 12V. Before I made the wire jump, I had no juice showing at the fuel pump plug, when the ignition was turned to run. So, does this mean that I probably have a defective relay, and definitely have a defective fuel pump? (FYI, the relays are not interchangeable, as each relay has a unique slot that fits only the ridge from its corresponding plug.)
AnswerHi John
Yes, if you have 12v at the fuel pump, measured between the two pins of the plug, and then you plug it into the pump and nothing happens, then the pump is not working.
The relay is probably defective, because you don't get 12v at the fuel pump plug or on the wire at the relay socket that goes to the plug, and because you don't hear it click. One last thing to check before you buy a new relay is to verify that the dark blue/yellow wire reads 0V for a couple of seconds when you turn the ignition to run, which if it does would cause the relay to click etc. if the relay were good. That does appear to be happening over at the ASD relay which shares that same wire, because that is what also causes there to be spark if you then crank the engine. But this would assure you that the circuit to activate the relay is correct and thus the relay is not working.
Roland
