65 replies to this topic

[nicksuth]

I'm only guessing here (still learning about the MPi) but it sounds like the injectors are dumping the fuel for some reason? The other possibility is that the fuel pump is letting the pressure back into the tank? I don't know for sure but would assume there is a non-return valve in the line from the fuel pump to the fuel rail possibly within the fuel filter?

I think this is a question for "Sprocket" as I'm no expert!!!

I'll have a search through some info I have to check this out

[Sprocket]

Doubtful your injectors are leaking as you have had them cleaned and tested. Plus if they were, you would be flooding the engine and it would be difficult to start.

Sounds like the regulator or the pump

[nicksuth]

Am I correct in thinking there is a "Non-Return" valve somewher in the feed line system to stop bleed back?

[Sprocket]

No, its in the pump

[El Chibro]

...also always a good hint in case of rought running MPI (and no other reason can be found):

The Rover Bulletin re. MPI Engine Loom Failiure

You will find the mentioned Ground Point in the Engine Loom, left of the Intake Manifold (if you stand in front of the Engine).
A bunch of 5 thin pink cables with a black stripe are connected together and covered by some isolating tape.

Those cables are sensor ground. They're providing ground for water temp sensor, intake air temp sensor, lambda sensor, throttle position senor and manifold absolute pressure (MAP) sensor. If this becomes faulty, you see a number of weird effects, but all of them related to those sensors.

BR
Ralf

I've been searching on all the engine sensors for long, and finaly Dougie's solution was the good one!

Thanx a lot!! ( and thanks to the "search" function that returned that old topic!! )

Edited by El Chibro, 13 March 2012 - 07:40 AM.

[Deeppockets]

Bringing this very old thread back to life...

 

I have had intermittent rough running and stalling for a while. Having previously found this thread I reworked the sensor signal ground splice in the loom (below the relay pack). At the time I was unsure then whether it had fixed the issue.

 

After laying the car up over winter I have started to look over it to get it back on the road for the summer and the rough running issue is still present - oddly when the steering wheel was turned to the right(?).  Looking over the sensor connectors yesterday for corrosion the MAP ground KB wire fell out of the back of the connector and on closer inspection the wire's insulation is failing elsewhere - just this wire, the other two seem OK.

 

I have seen something similar with another 90's car I previously owned where the wiring around the engine suffered from complete insulation failure, with lengths of copper strands being exposed. It seems that PVC insulation used does not like heat and the MPI MAP sensor cable is exposed to rising exhaust heat.

 

Once the ordered connector pins arrive I plan to replace ~10cm of ground wire and wrap all exposed engine bay wiring with TESA engine harness tape to prolong its life.

 

Update 9/4: New MAP sensor connector pin and section of wire back to the harness replaced and wrapped in protective tape. Engine now running well.

Edited by Deeppockets, 09 April 2024 - 06:27 PM.