Engine jerking

[Captain Jack]

So, drove up north on Saturday on a 300 mile trip and had some issues with the engine.

On two occasions within a minute of each other, while cruising at around 75-80mph, the engine jolted several times - felt like there was a complete loss of power for about half a second. Not quite the same as me letting go of the throttle pedal, it was rather violent. The car then drove fine for the remaining 100 miles and has been fine since. The jolt probably felt similar to what Sam's Focus does...

The obvious cause is the fuel delivery - perhaps air in the fuel lines, or an old fuel filter (it's at least 20,000 miles/2 years old) causing some blockage. Or... something else?

It did do this in the past as well but much less pronounced than this time...

Haven't plugged the PP2000 in yet due to other things taking priority this weekend but.. any ideas?

[Doggy]

PP2000 is the cheapest and surest way forward, as there's just so many things that could be your problem.

Put the stuff in the car - this is always helpful, because:
a). you're bound to get held up somewhere so you can plug it in while you're waiting.
b). The mere presence of diagnostic equipment can frighten some gremlins into submission

Good luck tracking it down.

[Captain Jack]

PP2000 gave me this. Looks like either the EGR is knackered or the mixer valve (what/where is that?). And ho-hum, if this is indeed related to the jerkiness, why is it trying to open at 80mph?

[Captain Jack]

More info...

Fault related to EGR throttle opening too low:



Butterfly stuck during post operation:



Butterfly stuck while driving:



So, clearly the EGR isn't opening properly. Either it's gunked up or there's a vacuum issue.

Rich, are you getting these issues as well, considering your EGR is blanked. And if butterfly mixer switches to EGR exhaust intake, there would be no air coming in at all for diesel ignition... unless you removed/modified the mixer valve as well to only allow fresh air in.

[RayneR]

I'm also suffering the same issue, i notice it more when i'm going up hill on 4th or 5th gear ... i really feal the loss of power of the car and doesn't response to the throttle of acceleration i have to switch to 3rd gear ..

ALSO there is a lot of smoke and my EGR is knackered on top but i have it blanked at both sides and on ECU.. so i don't think is because of that ... i did had an accident months ago and it was repaired but all the engine was removed maybe something is not well installed...

i don't have PP2000 but i do have some problems with the " turbocharger wastegate selenoid A " error... but i do find that the problem is the MAP sensor because it's very disgusting looking how it was installed it have hand made tube and it's somewhat glued to the sensor .. i have bought one already but i haven't installed.

But i also think the problem is not the MAP sensor...something with the fuel injection ???

Thank you.

[Captain Jack]

Had another one of those today. Only this time the engine was so starved of air that it died while on the outside lane on the M5 accompanied by an error message 'Engine fault : repair needed'. Pulled onto hard shoulder and restarted the engine without issues. Only it was in limp home mode and jerked again for a few seconds. Gah...

The computer log says 'engine anti pollution fault'. I don't have PP2000 on me so I don't know what exactly it logged but I am assuming the same thing. Once again, it did it after steady motorway driving. Except last time it didn't die or went into limp mode.

So...what can it be? EGR is the prime suspect but could it be the bitterly valve itself? I want to rip the whole thing out really but for now I need a useable car. So, do I try and clean the valve with one of those sprays or remove it and give it a good clean or simply replace it worth a new one?

Thoughts?

[Doggy]

Hasn't rwb got his egr blanked?

[GingerMagic]

I can't imagine the EGR being at fault when travelling at motorway speeds - I thought it only opened when ticking over or when slowing down...??

I'm guessing its fuel related, when was the last service Alex?

[Captain Jack]

EGR definitely opens at motorway speeds, at least on mine it does according to previous faults logged, rpm and expected EGR open value.

I am seriously tempted to get a remap to take EGR out but it does need a service too. Last one was this time last year.

[Captain Jack]

Hasn't rwb got his egr blanked?

He does and I don't understand how his works without issues. If the mixer valve switches to EGR only mode and there's no air, surely it would stall?

Also, doesn't it open when being needed to regenerate the DPF?

[Captain Jack]

Welp, I booked Thursday off to give it a full service along with cleaning the EGR and the mixer butterfly valve at the front of the engine. Just looking at it reveals that it's covered in a lot of soot. It all looks incredibly tight, so I'll need to dislocate a few limbs.

I inquired with Celtic Tuning to do the FAP/EGR delete and a mild remap and it would all set me back 295 squids. Could be worse.... So once I recuperate, I'll be going with them methinks.

[Captain Jack]

Well, fk. Read with PP2000 today and I had the following;

"Intermittent fault. Fuel high pressure regulation. Minimum pressure not reached."
"Intermittent fault. Fuel pressure regulator control. Pressure below reference value."

Yay.... So, fuel pressure regulator, sensor or an HP pump?!