Injector pump fault

wammers · Feb 23, 2015

olesmokie said:
Ok so I checked the in tank pump and that seems fine.

Will have a look at the turbo hoses. Anything else worth checking? re air flow restriction.

Not sure if it's worth mentioning but I don't get smoke when the problem occurs.

Cleaning out the intercooler maybe worthwhile. Maybe a lack of fuel on boost because of crap in hose from manifold to MAP sensor. Cleaning that and checking for splits and cleaning the MAP sensor inlet out may help. Just put the small tube on a can of contact cleaner gently into the MAP sensor inlet, don't force it in, then wash it out to clear oil and crap from it. Then give it a gently blow with an airline. See what you get. Does it have EGR maybe that is sticking open.

olesmokie · Feb 23, 2015

Erg is blocked.
I cleaned all the intercooler and stuff when I blocked th erg.
But worth checking again.
Is there a way to check the maf?

wammers · Feb 23, 2015

olesmokie said:
Erg is blocked.
I cleaned all the intercooler and stuff when I blocked th erg.
But worth checking again.
Is there a way to check the maf?

MAF has nothing to do with fuelling or how engine runs. Just there to control EGR. Nothing readable from MAF on diagnostics. All you will get if you put car on live data and disconnect MAF is "Air flow fault" which basically means no airflow info for ECU to operate EGR.

Datatek · Feb 23, 2015

Here we go again

EGR is operated by CPS, throtle position, MAP and engine temperature. MAF reports the reduction in airflow when the EGR is open allowing fuelling to be adjusted accordingly.
No way can just airflow through the MAF control the EGR.

wammers · Feb 23, 2015

Datatek said:
Here we go again EGR is operated by CPS, throtle position, MAP and engine temperature. MAF reports the reduction in airflow when the EGR is open allowing fuelling to be adjusted accordingly.
No way can just airflow through the MAF control the EGR.

Total and utter bull****. Engine RPM request or boost pressure request and power need controls fuelling. It has sod all to do with the MAF sensor. Keith you obviously know nothing about how a diesel engine works. They are throttled by fuel, reduce fuel, reduce engine RPM simple as that. The MAF sensor is there so the ECU knows the amount of exhaust gas being fed into the engine when EGR is in operation. Reduction in flow through MAF more exhaust gas, increase in flow through MAF less exhaust gas. The ECU modulates the EGR to control this. Fuelling is not adjusted because of airflow through MAF only by boost pressure or throttle request. Don't talk nonsense.

Datatek · Feb 23, 2015

wammers said:
Total and utter bull****. Engine RPM request or boost pressure request and power need controls fuelling. It has sod all to do with the MAF sensor. Keith you obviously know nothing about how a diesel engine works. They are throttled by fuel, reduce fuel, reduce engine RPM simple as that. The MAF sensor is there so the ECU knows the amount of exhaust gas being fed into the engine when EGR is in operation. Reduction in flow through MAF more exhaust gas, increase in flow through MAF less exhaust gas. The ECU modulates the EGR to control this. Fuelling is not adjusted because of airflow through MAF only by boost pressure or throttle request. Don't talk nonsense.

You are as wrong about the MAF as you were about the valve block solenoids

More gas through the EGR = less air through the MAF as I said.
Reducing fuel does not necessarily reduce engine rpm, like when descending a 1 in 4 hill with the throttle closed for example, as there is no throttle, reduction in airflow will be turbo dependant which is fuel dependant.

tomcat59alan · Feb 23, 2015

op2::high5:

wammers · Feb 23, 2015

Datatek said:
You are as wrong about the MAF as you were about the valve block solenoids
More gas through the EGR = less air through the MAF as I said.
Reducing fuel does not necessarily reduce engine rpm, like when descending a 1 in 4 hill with the throttle closed for example, as there is no throttle, reduction in airflow will be turbo dependant which is fuel dependant.

If you take a normal none turbo charged diesel engine, for reasons of simplicity. Turbo just complicates things. There is the same amount of air in the cylinder at tick over as when the engine is flat out. The only thing that changes to move the engine RPM between tickover and flat out is the injected fuel quantity. EGR is only used when the engine is lightly loaded. It does not work with the engine at tickover (throttle shut), under acceleration, nor under load. So with an EGR engine at a light load cruise speed at say 2000 RPM, there is a lot more oxygenated air in the cylinder than the fuel being injected needs to maintain that engine speed, this eccess air produces hot combustion which generates Nox. The EGR allows exhaust gas into the cylinders to replace the eccess amount of oxygenated air, therefore cooling the combustion and reducing Nox production. No fuelling is change in this process.

Grrrrrr · Feb 23, 2015

:fencing:

olesmokie · Feb 24, 2015

So yesterday. After checking a load of stuff I removed the cable connected to the MAF.

And the problem seems to have gone away. I've drive 25 miles with no reoccurrence.

So could it be the maf sensor? What I'll effect will there be of not havin it connected?

wammers · Feb 24, 2015

olesmokie said:
So yesterday. After checking a load of stuff I removed the cable connected to the MAF.

And the problem seems to have gone away. I've drive 25 miles with no reoccurrence.

So could it be the maf sensor? What I'll effect will there be of not havin it connected?

A faulty MAF can cause the ECU to become confused and misinterpret air conditions.

Injector pump fault

wammers

No longer with us, RIP

olesmokie

Member

wammers

No longer with us, RIP

Datatek

Well-Known Member

wammers

No longer with us, RIP

Datatek

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tomcat59alan

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wammers

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Grrrrrr

Technician, Bodgit & Scarper Ltd

olesmokie

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wammers

No longer with us, RIP

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