Need advice about fuel problem
Thread Starter
Intermediate
Joined: Jun 2003
Posts: 35
Likes: 0
From: glencoe AL
Need advice about fuel problem
First off, thanks for the help from my previous posts! Now, I have always had a fuel problem with my '86. In the past year I have gone through 3 fuel pumps!! They just burn out or something? Now, I have decided that my problem with this is somewhere in the electrical system. I have replaced the relay and noticed that when the car was off you could move the yellow wire going into the relay harness and the pump would start running?? No key in the ignition either! Also, the junction box behind the battery would make a clicking noise. I have just replaced another pump about 4 weeks ago and I am getting hard starts again and when in overdrive I can accelerate and the pump will start to cut out like it is going dead. Would replacing the relay harness help or is my problem somewhere else like the wiring in the dash{ bad ground, short?} This is really getting annoying and I don't want to trade or sell it. Thanks in advance.
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
In the older C4s it seems the insulation on the wires has a way of shrinking back from the connectors in the plugs. I'm guessing that when you wiggle that "yellow wire going into the relay harness" you are shorting power around the relay, directly to the pump. I can't guess, what it is behind the battery, that is clicking. Unplug the connector from the relay and inspect and correct any insulation problems. I think there is a tip on this at the top of the C4 Tech/Performance page, in the "sticky" FAQ post.
I don't know if that would be the cause of short pump life, however. Have you changed the sock with each pump change? The filter, too? Is there excess dirt or foreign material that is plugging the sock? Possibly the tank needs a good cleaning. Two items that WILL shorten pump life are a plugged fuel filter and running low on gasoline. A plugged filter makes the pump work harder that is should. A low fuel level allows the pump to run hotter than it should. If you are one that puts five or ten bucks in the tank until it is empty, your pump is running too much of the time without it's natural coolant. Either, and especially both will shorten the fuel pump life.
RACE ON!!!
I don't know if that would be the cause of short pump life, however. Have you changed the sock with each pump change? The filter, too? Is there excess dirt or foreign material that is plugging the sock? Possibly the tank needs a good cleaning. Two items that WILL shorten pump life are a plugged fuel filter and running low on gasoline. A plugged filter makes the pump work harder that is should. A low fuel level allows the pump to run hotter than it should. If you are one that puts five or ten bucks in the tank until it is empty, your pump is running too much of the time without it's natural coolant. Either, and especially both will shorten the fuel pump life.
RACE ON!!!
Thread Starter
Intermediate
Joined: Jun 2003
Posts: 35
Likes: 0
From: glencoe AL
I have changed the filter and sock each time. Gas tank isn't really dirty either. The relay harness' wiring insulation has shrunk though. I have also wondered about my fuel pump running when the car is off, but I have only encountered that once{recently}. I pulled into my driveway and after turning the car off I heard "not normal" pump noises for about 5 sec or so. Now, what in the hell would cause that?? It is really driving me crazy!
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
I experienced the wires going to the relay schrinking back about 3/4-1 inch, bare wires were touching one another. If you haven't checked them-CHECK THEM NOW! I suspect your wiring is toast-it's an easy fix, I'm surprised there hasn't been a report of fires caused by this.And it's most likely the source of your problem.
And quite honestly-everyone with an older C4 should be checking these-mines an 87.
