1997 855 GLT Cranks but won't start

RunningMike · Post by **RunningMike** » 28 Dec 2014, 09:19

The story so far:
Gone from starting with a very low idle (500 rpm) to not starting at all, but cranking. Previously the car felt weak and had a low idle. Sparks on all five cylinders, fuel pressure in fuel rail but spark plugs are mostly dry while cranking. On building up pressure in the fuel line, then removing the fuel relay and then cranking, the fuel pressure drops, so the injector is opening.
Have checked the MAF sensor, throttle position sensor, idling valve (don't know what this is actually called) and battery. Have tried locking and unlocking the car several times.
When I turn the key in the ignition the dashboard lights up, and while cranking the top line of lights blink slowly. I can't read error codes as I don't have the equipment for this.
It's a manual gear box, European model. Any suggestions welcome!

jamadams · Post by **jamadams** » 28 Dec 2014, 09:56

did you check the fuel pressure with a gauge? a weak fuel pump can cause this.

Post by **rspi** » 28 Dec 2014, 10:33

Find yourself a code reader. If you have spark, it has nothing to do with the alarm. Likely a MAF issue.

RunningMike · Post by **RunningMike** » 28 Dec 2014, 16:48

Checked it with a gauge that measures up to a 1 bar. It hit the seiling, so I can´t be sure it was the 3 bars, but well over 1 bar. I changed the fuel pump a year ago and it sounds like it´s running well.

Ok, a workshop will probably charge me $200 for even plugin a code reader in.

Post by **FLXC90** » 28 Dec 2014, 17:18

Try a squirt of starting fluid (ether) in the vacuum tree then attempt to start, if it starts, it's probably a fuel problem.
Does the engine crank at normal speed? You say the top row of dash lights blink slowly when you crank the motor, is it cranking slow as well?

RunningMike · Post by **RunningMike** » 29 Dec 2014, 03:35

I'll try the starting fluid tomorrow.

The engine cranks at normal speed when the battery is charged. I also tried with jump leads from another car so I had all the battery capacity needed. The top row of dash lights (plus "broken light" light in bottom left corner) blinks at a pace that doesn't seem to be connected with the speed of the cranking motor.

I measured the battery voltage to over 10V while cranking the engine and it sounds like it is turning over fine.

RunningMike · Post by **RunningMike** » 30 Dec 2014, 13:31

Tried the start fluid without success. It didn´t fire up.

I measures cylinder compression and the result with a cold enginge was 6.5, 5.5, 6.5, 7.5 and 7.5 bar (sorry guys for metric units) for cylinder 1 to 5. According to service handbook it shouldn't differ more than 2 bar between cylinders, so I guess that's OK.

Also got a OBD2-reader (ELM 327 with ScanTool software). I could read some sensors while pluged in, but no error code where detected. However, than might not be right since the car indicates an error code with two blinking diods on the ECC panel. I probably got the Motronic 4.4 ECU and that is supposed to be a bit tricky to read since Volvo didn't follow standard OBD2 protocol.

Any ideas?

Post by **misha** » 30 Dec 2014, 13:57

rspi wrote:Find yourself a code reader. If you have spark, it has nothing to do with the alarm. Likely a MAF issue.

Bad maf will not prevent the engine to start.It would start but run badly.

Post by **misha** » 30 Dec 2014, 14:00

RunningMike wrote:Checked it with a gauge that measures up to a 1 bar. It hit the seiling, so I can´t be sure it was the 3 bars, but well over 1 bar....

It MUST be from 35 to 43.5 psi.Around 2.5 to 3 bar min.

If fuel pump is ok i would say that FPR is bad.

RunningMike wrote:...probably got the Motronic 4.4 ECU and that is supposed to be a bit tricky to read since Volvo didn't follow standard OBD2 protocol...

Motronic 4.4 IS fully OBD 2 .

RunningMike wrote:...Sparks on all five cylinders, fuel pressure in fuel rail but spark plugs are mostly dry while cranking.

Injectors are not firing while cranking or there is no fuel in the rail.

RunningMike wrote:On building up pressure in the fuel line, then removing the fuel relay and then cranking, the fuel pressure drops, so the injector is opening....

Not necessarily.It could mean that fuel pressure drops because of the bad FPR.It could be leaking internally.

Post by **erikv11** » 30 Dec 2014, 14:33

Good analysis by misha. It does sound like either the fuel injector relay is bad (gray one up under the fan shroud) or the FPR is shot. I would probably suspect the relay first.