Hi,

I have a 1986 Volvo 240DL and after having the front and rear fuel pumps changed the car now struggles to start when it's been sitting for more than an hour or so.

When I turn the key into the start position, and just hold it there, it's trying to turn over but takes a good 10 seconds or so of struggling before it finally starts. If the car has been used and is warm it starts right up as it should.

My mechanic seems to think the rear fuel pump needs to prime itself before being started and that I should turn the key until the electric goes on and leave it for a few seconds before starting the car. This doesn't seem right to me because the car never had to be started like this before and you shouldn't have to do this just to start your car.

Anyone deal with this themselves after changing the fuel pumps?

Thanks!

 

Poor hot start can be caused by low or no residual pressure. When cold more fuel is injected so the problem is masked.

Check the residual pressure in the fuel rail. That is controlled by the check valve in the main fuel pump and the fuel pressure regulator on the other end.

The "turn key a few times" before trying to start the car - is priming the fuel system, and is a way to test for lack of rest or residual pressure. (due to leakage somewhere - fuel pump check valve, pressure regulator, or rarely an injector.

 

Thanks for the info. I'm gonna run this by my mechanic and see if he was already aware of it. I'll check back once I find out.

 

a quick test for the FPR is to pop the vacuum line off when the fuel rail has pressure (say right after the pumps have run). If fuel leaks out, it means the FPR is bad (ie torn diaphram). May not always leak this way but its an easy test.

 

I'll have my mechanic do the FPR test as well next week when he has the car. I'll post back after I get the results. Thanks!

 

So I finally got this sorted out and even though the fuel pressure regulator was replaced in October it was bad again. It's swapped out now and all good at the moment. Thanks for the responses!

 

Hopefully it was free under a 1 year warranty. Thanks for checking in.

 

I purchased a different one elsewhere but I did indeed get a full refund on the bad part.