MAF and AFR's

[TSiTalonawd96]

Hey guys, im kinda new to DSMs but I have a pretty good knowledge of all cars. Let me tell you my scenario first... I have a 96 Talon TSi AWD. It has a hybrid turbo (14b with 16g internals), catback, K&N, hard piping, BOV and some other dumb stuff. Right now im running 15-16psi. Everyone tells me this is about max for the stock fuel system BUT once I get under boost my AFR's go to at least 10 to 1. (my AEM stops there). After my RPMs pick up it levels off at about 10.4 to 1 which obviously is very rich. Seems to me you could push it harder if im running that rich?

This morning I let it idle for awhile and it started loadin up really bad so I took it down the road and beat it and it cleared up then the CEL came on (P0100) which is a MAF sensor. Could this be why im running so right even at 16psi? or is that normal without a SAFC?

I tried taping on the MAF sensor with a screwdriver handle when it was running and it didnt miss a beat.. Anyone got any experience/info on all of this?

^^^**running to rich... not right, sorry.**

Its been running fine ever since also

 

[Gstclipse69]

Well if the wideband is correct then you are a little rich. Most shoot for about an 11:1 afr. However do you have a logger of any sort to see if you are getting any knock? On a 2g you are going to have to look at the timing curve under boost to see if it has any dips in it. It should be a steady incline under boost. Before you turn up the boost you need to check for knock and make sure your afr are inline.
Do you have an upgraded fuel pump? You are somewhat rich and may be able to up it just a little but beware you are on the verge of running out of fuel. Next on your list is a tuning device and upgraded injectors.

 

[jrohner]

The stock fuel map is in the 9's, so 10:1 is no surprise. They set them ridiculously rich from the factory in case there is an issue that leans it out so there's no damage to the engine. More boost isn't going to make it leaner unless you're running out of fuel (plugged fuel filter, or fuel pump just can't keep up).

 

[delta448]

The stock fuel table targets AFRs richer than 10:1 when under more than 10psi of boost from 4000 all the way to redline.

The reason you can't "push it harder" is because of fuel cut primarily. Fuel cut is like hitting an invisible brick wall and will get your attention very quickly. Fuel cut occurs when the ECU reads a too high airflow per rev. and tries to save the motor. You must have some type of tuning hardware in order to bypass fuel cut.

 

[TSiTalonawd96]

^^Good stuff guys, finally some people who can give me good advice as well as the whys. So I guess for now I should just leave it alone and start buying stuff like a front mount, injectors, pump, and a SAFC .

Kinda of topic but whats a good but cheap logger?