installed the maf the car seems to stutter under boost

[j5819n]

So i have a 1990 eagle talon tsi awd and i have a boost gauge, catback, mbc, and i just installed a second gen maf. After i installed the maf the car seems to stutter under boost and sometimes backfires. I just bought new plugs and wire that i am putting on on saturday. I am wondering how to stop the backfire and stutter. Safc maybe, or would i have to get the whole setup safc, fuel pump, and injectors help please.

oh and i also have a data logger on the way

No what would you suggest? I mean i put on the 2g intake pipe and a new filter but thats it.

Did you change anything else while you were at it?

No what would you suggest?

 

[EmeryatSTM]

Once you have the logger we can learn a bit more. Where did you get the maf from? When they are bad they do this to a certin extent. The maf will make the car run about 10% leaner then stock, so you may want to look into that as well.


-Em

 

[j5819n]

i bought it from a guy off dsmsource.com oh and it is not everytime is what i don't understand because one time it will pull hard all the way through gears then one time it will stutter.how could i check it?

 

[kenamond]

Did you change anything else while you were at it?

 

[pitbull419]

Afc or safc or any other apexi air fuel tuners and a set of 550's should fix your problem.
You need something to compensate for the greater amount off airflow.

 

[Icarus]

As I understand it, 2g MAF on 1g will run lean as was posted by EmeryatSTM. Basically your ECU sees less air than there actually is. 550s will bring you pretty close to the normal and then use the SAFC for minor adjustments. You will need a logger for tuning. Also at that point and certainly before you start adding boost, you will need to upgrade your fuel system. This is why:

If you look at RRE's flow numbers for the stock fuel pump, you will see that at 14v (re-wired fuel pump) there is enough flow for 132Lph at 43psi of fuel pressure (0 boost). The amount of fuel 550cc injectors require at ~100% duty cycle is 132Lph. As soon as you add boost you will exceed the the pumps ability to supply fuel at 100% duty cycle, e.g. at 15psi of boost you will only have enough fuel to support ~76% duty cycle on 550cc injectors. That is why most people upgrade the fuel system early on.

RRE Instructions

 

[j5819n]

alright well it looks like my path is going to be the walbro 190 fuel pump, then a safc, then prob some 550cc injectores and i am thinking that will fix my problem.

 

[dsmtalontsi95]

^+3 on the afc and 550's

 

[pitbull419]

I would really get the apex first. Driving you car while running lean can have a deadly outcome.
Of course with that you will also need to get a air/fuel ratio gauge.
If I was you I would put the 1st gen maf back on untill you get the apex and a/f gauge.

 

[BoostFrenzy]

With a 190 on a 1G, you also might want to think about a FPR. I know most 2G's can take a 190 on a stock FPR, but I think it is too much for a 1G to handle so you will be over running it.

Just something you will need when you upgrade your fuel system.

 

[pitbull419]

With a 190 on a 1G, you also might want to think about a FPR. I know most 2G's can take a 190 on a stock FPR, but I think it is too much for a 1G to handle so you will be over running it.

Just something you will need when you upgrade your fuel system.

Not true. the stock fpr on a 1g is enough to handle a 190. It is when you go to a 255 you ned a afpr, because it will overload the stock fpr.

 

[j5819n]

ok well i turned my boost down to nine pounds just to help out a little bit and alright i will just look into getting both the afc and the pump