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turb00le

960 cranking, no start

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Hi, i'll give it a shot "overseas" in the hope that someone got some better ideas before i set the car on fire...

 

So, I got a 1994 965 that seems to have some electrical issues, not the first time.

 

It all started when I replaced the auto transmission with a M90. At that stage the car had M1.8, the PNP switch was just bypassed to make the startermotor turn.

 A few weeks later, an exhaust valve were burnt. So, I rebuilt a head and replaced it.

Then it refused starting, or more like a bingo; It might start it might not, might require almost emptying the battery before starting. When it suddenly started it ran like a charm.

This continued for a while untill i got pissed and simply threw the M1.8 in the bins and replaced with a M4.4 out of a S90 manual, finally everything was correct With no jumpers etc.

I finally got it to run correctly half a year ago until now when it turned out just the same... Absolutely all sensors, coils etc were swapped from the S90.

It cranks but wont start. Sometimes it starts just before the battery is flat, currently i have emptyed two batteries with no sign of life.

What I have done so far:

-Checked DTCs, no codes except for the fan powerstage.

-Replaced the fuel pump With a walbro gs341.

-Swapped some relays for ignition and fuel pump.

-Replaced the spark plugs a week ago.

 

Any ideas???

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I'm not very good at the 960, but on an 850, we had the same problem and it was the gray relay on the fan shroud (the ECU relay). When we were cranking, the check engine light was turning on and off randomly and the car would, or would not start.

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25 minutes ago, Midnight Caller said:

I'm not very good at the 960, but on an 850, we had the same problem and it was the gray relay on the fan shroud (the ECU relay). When we were cranking, the check engine light was turning on and off randomly and the car would, or would not start.

That's the fuel pump/main relay right?

I just tried to "hardwire" all the relays (fuelpump, ignition and main relay) with no luck...

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Yes, on the 850 that's the main ECU relay... But on my S70 there's no such relay anymore (M4.4).

Did you try searching for some wiring diagrams ? (www.volvowiringdiagrams.com) and see if all the wires to the ECU are ok ?

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I have the oem diagrams for my car.

I have not started measuring sensor values at the ecu connector yet.

Any way to check if the camsync sensor is working properly? For the crank sensor volvo specifies that is should give som uV AC signal while cranking, about 500 or something.

Probably similar to the S70, my car is M4.4 too (used to be M1.8)

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Just tried to replace the camshaft sensor, will do the cranksensor in an hour or two...

Will also flash stock .bin to the ecu.

If not, cheap 960 for sale in norway :-)

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Do you have a diagnostic tool called a 'noid' light.  It clips to the injector wiring and blinks every time the ECU tells the injectors to open.  It would help to know if you have spark and fuel.  I am wondering if you have a loose ground in the engine compartment.  These ECU's are very sensitive to good grounds and if even one is not attached well it will act sporadic, turning off fuel and spark.

 

DEWFPO

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I seem to remember people having similar problems years ago. It had something to do with the ignition modules ( IIRC on the left motor mount area) missing a ground after intake was removed.

Might want to double check that area.

Rod

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I got a DTC that might be of interest:

128;Temperature: Elec. equipment box ;> 100 °C

Rkam suggested that it might be some short circuit?

Anyone have a clue what might throw this code?

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Replaced the ECU a couple of days ago. It started right away...

Since that ecu refuses to fire all six sylinders I swapped back to the one I was running (new from Bosch 6 months ago).

Gave it a try and it started right away...

Did a little cleanup in the wiringharness inside the car, taped it and routed it neatly. Car started and everything looked allright.

Moved the car into the driveway, morning after: Dead.

Swapped ECU again; Dead.

Did some wiggle wiggle in the wiring; Dead.

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When it won't start, pull a spark plug, ground the plug, and see if it is sparking? If it is, pull an injector harness plug and see if that's getting a signal.

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Did some testing with a loose coil and plug on the head, no spark.

I'm suspecting that this has to do with the ECU and ignition grounding.. Will rewire all ground connections when I get home from work.

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I believe both the cam and crank position sensors not being plugged in /failed will result in no spark with M4.4. I know from personal experience that an unplugged ECT (coolant sensor) will prevent starting, but I'm not sure if that is also a spark cut. 

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Hmm... I will try to replace both sensors today.

Finished up the grounding yesterday, nothing changed.

It smells like carb and distributor ignition is on its way....

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Done more testing on the car, the more i check the less i understand why the piece of s**t won't start.

Pulled the wiring harness out of the car and visually inspected it for any damages.

Checked pretty much every connection and wire.

When I connect the headphone port of my laptop to the crank sensor connector and uses crankwheelpulser to generate the signal I get spark.

When I plug in the sensor, nothing.

Sometimes, maybe once a battery (fully charged to empty), it will start, but dead if i stop it and retry.

The sensor were replaced yesterday, tried with stock  gap and reduced gap.

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