D-Jet fuel pump query

[Aussiecsi]

So, my car has done about 2,000 km's on new engine with pretty much all new parts such as injectors , switches etc. Lately, it starts but feels like it's running on 5 cylinders ...few minutes later it inexplicably idles perfectly ...seems to be ok and then drive and back to rough idle . One nagging thought is the aftermarket fuel pump which seems to have done the job to date , however, from memory it has always had an audible buzzing sound which will continue while the ignition remains "on ". My two mates have D-Jets and once the ignition is "on" the fuel pump is only audible momentarily when ( presumably) the fuel line has been primed . I assume the continual "buzzing" sound means fuel is being pumped even though the engine hasn't fired ? Thoughts ?.Thanks, Simon

 

[sfdon]

Loose injector connector is an idea.
It was a bad design. Check each plug. Usually one of the ones nearest the fan.

Your pump has been wired wrong. No fuel pump is allowed to run unless the engine is actually turning except to prime the lines.

 

[Aussiecsi]

Thanks Don, the plugs feel pretty snug ( I had the harness/connectors /rubber boots etc refurbished ). Noted about fuel pump ...will get that sorted regardless . Will probably need to work through troubleshooting list ....anything "obvious" I should look at ?...btw, have installed 123 ignition hoping that would help ...certainly helps when starting and very smooth when engine is "working " . I don't think it could be plug(s) ( fresh NGK's) . Could injector relay be a potential problem?...or is that something that either works 100% or doesn't ? Cheers, Simon

 

[Simufly]

Fuel pressure sensor could be the problem

 

[Aussiecsi]

Fuel pressure sensor could be the problem[/QUOTE

...I hope not ...is that something that can work ok intermittently ?...I thought once it failed it was "final"

 

[Christopher]

My fuel pump constantly buzzes too. Not just to prime.
I had thought that the cut out was a feature of the earlier model, and maybe read here previously that was the case, although can't substantiate this. I understand the safety aspect.
My wiring appears to be all original. Does anyone else with a series II car have the same issue ?

 

[sfdon]

Take the injectors out of the equation by listening to them one by one with a screwdriver held to the ear when you next find the engine stumbling.
Heat soaked injectors can seize up especially when they are brand new.

 

[sfdon]

Check to see if pin 85 at your fuel pump relay has been jumped to permanent ground instead of to the ecu.

 

[Christopher]

I've got a feeling it could be Don - will check. Thanks

 

[Cornishman]

My series II also runs the fuel pump all the time. I have searched and searched to find out how to stop this. Relay is wired correctly.
I think it is that the ecu does not turn it off when it no longer gets the signal from the injector points.
I have a spare ecu to try to stop this. After that I am stuck.

Simon
Try cleaning the injector points, car missed on start up and I tracked it down to this. I removed them, washed in petrol and replaced them.

 

[sfdon]

My series II also runs the fuel pump all the time. I have searched and searched to find out how to stop this. Relay is wired correctly.
I think it is that the ecu does not turn it off when it no longer gets the signal from the injector points.
I have a spare ecu to try to stop this. After that I am stuck.

Simon
Try cleaning the injector points, car missed on start up and I tracked it down to this. I removed them, washed in petrol and replaced them.

It seems a lot simpler to test for ground at pin 85? Than swapping out an ecu

 

[Aussiecsi]

Ok, seems one step forward , two steps back ...here's the latest . The engine turns over but no longer fires ...it did fire initially from the cold start injector but died as soon as the fuel vapour in the plenum was spent . There is spark from the ignition leads .
I'm trying to do things methodically before pulling stuff apart . Presumably if the cold start valve has worked then fuel supply/pressure is not the issue ? It seems that all the injectors are now not working /spraying at all (?) .....I thought if it wasn't firing that there would be a smell of unignited petrol but didn't seem to be any smell which to me suggests no fuel is being pumped via injectors . The ohm resistance on the MPS is within spec range ( haven't done vacuum test ) . Could it be a dodgy injector relay ?...btw, where is this relay located ?...I believe the relays adjacent to the MPS are for cold start and starter motor ?.
Bloody frustrating ...I have Harry "The Torch" on standby . Cheers, Simon

 

[sfdon]

Verify the plug to your MPS is in all the way and in correctly. Match the numbers on the wires to the numbers on the MPS.

 

[teahead]

Pull the hose in the fuel line in the engine compartment, put in a bottle, and see if you get any fuel.

 

[Aussiecsi]

saga continues ...-
- pulled fuel line to cold start injector ...fuel pumps when ignition " on. "
- pulled both cold start relay and injector relay ,tested and both are working .
- there is power ( 12. 5v from memory ) to both ECU pin 16 and pin 24 ( injector drivers ) .
- substituted another ECU ...no change ...plan to try a 3rd ECU that's known to work .

It seems that there is power going to the ECU but nothing appears to be getting through to the relays and injectors ...I don't think much point pulling the injectors to test spray if there's no power ( apparently ) to the plugs or relays ?

Any other ideas ? Cheers, Simon

 

[sfdon]

Push down quickly on your throttle linkage in Engine bay with key on.
You should hear your injectors clicking.

 

[Aussiecsi]

Push down quickly on your throttle linkage in Engine bay with key on.
You should hear your injectors clicking.

No joy Don....going to put my ECU in another "working" D-Jet car and see if it does the job...hopefully it will pick up some CSL DNA . Stay tuned.

 

[adawil2002]

Sounds like the MAP (Manifold Air Pressure) sensor needs to be rebuilt. It's located on the brake servo bracket.

 

[sfdon]

Just checking-
What year model?
The 1974 harness is different.

 

[Aussiecsi]

Sounds like the MAP (Manifold Air Pressure) sensor needs to be rebuilt. It's located on the brake servo bracket.

....seems to be more of a lack of current from the ecu Andrew ... not sure that a dodgy MAP would result in "zero " current to injectors ? Also tried the Mercedes MAP that it used/ran on for years but no change.