MAF Related issue
Discussion
Looking for a bit of help. I have just supercharged my car with a Mini charger, and TRLane brackets and all the necessary bits!
Now for the engine management i have got a AEM FIC piggyback ecu, which is working brilliantly with the supercharger to get the ignition and fuel correct.
Now the problem. Ever since i have installed the charger, i have had issues with the car having massive hesitation, and almost dying, at low rpm. Now, at low rpm, with partial throttle, the car is still running on the stock ecu, and the aem isn't changing anything. I have sort of narrowed the problem down to the MAF, by disconnecting it, going for a drive and the car acting exactly the same way.
Basically the cars afr's go above the 18 that my gauge can show(so a little bit dangerous! :|) The maf is also reporting voltage when it is connected.
Could it possibly be down to dirt in the maf from where it was disconnect and left lying about for a few days whilst i bolted other bits into the engine?
Now for the engine management i have got a AEM FIC piggyback ecu, which is working brilliantly with the supercharger to get the ignition and fuel correct.
Now the problem. Ever since i have installed the charger, i have had issues with the car having massive hesitation, and almost dying, at low rpm. Now, at low rpm, with partial throttle, the car is still running on the stock ecu, and the aem isn't changing anything. I have sort of narrowed the problem down to the MAF, by disconnecting it, going for a drive and the car acting exactly the same way.
Basically the cars afr's go above the 18 that my gauge can show(so a little bit dangerous! :|) The maf is also reporting voltage when it is connected.
Could it possibly be down to dirt in the maf from where it was disconnect and left lying about for a few days whilst i bolted other bits into the engine?
Are you doing anything with the AEM to pull fuel out of boost? The stock ecu should cope with steady speeds and pull fuel for you but accelerating/decelerating out of boost will run from the built-in ecu maps and will run very rich. Same applies to dropping down to idle; by the time the ecu catches up with the real fuel requirements its already stalling. That's my experience with EMB which is very similar anyway. Out of boost and idle needed an airflow map to trick the ecu into pulling fuel.
Yep i am pulling fuel out of boost. It is pulling about 36%, which the car was driving fine on before it was supercharged as i made sure to test it worked first!
The car is absolutely fine at full throttle or above 4k rpm though, which from what i have read, the maf's input isn't used by the stock ecu under these conditions, which pushed me further to thinking it was the maf
The car is absolutely fine at full throttle or above 4k rpm though, which from what i have read, the maf's input isn't used by the stock ecu under these conditions, which pushed me further to thinking it was the maf
vigoro said:
Yep i am pulling fuel out of boost. It is pulling about 36%, which the car was driving fine on before it was supercharged as i made sure to test it worked first!
The car is absolutely fine at full throttle or above 4k rpm though, which from what i have read, the maf's input isn't used by the stock ecu under these conditions, which pushed me further to thinking it was the maf
The MAF is used during all conditions, it's the primary input to how much air is entering the engine (and consequently how much fuel is required). Your MAF will be pegged at max with FI, there's no resolution above amostpheric air mass left in the MAF, It's partly this reason us MX5 owners have to fit replacement ECU's/piggybacks when adding FI to a car.The car is absolutely fine at full throttle or above 4k rpm though, which from what i have read, the maf's input isn't used by the stock ecu under these conditions, which pushed me further to thinking it was the maf
I think you're confusing MAF with the Lambda sensor which is indeed ignored at WOT.
Richyvrlimited said:
The MAF is used during all conditions, it's the primary input to how much air is entering the engine (and consequently how much fuel is required). Your MAF will be pegged at max with FI, there's no resolution above amostpheric air mass left in the MAF, It's partly this reason us MX5 owners have to fit replacement ECU's/piggybacks when adding FI to a car.
I think you're confusing MAF with the Lambda sensor which is indeed ignored at WOT.
Ah right!I think you're confusing MAF with the Lambda sensor which is indeed ignored at WOT.
The lambda sensor seems fine, it is giving an output which is showing up on my logs and all the cabling seems fine.
The other reason i think i may be the maf is it may have been slightly damp when i reconnected it, as it was raining when i was installing everything!
NeoVR said:
The standard ECU cant run injectors that large.. generally the ECU can compensate for up to 320cc's
it does sound like its going far too rich when you hit the throttle.
As long as fuel is being pulled using an airflow map then it should be able to handle them. Having said that, I had 350cc injectors on mine with the EMB and it didn't really like them much and the Mk2.5 ecu is a lot more forgiving than the Mk1 1.6 was. I know the general advice is normally to go no bigger than 320cc on the Mk1 ecu.it does sound like its going far too rich when you hit the throttle.
Seem to have sorted this now!
It was sort of maf related, but the maf wasn't doing anything wrong. I forgot when the AEM FIC got put in i had to set the maf clamp to a certain value, and then alter the maf table by 13.3% everywhere to get the car to run smoothly, start properly etc. Done this tonight and it has started working!
Car feels like it wants to rev freely a lot more now, just need to get fueling sorted now
It was sort of maf related, but the maf wasn't doing anything wrong. I forgot when the AEM FIC got put in i had to set the maf clamp to a certain value, and then alter the maf table by 13.3% everywhere to get the car to run smoothly, start properly etc. Done this tonight and it has started working!
Car feels like it wants to rev freely a lot more now, just need to get fueling sorted now
vigoro said:
MX-5 Lazza said:
MAF clamp? Don't you mean O2 clamp? I've never heard of a MAF clamp.
There is a max voltage clamp for the maf in the setup of the FICMX-5 Lazza said:
What's the idea of that then? The O2 clamp is there to tell the ecu that it's getting a steady stoich voltage so it doesn't mess with the fuelling in boost allowing you to fine tune it. I can't think what a MAF clamp might be used for.
I think when you get out of the MAF's range it's reading is erratic rather than pegged at 0v (MAF's go 5v - 0v, AFM's go 0v - 5v).Gassing Station | Mazda MX5/Roadster/Miata | Top of Page | What's New | My Stuff