Maf g/s readings

honda boi

Can anyone tell me what the maf g/s readings are for a good one?
Mine is reading 10-13 g/s at idle.
About 70-90 g/s at around 2500rpm.
I only found one page with a 2006 1.6tdci focus with 6 g/s at idle.
And 40 g/s at 2500rpm.
Not even sure if that's meant to be a correct reading.

rex-x

honda boi wrote: »

Can anyone tell me what the maf g/s readings are for a good one?
Mine is reading 10-13 g/s at idle.
About 70-90 g/s at around 2500rpm.
I only found one page with a 2006 1.6tdci focus with 6 g/s at idle.
And 40 g/s at 2500rpm.
Not even sure if that's meant to be a correct reading.

Every car and engine is totally different. there are no 'good' readings. The maf reading will drop significantly when the egr is open.

honda boi

rex-x wrote: »

Every car and engine is totally different. there are no 'good' readings. The maf reading will drop significantly when the egr is open.

Any idea on the 1.6tdci engine?
My egr is blanked off

rex-x

honda boi wrote: »

Any idea on the 1.6tdci engine?
My egr is blanked off

Is the egr properly mapped out? just blanking it will cause problems.

The flow through the MAF depends on engine temp, the engines year of production and horsepower level, egr opening, rpm, throttle position amongst other things like regeneration state. what exactly are you trying to diagnose?

If you were to look at your initial figures, the 6g/s of the other car will likely have its egr opening, this will provide the extra 6g/s of yours. Same as 2500rpm, with no egr you need extra flow through the MAF as the air has to come from somewhere.

honda boi

rex-x wrote: »

Is the egr properly mapped out? just blanking it will cause problems.

The flow through the MAF depends on engine temp, the engines year of production and horsepower level, egr opening, rpm, throttle position amongst other things like regeneration state. what exactly are you trying to diagnose?

If you were to look at your initial figures, the 6g/s of the other car will likely have its egr opening, this will provide the extra 6g/s of yours. Same as 2500rpm, with no egr you need extra flow through the MAF as the air has to come from somewhere.

Thanks Rex ,didn't think it was as complex as that.
Just thought it worked on how much throttle you give it and speed.
Egr not remapped just blanked off with a blank plate.
Just going over things with the car and was just looking at seen if the maf is operating correctly or if it would need a clean/replacement.
Ah I see so with my egr being blanked my car is reading double the g/s.

rex-x

honda boi wrote: »

Thanks Rex ,didn't think it was as complex as that.
Just thought it worked on how much throttle you give it and speed.
Egr not remapped just blanked off with a blank plate.
Just going over things with the car and was just looking at seen if the maf is operating correctly or if it would need a clean/replacement.
Ah I see so with my egr being blanked my car is reading double the g/s.

Your lack of egr is causing the higher MAF reading yes but you shouldn't just blank the egr on that engine without properly mapping it out. You will have an air doser (throttle like plate) that closes before the egr opening to force more egr gasses into the intake. With it blocked off and the air doser not mapped to stay open it wont be doing you any favours.

g/s is a fairly uncommon unit to measure 1.6 hdi MAF readings, you would likely find more results searching for mg/r (same deal different unit)

Audioslaven

rex-x wrote: »

Your lack of egr is causing the higher MAF reading yes but you shouldn't just blank the egr on that engine without properly mapping it out. You will have an air doser (throttle like plate) that closes before the egr opening to force more egr gasses into the intake. With it blocked off and the air doser not mapped to stay open it wont be doing you any favours.

In what way will it be doing you no favours? I understand the turbo may get hotter as there is more air been introduced but is there anything else?

rex-x

Audioslaven wrote: »

In what way will it be doing you no favours? I understand the turbo may get hotter as there is more air been introduced but is there anything else?

Aside from the fact egr gasses are actually good for power and efficiency (They cool the combustion) in his particular case his intake will be up to 80% blocked off by the air doser as it is expecting the air to come from the egr passage which is after the air doser.

You can see in this image its basically a throttle flap that blocks the air from the turbo to force more egr air into the intake:



Having the egr blanked off but this still functional is not a good thing. Some models have 2 air dosers and additional parts.

Audioslaven

rex-x wrote: »

Aside from the fact egr gasses are actually good for power and efficiency (They cool the combustion) in his particular case his intake will be up to 80% blocked off by the air doser as it is expecting the air to come from the egr passage which is after the air doser.

You can see in this image its basically a throttle flap that blocks the air from the turbo to force more egr air into the intake:



Having the egr blanked off but this still functional is not a good thing. Some models have 2 air dosers and additional parts.

Ok I get that it may stop air to the turbo but in my car similar engine to OP, I don't have that flap AFAIK. I have got around 9g/s on idle (if I remember correctly) but when I blanked mine, the performance improved. I just assumed I was burning leaner now resulting in a better performance. I get that it may get hotter but that was it.

rex-x

Audioslaven wrote: »

Ok I get that it may stop air to the turbo but in my car similar engine to OP, I don't have that flap AFAIK. I have got around 9g/s on idle (if I remember correctly) but when I blanked mine, the performance improved. I just assumed I was burning leaner now resulting in a better performance. I get that it may get hotter but that was it.

It depends on the age of your car and the ecu controlling it. A healthy engine wont run better without the egr but egr gasses are nasty when they mix with crankcase vapours (sludge). Its also possible your egr was stuck open and blanking it fixed that?

Diesel doesn't quite have the same rich/lean air fuel setup a petrol engine will have and your engine wont be any leaner as a result, the MAF reading being higher shows the extra air just comes in via the intake instead but if an air doser is present will be lower than they should be and the MAF tables in the ecu is the last line of fuelling control so if airflow is limited then so will fuelling be and therefore power.

Audioslaven

rex-x wrote: »

It depends on the age of your car and the ecu controlling it. A healthy engine wont run better without the egr but egr gasses are nasty when they mix with crankcase vapours (sludge). Its also possible your egr was stuck open and blanking it fixed that?

Diesel doesn't quite have the same rich/lean air fuel setup a petrol engine will have and your engine wont be any leaner as a result, the MAF reading being higher shows the extra air just comes in via the intake instead but if an air doser is present will be lower than they should be and the MAF tables in the ecu is the last line of fuelling control so if airflow is limited then so will fuelling be and therefore power.

cheers. I see what you mean. Its a 2008. I actually cleaned it but decided to blank it. i had no issue with the EGR. I noticed an slight increase in power. I have it blanked 2.5 years and I have not noticed any issue todate.