Fuel pump problem (i think)

Post Mon Jun 06, 2016 9:27 pm

Hi.
I have a tech1 1987 sport and it has a fuel pump problem i think.
After start up it runs fine for couple minutes then slowly starts to miss fire and then bogs down struggling to remain running at all. If its left alone for 5 mins or so it will pick itself up and go back to normal.

When it does this i have noticed that the fuel pump under the car ns sill gets noticibly louder. Is there a internal pump in tanks that supplies this pump and could be failing or is there just the external pump?

Thanks.

Post Mon Jun 06, 2016 10:01 pm

cherjaim wrote:
When it does this i have noticed that the fuel pump under the car ns sill gets noticibly louder. Is there a internal pump in tanks that supplies this pump and could be failing or is there just the external pump?

Thanks.

Some seem to have a lift pump in the tank, and others seem to manage with just a pick up pipe.
Easiest way to check is to lift up the rear sear cushion, remove the oval access panel on the RH side, and see how many wires go to the assembly. Three wires and one plug are for the fuel level sender, so an assembly including a pump will have five wires in total and a second plug.
A noticeable increase in noise from the pressure pump is a sign of a failed lift pump.

Post Mon Jun 06, 2016 10:54 pm

Thanks for that.
Ive had a quick look and there are 3 wires going into it so I'm guessing i only have the external pump.
I rang the local factors today and they said the external pump is £32 plus vat so i will order one and see how it goes.
Will post back once its fitted.
Thanks.

Post Wed Jun 08, 2016 8:27 pm

I fitted the new fuel pump and its doing the same thing. starts to splutter as the fuel pump hum gets louder.

I have put £20 fuel in thinking it may be running out or something. I have noticed that the fuel gauge is still showing empty.

I disconnected the plug under the back seat and the gauge dropped to nothing then when reconnected it went back to low fuel level (light on).

Ive tried disconnecting engine sensors one by one when it is running and all seem to be functioning as they should.

any ideas anyone?

Post Wed Jun 08, 2016 8:52 pm

£10 fuel pressure gauge kit from ebay, and see what's happening. Facts are so much better than guesses.

Post Wed Jun 08, 2016 9:20 pm

what sort of pressure should i be hoping to find?

Will ask the mechanic over road if i can borrow one.

Any idea why it only does it when the pump hum is more noticeable?

Post Sun Jun 19, 2016 7:13 pm

PROBLEM SOLVED!.

Decided that the tank should be removed to further investigate.

My long suffering mechanic friend removed it and was noticed that there was oil in the tank and a lot of sediment. Cleaned it all out and was just about to reinstall when he noticed that the fuel line form the sender/pick up to the external pump was 'crimped'.

The tank had been replaced 8 years ago by a local reputable specialist (i found the receipt in the paperwork) and they had routed the pipe incorrectly causing it to be crimped in 3 places against the body.

Tank cleaned, new pipe and put back together and all is good in the world again.

Thanks for suggestions.