Say when People like Van Aaken do turbo conversions etc etc, does the AFM need modding?

Say if you could add the extra fuel you needed on boost via a 5th inj or somthing, is there any problems with the AFMs not liking boost and shutting the engine down?

I know this is the case on some cars (turbo and non-turbo cars that have been converted) where it senses over a certain amount, shits itself, thinks its an error as the car should never normally get that much airflow, and goes into limp home mode or just cuts the fuel all together.

How can you stop that happening IF it happens? Ive heard of "fuel cut defenders" or whatever, that stop the above i think, but think thats only on certain cars, not all, is it?

Anyone got a clue how these shoddy conversions work?

 

on my 4x4 after about 2-3psi ish the AFM would be fully open

this wouldbe the car's fueling limit.

so the extra injector driver thingie would register this boost and inject XXX fuel based on the map sensor input... it would be taking into account that the std management adds SOME extra fuel.

mine fueled ok @ 6psi up to about 3k without extra injectors above this is was lean as fook

 

a shonky old onion turbo i had was converted like this!
Using a the original Mfi wiring loom and no 5th injector! it ran lean as fuck!
never blew up though!
I assume with a 5th injector in there there wouldnt be a problem with the airflow meter as it didnt seem to effect it on the onion.

 

Well at least it didnt cut out or anything as it thinks theres a fault, some do, and thats what im wondering about...

Anyone know anytihng about E30 BMW engine managment?

 

why steve...

I can ask at work but need more info on the problem!

alex

 

generally bmw use very sophisticated management for the class of car and time. like individual knock sensors for each cylinder etc, etc.

E30 is old boxy shape 3-series?

you know yourself that these 'shoddy conversions' are just that. for less than the cost of a fifth injector kit, and a bodge to the afm signal, you could buy a megasquirt programmable fuel ecu and do it properly.

have a search around for it - hint, type megasquirt as one word in a search engine - mega squirt gives entirely different results (that i'm sure you've already visited )

 

Basicly Alex i just want to know if early (1985) E30 325i managment shuts down or anything when it sences what it thinks is a far too large amount of air going thru the airflow meter, or if it just maxes out and stays at the max amount.

Just some managment systems cut the ign etc when they sence boost or a certain amount of boost, thinking its a AFM error.

And if so, how you trick the AFM signal to stop it doing so...

foreigneRS--

Yup, E30 is that shape.

The megasquirt looks good, but ive no time (or skill ) to make it, and a bodge is more than good enough, trust me

 

you can buy them ready made on ebay, just twice as expensive as making it yourself

 

the response the AFM gives the ECU is proportionate to the boost, its the ecu which compars the singal form the AFM to its map table and will decide that there is too much air coming in so shut down, my evo 6 did this one a free flow pipe, decat and air filter were fitted, the best solution at the time was to fit the ralliart sport ecu, this was simply a plug and play swap of the ecu which allowed boost levels of 1.5 bar safely, the airflow itself though is not just dependant on boost produced, the density and temperature of the air are also calculated and taken into consideratiopn, so for axample my car would boost cut at 1.1 on one day and then only 0.95 the next,

other option is to bin off the AFM and fit a map sensor with a ecu mapped to it

do NOT use fuel cut defenceer as all it does is modify the singal form the afm and kid the ecu that it is actually gettin gless air than it is - risk of running lean badly and conditions for maximim smoke

 

Like i said, this is for a total bodge cheap nail of a turbod 1985 325 bimmer, and im not willing to spend any real money on it.

Extra fuel can be covered by a shonky 5th inj setup or similar, jus need the AFM to not to shut the ECU down (IF it does on a BMW)...

 

Yes it will work...

The ECU will notice the AFM is out of range and ignore the sensor... so to that end you could completely remove the AFM and remove that restriction! The only down side to that is you will get longer warm up periods!

Alex

 

and shit off boost response probably