maft genII problems

[Spiv]

Finally got to the point that I could install the genII I bought a while back, but not having much luck with it just yet.

The good: it runs, it monitors everything it should, seems to be putting out a reasonable KV reading to the ECU, etc. Even reads my ZT2 output correctly (matches what I get on the laptop).
the bad: it barely runs, and air/fuel is all over the place. The Vf jumps around, usually settling for a few moments on either 4.8, 3.4, or 1.1 volts.
the ugly: tip in is as bad as when my TPS sensor was giving up the ghost. The current TPS reads .5 to 3.5, and the off idle on it checks out fine.

I must have a setting wrong somewhere in the system. Best guess is the sensor type, which I currently have set to 3.5" lt1 on the input, and supra mkIII on the output. Not sure how to identify the sensor, got it off a friend who deals in GM stuff.

I also currently have the sensor where the old KV sensor was (temporary solution, till I get my FFI finished). No air filter on it while I'm trying to get it running. Any of this could cause the problems I'm having?

Any advice? Ideas? Condolences?

 

[hottscennessey]

is the sensor before the turbo inlet (pull through) or in IC piping (blow through)?

you can tell the sensor type by measuring it. 3.0 will have a diameter of 3", 3.5 will have a diameter of 3.5".

 

[drjonez]

post settings in the gen II, wiring set up.

 

[Spiv]

pull through right now. Sensor housing inlet is 3.5", but not sure if that's "LS1 aluminum," lt1 3.5", or if the sensor itself is 85mm (ls1/ls6 85mm). Obviously, it would help if I knew what car it came off of.

Settings:

MAF in - ls1 al (tried others)
MAF out - supra MKIII
cylindiers - 6
disp - 3.0
load - use maf/rpm
main scale -26.5 (same setting I used on the SAFC previously), also tried at other settings
v-out 1 - 2.5
v-out 2 - 3.6
afterstart - 0
lo - 36.4
mid - 100.1
high - 143
F out max - 0
MAFlim tps - 0
MAF lim - 0
MAF krpm - 0
idle flow - 1
idle filt - 2.0
af delay - 0.2

wiring:
orange - zt2 white wire (its output)
purple - same place on the chassis as the wideband ground
blue - tps
green - KS on ECU (spade lug disconnected from KV wiring)
pink - 12+ ignition, and + on MAF (black/red onecu)
brown - air temp, THA on ecu
gray - not connected (no HAC mod, I live in florida where there is no altitude)
white - rpm (IGT on ecu)
yellow - F on MAF
black - ground, brown on ECU and "-" on MAF

help appreciated guys, I'd really like to get this thing running

 

[drjonez]

what happens when you zero out mainscale?

 

[Spiv]

same thing. Right now the idle runs at about 11:1 a/f, doesn't seem to have much effect.

 

[drjonez]

any codes?

 

[Spiv]

Nada. I just had a thought while reading through some stuff, the air temp sensor says "splice" where the others say "tap" for the pro. What exactly is meant by that (the diagram just shows it tapped in to the wire like the rest?)

 

[Spiv]

still no luck, can't keep messing with it tonight without pissing off my neighbors too much.

Right now it seems like it starts up pretty good, even had good tip in for the first 10 seconds of running. After that it starts getting richer and richer at idle and eventually gets to where anything will make it stall out.

Something must be making it think it's way off and compensating.

 

[drjonez]

Nada. I just had a thought while reading through some stuff, the air temp sensor says "splice" where the others say "tap" for the pro. What exactly is meant by that (the diagram just shows it tapped in to the wire like the rest?)

splice/tap area approximately the same thing. either way, if the stock AFM has been removed it's not a problem.

 

[Spiv]

hm. So what would cause the computer to slowly continue to add fuel until it kills itself like that?

 

[drjonez]

still no luck, can't keep messing with it tonight without pissing off my neighbors too much.

Right now it seems like it starts up pretty good, even had good tip in for the first 10 seconds of running. After that it starts getting richer and richer at idle and eventually gets to where anything will make it stall out.

Something must be making it think it's way off and compensating.

interesting. i'm a bit concerned about the huge mainscale correction. what happens if you put that to 0? what are you reading on UserTn?

 

[Spiv]

mainscale == usertn. I guess I'll be zeroing it tomarrow morning to try again.

Question though: is there a reason I /shouldn't/ be compensating for the injectors?

 

[CRE]

So you're pulling 26% from the mainscale AND from the UT? (Sorry if it's a dumb question I don't know the Gen II at all)

What size injectors are you using?

 

[Spiv]

no no, the usertn is a display of the total amount being adjusted by the gen2. IE the mainscale + the rpm/load adjustment + whatever else.

Running 550cc injectors

 

[drjonez]

Question though: is there a reason I /shouldn't/ be compensating for the injectors?

injector compensation is retarded. realize that by using a correction that large you're drastically altering airflow and timing. drop fuel press if you need to have a correction that large.

 

[Spiv]

hmm...it seems like the a/f tracking is kicking in, I set the desired @ 2000rpm (and presumably below that) to 14.7 and suddenly it wants to be lean all the time (like 16-17:1 a/f). All the minimum settings for the tracking are well above what it's at (min load @160 or something, min tps @ 4.0 even though my tps won't go over 3.6, min rpm @ 3200).

Put the mainscale at 0, of course, but that had no effect till I changed the 2000rpm fuel tracking. What could be making it decide it should be tracking at idle?

 

[drjonez]

what happens to usertune when you get to 2000?

 

[Spiv]

ok, I got it to go out for a drive tonight. I set the 2000 and 3000rpm points on the afr tracking to 14.7, which it now holds as the "target afr" in the monitoring stuff. Even so, it wouldn't get there without me pulling at least 15% fuel out on the mainscale, and it runs super rich under and boost (which is fine, safe, tunable). I think I must have created a leak in the system somehow while doing this mod, because while cruising in closed loop it tracks perfectly to 14.7, but damn near stalls when I let off the gas. If I've been cruising it will stall off the line if I don't give it enough gas (and often stumbles for a moment when I do).

I will say if it turns out a leak is the problem, unless this turns out to be a real doozy, I'm guessing this setup (genII + ls1 maf) is much more sensetive to stalling than the stock AFM was.

But the good news so far is that I did drive it, it did boost, and it did act like a proper flow meter for the most part. I must be on the right track.

 

[TurboStreetCar]

still no air filter? are you running stock clutch fan? they create a lot of turbulence if you put your hand in between the fan area and the MAF it will clear up a little, i have the same setup and i want running an air filter at first because i didnt have one that would fit over the 3.5 inch maf. it would run really erratic all the time especially at idle but when i would put my hand over on the side of the maf and block the turbulence from the fan it would clear up almost instantly.

Read whatever numbers you can off the maf, if you have the same maf as me its not programmed into the gen 2 and you will have to adjust the maf scaling in order to get it to match, its what i had to do. if you give me the part numbers and they match the ones i have then ill post my scaling parameters and it should get you running somewhat close.

in the mean time get an air filter because it will help alot. Dont worry once you get it tuned up youll love the gen2.