my 97 960 sw didn't throw a code .still won't start

diyer97 · Post by **diyer97** » 28 Dec 2010, 07:24

Just used a newly bought Actron Pocket Scan Plus CP 9950 on my dead volvo but it didn't pull any codes. Also recalled when it experienced the first power cut out at a stop light and didn't start in a supermarket on second incident I brought her to a shop to check it out..the mechanic said NO CODES....
Any ideas people?
Thanks,
Ken,

It still won't start but I think I narrowed down the problem to fuel delivery problem ....there are no fuel at the fuel rail
pressure release valve...I'm going to test the in-tank fuel pump./and other fuel pump...I know the fuel pump relay is good
because i used a different,good relay still no pumping ...
but why the car didn't throw any codes..

Kmaniac in California USA · Post by **Kmaniac in California USA** » 28 Dec 2010, 08:31

diyer97 wrote:It still won't start but I think I narrowed down the problem to fuel delivery problem ....there are no fuel at the fuel rail pressure release valve...I'm going to test the in-tank fuel pump./and other fuel pump...I know the fuel pump relay is good because i used a different,good relay still no pumping ...

Sounds like you have found your problem.

diyer97 wrote:Just used a newly bought Actron Pocket Scan Plus CP 9950 on my dead volvo but it didn't pull any codes. Also recalled when it experienced the first power cut out at a stop light and didn't start in a supermarket on second incident I brought her to a shop to check it out..the mechanic said NO CODES....Any ideas people?

Codes are generated by the engine management computer. The computer monitors the operation of numerous electronic and electrical devices that effect fuel metering and ignition timing. When these electrical or electronic devices malfunction in a way detectable by the computer, it generate and stores a code. The fuel pump, however, is not controlled or monitored by the computer. So if your fuel pump dies, you are not going to get a code.

diyer97 · Post by **diyer97** » 31 Dec 2010, 17:25

The scanner gave me no codes but followings are some phrases from the scanner:
Misfire monitor ready, fuel system ready, comprehen comp ready, MIL off,O2 sensor not ready,exhaust gas rec not ready,
Htd 02 sensor not ready,second air sys not ready, evaporative sys not ready,catalyst not ready,Htd catalyst not ready....Will
someone shed some lights on these for me please?
A. the right yellow relay is fuel system relay. is this a master fuel control relay?
B. How do I test the in-tank fuel pump (also called sending unit right?)...this is what i did: I measure the red wire
after i turned the key to pos II but not cranking and the reading is like .05v ...,the other wire like light blue color not
registered anything... Do I need to crank in order to read them correctly? And if they don't register anything (no reading)
can I say that the faults are with the relays or wiring but not the sending unit (the pump itself) ?
Thanks a lot
Ken

Post by **precopster** » 31 Dec 2010, 18:34

Don't bother with the in-tank pump. My Volvo 960 starts just fine with half tank of gas and in-tank fuse pulled.

In your previous post didn't you say you already swapped the relay?

The main pump will prevent starting.

diyer97 · Post by **diyer97** » 31 Dec 2010, 18:52

yes, I did use a different relay. and the car still won't start..
Mike, can you explain why the main pump will prevent starting?

Post by **precopster** » 31 Dec 2010, 19:10

Its function is to provide 80-90% of the fuel pressure. My own genuine pump failed at 120K miles and I had similar symptoms.

If you can provide power to the pump by bypassing the relay and shorting the live +12V at the relay to the pump positive terminal (also at the relay) this as about as definitive a test as you can perform, short of crawling under the car and testing for +12V at the pump while you have this short in place.

In normal operation the pump's power is cut when the ECU doesn't receive cam sensor or crank sensor input, to prevent fuel spillage in the case of an accident.

diyer97 · Post by **diyer97** » 31 Dec 2010, 19:34

Thank you, Mike!
Will do the "bypassing the relay" tomorrow, the New Year Day, and let you know.
where is the main fuel pump that you mentioned..i supposed it's under the car but its location? If shorting the fuel relay
and the pump works then I still have to replace the pump anyway, right? ...Also my 97 volvo 960 sw has 139K miles on it..
like you said what happened to yours at 120kmiles..then my pump's time has come.
HAPPY NEW YEAR!!! to you

Post by **precopster** » 31 Dec 2010, 22:05

In right hand drive models, it's under the passenger seat. It may be under the drivers seat in the U.S. It's located behind a cage with four bolts going through four rubber grommets. The fuel filter is close by. It may pay to replace the fuel filter while you're there and have things apart.

The test about bypassing the relay is only to be totally be sure that +12V power to it is present. If you're not convinced and fear that the wiring to your pump is suspect just run 12V directly to the pump and see if it spins.

Best Wishes for the New Year & let us all know how you go.