datalogging and drivability issues

[QWKSNKE]

As you may or may not know, I recently installed 60# injectors and picked up a 55# MAF (Pro-M univer). Well last weekend and this weekend Italian LX and I did a good bit of driving trying to dial in the MAF curve.

Issues.....

1st) I am having a lot of bucking when attempting to cruise at a steady speed. Also noticed when I hit WOT it will stumble for a minute, pick up and run strong for about 1500 rpm, and then start stumbling really bad.

2nd) KAMRF's are not moving. Drove around 60 miles today and the KAMRF's never moved. What causes that? This has never been a problem in my car after resetting them. Car is not in OL when we are observing them.

[93Cobra#2771]

1. Bucking - usually a lean condition at those points - try richening the MAF curve up in those areas. I assume this is with light throttle, or no throttle?

WOT stumble - separate from the bucking, I'm guessing you have too much "accelerator shot" - the 60's don't need as much as the 42's, so scale back your function/accel enrichment multiplier and see if cutting fuel back will help.

2. KAMRF's not moving? I seem to recall a few people having that issue on the tweecer board. Good luck finding the old post

Are you SURE it's not in OL? There was a bug in CalEdit that didn't light the OL/CL flag correctly. If KAMRF's are not moving, you either have your MAF transfer curve PERFECT *yeah right*, or you in in OL. The new MAF curve prob. has your load values off some, so what once was light load may now be heavier load or vice versa.

Maybe Clint or Dale will chime in here, as I have zero experience tuning blown combos.

[Italian LX]

Originally Posted by 93Cobra#2771

1. Bucking - usually a lean condition at those points -

I thought bucking was usually due to being too rich or too much timing.

Originally Posted by 93Cobra#2771

Are you SURE it's not in OL? There was a bug in CalEdit that didn't light the OL/CL flag correctly. If KAMRF's are not moving, you either have your MAF transfer curve PERFECT *yeah right*, or you in in OL. The new MAF curve prob. has your load values off some, so what once was light load may now be heavier load or vice versa.

Yeah, that's what we were thinking. We datalogged the loop condition and it seems to be staying in CL during normal cruising (and we verified that it goes into OL when the TPS gets above 2.70v).

The loads do seem to be high under acceleration, but they linger around 25-35% during normal cruising. I would think that would be low enough to allow logging of new fuel trims.

The weird part is that the BANK1 KAMRF's do fluctuate down to .996 during some conditions, but that is all.

[QWKSNKE]

Originally Posted by Italian LX

Yeah, that's what we were thinking. We datalogged the loop condition and it seems to be staying in OL during normal cruising (and we verified that it goes into CL when the TPS gets above 2.70v).

you have that backwards. Should be CL during cruising and OL above 2.7 volts on the TPS

[Italian LX]

Originally Posted by QWKSNKE

you have that backwards. Should be CL during cruising and OL above 2.7 volts on the TPS

Ooops. I was typing fast and didn't proof read.

. . . i'll edit it.

[Dale McPeters]

Take a look at this link Chris M. made a post on the 60lb/hr injectors on a car that he tuned.

http://eectuning.org/forums/viewtopic.php?p=31774#31774

Might give you a better starting point?

[Wicked]

Originally Posted by Italian LX

I thought bucking was usually due to being too rich or too much timing.

You can get bucking with lean or rich, same way a backfire can occur due to either.

If your fuel trims are not changing then that is obviously the culprit because there is no feedback to add or subtract fuel during closed loop. What have you done lately that might have caused this?

[QWKSNKE]

Originally Posted by Chris Murreen on EECtuning.org

I don't have them but did tune a car with them (97 Cobra). They run rich at idle. Here is a good starting point for you.

High slope - 60
Low slope - 72
Breakpoint - .000029892

Injector_comp_batt_volt
VBat Mult
15.999756 0.3389
15.000000 0.3389
14.000000 0.4121
13.000000 0.4893
12.000000 0.5908
11.000000 0.7412
10.000000 0.9336
8.000000 1.4463
6.000000 2.5410
0.000000 2.5410
0.000000 2.5410
0.000000 2.5410

crank_fuel_pulsewidth
65534.000000 0.00140
180.000000 0.00140
150.000000 0.00197
70.000000 0.00349
40.000000 0.00700
20.000000 0.00909
0.000000 0.01401
-20.000000 0.02242
-40.000000 0.02451
-65536.000000 0.02451
-65536.000000 0.02451

I am confused because I think the tables are different between the late model and fox body cars.

i went ahead and started changing one of my files to reflect the cranking pulse width. Significant change compared to what I had but I feel like that his are correct.

On the Injector_comp_batt_volt is this different than injector offset vs battery voltage? It looks similar but the parameters are slightly different than what Chris listed.

[86GT]

Be careful with the battery offset function. The EEC-IV and EEC-V use different hardware drivers for the injectors. This means the offsets for a given injector size will be different for an EEC-IV verse an EEC-V.

If I recal correctley the EEC-IV requires .6 volts on the driver to open the injector and the EEC-V requires .75 volts. It does not seem like much but it will affect the offsets.

[QWKSNKE]

thought something was different. that's why I just saved the file I changed and did NOT write it to the pcm yet (wanted more info )