Fuel pumps continuously primes
02-18-2017, 04:22 PM
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Fuel pumps continuously primes
Hey guys
i have a C5 S6 and it has a 17908 code for the fuel pump relay. It runs and drives fine. When I put the key to accessory I hear the fuel pump come on to prime but it never stops. I pulled and tested the relay and it seems fine. What would make it so the ECU continually tells the pump to run before the engine is started?
i have a C5 S6 and it has a 17908 code for the fuel pump relay. It runs and drives fine. When I put the key to accessory I hear the fuel pump come on to prime but it never stops. I pulled and tested the relay and it seems fine. What would make it so the ECU continually tells the pump to run before the engine is started?
02-18-2017, 05:42 PM
#2
Hey guys
i have a C5 S6 and it has a 17908 code for the fuel pump relay. It runs and drives fine. When I put the key to accessory I hear the fuel pump come on to prime but it never stops. I pulled and tested the relay and it seems fine. What would make it so the ECU continually tells the pump to run before the engine is started?
i have a C5 S6 and it has a 17908 code for the fuel pump relay. It runs and drives fine. When I put the key to accessory I hear the fuel pump come on to prime but it never stops. I pulled and tested the relay and it seems fine. What would make it so the ECU continually tells the pump to run before the engine is started?
Now, it is possible, (I haven't looked in manual) for your engine that there is second "transfer" pump. Could that be the one?
Pull the rear pasenger seat (under right side) you should see the pump connector. Take that out and test with 12v light. That should answer your question.
02-20-2017, 01:00 PM
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When I pull the 327 relay for the pump and put the key to accessory I don't hear it come on so it's def the main pump (if there is event two). Does the fuel pressure regulator have any feedback loop? Could it not be reaching adequate fuel pressure?I'm gonna look for bad grounds or something. Other than that maybe a new ECU?
Last edited by nymk2gti; 02-20-2017 at 01:04 PM.
02-21-2017, 09:29 AM
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looks like I found the culprit. Someone wired up a relay that goes behind the pump relay. I the pump relay is in too I took it out for the pic. If I pull either relay the pump shuts off. Maybe just someone bypassed the relay with an always on one for some reason. Gotta pull it down and trace wiring. No wonder I was the only one with this issue!
02-21-2017, 04:19 PM
#6
looks like I found the culprit. Someone wired up a relay that goes behind the pump relay. I the pump relay is in too I took it out for the pic. If I pull either relay the pump shuts off. Maybe just someone bypassed the relay with an always on one for some reason. Gotta pull it down and trace wiring. No wonder I was the only one with this issue!
02-27-2017, 06:30 AM
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Ok so Im not sure how, but i fixed it. It had a bunch of central lock codes. I neglected to check the immobilizer measuring blocks to see what they were set to before clearing all the codes, but the immobilizer light was not on. But once i cleared all the codes, the immobilizer was set to 1 and the signal was restored via the red/blue wire from the ECM. Dunno why they originally jumped it, somebody must have just said f it im not gonna diagnose it. It was a hack job wiring too so it must have been someone with little understanding. Oh well problem solved!
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