I'm hoping you geniuses can help me out.
I have an 88 formula running with the following:
ARAP code
Accel 24# injectors
inj constant set at 23
355cid
0 spark retard with stock ARAP spark tables
43 psi of fuel at prime

The car has started to run leaner and leaner. I haven't even gotten it up to 24# in the prom yet. Now it looks like I'll be dropping it to 22 in the hopes of not running too lean. My BLM's are now hanging around the 140 range at hot cruise and idle. Giving it gas does drop it down to the high 120's low 130's.

Anyone have any ideas on what I should look for? Need more information?

 

Bad O2, vacuum leak?

/N.

 

New O2. unless it lags or is going bad already.
Vacuum at idle is 17. I believe this is considered good.

 

How long has it taken for this to happen?.

It's almost too easy to point at the EFI, rather then diagnose the mechanical end of stuff.
Test the fuel pressure reference line on and off, and at WOT.
Any doubt about the fuel filter, toss one on. BTW, I've seen a filter get plugged with 3 tanks of bad gas, and it was in less then a week, so I don't assume the FF is good anymore, after that fiasco.

BL's during transistional throttle movements are meaningless. BLs only are meaningful at idle, and light cruise.
HTH

 

Add fuel to VE and PE

 

The car's been actually lean for the past week now. In the 2 months it's been on the road I have yet to bump the constant to 24.
I'm leaning away from the FF due to not feeling any loss of power in the top end. And yes it is 1 month old. If I can't find anything else I'll change it again. At least this time I won't have to cut the line and put in compression fittings.
I run BL's of 136 or so at cruise and 140 at idle. 2 weeks ago I was at 124.
I believe it may be something mechanical but if I can't find anything I'll run full stock ARAP again to see if the BL's change.
Today I changed the MAF power relay because running stock 305 programming it would occasionally throw a code 34. Hasn't done it at all with ARAP but I'm hoping that was the problem in skewing the numbers.

I want to hold off on VE and PE until I can run constants of 24 without being so far off on the BLM's.

Does this info help?

 

Update:

My fuel pressure is good. At light cruise it's around 36 and at wot it's 46. Light accelleration is 40. That to me rules out the pump and filter.
On the other hand I just hit hot idle BLM's of 156 today. The computer has definitely learned since on a nice drive today the INT's were nailed on 128. The block learns were all over depending on the cell number. Seems the higher the cell number the leaner the BL's.

Any other ideas? Do I have to play with the PE and VE tables even though I'm running ARAP on a 355?

 

Hmmm,
Maybe run some good injector cleaner thru it.
Try some Berrymans' or GM fuel injector cleaner.
GM seems to have some new stuff that while expensive seems pretty good.
P.S.
Don't bother with the alcohol based stuff that comes in plastic bottles.

 

I'll try that. Although I'd find it odd that they're plugged. I just replaced them with Accel's 1K miles ago.
Do you know which bin belongs to a we'll say 89 5.7 A4 MAF TPI 165 comp?

Maybe I'll flash a prom with the stock bin and see how that works as well. At least it'll give me another avenue to pursue.

I've heard some good reviews on that Techron inj. cleaner. What are your experiences or thoughts with it?
It's off to the stealership with me.

 

Any other ideas?

 

Has weather taken a sudden change? getting hotter or colder?
are you sure this just started or has it always been.

 

No sudden change in the weather. It has always been if you're referring to the last 3 weeks.
I found that my distributor loosened itself and my base timing moved over to ~5atdc. I moved that back to 6btdc and now the car's pinging like a change counter. I popped in the ARAP chip that I had just burned with the APYP timing table and the pinging didn't even slow down. This whole time I wasn't registering knock on my laptop. Gonna look into that now. Looks like I also may have a slipped balancer/timing mark.

While setting my base timing yesterday I noticed that on my laptop it said 20 degrees. With the EST disconnected shouldn't it show what base is or is 20 correct?

 

ok, maybe i will get help here, but im not holding my breath.....


I have scanned my car 2 days in a row, one at mid afternoon, one at night, and the BLM's are showing very lean. as lean as 156. I dont have any prom stuff, just the scanning software and i want to know what could cause this? also, when i reved the engine, the blm's went to about mid 120's... which i belive is good (new at the whole tuning game) but then went right back up wot 150's... now i see vaccum leak as a possible answer, and is very possible as i have taken off my plenum about 400x in the last 2 months but havent heard any tell tail signs of a vaccum leak as i had my engine scanned at the TGN and it was running about 140's there, with about 8* retarted... now its fixed and im running really lean. The winaldl flashes the rich flag, but blm's still stay at 153. any ideas? Im about a click away from ordering a holley afpr at this moment. thanks guys...

 

If your MAF has screens removed that is probably why.
How to fix it? Rescale the maf table 1, you can use a AFPR but then you will be rich everwhere else,or put screens back in.

As long as BLM's go no leaner that 159 than you are ok unless you have a drivabilty problem. Other than that it can cause your WOT to be more rich than it should be because of ECM compensation for the lean lower RPM. Its a safety feature, if the ecm senses a lean condition it will add the % lean to the wot fueling.