MG-Rover.org Forums banner

1 - 7 of 7 Posts

·
Registered
rover_45
Joined
·
10 Posts
Discussion Starter #1
Dear all, bit of help please; had the clutch changed a month ago, since when had engine light on (top left), checked all connections etc all ok, then car cut out completely after I changed Mafam setting lower, also, other engine warning light then came on! Fault code registered as EGR valve, so changed this (old one not clogged up), top light went out but when starting, fumes still a bit smelly, startup idle erratic & a can run a bit clunky for first few mins until it settles, so changed EGR actuator, next few days all ok, but now erratic is slowly returning, ideas please? (Mafam with Pierburg 5 years, de-cat, straight through turbo outlet pipe).
 

·
Registered
Joined
·
2,419 Posts
The most common reason I have found for erratic running is slack fuel pump belt, which can cause the timing to become unstable. Glow plugs not operating can cause cold starting to be a little miss firing but this should settle after a minute of running. EGR, MAF, AMP won't affect running or starting but the latter two will limit the revs to about 4000 rpm if disconnected. The other possibility is the fuel pump is on its way out or there is a bad connection between the ECU mounted adjacent the battery and the fuel pump. There are 6 connections, I seem to recall these are the 12 volt supply to the pump, CAN bus communications, fuel shut off and rpm feedback. I always get a fault code on mine (2005 reg 45 diesel) suggesting short circuit on EGR actuator, this has no impact whatsoever and I think it is wrongly reported.

Also check the crankshaft sensor, but the engine runs ok with the needle lift disconnected, as I found out when I forgot to connect it. It logs a fault code though.
 

·
Registered
rover_45
Joined
·
10 Posts
Discussion Starter #3
The most common reason I have found for erratic running is slack fuel pump belt, which can cause the timing to become unstable. Glow plugs not operating can cause cold starting to be a little miss firing but this should settle after a minute of running. EGR, MAF, AMP won't affect running or starting but the latter two will limit the revs to about 4000 rpm if disconnected. The other possibility is the fuel pump is on its way out or there is a bad connection between the ECU mounted adjacent the battery and the fuel pump. There are 6 connections, I seem to recall these are the 12 volt supply to the pump, CAN bus communications, fuel shut off and rpm feedback. I always get a fault code on mine (2005 reg 45 diesel) suggesting short circuit on EGR actuator, this has no impact whatsoever and I think it is wrongly reported.

Also check the crankshaft sensor, but the engine runs ok with the needle lift disconnected, as I found out when I forgot to connect it. It logs a fault code though.
Hi Bunny_Brain, thanks for great response. Today it started fine, ran fine then after a few mins cut out, then started after a minute, the lower management light came back on too. I've checked connections as you suggest, can't see anything wrong or lose at a glance. It's random, some days starts & runs fine, another day it'll start & 'mis a beat' within the first few minutes but that's all then it'll be fine. Only since the clutch was changed, like something has been disturbed! Any other ideas welcome.
 

·
Registered
Joined
·
2,419 Posts
Hi Bunny_Brain, thanks for great response. Today it started fine, ran fine then after a few mins cut out, then started after a minute, the lower management light came back on too. I've checked connections as you suggest, can't see anything wrong or lose at a glance. It's random, some days starts & runs fine, another day it'll start & 'mis a beat' within the first few minutes but that's all then it'll be fine. Only since the clutch was changed, like something has been disturbed! Any other ideas welcome.
Just as an experiment, try unplugging the crankshaft sensor (easier said than done) and see if the engine runs at all. I don't know if it will or not but the crankshaft sensor is one of the critical components of the fuel injection timing algorithm. If it does not run then this is one possible culprit but they are very reliable and also in a vulnerable position to get disturbed when doing clutch changes. Other than that I would suspect the fuel pump. They can fail intermittently because the normal failure mode is bad bond wire joints on the circuit board. Mine cut out twice before it died completely and it was the ECU on top of the fuel pump. I had a new one fitted at 500 quid and all was good and still is.
 

·
Registered
rover_45
Joined
·
10 Posts
Discussion Starter #5
Couldn't find any issues with wiring or connections at all inc under the battery tray & fitted a new fuel filter just in case that was blocking, saw your post after I got home from a friends garage, so haven't tried unplugging the sensor yet, bit damp out now, but all looked ok at a visual inspection earlier. The code by the way for the pump error was P0251 Fuel pump control unit - was that the code you had can you remember? I'm guessing £500 was for a whole new pump?
 

·
Registered
Joined
·
2,419 Posts
500 quid (in 2011) was for new pump ECU which includes both timing and fuel quantity solenoids and they also fitted a new pump head. Refurbished by then Bosch agent CF Parkinsons in Lincoln. I use an SP ACR 4 and it does not give fault codes in that format but a full descriptive text string, I got fuel quantity solenoid error but the pump ECU was dead.
 

·
Registered
rover_45
Joined
·
10 Posts
Discussion Starter #7
500 quid (in 2011) was for new pump ECU which includes both timing and fuel quantity solenoids and they also fitted a new pump head. Refurbished by then Bosch agent CF Parkinsons in Lincoln. I use an SP ACR 4 and it does not give fault codes in that format but a full descriptive text string, I got fuel quantity solenoid error but the pump ECU was dead.
I don't suppose you know of or can recommend someone else who could supply an ECU or an exchange pump? It could be a bit close to writing the car off, if this is the fault, I'm just being prepared as I need the car in use! Started & ran fine the past 2 days, but the fault has been a bit random. Also, do you happen to know online where I can get an OBD unit to turn the light off if it comes back on (lower engine warning light) - many units don't talk to this car unfortunately. Appreciate the help.
 
1 - 7 of 7 Posts
Top