running out of get up and go.

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Mark Piercy said:
I have ran it before with the map unplugged as I had a noise from the FIP, it turned out the intank wasn't supplying enough file and the FIP was trying to compensate for it?? The sound went when the pump was replaced. But I can confirm that it'll run with both the MAF and map unplugged as I have tried this before to rule out the issue at the time.. I did however notice a small drop in power and a rise in the MPG but it could be driven quite happily and with ignorance if not known about... And.... Not lamp on the dash for any of the above...:)
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I ran for some time with the MAF unplugged as an experiment. As you have found, a little more fuel is used and the car would smoke under hard accelaration.
 
wammers said:
No they don't, apart from what i said before, it's just that you don't understand what you are reading.
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Very hard not to understand, it's written in words of one syllable.
You also confirmed in a post a week or so ago that a duff MAF causes loss of power because as you put it the ECU goes crazy. It's not down to EGR miss operation because it does it with the EGR disabled.
 
Datatek said:
Very hard not to understand, it's written in words of one syllable.
You also confirmed in a post a week or so ago that a duff MAF causes loss of power because as you put it the ECU goes crazy. It's not down to EGR miss operation because it does it with the EGR disabled.
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Yes it does when the ECU does not receive expected signals it can cause it to lose the plot. Allow me to inform you that one of the descriptions of what the MAF does on the diesel in RAVE can be interpreted as how a MAF works on a petrol engine. It does not relate to a diesel in any way. I know that obviously you don't. The airflow through the MAF sensor on a diesel apart from it's temperature as explained earlier has no effect on fuelling in any way.
 
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wammers said:
Yes it does when the ECU does not receive expected signals it can cause it to lose the plot. Allow me to inform you that one of the descriptions of what the MAF does on the diesel in RAVE can be interpreted as how a MAF works on a petrol engine. It does not relate to a diesel in any way. I know that obviously you don't. The airflow through the MAF sensor on a diesel apart from it's temperature as explained earlier has no effect on fuelling in any way.
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I might believe that if disconnecting the MAF did not cause an increase in fuel consumption.
RAVE is quite clear:-
IMG_0854.jpg

I might also believe that RAVE is wrong if I had not done tests that prove it's correct.
 
Keith you are talking nonsense. Airflow through the MAF has nothing to do with injection fuel quantity. Fuel injected is subject to power/RPM request. The higher the throttle request the more fuel is injected to achieve that request.. The more fuel that goes in the faster the engine turns. Air in the cylinder for any given manifold pressure RPM is constant. There is ALWAYS more air in the cylinder than is needed for combustion. Fuel is NOT injected subject to airflow through the MAF sensor. You don't know what you are talking about. You CANNOT fuel a diesel engine subject to airflow through the MAF sensor it is not possible, because diesel engines DO NOT run at a set mixture ratio as do petrol engines. At idle the air/fuel mixture ratio will be well over 100 to 1.
 
wammers said:
Keith you are talking nonsense. Airflow through the MAF has nothing to do with injection fuel quantity. Fuel injected is subject to power/RPM request. The higher the throttle request the more fuel is injected to achieve that request.. The more fuel that goes in the faster the engine turns. Air in the cylinder for any given manifold pressure RPM is constant. There is ALWAYS more air in the cylinder than is needed for combustion. Fuel is NOT injected subject to airflow through the MAF sensor. You don't know what you are talking about. You CANNOT fuel a diesel engine subject to airflow through the MAF sensor it is not possible, because diesel engines DO NOT run at a set mixture ratio as do petrol engines. At idle the air/fuel mixture ratio will be well over 100 to 1.
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I suspect that your garage closed before electronic control of diesel fuel injection arrived, all modern diesels use a MAF to adjust fuelling to compensate, for among other things, atmospheric pressure. The higher the throttle request the more fuel is is injected but there never was a direct relationship even in mechanical as the governor related the fuel injected to the RPM, the finer that control can be made, the less smoke will be produced due to over fuelling.
Unfortunately in the case of the M51 it's a bit crude but test results often disprove theories, if the MAF has no effect, why would fuel consumption increase with the MAF unplugged even with the EGR disabled?.
Anyway I'm flogging a dead horse, you believe what you want to believe, I believe what I find out from testing.
 
Datatek said:
I suspect that your garage closed before electronic control of diesel fuel injection arrived, all modern diesels use a MAF to adjust fuelling to compensate, for among other things, atmospheric pressure. The higher the throttle request the more fuel is is injected but there never was a direct relationship even in mechanical as the governor related the fuel injected to the RPM, the finer that control can be made, the less smoke will be produced due to over fuelling.
Unfortunately in the case of the M51 it's a bit crude but test results often disprove theories, if the MAF has no effect, why would fuel consumption increase with the MAF unplugged even with the EGR disabled?.
Anyway I'm flogging a dead horse, you believe what you want to believe, I believe what I find out from testing.
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As explained earlier if you bothered to read it. The ECU uses the temperature of the air in conjunction with fuel temp to determine air density, fuel density. The amount of fuel to be injected to suit throttle demand is then adjusted minutely by the ECU to suit conditions. The fuel injected is determined by the throttle power request NOT by the amount of air passing through the MAF sensor. In pre EGR engines air temp was measured in the manifold after the turbo. When EGR was introduced that sensor was deleted and it's parameter in the ECU became a fixed -38.88 value. The temp reading from the MAF sensor is used as a substitute for that sensor. So the only thing the ECU actually needs from the MAF unless EGR is active is the temp reading. Air flow is of no consequence to the ECU unless EGR is active, in which case the reduction in airflow represents the amount of exhaust gas being ingested. The ECU will then modulate the EGR valve to ensure sufficient oxygenated air is present for clean combustion at the requested throttle power demand. IF the temp reading from the MAF is not available, the ECU uses a substitute value based on a preset value and fuel temp only. If you read through RAVE it is all in there, albeit in some cases a little vague and open to misinterpretation by those with no knowledge of diesel mechanics. Like you and a few others on here basically.
 
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wammers said:
... no knowledge of diesel mechanics. Like you and a few others on here basically.
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I suspect I am not alone in having only a rudimentary knowledge of how an old diesel engine works, let alone one of the newer ones. I'd even go as far as saying I am in the majority.

Learning a little here though. Through discourse we learn ... and fiddling with the beast, of course.
 
Grrrrrr said:
I suspect I am not alone in having only a rudimentary knowledge of how an old diesel engine works, let alone one of the newer ones. I'd even go as far as saying I am in the majority.

Learning a little here though. Through discourse we learn ... and fiddling with the beast, of course.
Click to expand...

New diesel engines work in exactly the same way as old diesel engines.
 
Henry_b said:
I can feel a duel coming on, between Data and Wammers.........

handbags at Dawn :p:D
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No need he is wrong period. It is for people to listen and learn or remain ignorant. Bit like the dickhead in one thread who reverse engineered (his words) ECU outputs. He seriously thought that a certain airflow through the MAF represented a certain injected fuel quantity. In other words fuel was injected to match the airflow. When in fact it is the other way around. The more fuel the faster the engine turns, the faster the engine turns the more airflow. Bloody idiot.
 
Ok guys, let's leave that one to sleep it out. Please:p..



Fùcking running away and fast.....










See me go.......






Not quite.......




Yet.....










....
.


.
 
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