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99 V6/5spd died, fuel pump?

4K views 16 replies 9 participants last post by  Pauline B5 
#1 ·
My 99 V6/5spd Passat quit running the other day. It has been a pretty good car so far (115k miles), I changed the timing belt and all associated parts about 20k miles ago and it's had no problems until now.

Last week when I was driving home from work at 3:00 am the car seemed like it was hesitating, like it was in a gear too high or something. I thought maybe it was just cold as this was right after I started it. My wife drove it the next day and said it was "hiccuping", I think it was the same thing I noticed. Well, she was headed home and it just cut out completely and quit running right at the end of the driveway. Good timing to break down I guess.

It cranks over but doesn't sound at all like it wants to start. First thing I checked was to see if I could feel/hear the fuel pump running. Nope. I pulled the fuel line off the rail and had my wife turn on the key, nothing comes out of the line. I don't know if it should or not though.

I also have a CEL. I don't have a VAG/COM so no idea what's going on there. Any insight anyone can give me? It seems like fuel pump initially but I don't like just throwing parts at a vehicle to fix it.

Tom
 
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#4 ·
Update: Voltage at the fuel pump and at the fuel pump fuse is 4.8 volts. This doesn't seem right to me! I don't have a Bently manual but am using a Haynes, it says there is a fuel pump relay under the column but I don't know which relay it is. Any help?

Tom
 
#10 ·
This is the relay panel under the steering wheel? It is marked 384 on my car. I removed the relay and I am still getting voltage to the fuel pump and the fuel pump fuse (#28), about 4 volts with the key on. I removed all of the relays one at a time and still get voltage to the pump when the key is on.

I read voltage at relay #4 on the panel, it's weird.....the voltage is all over the place, it will read 12v all the way down to 5 or 6. Then it goes back up and back down. Anyone???
 
#7 ·
Update: I charged the battery and pulled the cover under the steering wheel to feel the relay when I turned the key on. I can feel it clicking but am still getting low voltage and no sign of starting. I installed the battery from my 01 Passat and have the same voltage at the fuse and pump. I'll be swapping fuel pump relays tonight hopefully for more troubleshooting.

Can a VAG/COM read codes when the engine is not running? Anyone in San Diego have one available?
 
#9 ·
It isn't the original battery, but it's been in there since I owned the car (3+ years). As I mentioned in my post, I charged it and swapped it with my other Passat battery. I also have used jumper cables from my truck while trying to start the car. All of the above still leads to low voltage at the fuel pump and the fuel pump fuse.
 
#11 ·
I'm glad we have two VW's so at least one can run at a time.

I've been working strange hours so I don't have time to troubleshoot this thing as much as I'd like. Anyway, I made some jumper wires from the accessory power plug in the trunk to the fuel pump and I can hear/feel it running. The car still doesn't start but now I know the pump isn't bad.

What would cause the weird power fluctuations at the relay?
Why am I only getting 4.5 volts to the pump?
Is there something in the system that reduces voltage to the pump during operation and it's maybe messed up?

Help!
 
#14 ·
lo volts to fuel pump

I picked up the thread from tntmo regarding 4.8 volts to the fuel pump:whistle. I am a new member and I'm having the same problem on a '99 Passat 2.8L. About 4 volts on mine. Was anyone able to resolve this problem? Mine also seems to be getting "feed back" voltage in the system. I am getting 4 volts on the ground side of fuse #29, even with the fuse removed. What the?!!! Any suggestions will be appreciated.
 
#17 ·
I picked up the thread from tntmo regarding 4.8 volts to the fuel pump:whistle. I am a new member and I'm having the same problem on a '99 Passat 2.8L. About 4 volts on mine. Was anyone able to resolve this problem? Mine also seems to be getting "feed back" voltage in the system. I am getting 4 volts on the ground side of fuse #29, even with the fuse removed. What the?!!! Any suggestions will be appreciated.
What is your engine code ?

Fuses generally and fuse 29 don't have a ground side; and fuse 29 doesn't feed the fuel pump. The voltage at fuse 29 is probably normal. If there is about 4 volts between FP plus and a good ground (with FP connected), the FP relay is the first thing to check.
 
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