P80 Fuel Pump Relay Repair master thread 9434138 9434225 Topic is solved

Post by **Ozark Lee** » 17 Dec 2012, 21:18

The fuel pump relay turns on the fuel pump and nothing else. Replacing or repairing the relay will not correct a "no spark" condition.

You can try replacing the ECU but they normally aren't prone to failure. Fire up a new thread with all of the background on your car and we can try to help you get it running again.

...Lee

tappolon · Post by **tappolon** » 22 Dec 2012, 12:30

OK, yep. ECU didn't make a difference (and the one I got which is suppose to be for this engine didn't even match what was already in there), but bypassing the ignition switch-to-fuse box-to-ignition coil circuitry got it started and everything working. So yeah, the fuel pump relay had nothing to do with that condition. Thanks Lee. And I will start a new thread to get some input on what could be causing a short in that circuit. T

Post by **jtp** » 10 Jan 2013, 12:29

I've never soldered on a circuit board before, just car wires. I really don't want to fry this thing.

I have a Weller 100/140w gun and a little Weller butane tool with a solder tip I can throw on there. 18 gauge wire takes forever to solder with the butane iron. If this board takes as long I can see myself trying with the gun. Would using the gun be a bad idea?

Thanks for all you help Lee!!!!!

Post by **jreed** » 11 Jan 2013, 05:38

I recently bought a small 30W pencil tip soldering iron from HF for about $5. I'd recommend it for the type of circuit board repair you are looking at. I have used it three or four times over the past few months and it works well.

Post by **cn90** » 11 Jan 2013, 07:33

I just want to add to this excellent DIY a quick side note...

Go to autoparts store and buy stuff to make a jumper wire with Fuse (I think 15A is good enough).
Buy the "spade connectors" and crimp to both ends of the jumper wire and keep this thingy in your glove box just in case.
This whole thing will cost you $3.00.

If you get stuck in the middle of nowhere from a bad fuel relay, jump the terminals 15 and 87 as shown below to get home.
Even with the jumper wire connected like this, once you remove the key, power to #15 is cut off, so the fuel pump will stop running once the key is removed from the ignition. I have tried and verified that this is true...

bronson75 · Post by **bronson75** » 13 Jan 2013, 11:20

cn90 wrote:I just want to add to this excellent DIY a quick side note...

Go to autoparts store and buy stuff to make a jumper wire with Fuse (I think 15A is good enough).
Buy the "spade connectors" and crimp to both ends of the jumper wire and keep this thingy in your glove box just in case.
This whole thing will cost you $3.00.

If you get stuck in the middle of nowhere from a bad fuel relay, jump the terminals 15 and 87 as shown below to get home.
Even with the jumper wire connected like this, once you remove the key, power to #15 is cut off, so the fuel pump will stop running once the key is removed from the ignition. I have tried and verified that this is true...

Coming from a world of Mk1 water-cooled VWs, I know this 'mod' very well.
I never drive my Scirocco without a fuel pump jumper in the glovebox!

MaxIcon · Post by **MaxIcon** » 23 Jul 2013, 22:42

Very helpful thread - I hope this clears up my intermittent stalls!

For those with the 89 8797 000 relay, the question came up about polarity on the 100uF 16V cap. Mine has a black "-" on the top, next to the 100uF marking, that is on the negative side. I verified that the 100uF and 22uF caps are connected to the same trace on the negative side.

von50 · Post by **von50** » 26 Sep 2013, 17:56

I have an 89 760 turbo and I had my mechanic replace the intank fuel pump twice in 6 months. I bought a new striebel fuel pump relay about a year and a half ago and it has worked fine since, but I am having the same problem of the car failing to start when it gets hot again after an hour of driving , then half an hour later starting right up.
I used to work in a motherboard factory and heat would change the value of the resistance and make them fail our testers, also capacitors have an oily fluid inside that can leak and then lose the ability to hold charge when they get older. I think you need a cap tester, I have heard that a multimeter doesn't work. I am going to pull the relay (mine is on the passenger side kick panel) and see if swapping caps fixes it, that would be cheaper than buying another tool. Thanks
(There is also a 40 amp brake relay by the strut tower on the driver side under the hood that I replaced and it failed within 6 months. My mechanic found that one and when he replaced it the car ran great for the next year and my gauges started working properly again.) I suspect that high heat environment is tough on the electronics.

von50 · Post by **von50** » 26 Sep 2013, 18:19

on my lighting relay (the big dual relay that lists for 150 US) the magnetic switches had developed cracks in the solder joints. I was able to resolder those and it continued to work for more than another year!

Post by **jreed** » 26 Sep 2013, 19:03

I recently swapped out the capacitors on my emergency blinker switch and my ECC unit, as a form of preventative maintenance. I posted short write-ups here:
On the emergency blinker:
https://www.matthewsvolvosite.com/forums ... =1&t=57932
And on the ECC circuit board:
https://www.matthewsvolvosite.com/forums ... =1&t=58028

P80 Fuel Pump Relay Repair master thread 9434138 9434225 Topic is solved

Re: Fuel Pump Relay Repair