bosch 044 fuel pump running constant on prime with ignition on it only does this when the engine is hot! could this be connected to my bad hesitation issue? cheers. sierra cosworth 2wd L6 ecu stage 3.

 

Im sure mine runs constantly sometimes too.

As long as your getting good fuel flow i cant see why it would cause the car to be hesitant.

When was the last time the fuel filter was change

 

If the fuel pressure regulator was failing or set wrong then the pump could keep running ask it would be opening lower and running fuel back to the tank which in theory could cause an issue....I guess it would run lean? If you can swap out the pressure reg then it is one less thing to worry about but more expense....that or fit a gauge to see what it is doing?

 

thanks lads i have replaced the fpr already. also i put the multimeter on the fuel pump whilst the car is running and im getting 11.5v does this sound ok?

 

The ECU determines the prime duration, which can vary with temperature, as such I would look toward the CTS, which would also cause running issues.

Martin

 

so how does the 11.5v sound? also its got a brand new CTS

 

its ok-but if you ran a thicker power wire and nice thick earth cables as practicable[switched] it would improve a bit

 

i would want to see higher than 11.5 volt that will no doubt drop further under load

 

I would hope that is without the engine running.

Martin

 

with the engine running on idle martin

 

so i take it that voltage is really too low for the pump? you rekon that is whats causing the horrible stutter hesitating? also surley if i was not getting enough fuel i would be running very lean? yet my spark plugs are very sooty which would indicate rich? cheers

 

11.5 volts to pump shouldnt make it splutter but could be better[thats providing your alternator and battery are good]
run a good quality thick power cable to the pump[use an msd kit if you dont want to make one up-its not expensive] also make sure earths etc and any relays switching your pump on are fresh
it also helps to have a known good condition,quality fuel pump too

these are very old cars now and any replacement of the wiring done correctly always helps-some of the wiring was marginal when new-after all the years it doesnt get any better

 

Then yes that is too low, as mentioned that is without load, so it will drop further.

A melt down can occur as the result of this, you can't really tell by the plugs. Ideally you want to be seeing the power from the Alternator.

The wiring, along with the fans are two common problems, in this case it's due to the old wiring, which builds resistance with age.

Martin

 

cheers for the input lads, the alternator is brand new however it is a 65 amp dunno if thats a big issue? as i dont have heated screen etc. the fuel pump is a brand new bosch 044 new fuel tank and lines. i have ran a wire from the original fuel pump relay to the pump and i have attatched the earth from pump to spare wheel well. the list of new parts goes on, cheers.

 

It needs rewiring from the battery, as your still using the original supply.

Also the spare wheel well isn't the best ground, as it's most likely rusty.

Martin

 

i now have it from the battery and there is no rust on the car lol cheers

 

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