3,2 Diesel Surging and Lagging under acceleration
Posted: Thu Nov 24, 2011 2:48 pm
Hi Chaps,
I'm posting this here - was originally posted in Drivetrain but turns out to be a fuel system issue:
Day 1
Had my 90k service done at Mitspro last week. Asked them to check the ATF and change if necessary, which they did. After about 400km of trouble free post-service driving, the status changed. While accelerating my engine now sounds like it's surging and lagging, as if i were applying and releasing pressure on a clutch.
The effect on the momentum of the car is negligible, and the rev counter doesn't report any discernible effect, but the sound is definitely one of the engine revving and dropping and revving and dropping in each gear.
Day 2
So i went by Mitspro this morning and described the issues. He looked at the fluid level, smelled it, listened etc and declared the tranmission fit for service.
So I took him for a drive at his request and he quickly listed one of the following possible causes for the wavy revving. Diesel filter may be the problem, or some valve in the fuel system, a pully on the traction control system, possibly the SQL for the injectors must be reset, or dirt diesel.
He changed the filter - wasn't that! Diesel didn't seem dirty or have water in it
So now i'm going into a dealer that has the latest diagnostic equipment for a BK (Mitspro equipment hasn't arrived yet) this afternoon and hope to God that they can tell me what is going on. driving my car for more than 20 minutes is like catching a ride on a refugee laiden row boat... makes me a bit nervous and a bit more 'sea-sick'!
Day 3
Went to Mitsubishi East Rand in the afternoon. They, like Freek, are adament its not the ATF or TC. Must be a fuel supply problem. or electronics! So they disconnected the cruise control. It wasn't that!
Going in again tomorrow for the following two tests:
1) The actual diesel - if its this i'm going to jump for joy, but also sh!t myself out for having not started there in the first place.
2) The supply valve in the fueling system...
I wait with baited breath!
Day 4
RESOLUTION!
So it was the Supply Control Valve in the fuel pump! No idea what caused it but I'm putting it down to rubbish diesel from Haartebeesport Engen. just a few kilos after filling up the trouble started and the Mechanic at Mistubishi east rand mentioned that poor quality diesel could be cause.
Anyway, the valve started sticking and lead to the surging and lagging. The motor is starved, then pumps more fuel which opens the valve, then it returns to normal operating parameters and the whole problems starts again.
The Valve was replaced at a cost of R2590 which i was going to pay until SA Warranty were pressured. This is another story! They refused to cover as their 'telephone mechanic' didn't even know what the valve is, so said they would only cover the fuel pump. They had to literally be taught about what makes up a fuel pump and that it would be in their financial interest to replace this small component instead of the whole flipping pump etc etc. Anyway, they came to the party.
Problem is solved! I'm thrilled as i was having serious doubts about my purchase.
The problem was apparently nothing to do with Mitspro service. I'd like to thank Freek for his advice which helped point us in the right direction. He didn't get the job purely since Mitsubishi East Rand helped get the work done for nothing. They really worked hard, beyond my normal experience with mainstream dealerships.
Gareth
I'm posting this here - was originally posted in Drivetrain but turns out to be a fuel system issue:
Day 1
Had my 90k service done at Mitspro last week. Asked them to check the ATF and change if necessary, which they did. After about 400km of trouble free post-service driving, the status changed. While accelerating my engine now sounds like it's surging and lagging, as if i were applying and releasing pressure on a clutch.
The effect on the momentum of the car is negligible, and the rev counter doesn't report any discernible effect, but the sound is definitely one of the engine revving and dropping and revving and dropping in each gear.
Day 2
So i went by Mitspro this morning and described the issues. He looked at the fluid level, smelled it, listened etc and declared the tranmission fit for service.
So I took him for a drive at his request and he quickly listed one of the following possible causes for the wavy revving. Diesel filter may be the problem, or some valve in the fuel system, a pully on the traction control system, possibly the SQL for the injectors must be reset, or dirt diesel.
He changed the filter - wasn't that! Diesel didn't seem dirty or have water in it
So now i'm going into a dealer that has the latest diagnostic equipment for a BK (Mitspro equipment hasn't arrived yet) this afternoon and hope to God that they can tell me what is going on. driving my car for more than 20 minutes is like catching a ride on a refugee laiden row boat... makes me a bit nervous and a bit more 'sea-sick'!
Day 3
Went to Mitsubishi East Rand in the afternoon. They, like Freek, are adament its not the ATF or TC. Must be a fuel supply problem. or electronics! So they disconnected the cruise control. It wasn't that!
Going in again tomorrow for the following two tests:
1) The actual diesel - if its this i'm going to jump for joy, but also sh!t myself out for having not started there in the first place.
2) The supply valve in the fueling system...
I wait with baited breath!
Day 4
RESOLUTION!
So it was the Supply Control Valve in the fuel pump! No idea what caused it but I'm putting it down to rubbish diesel from Haartebeesport Engen. just a few kilos after filling up the trouble started and the Mechanic at Mistubishi east rand mentioned that poor quality diesel could be cause.
Anyway, the valve started sticking and lead to the surging and lagging. The motor is starved, then pumps more fuel which opens the valve, then it returns to normal operating parameters and the whole problems starts again.
The Valve was replaced at a cost of R2590 which i was going to pay until SA Warranty were pressured. This is another story! They refused to cover as their 'telephone mechanic' didn't even know what the valve is, so said they would only cover the fuel pump. They had to literally be taught about what makes up a fuel pump and that it would be in their financial interest to replace this small component instead of the whole flipping pump etc etc. Anyway, they came to the party.
Problem is solved! I'm thrilled as i was having serious doubts about my purchase.
The problem was apparently nothing to do with Mitspro service. I'd like to thank Freek for his advice which helped point us in the right direction. He didn't get the job purely since Mitsubishi East Rand helped get the work done for nothing. They really worked hard, beyond my normal experience with mainstream dealerships.
Gareth