Hi all, I've just got back from having a RR test to find that its running lean past 5k RPM

I've been told its the MAF/airflow sensor...

Just wondering if this would flag a CEL light or not as i'm getting the all clear steady flash straight away, although there does seem to be a slight crack in the pipe next to it

Just thought i'd check with you guys before i purchase both bits.

 

the MAF code might not come up even if it is faulty-- didn't with me, i just got knock sensor code an then retarded timing!

 

Oh Ok, did you replace it and the problem go?

Thanks for the rapid reply by BTW

 

Just looking at your "view my Scooby"..... with all the mods you have why not ditch the MAF and use the readings from the MAP sensor........I'm sure the Simtek can do this

Shaun

 

The Simtek is designed to work off a map sensor, I am thinking of getting one, would you recommend it.

 

Is the ESL chip a generic one or is it custom mapped? If it isn't custom mapped then this could be the answer?

Assuming here the Simtek is still a future mod

 

Yes the simtec is still a near future mod, at the moment its the ESL board.

This was the early ESL board thats NOT the live custom map, although it was semi custom as i brought the car to Andy@ESL and he slightly ajusted it to suit my car as close as he could without a Rolling road etc... just to best suit my mods at the time.
Since then i've had the de-cat and a few other things.

I do have a slight crack though in the pipe near the Maf (induction pipe area)

 

your welcome mate!
always a good idea to replace any pipes with crackes... not sure what pipe you mean though-- the big induction pipes that feed to and from the MAF?

Yes i replaced my MAF, reset the ECU and it semmed fine for about 15mins... then CEL came on again registering knock again! but this was just crusing very gently off boost after the reset. the light then went out and it seemed ok and did not stay on all the time like it did before. in fact it STILL comes on at start up all of 4months later, but goes off and stays off. Further more it has been on the dyno twice since and ARF is fine and zero det, so the CEL is just a relic. But to answer your question, yes the replacement MAF did solve it as the performance went back to normal, etc. Also it was ticking over at 2K rpm for about 15mins after startup, the replacement MAF solved this too

 

Top man.

Thanks for all your help, shall look a bit closer and let you know what the score is...
Just dreading melting a piston once again with it running lean

Thanks again buddy

 

hi mate, yes please tell us all how you get on.
just thinking if there are anymore details i can add... hmm... Well my theory as to WHY the CEL came up with a knock sensor report after fitting the new MAF and resetting the ECU was that maybe the ECU advanced to max untill it started hearing the crackeling of imminent det and backed off a step... enough to throw a CEL but not enought to drop boost and back everything off.

At the worst point my car felt like it had lost about 50-60bhp, which i'm sure must have been down to lowered boost. So i was given all these tangable warnings that went beyond just a light on the dash. the replacement MAF removed these syptoms and like i say fast or otherwise dodgy idle is a big sign of tired MAF too.

I don't know how lean you are running at higer RPM-- my AFR at 5000rpm is around 12.0 (sorry dunno the units so might be useless lol!), which i understand to be a bit rich if anything? but obviously different cars. Could be your AFR is borderline for det-- did they not check for det with cans when it was on the dyno too??? would explain the lack of a CEL. In any case i think a new or otherwise replacement MAF would be a good place to start, then RR it again and see where you are at. Leaving it till the performance is being altered will give you a clearer picture of everything, but obviously its best not to arrive there!


ps i have not concidered any of your performance mods in any of this cause i don't have any and can't really say! thought i better limit my waffeling to my own experiences

 

I see. It wasust running laen at 5krpm. I dnt have the ppr work at the mo so cant give all yhe info unfortunatly.

260bhp then they bkd off but was still rising?

 

hi mate how do you know if you melt a piston ive been driving with a faulty maf sensor for a wile now and now my car make a grinding noise whe you start and turn of revs fine no noise almost like engine mount gone no loss of power does this sound like piston cheers warren