97 850 NA voltage to fuel pump

Post by **januwan** » 05 Apr 2015, 00:26

How do I check voltage to the fuel pump?

I can crank but no start. I have no fuel at the rail, I did the relay test, no difference. Everything was fine yesterday.
I suspect it is fuel pump but would like to confirm it. I had few episodes last year. During the first start in the morning the car would start perfectly but it sounded like it runs on 4 or 3 cylinders only. Once the accelerator was pressed everything was fine. I suspected it was a check valve.

This time it's different I can only crack but no start. Is there anything I should check before I buy the new insert.

Appreciate any guidance

Post by **misha** » 05 Apr 2015, 05:08

Jump fuel pump relay with a paper clip or bring 12v directly to fuel pump just to see if it's working.

Post by **erikv11** » 05 Apr 2015, 07:31

To check voltage at the fuel pump, pull the cover on the pump and look for the connector that runs to the fuel pump. It is at the end of a short harness. When you turn the key to position 2, the relay will send 12 V to the pump for a few seconds, use the black wire and the red wire. Or if you jumper the relay, there should be 12 V at all times when the key is on.

The fuel pump cover is near the passenger rear wheel.

Post by **cn90** » 05 Apr 2015, 08:05

As already mentioned by others, jump 15 and 87 at the fuel relay SOCKET.

If car runs, then relay is bad, if fuel pump does not run (listen for noise at fuel pump) or fuel at shrader valve), then fuel pump likely bad.

For insert, google Bosch 69693, about $100 online.
Search for tricks written by "stephansvolvo", basically removing the black plastic casing first.

Post by **precopster** » 05 Apr 2015, 15:55

Be VERY careful when applying voltage to the circuit if testing with a meter at the fuel pump. There's no fuel to cool the pump so if it fails to turn and gets hot this may be very dangerous near an open fuel source.

Post by **januwan** » 05 Apr 2015, 17:29

Thanks for all the info and warning.
I did shorted 15 and 87 (as mentioned in my first post) but the car did not start. I do not hear anything with key in the position II with the relay or jumper. I wanted to check voltage at the pump to make sure it is the problem but precopster scared me

.

I going to buy the insert. CN90 where can you find it for $100 or less ? The cheapest one, I found, is on Amazon for $137 but it says it will not fit my car (97 NA base). Is there any simply modification one has to do to make it work.

Appreciate any advice

Post by **erikv11** » 05 Apr 2015, 18:10

The Bosch insert is not $100, I don't think it has been that cheap in a few years, it is more like $130 like you said. You might be able to find it for a few bucks cheaper on eBay, but be very very careful it would be easy to end up with a non-Bosch part when shopping there.

Post by **erikv11** » 05 Apr 2015, 18:19

By the way: Mike's (precopster's) warning is a good one, but do understand that the whole point is to check the voltage with the fuel pump unplugged. This of course eliminates any chance it can overheat. You unplug the pump, but leave it in the tank, so there is also no risk of a spark igniting the fuel, and check the voltage at the harness. In other words, done correctly there is zero risk. It is a standard diagnostic test.

Post by **precopster** » 07 Apr 2015, 07:44

There's a guy over here selling Bosch pumps for P80s for around $82 on Aussie eBay. That's about $65USD Precision Parts or words to that effect with a green and red logo.

Perhaps get a price inc postage. His Bosch pumps are genuine Bosch with a slightly different part number.

Yeah didn't mean to scare you off the diagnostic just be aware of what is there. Meters have very high impedance in voltage range so there will be zero sparks.

Post by **cn90** » 07 Apr 2015, 07:54

januwan wrote:...I going to buy the insert. CN90 where can you find it for $100 or less ? The cheapest one, I found, is on Amazon for $137 but it says it will not fit my car (97 NA base). Is there any simply modification one has to do to make it work.

Appreciate any advice

Don't worry about amazon mumbo jumbo...
The Bosch 69693 fits your car, search for posts by "stephansvolvo".

Re price: my bad, I bought it for $80 2 years ago. It is now $130 as others said.
Bite the bullet and get the Bosch, which will easily last another 150K as long as you don't run the gas tank dry (I keep mine above 1/4 all the time).