Tuning Question. E-prom Chip/AFC

[BaddAssGst]

So I finally got everything together and a buddy of mine were out tuning the car last night. I have a chipped e-prom (660s, 2g maf, 11.7:1 a/f, etc) and an AFC. Basically when we started it, we zero'd it out and started there. The car felt OK but should've had more power.

When I would go WOT, my narrowband (i know) would go completely into the lean side and the laptop (pocketlogger tuning) would show the o2 sensor going dead (0 volts). This is where we richened it up quite a bit (15-20%). The o2 sensor started to come back and the car had a ton more power then we started with. The more we richened it up, the faster the car got. We ended up richening it up 42-49% and this was where the o2 sensor started going into the "rich" side of the a/f gauge.

We got it semi-tuned for 19-20psi and the car definitely rips. I was seeing no knock at those levels but didn't want to turn it up to much because of the condition the tune was in.

Any ideas? Or if you need more info?

Sorry for the length, thanks guys!

 

[rsr93]

i dont think your chipped for 660's... you should not have to add all that fuel..

and how do you know your base afr you started at is at 11.7:1 if your using a narrowband and not a wideband?

you should get a wideband and confirm your afr. and find out what that chip is actually chipped for its not 11.7:1 afr with 660's if you have to add that much fuel to get it to feel ok.

 

[BaddAssGst]

i dont think your chipped for 660's... you should not have to add all that fuel..

and how do you know your base afr you started at is at 11.7:1 if your using a narrowband and not a wideband?

you should get a wideband and confirm your afr. and find out what that chip is actually chipped for its not 11.7:1 afr with 660's if you have to add that much fuel to get it to feel ok.

DsmChips made a custom chip for what I wanted. So I know it's compensated for 660s and the AFR is 11.7:1.

We've somewhat narrowed it down to possibly a faulty AFPR that isn't rising with boost.

Other then that, I'm somewhat lost.

 

[steve]

It sure doesn't seem like your fuel system is working right.
Have you tried connecting a adjustable pressure source to the AFPR and make sure that it tracks?
What do your fuel trims look like?

Steve

 

[andymoraitis]

Kyle,

I'm with Steve on this one. We can basically narrow this down to a fuel supply issue or missing airflow since the logger is dropping Hz counts. As we mentioned in our PM's, I would look at:

1. Failing O2 sensor
2. Failing fuel pump
3. AFPR is not functioning correctly.
4. MAF has had it.

I would really pursue the fuel angle first and make sure that you're getting good voltage to the fuel pump. Also, please let us know what your base fuel pressure is and if you can post a log showing IDC's that would be even better.

Hang in there. We'll get this solved.

Andy

 

[BaddAssGst]

It sure doesn't seem like your fuel system is working right.
Have you tried connecting a adjustable pressure source to the AFPR and make sure that it tracks?

What exactly do you mean here? I'm not following.

What do your fuel trims look like?

Low - 110
Mid - 111
High - 113

That's with the base pressure set at 43psi according to the FPR gauge.

 

[steve]

It sure doesn't seem like your fuel system is working right.
Have you tried connecting a adjustable pressure source to the AFPR and make sure that it tracks?What exactly do you mean here? I'm not following

.

You apply pressure to the nipple on the AFPR and check that the fuel pressure changes as you do so 1:1.

Low - 110
Mid - 111
High - 113

That's with the base pressure set at 43psi according to the FPR gauge.

So your running you fuel pressure 7 psi over stock (36psi) and your fuel trims still read lean. That's a problem.

Steve

 

[BaddAssGst]

You apply pressure to the nipple on the AFPR and check that the fuel pressure changes as you do so 1:1.

Ok, that makes sense. I'll go out and possibly test it tonight and be back with a response.

So your running you fuel pressure 7 psi over stock (36psi) and your fuel trims still read lean. That's a problem.

Well, I had the chip set to run base pressure at 43psi. I'm going to richen it up around 1400-1700 (my idle ) and see how rich I have to make it to get the trim to drop 100%.

I'll be back in a while with a report.

 

[BaddAssGst]

It sure doesn't seem like your fuel system is working right.
Have you tried connecting a adjustable pressure source to the AFPR and make sure that it tracks?
What do your fuel trims look like?

Steve

Steve,
I set it up as a boost leak test and ran 20psi through the system while using the self-turn-on fuel pump connector. I ended up with 63psi. (43+20) So that tells me then FPR is working correctly on a 1:1, correct?

I got the low fuel trim down to 100-101% by zeroing out the AFC on the low-throttle adjustment. My mids and highs are still lean (111% and 116%). My AFC settings for high-throttle are as following. 1k-3k are set to 14% ---- 3.5K ) 14% ---- 4k) 24% ----- 4.5k) 31% ---- 5k) 37% ---- 5.5k) 38% ----- 6k) 41% ------ 6.6k) 46% ----- 7k) 50%

WTF

 

[BaddAssGst]

You can see it there that the whole band is richened up yet I still have lean fuel trims.

Also, when I got my fuel trim down to 100%, the car was just idling. I just let it get to operating temperature and started zeroing out the AFC. It eventually dropped to that level but the car was not driven at all (if that makes a difference).

 

[steve]

Please remember that high throttle setting on a SAFC should never have any impact on fuel trims. You should only be using them when the ECU is in open loop. That means you have to use a wideband to tell how far off you are in truth.

You have me confused when you say that the trims went back to 100% by zeroing out the AFC on the low-throttle adjustment. It sounded like you were running positive corrections before.

Sounds like your AFPR is tracking so now you need to make sure that the fuel pump is able to keep up. Pushing 63 psi when your not using any fuel is easier than pushing 63 psi @ 160 l/hr.

Did you have the injectors flow tested before installing them or get a flow sheet with them?

Is your 2G MAF unhacked?

Steve

 

[BaddAssGst]

Please remember that high throttle setting on a SAFC should never have any impact on fuel trims. You should only be using them when the ECU is in open loop. That means you have to use a wideband to tell how far off you are in truth.

You have me confused when you say that the trims went back to 100% by zeroing out the AFC on the low-throttle adjustment. It sounded like you were running positive corrections before.

Sounds like your AFPR is tracking so now you need to make sure that the fuel pump is able to keep up. Pushing 63 psi when your not using any fuel is easier than pushing 63 psi @ 160 l/hr.

Did you have the injectors flow tested before installing them or get a flow sheet with them?

Is your 2G MAF unhacked?

Steve

Actually, I'm quite confused by that now. I'was running positive correction (richer) so by leaning it out (to zero it out) it should've gotten leaner. But the trims actually dropped.

The injectors weren't flow tested before I installed them because they had low mileage, I ASSumed they wouldn't need it.

What can I do to make sure the fuel pump is still flowing like it should? The guy told me it is indeed a Walbro 255 pump.

The MAF is unhacked and all 5 screen are still intact.

 

[BaddAssGst]

The MAF is unhacked and all 5 screen are still intact.

Speaking of the MAF, I pulled it out to verify it was unhacked, went to put it all back together and I'm now throwing code 12 (airflow), 13 (iat), and 25 (baro). The maf is plugged in all the way and I can verify it by hearing it "click" into place.

Maybe try a new MAF?

 

[steve]

Clear the ECU error codes and see if they come back.
If they do check for the right voltages at the connector before swapping the MAF.

Steve