91 740 doesn't start please help

neworleans · Post by **neworleans** » 11 Oct 2011, 18:41

Hello,

I have a 91 740 that cranks but doesn't start.
I replaced the fuel pump in the tank and checked the relay. Relay is fine.
The car has been sitting for about a year so after replacing the fuel pump, i pumped out the old fuel and put about 4 gallons of fresh gas. I didn't get a chance to replace the fuel filter. None of this worked...

Any ideas what could be causing the problem?

Thanks...

russellengineering · Post by **russellengineering** » 11 Oct 2011, 21:51

940 starting problems.pdf: (264.09 KiB) Downloaded 215 times

740 ignition checks.pdf: (1.23 MiB) Downloaded 214 times

Hi NewOrleons,

Here are my quick thoughts as a decent shade tree mechanic, I did not say expert though!

- Does the main fuel pump energize when you first turn the key, is the tank pump energizing when you turn the key?
- Have you read the codes from the OBD? I think it has it for that year.
- Is fuel getting to the cylinders? If not you could have a blocked fuel filter, bad main pump, or a broken fuel pressure regulator.
- Do the spark plugs spark when starting?

Here are two files that BillofDurham posted before that I saved. The 740 file is right on for ignition issues. The 940 file covers the no-start when cold analysis real well and would be a good first start.

Good luck,

Dave

neworleans · Post by **neworleans** » 11 Oct 2011, 23:10

Dave thank you for your response.

Here is the history of the car.
I bought the car about a month ago in non-running condition. The owner sprayed some started to the ETM and it ran for a couple minutes then died. I offered him 500 bucks and got it. I know a volvo mechanic whom i thought would have a chance to come fix it but he hasn't yet so I tried to do things by myself while waiting for him.

I am not so good at it but can change basic things like oil, tranny fluid, brakes filters etc.
I found a website that explained how to replace the fuel pump in the tank so I did but didn't work.

What I am planning to do is to replace the fuel filter this coming weekend and when do that I am planning to crank the car after taking off the fuel filter and see if there is any fuel coming from the line...

Would that be a good way to check if the pumps are working?
I think I need to figure this out first to get to the other steps like checking the spark plugs and etc...

Post by **billofdurham** » 12 Oct 2011, 12:43

For an engine to run you need two things - fuel and fire. As the previous owner sprayed starter fluid into the engine and it ran I would say you had fire but no fuel.

Changing the filter may not be the solution. Although it won't hurt in the long run I do not believe in just throwing parts at a car without trying to justify it.

In this case you have replaced the in-tank pump but did you find out if the old one was not working? The relay is fine so, in theory, the pumps should work. Can you hear them when you switch on the ignition? The main pump is easy to hear as you are sitting on top of it. The in-tank pump is harder to hear but you can remove the fuel cap and listen at the fuel filler whilst someone switches on the ignition. As an alternative to this you can remove the access panel in the luggage area and listen for/feel the in-tank pump.

A quick way to check for fuel reaching the engine is to crank it and then remove one of the spark plugs. If it is wet you have fuel flow.

Is the radio suppression relay in the engine compartment working? If not, no fuel will be pushed through to the injectors.

What I am planning to do is to replace the fuel filter this coming weekend and when do that I am planning to crank the car after taking off the fuel filter and see if there is any fuel coming from the line...

That would only check the in-tank pump as the filter is between that and the main pump. You wouldn't need to crank the engine merely switch on the ignition as the pumps are electric. However, this can be a dangerous way to check for fuel flow as you would be pumping an inflammable liquid into the open air.

Bill.

neworleans · Post by **neworleans** » 15 Oct 2011, 00:46

Bill, thank you for your message.

Here is the update, my friend who is a volvo mec came over today and checked everything. Electrically everything works.
The conclusion we came up with is that the fuel pump I installed is not pumping the fuel all the way to the engine. He thinks that the fuel pump I've installed is a pre-feed pump that pumps the fuel to the main fuel pump which my car doesn't have.
This car has only one pump and it is in the tank.

I've attached the picture, the fuel pump in this pic is the original fuel pump that came out (size wise it is a lot bigger than what I installed) , and the fuel pump I installed came in this box which has the 3507436 part number (fcpgroton).

There is 2 numbers on this original fuel pump; 3531165 and 6443306, I searched for both numbers at fcpgroton but didn't give me any results. So at this point which fuel pump I need to get?

Post by **billofdurham** » 15 Oct 2011, 13:14

Your car has the Regina system and the pump number is 3507736. FCPGroton do have it listed here.

Bill.

Post by **fazool** » 15 Oct 2011, 14:44

Why did you replace fuel pump parts? Was there no fuel?

If you have fuel it is like;ly a spark/ignition problem.

Crank the car for a while then smell the exhasut pipe. If fuel is flowing it will smell of unburned gas. Also try shooting some starter fluid in the air intake. If it STILL does nothing then it may be ignition related. Check your spark plugs for spark (very simple).

On my 86 740 the same thing happened and it was the ballast resistor - very easy replacement.

neworleans · Post by **neworleans** » 15 Oct 2011, 14:51

Bil,

Should I get this instead of the one at FCP? (FCP is not accepting the return for fuel pump I got because I already used it)

http://www.eeuroparts.com/Main/PartDeta ... id=3507736

Post by **billofdurham** » 15 Oct 2011, 16:32

No reason why you shouldn't. It is cheaper and just as good. You may consider getting the filter screen at the same time if yours is suspect.

Bill.