8 replies to this topic

[Minivabnman]

When returning from a recent car show my car started to what i thought was a missfire, after struggling to get it home i did the usual checks of checking spark plugs and compression test, the comp test showed 200 psi on all cyls, and the plugs were of varying colours. I replaced the plugs with new and also the leads in case one was breaking down.Using the "Textbook" handheld unit it came up with only one fault code, "High voltage output at the temperature switch, the said switch was replaced with a new one, connection cleaned and refitted, cleared the codes and re tested the system, no codes found.

 

Testbook, indicates both Camshaft sensor and throttle switch are functioning correctly

 

I have another MPI which I started changing over electrical components:

1. Coil Pack

2. MAP sensor

3. Manifold Temperature sensor

4. New Cranckshaft sensor fitted

5. New Petrol filter fitted

 

I've even replaced the head gasket.

 

    all to no avail,

I don't have the correct adaptor to carry out a fuel pressure test, could it be the petrol pump not delivering sufficient pressure

 

The car starts and will tick over, it will even increase engine revs while standing still but as soon as you try to drive it it bogs down, the car will drive on a downward slope as long as you don't ask it to accelerate.

 

I'm at my wits end and looking for inspiration.

 

any suggestions

[viz139]

Sounds like it could be fuel, did you fill up on the run?(bad fuel) Possibly one injector failing?

[Minivabnman]

No, filled up the night before travelled approximately 30 mile before problems started earlier in the day

[pete l]

Check your air pipes around the inlet manifold, sounds a bit like a split air hose, I had this on mine.

[bpirie1000]

Sounds like a problem to me. Kind of need acceleration....

Check earth leads and make sure the engin is not rocking to far under load(accelereation) thi s can break connections and cause issues such as your having.

Have any of the sensors in the injection system been bashed at all?

Maybe even worth a fuel pipe check make sure not kinked and even contemplate a filter change for the fuel.

[pete l]

Yes, broken wires in the loom going to the inlet manifold, map sensor, throttle pot, iac valve, common problem.

[Alice Dooper]

30 miles after the refuel could be just enough for the old fuel at the bottom of the tank to be used up.  Bad fuel still a possible.

 

maybe the refuelling pushed some goo into the fuel filter??  

 

Second the engine earthing idea.  Long run reliability is important to us so I’ve added an extra earth strap to the engine as well as keeping all the earth points well serviced.

 

I’ve seen issues with brittle wiring in MPI engine bays before too.  On my own car, the fuel pump wiring at the main relay had the issue.  I know the wiring is about 20 years old bt the quality of some of Rovers materials is really questionable.

[Minivabnman]

I seemed to cured the problem with replacing the petrol pump, time will tell

Edited by Minivabnman, 11 October 2021 - 08:56 PM.

[dan1zo]

I had something similar to this. Sounded like missfiring and just dropping power.

 

I did all the electrical checks etc. that people posted.  Turned out it was a split fuel hose connected to the fuel pump.  Since it was inside the tank i hadnt throught to look at it.  But just meant it wasnt getting enough fuel.