Son's 1995 850 is a no-starter. No warning. Car was fine, running errands, after one of the stops it won't start.

Starter runs but engine doesn't even try to catch. Battery seems good - cranking sounds strong (over the phone) and he also tried jumping.

Found some notes related to no-start condition. Seems that likely causes are:
- crank position sensor (will set a code?)
- fuel pump relay (no code)
- MAF sensor (not sure, but maybe no code)

Because he had been driving the car I do not suspect lawn mower syndrome. However, if all else fails can try cranking with gas pedal floored after above if any chance that'll work.

Think I have one opportunity to diagnose remotely before he has to have it towed. Plan is:

1. Check codes (I know how to do that)
2. If no code them jumper the fuel pump and try to start
3. If no success then disconnect the MAF and see if it will start in limp-home mode

Anything else I can have him try? He is working in a parking lot and does not have a lot of tools.

Thanks for your help,

Terry

Could it be the fuel pump or a related issue? Here is my recent (likely related) experience with our 1995 850 turbo sedan (200+k miles and 17.5 years in our hands). I drove around for a few errands and everything was fine. I parked our car in our garage for ~ 30 minutes; then I wanted to drive somewhere else. The car would not start. There were no codes and everything else seemed fine. Based on past readings/experience, I suspected the fuel pump relay. I did get a new one, put it in, but the problem remained the same. After I checked whatever I could (my knowledge is rather limited however), I decided to have our car towed to my indy mechanic. I let my mechanic know that my car is coming in tow and I called AAA (as a AAA member). The first AAA truck driver that came checked the battery (which is practically new) and electrical system and everything was fine as I suspected too. That AAA driver called in another AAA tow-truck this time to tow my car to my mechanic's store. (Here it is where it gets interesting and ...funny!) The tow truck driver asked me what are the symptoms and after I explained them to him, I also added that it may be the fuel pump since it is still the original one, although I did not really know what the problem was.

NEXT, he went to the back of our car and he pushed it up and down a bit vigorously (I am almost laughing at this time since this move seemed to be unrelated to the towing). After that, he got underneath the back of the car and he banged the gas tank with his hands a few times. Then he came back up again. I barely kept my laughter when I asked him what was he doing. His response was: "sometimes, a small piece of dirt may temporarily clog the fuel pump". Sure enough, my car started right after that, and there was no need for towing! 300 miles later, it is still doing great! I had never heard of such a 'fix'. My mechanic stated that this may/will happen again, but it is unknown when.

If this experience turns out to be helpful to you, please let us know. Good luck!

First, check the gas gauge!

If he has a folding torx tool, remove the fuel pump relay #103 and jumper 15/87 with a paper clip.

Do NOT unplug/plug the MAF with the key in position II, the car must be off.

Crank position sensor will be tough with out tools...

Klaus
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Volvos should be saved from the junk yards, not donated.

Thanks Klaus,good info. Long story short, tried to read codes using Haynes manual instructions and got nothing from A6. Got tired of this, so tried to start the car and vrooom! it worked.

Got home, looked up better instructions for code reading and found that A6 is not always the right one.

Got these codes:

A1:
2-2-3 (Throttle position signal too low?)

A2:
1-1-1 (all good)

A3: 1-4-2

A6: Flickers (I guess this one does not do anything on this car)

A7:
1-2-2 (Temp. sensor interval too long?)

None of these should cause a no-start. No cam position sensor error, so that common failure point is apparently ok. Hard to diagnose further since the car is working now. I'm thinking of buying a fuel pump relay as these seem to be common failure points. Install new one, keep old (possibly ok) one in the car as a backup). Keep going and hope for the best. If it dies will try the last step, unplugging the MAF and (hopefully) limping home.

Thanks for your help,

Clear the codes if you can, some of them can be old. I usually check and clear when I change the oil.

The A-1 code should go away, if not, clean the switch contacts.
A3: 1-4-2 is a faulty brake pedal switch. Of course, if the brake pedal switch is really broken, then you wouldn't be able to shift out of park.

A-7 = ignore for now, that is your instrument panel and probably left over code.

The A-6 is your ignition!! Was the car door closed when you read the codes? Sometimes an open door will trigger a flicker. This is the one you need to get a reading on.

Klaus


--
Volvos should be saved from the junk yards, not donated.

I thought A6 was the right one too, that is what Haynes said to use. Tried several times to get a reading from it with no luck. I told him to shut the doors based on advice in one of your previous posts. I assume he did, we mentioned it more than once.

I found a site saying motronic computer does not use A6 so I figured I must have that brand. Got me. It is a 1995 GLT (not turbo).

We will try again with A6. He said it lights up when plugged into A6 but I think the light does not go out when he pushes the button. Will be sure everything is closed when we try tomorrow.

Thanks again,

Terry

If that doesn't work, have your son drive to any local autoparts store, they usually give out scanners that you can use in the parking lot. The port is under the 'coin' tray.

Lots of luck,

Klaus
--
Volvos should be saved from the junk yards, not donated.

Update on intermittent no-start and cannot read codes from A6:

Car would not start again so we were able to test jumpering the fuel pump relay. Car started right up. Seems like relay is the problem.

His relay is yellow and has 5 pins (87A and extra 87B in the middle). Most replacements and the one on my '97 have 4 pins (we are not in the same place or I would just plug the relay from my car into his to test it).

Have read discussion on 4 vs. 5 pins and yellow/red/green relays: it seems the bottom line is the 4 pin works in all 850s and the middle is a extra, unnecessary ground. Hope so.

I already ordered a 4-pin on ebay yesterday, before we diagnosed. Figured it was good to have. So help is on the way.

Options:
- wait for relay to arrive in mail and hope 4 pin works
- Fix the existing relay: replace capacitors, check solder joints.
- BIG QUESTION: if he drives the car and gets stranded, is it possible/safe to drive with the relay jumpered?

Still cannot read codes from A6. Acts just like a bad wire: flickering sometimes, light on all the time sometimes. Son will drive to auto parts store to use code reader if he is thinks he can get back.

If the relay is the problem, there will not be a code for that, or any other fuel delivery problem.

Can you drive with the relay jumpered? Yes. I don't suggest you do that: the jump wire gets very HOT. The relay has a rollover off switch in case of accident.

Will the 4 pin work in a 5 pin slot? Yes, but obviously not the reverse.

Soldering the connections is usually the solution, the diodes seldom fail.

We are glad to hear that it is a simple fix.

Klaus
--
Volvos should be saved from the junk yards, not donated.