S

Sasizza

New Member
HELP NEEDED PLEASE
I have a 1998 p38 dse man M51 engine done 68k miles.... It has developed a fault that no one seems to know how to cure.... As you come to a halt and the revs drop as they should, it misfires until it comes to a complete stop then settles back to running on all 6 cyl....
It is not injectors and its had a new inj pump.... No fault codes are apparent when diagnosed at standstill and if diagnosed when driving have had fuel actuator ( in the inj pump which is now replaced ) and lift needle in inj 4 which governs the idle and is also new....
Has anyone had the same fault ??? Joe :((
 
Sasizza said:
HELP NEEDED PLEASE
I have a 1998 p38 dse man M51 engine done 68k miles.... It has developed a fault that no one seems to know how to cure.... As you come to a halt and the revs drop as they should, it misfires until it comes to a complete stop then settles back to running on all 6 cyl....
It is not injectors and its had a new inj pump.... No fault codes are apparent when diagnosed at standstill and if diagnosed when driving have had fuel actuator ( in the inj pump which is now replaced ) and lift needle in inj 4 which governs the idle and is also new....
Has anyone had the same fault ??? Joe :((
Click to expand...
Worth looking at the in tank lift pump to see it's working, at 68K miles it should not have needed a new injection pump.
Has the fuel filter been changed recently?
Was the replacement injection pump a re-con unit or just secondhand?
 
Only 68k miles? That's nothing. Did he miss a digit off?

Surprised anything needed changing at that mileage. Has it had any biodiesel or similar put through it?
 
Diesels don't misfire unless there is a duff injector or a sticking valve.
 
Have been told its the low speed idle valve or sensor, will post the results to help anyone who may have the same problem ....
 
Sasizza said:
Have been told its the low speed idle valve or sensor, will post the results to help anyone who may have the same problem ....
Click to expand...
There is no low speed idle valve or sensor:rolleyes:
Take it somewhere that know what they are talking about.
 
Sasizza said:
HELP NEEDED PLEASE
I have a 1998 p38 dse man M51 engine done 68k miles.... It has developed a fault that no one seems to know how to cure.... As you come to a halt and the revs drop as they should, it misfires until it comes to a complete stop then settles back to running on all 6 cyl....
It is not injectors and its had a new inj pump.... No fault codes are apparent when diagnosed at standstill and if diagnosed when driving have had fuel actuator ( in the inj pump which is now replaced ) and lift needle in inj 4 which governs the idle and is also new....
Has anyone had the same fault ??? Joe :((
Click to expand...

Have the same issue, if you hold the RPM at 1000 while using the left foot on the brake pedal it's fine

soon as you let off the gas pedal idle bounces (like a petrol misfire) then cuts out :-/

I'm not using my RR at the min but I'm guessing it's the in tank pump causing my issue as no fault is logged on the Nanocom, and I replaced my pump with a cheap and cheerful eBay special :rolleyes:
 
Sasizza said:
Have been told its the low speed idle valve or sensor, will post the results to help anyone who may have the same problem ....
Click to expand...

There is no idle valve. But there is an idle switch on the throttle pot that engages at a low throttle position. That engages idle control were the idle fuel is controlled by the ECU via the quantity servo, according to engine load speed, extrapolated from CPS sensor readings.
 
JohnnyCrash said:
Have the same issue, if you hold the RPM at 1000 while using the left foot on the brake pedal it's fine

soon as you let off the gas pedal idle bounces (like a petrol misfire) then cuts out :-/

I'm not using my RR at the min but I'm guessing it's the in tank pump causing my issue as no fault is logged on the Nanocom, and I replaced my pump with a cheap and cheerful eBay special :rolleyes:
Click to expand...

following up from this, today I removed the in tank pump and set up a bench test, and seemed to run fine. This is not really what I wanted as I suspected the pump was causing the idle issue.
 
JohnnyCrash said:
following up from this, today I removed the in tank pump and set up a bench test, and seemed to run fine. This is not really what I wanted as I suspected the pump was causing the idle issue.
Click to expand...
Generally, they will idle fine with a dead in tank pump especially if the tank is more than a quarter full.
 
Datatek said:
No idea, Wammers is the injection guru. I think the guy that repaired it either turned the brass stop post round to present an unworn surface, or sleeved it, can't remember which.
Click to expand...

I've a spare FIP I can pick up tomorrow to strip for parts, and I'll have a dig around on here for the thread :)
 
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