91 940se no start Topic is solved

rickbrk · Post by **rickbrk** » 18 Jan 2021, 21:36

1991 940 se all original. Has been running fine drove home from work, went out later and it won't start. I have it narrowed down to a fuel issue. Spray ether in it, it will start. Tank has fuel, I can hear the fuel pump running and the relay clicking. without ether it will fire for just a second like it wants to start but won't. Where should I look, weak pump maybe? Any help would be appreciated..

Post by **RickHaleParker** » 19 Jan 2021, 01:39

Try turning the key to POS II, wait 20 seconds then crank to start.
Is there fuel pressure at the fuel rail?
Clogged fuel filter?

rickbrk · Post by **rickbrk** » 19 Jan 2021, 05:32

I have tried waiting with key on but still no start. After work today I'll test the fuel pressure and post the findings.

Post by **RickHaleParker** » 20 Jan 2021, 13:38

rickbrk wrote: ↑19 Jan 2021, 05:32 I'll test the fuel pressure and post the findings.

That will help narrow it down to fuel delivery or fuel injection.

Hold on: You said it tries to start without either. I take you mean it hits but will not start. If so that indicates the cylinders are getting fuel. This is symptoms of a jumped timing belt. The timing belt can jump just enough to cause a no start condition without interference. A weak Tensioner is one thing that can cause this condition.

It could also be a incorrect Air/Fuel ratio due to unmetered air. Look for air leaks on the intake side and exhaust side.

rickbrk · Post by **rickbrk** » 20 Jan 2021, 13:58

I think I have it narrowed down. I have tested the injector and fuel pump relay and even joe's the fuel pump relay but I'm getting no power to the main pump. The in tank pump is working just o power to main pump.

Post by **volvolugnut** » 20 Jan 2021, 14:06

Can you connect temporary power to the main pump and try to start? If that works, then your main pump is fine and the electric supply/ fuel relay is at fault.

volvolugnut

rickbrk · Post by **rickbrk** » 20 Jan 2021, 14:31

I'll try to power the main pump. I did take the relay out and jump 30, 87\1, and 87\2 and all that did was power the in tank pump.

rickbrk · Post by **rickbrk** » 20 Jan 2021, 15:34

Ok, I put direct power to the main pump and you can barley hear or feel it run, I was expecting a good hum coming from it. It tried a little harder to start ran for a split second and stalled. Does the pump get constant power when the key is turned to the run position? Last night when I put the key to ll and a volt meter on the pump terminals I got 0 volts. Then I pulled the relay and jumped the plug and still no voltage. But since it seems to be very week when the pump is ran off the battery maybe it's time for a new pump and filter.?

Post by **volvolugnut** » 20 Jan 2021, 16:07

Sounds to me like:

The fuel filter is badly clogged. You could remove and drain backwards to check for sludge or just replace if it is old.

The main fuel pump is dragging/ worn out. I think these still had brushes and gears to wear. If the car was not run for a long time, it could have rust and junk jamming the works.

volvolugnut

rickbrk · Post by **rickbrk** » 28 Jan 2021, 15:59

I don't even want to admit what the problem was but po said it was changed recently. It was a very clogged fuel filter.

New filter and pump while I was add it. Started right up. Thanks to everyone for the help.