# Weird Problem



## jimbbski (Jun 3, 2007)

I have an '88 Scirocco w/16V & Cis-E. It runs fine except when I "get on it". Then is sputters and even stalls out. Sometimes it restarts and sometimes it doesn't. When it doesn't it's because the fuel pump is not running. Turn the key and nothing happens. 
I was able to duplicate the problem when I had the car idling with the hood up and I started to check the underhood wiring. I touched and moved the wires coming from the throttle body, the ones for the closed and full throttle position switches. The engine stumbled the first time I moved the wires and when I did it again the car stalled. I tried to restart it and I could not hear the fuel pump run or the relay click. 
Now I would think that there is something wrong with the wires, perhaps a internal break in one or more of them, there are three, or a bad connection at the plug. I did check the plug and it seems OK.

What I would like to know is, if anyone can tell me, is how these switches and their wiring could effect the power supply to the fuel pump relay? Or am I missing something obvious?


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## WaterWheels (Aug 14, 2005)

jimbbski said:


> What I would like to know is, if anyone can tell me, is how these switches and their wiring could effect the power supply to the fuel pump relay? Or am I missing something obvious?


The wires to the throttle switches, three in all, have nothing to do with the fuel pumps and I see no way they can have an effect on them. I'm wondering if you made a common mistake. The ignition key has to be turned to the off position before trying to restart or the fuel pumps will not come back on. So, did you just reach in and try to start by turning the key to the start position, or re-set the relay by turning things off first? 

As for the problem itself, it could be one of a few things. I do believe there could be a problem with your throttle switch wiring, but I don't see it causing the problem you first described. Maybe a bad ignition switch, maybe a bad pump relay, faulty wire or some other thing in the pump electrical system/path. I would start be "hot wiring" the fuel pump and driving that way for a while. If the problem goes away the replace the relay. Harder to reach, but still not so hard, is the ignition switch which you can hot wire also for a day or two. When it dies, what happens with the dash/warning lights? Try to wiggle the ignition switch while running or when the problem starts to happen, any effect?


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## jimbbski (Jun 3, 2007)

The relay has been checked and I have a spare. The stalling occurs with either one in place. I have removed the ign. switch and checked that out as well. It also works fine. 

The reason I ended up checking out the wires from the engine to the harnes on the car was that the prolbem only happens when I accerate hard. Since I have only done this in 2nd gear so far thats all I know. If the engine rocks when I do this it could cause the wires to move and shut off power to the fuel pump. Remember after a few seconds the only way the fuel pump relay get power is if it gets a signal from the ignition/dist. through the black boxes on the car. 

hard wiring the pump to run all of the time could confirm this. I have thought of that but wanted to see if anyone has any other thoughts.

And yes i do turn off the key al the way before trying to restart the car. Sometimes is restarts and sometimes it doesn't. i had to tow the car a short distance home one time and another time it had to be towed out of pit lane at a race track where i had planned on running it in a HPDE. It refused to start and had to be pushed onto my trailer to get it home.


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## WaterWheels (Aug 14, 2005)

From what you have said so far then I would have to think that there might be a bad connection "within" the wiring harness somewhere. This can and has happend, although not that often that I have seen. I don't see the wires to the throttle being the problem as the engine will run with this connetor removed from the throttle, but by moving these wires you could be also moving other wires inside the harness. Try moving the harness around in other areas while it is running. The grounds inside are just crimped together with some kind of "glue" and they can break loose. If you determine that by moving the harness the problem can always be repeated, then find yourself a good used harness and swap it out. They can be repaired also if you don't mind taking the time to trace the wires and do it. 

You're description of the fuel pump recieving power via the ignition is a bit off, but if the ignition is effected somehow through the wiring harness, ignition and fuel are combined in that harness, then the pump could be stopped.


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## jimbbski (Jun 3, 2007)

I will be picking up another Scirocco next week. It's a parts car with most of the mechanical parts there but missing most of the interior. I'm buying it for the windshield and transmission as spares as this car will be raced in SCCA ITA class next year. 
It would have been this year if not for this problem. 

I will be posting this car for sale in the classifieds soon, once I pull what I need.


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## jimbbski (Jun 3, 2007)

It seems that the problem is fixed subject to further tests.
I replaced the high pressuer fuel pump. I had a Paulburg pump and replaced it with a Bosch.
World of difference. 
I learned my lesson, always go with OEM brand parts.


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