P38A MAF woes
- Thread starter cornishboater
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In that case it's easier. Pin-1 = 12V, Pin-3 = Ground, and Pin-2 is the output to the ECU.
The description in RAVE is not quite correct, because the IAT is in the air-filter housing. The attached LR System doc has the correct description on 4th page.
MAF voltage should be about 1.4V at idle. (see P41 in "GEMS by Poole")
The description in RAVE is not quite correct, because the IAT is in the air-filter housing. The attached LR System doc has the correct description on 4th page.
MAF voltage should be about 1.4V at idle. (see P41 in "GEMS by Poole")
Only use a gems maf, and better 2nd hand oem than a new one which is supposed to do the same job. Re your screenshots...in pic1 there shd have been air flow, i guess the engine was off. Probably unconnected, but your idle ref voltage is quite high...using Write settings ( as in one of ur pics) you can write it to 0.625V. Current air flow at 32 was quite high for idle. Pls be aware that adaptive settings only learn above min tank level, not sure if 1/4 or 1/2. IAT temp i looked at it in detail in the past...v8s all read wrong ( or nano does), but doesn't seem to do much ( I have put additional resistance in line on mine to get better temp reading) so that is a distraction. Poole by Morgan and lucas gems nanocom guide are your best refs. I will probably be in Corfe C next weekend if you want to try a "known good" maf off mine. Cd be worth removing/ cleaning the iacv and the ports on the throttle body. Leave the tps in place
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cornishboater
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Thanks guys, there is something to get on with then 
cornishboater
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Many thanks, lotsa info to get on with there, the engine was idling on the old MAF for all screen shots, odd about the airflow bit, I did wonder but I am not au fait with using engine diagnostics so I wouldn't fully know what I am looking at!
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Also check that GEMS is set for the correct engine size. 2nd screen in settings menu.
Once you get the settings in the right ballpark, you should do some drive cycles to train the ECU.
Once you get the settings in the right ballpark, you should do some drive cycles to train the ECU.
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Those short fuel trims are really low
cornishboater
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Just to update. I have again tried the 2 new MAFs with the same ending, chugging black smoke and backfiring. I have now fitted a good used one from James Coleman (SAGEM OEM) and tried it, it started but was really rough. I checked for any faults (none) and then did the adaptive reset, suddenly we jumped to a nice even tickover. I also have numbers coming from the Nano that although don't meet the norm I have to yet drive it to get the ECU to adapt. It also revs cleanly and idles perfectly!! I then again tried one of the 2 "new" ones (the one from Island 4X4) and straight back to chugging, black smoke and backfiring.
It seems that the GEMS setup is very fussy as to what you stick in it, a good used OEM rather than a chineseum replacement, well, lesson learned now and a heads up if anyone is thinking of doing the same
It seems that the GEMS setup is very fussy as to what you stick in it, a good used OEM rather than a chineseum replacement, well, lesson learned now and a heads up if anyone is thinking of doing the same
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Unfortunately some parts ain't worth the cardboard box they turn up in 
Job well done lad
Job well done lad
cornishboater
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Believe me there were a multitude of cuss words, some really, really naughty onesUnfortunately some parts ain't worth the cardboard box they turn up in
Job well done lad
Funny thing is a local chap pulled in in a s3 Landy and asked if I wanted to sell it, hmm, the thought had been crossing my mind, trouble is it would be like selling one of my kids, however, it all depends on the greenbacks methinx.
cornishboater
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One thing is that I didn't expect 2 "new" MAFs to be totally useless!Believe me there were a multitude of cuss words, some really, really naughty ones
Funny thing is a local chap pulled in in a s3 Landy and asked if I wanted to sell it, hmm, the thought had been crossing my mind, trouble is it would be like selling one of my kids, however, it all depends on the greenbacks methinx.
Datatek
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Duff new parts are sadly all too common these days
Grrrrrr
Technician, Bodgit & Scarper Ltd
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Good luck getting your money back off Island-4x4.
cornishboater
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Just a quick update, after fitting the used SAGEM MAF I have now managed to go for a reasonable drive around to get the ECU to adapt to the change. It is now a very different car, smooth as silk, idles as steady as a rock, no hesitation when pulling away in a hurry and just generally feels very different to drive. I think the old MAF had been knackered for quite some time, I can now go up to traffic lights without having to use the 2 footed mode and the thing bursts into life every time i turn the key!! Life is good (so far)
Cheers everyone for your input
Cheers everyone for your input
Grrrrrr
Technician, Bodgit & Scarper Ltd
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Now the question us, how do we get this inadequate crap off the market before others become a cropper? Trading Standards?
cornishboater
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Now that the car is seemingly running fine on the used MAF I thought I might try to see why 2 new MAFs do not work. One that I got I have managed to get a refund but the one I got from Island 4X4 I have not heard anything from them regarding a return/refund (as mentioned in a previous reply) so I have one to play with. My question is is there anyway to actually test it off of the car with a DVM, I am not going to attach it again because I don't want to disturb the parallel universe that is my engine. There surely must be a way to test with a meter off of the car. Any thoughts
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Google AI says 2.5ohms to 3.1ohms across pins 2 & 3. Diagnostics should show airflow readings, but not sure what values are expected.
range rover p38 v8 maf resistance
range rover p38 v8 maf resistance
Grrrrrr
Technician, Bodgit & Scarper Ltd
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Now that's a good question.
What can we measure? Resistance? However, you would have to measure that resistance at different air-flows as resistance with no airflow may not be representative. Hair dryer?! Airline with flow meter?
