Need some help.

1st things first, relative mods.

1200 RC engineering injectors (scaled to 943, when i change Fuel map to 11.5afr the scale of 943 seems to match my map the most.)
walbro FP
Injen IC pipe kit
megan o2
no name DP
test pipe
magnaflow catback.
****ty ca. 91 oct.

Issues:
1. When im driving around town with A/C on and i let off the gas while im coming to a stop (car is in neutral) the car turns off. Car seems to drop to about 500 RPMs. when the car doesnt turn off itll go up to about 800. When it does turn off it just shuts off. It seems to only do this with the AC on.

2. When im in gear and let off the gas to engine brake sometimes my AFR stays anywhere from 12-14:1. When i was on a stock map i would notice that when i would engine brake My afr would go to full lean.

3. In the day time it takes several cranks for my car to start. since i got my fuel trims closer to 5% it seems like it cranks less but still isnt perfect. Currently trying to make minor cranking enrichment adjustments.

Fuel Trims.
When AC is off my LTFT low is at about 3%. LTFT mid is about 2.4%
When AC is on my LTFT low is at about 8%. LTFT mid is about 3.5%

does anyone have any tips, suggestions, anything. I want to get good drievability.

before i forget here are my Latencies.
volts...Latencies
4.69 .. 3.312
7.03 .. 2.088
9.38 .. 1.896
11.72.. 1.200
14.06 .. 0.840
16.41 .. 0.720
18.68 .. 0.480

 

I had this same problem with my A/C functions as well. My fix was to adjust the Target RPM with A/C on value and the target rpm at idle. I bumped my values to the 1000-1100 range for A/C on and around 900-1000 for idle with A/C off. The options to change those value should be available in stock and tephra roms. As long as your fuel trims are correct it should at least help with your problem. Good luck.

 

Also, it helped with drivability when I kept my fuel trims just on the negative side of 0. When I went positive, I noticed my car would go to the rich side of things much quicker. My trims are something between -2% and -4% on low and mid trim. To speed things up you should reset your ecu by pulling the battery for 5 mins or your car will use the existing fuel trims until it settles on the new ones (generally 20 mins or so). Maybe this will work for you as well.

 

If he has a IX, simply reflashing the ECU will reset fuel trims.

 

Good to know. Thanks.
I think I reset the trims on my 8 as well by flashing from tephra v7 map to the stock map then back to my v7 map. However, I don't recommend this. Curious... Can anyone confirm this way works for resetting fuel trims on 8s?

 

Clean your MAF with electronics cleaner...

 

I believe evo 8 you have to pull battery. You can drain it quicker if you hold the brake down for a few seconds (at least suby's). Evo 9 you just have to reflash.

thanks for tips.
If i cant tune idle it to be in the upper 800-900. My last resort will be in the 1000's.



I do.
I just did that when i got home from work. Now i have to shower and go to my 2nd job. Will post updates later. Im surprised how dirty the maf was. The drops from the cleaner were dripping black! I cleaned until they were clear.

 

so i cleaned the Maf with electronics cleaner. Seems to have helped alittle. when im cruising and i let off the gas there is still a little drop in RPMs. I can say that the car doesnt seem to turn off.... At least not yet.

 

May need to back out the idle screw a tad..

 

All you symptoms say that the injectors are incorrect scaled. And it doesnt matter if the fuel map doesnt match the actual AFR (I know suby people like to have it match, but it doesnt matter. Just think of the number as an arbitrary number, lower means richer, higher means leaner). I think you have the scaling too high, which makes it lean and not have enough fuel to start. Try lowering your scaling. Lower scaling = more fuel

You should NOT have to make any cranking enrichment adjustments. Thats only needed when on E85.

Also, dont mess with the idle screw, unless you using EvoScan to set it properly.

 

You do not match your afr to the afr in the fueling maps! Those numbers have nothing to do with actual AFR. You need to get yourself a pro tuner to tune the car, then if you want to play with it after that, maybe you will have picked up some more insight.

 

When i tried the scaling on merlins guide and on the tunning scale thread my car would run to lean. Fuel trims were hoovering at around 10 both low, mid, and STFT. As i would lower that number the fuel trims would get closer to 0. I stopped at about 943. Fuel trims were within %5. i changed my fuel map to 11.5 and well it happens to also kinda match that. By maybe .2-.3. fuel trims are within %3.

As far as cranking goes. I have to hold my throttle down, opening throttle body letting more air in. If i dont hold it down it cranks alittle longer.

I adjusted cranking enrichments using this info. from Merlins guide.... new cranking enrichment IPW= old IPW x ( old injector scale / new injector scale). (page77 bottom of page) If you switch to E85 you have to multiply by 1.3 and round to nearest whole number. (page 78)
After i did that step it reduced cranking time.

Im not going to mess with Idle screw at all. Shouldnt have too.

What do you suggest my next move is. lower Scaling to make it richer?

Thanks for feedback, i appreciate it.






I understand if i lower .2 on my fuel map actual afr should change by .2 And i understand my fuel map may in fact never match actual AFRs. Im okay with that. The first time im looking to get out of tunning is 1. Get good driveability. 2. safety 3. power.

Matter a fact. I still havent messed with fine tunning fuel nor timing. I decided not to until i can get some driveability issues worked out. when i changed it to 11.5 afr i wanted to see how close it was to actual map. it was within .2-.3. After that i changed my fuel map to how it was. I felt it was safer since it was richer.

 

First of all, just because fuel trims are on, doesn't mean injectors are scaled correctly.

Next, like I said, u should not have to mess with cranking setting on pump gas. Ur starting issue is from the injectors not being scaled right IMO.

Yeah, try lowering the scaling and see how that works.