OK, here are some checks. Car runs fine right now hasn't shut off since last Wednesday.

Check engine light is not on.
Cooling fan comes on when AC is turned on, OK.
Car is a 1996 850 R (turbo)

1) Fuel pressure = 37 PSI @ idle
2) No gas in the oil
3) Fuel injectors are not leaking
4) All ignition wires ans vacuum lines appear to have good connections
5) Spark plugs looknormal. Normalburning. Approx 25K miles on them.
6)How do you check the ignition coil and curcuit ?
7) Where is the engine speed sensor and how do yoy check it?
8) How do you check the thottle switch?
9) Idle valve ohms out at 9-14 ohms, OK.

I checked fuel pump relay. Info says,

"Remove the fuel pump relay. Connect jumper wire between fuel pump relay terminals no.1 and no. 3.
Turn ignition on. If fuel fuel pump does not start, go to next step. If fuel pump starts, replace fuel pump relay."

I assume they mean if the engine is dead but the fuel pump did start when I did this. In my opinion the fuel pumpwas a weak sound. I had to open the trunk lid and the spare tire lid to hear it.

Any other thoughts are welcomed.

I will try to idle it until it shuts off today and perform more checks.

Thanks, Guy

 

Hello Guy,

As I just came back from a long day's work, my eyes are quitting. I'll try to reply to your questions tomorrow night.

Sorry for being lazy[8D].


JPN

 

I let the car idle for nearly one hour yesterday and tried to drive away and it stalled. So I simulated the problem. I was able to check the coil fire (good) and one spark plug wire fire (good) before it would restart after 5 minutes so I guess it is fuel related . Agree?

 

Hi Guy,

Yes, I agree that it is very likely that the fuel pump/relay is on its way to failing.

According the factory manual, the correct pressure is 43.5 PSI, at 12V, 68F, with engine of and fuel pump relay bypassed (?).

Apparently, the engine is struggling to keep the correct idle speed, especially when there's additional loads (A/C, transmission engaged, etc...). After correcting the problem, I would give the car a good tune-up, including cleaning of EGR valve, throttle body, replacement of air & fuelfilters, ignition components, a large bottle of Techron fuel system cleaner, clean or replace all PCV components, etc...

As to the questions you wondered, please see attached pics. Testing the speed sensor on the engine requires Volvo testing equipment. Note, that there is another engine speed sensor located on the transmission. If the ECU could tell us codes, it would be easier to resolve the problem, but without codes, fixing the problem is a bit more difficult.

I hope this helps in getting rid of the problem.


JPN

 

What about fuel filter ? That could contibute to the problem too, correct ? Is there a way to rebuild the fuel pump or do you purchase as one unit ?


Thanks, Guy

 

I apologize that I haven't read through this thread but.....

Fuel filter should be performed as regular maintenance. About every 40,000 miles, but it doesn't hurt to do it earlier because they can get dirty pretty easily. Plus, they're cheap. 20 dollars or so.

For the pump, you're better off buying an insert. The install is very easy, and you can find them on Ebay or at FCP or eEuroParts. Just be aware that there are 190lph (stock) and 255lph pumps. The 255 lph have been known to run louder, but I have never expierienced this problem.

 

I just simulated the stall for about 5 minutes again. During that time I tried the fuel pump relay out of my 98' S70(is the same part number) and that did not start the car. After this I tried running it for about 30 minutes but could not get it to repeat.

So you think fuel filter change then maybe a fuel pump insert might be the best bet.

Where is the fuel filter located ? and the fuel pump?

Thanks, Guy

 

^I haven't read through the entire thread, but if you think you've narrrowed the problem down to these two issues, then I would recommend changing both. I will read this thread later tonight.

Fuel filter
http://volvospeed.com/Repair/fuelfilter.php
And the pump is located in the trunk. If you lift up the trunk matting, you'll see two metal covers. The larger one is where the pump is housed.

 

Hello Guy,

Although replacing the fuel filter will benefit, I highly doubt that it is causing the problem you're having, though I could still be wrong. I replace mine at every 3 years/30,000 miles.

When you do the filter, be sure to relieve the system pressure. Have an empty glass jar, catch any spilled fuel and pour it back into the fuel tank rather than pollute the environment. If you have difficulty removing the quick-disconnects, try twisting the hoses as you pull.

Letus know what your plans are.


JPN

 

I now really doubt it is the fuel pump causing this now. I cleaned the throttle bodyandhoses and have put a bottle of "Seafoam" in thefuel tank to clean the carbon, etc.. out of the system. Iplan to clean the EGR valve(tell me where it is). I haven't gotten the carto repeat the stall again but I plan to change the fuel filter, distributer cap, and rotor button. I really don't know what else to do but Iquestion the throttle body switch because I don't hear a distinct "click" when the thottle body switch is engaged. Also what a bout the MAF ? I read other threads that had a MAF sensor causing these problems. Is there any way I can test the MAF ?

Please advise.

Thanks