CAR IS REALLY LEAN HELP

[SVTPIC]

hey everyone, im new to the boards here but not to mustangs. Just purchased my first SN 2 months ago after owning at least 15 foxs and having nothing but troubles! i bought the car stock with a powerdyne, went lean on # 7,burnt the piston and took it from there.
heres the build... 94 cobra, dss306, b-31 cam, ported twisted wedges,1.6 scorpions, stock cobra upper n lower, 75 mm t/b, 80mm pmas velocity, 30's, 9lb powerdyne, Vortec FMU 255 in tank, bbk inline aeromotive reg, shorties, catted bassani x, slp bullets etc. NO TUNE! if i watch the car on the scanner, my short trims go nuts..it goes from 8, 12,27, then finally peg 33 and send the car into a fit. does it just need a tune?? i hear the j4j1 ecu is very touchy to mods, is this the end result?? NO Vacuum leaks, 45 psi fuel pressure. tps is at .99 iac in new, 02's new..lol..ive never had anything like this happen, ive ran way wilder combos on a9l's and never had any issues. should i swap the a9l? and info is greatly appreciated. another thing, anyone running a b-31 cam or similar??if so waht kind of vacuum #'s are u pulling??

thanks
mike

 

[Paul]

NO TUNE!

There's your problem.

 

[ryclef331]

An FMU on these cars is not going to work very well at all. The cam will throw the computer a curve ball....then stack on top of that a blower causing turbulence at idle across the maf....its going to have trouble idleing. I'd ditch the FMU, pick up an aftermarket maf cal'd for 30lbers and injectors. THEN, tune it.

 

[SVTPIC]

ryclef..my meter is calibrated for the 30's. did u guys experience similar things with your mods without a tune?? my vacuum is another thing thats got me scratching my head...im starting to think i may have tightened my rockers down too much...anderson told me to set them at zero lash then a full turn after zero..i was like WTF. i set them at zero then a 1/2 turn. im only making like 8 to 10 inches of vacuumat idle and like 18 on decel. the cam has a 112 lobe sep so that shouldnt be a factor with vacuum. base timing is set @ 10. the car goes to ACA in wilmington de. to get tuned on the 2nd..im just trying to make sure everything is in working order before the tune.
thanks for the quick replies

 

[ryclef331]

ryclef..my meter is calibrated for the 30's. did u guys experience similar things with your mods without a tune?? my vacuum is another thing thats got me scratching my head...im starting to think i may have tightened my rockers down too much...anderson told me to set them at zero lash then a full turn after zero..i was like WTF. i set them at zero then a 1/2 turn. im only making like 8 to 10 inches of vacuumat idle and like 18 on decel. the cam has a 112 lobe sep so that shouldnt be a factor with vacuum. base timing is set @ 10. the car goes to ACA in wilmington de. to get tuned on the 2nd..im just trying to make sure everything is in working order before the tune.
thanks for the quick replies

I go 3/4 turn on my lash. some can get away with a full. I used to do a full turn but the last time I did the car ran fine on motor but when I went to spray it, it backfired and blew the airfilter clean off the car. I checked everything on the nitrous system but nothing was wrong. Called compucar and they said do the valve lash again. Come to find out, it was holding one or more valves slightly open. Not enough to notice on motor but enough to ignite the nitrous in the intake. However, I don't think that is the case with your car. The problems you describe though are typical though for our cars. However, I am not sure why you'd run bigger injectors and maf AND an FMU. What fuel pressure regulator are you running? If you have one that is capable of boost referencing, then you shouldn't need one. Boost referencing meaning that for every 1 lb of boost the car makes, the fuel pressure should go up 1 lb as well. You sound like a smart guy so I won't go in to much into how that works. I can if you need me to though. Running a boost referenced FPR should negate any need for an FMU. I've got a pretty gnarly cam in my car but I've never checked the vaccum signal strength at idle. However, after my last dyno tune session, I have almost zero issues with idle (slight surge when its cold but it settles down once its warmed up).

 

[Mr. OAM]

You can't think of vacuum the same way you would on an N/A engine because you are pressurizing the manifold with the supercharger.

What I have usually heard on hydraulic lifter preload is 1/2 turn after zero. We just want to be sure to get the plunger off it's seat. One full turn sounds like a lot.


Steve

 

[SVTPIC]

You can't think of vacuum the same way you would on an N/A engine because you are pressurizing the manifold with the supercharger.

What I have usually heard on hydraulic lifter preload is 1/2 turn after zero. We just want to be sure to get the plunger off it's seat. One full turn sounds like a lot.


Steve

oam...im gettin 10 inches at best with the blower belt OFF,,i think i went to tight on my valves and may have one hanging open..i called anderson today and they said i should have at least 14-16 inches when the car is warmed up. i went half a turn after zero lash..people have been tellin me i should have went a 1/4 turn in stead..its got 550 lift springs in it now. I think im pushing it with a .544 lift cam. what do you think

ryclef..im, running an aeromotive FPR, i thought it would be safer to run the FMU though,i got the 6:1 disc in now meaning its supposed to add 6psi of fuel per pound of boost. im starting to think i should ditch the 30's anyway and go with 42's. i dont think the 30's are gonna cut it. whats your thoughts

 

[2plus2]

I would get the 42's and can the fmu.

 

[SVTPIC]

I would get the 42's and can the fmu.

im thinking the same thing

 

[vettekiller3]

ya im going to agree with rycleff FMU's arent the way to go. maybe pump your fuel pressure up a tad but your biggest problem is no tune! you need to get inside the ecu(so to speak) and reset the parameters

 

[SVTPIC]

well i just installed my aem wideband and it only has a lean condition at idle like 18.1 lean lol. once u go down the road it goes from 14.6 to 15.1 then un der boost it goes like 10.3(which is pig rich) but very safe. im waiting on my 42's/maf then getting tuned. I must say even though an FMU is a "BANDAID" of sorts it sure as hell works...im gonna goto the track tonight and get a baseline run withy the 10:1 disc in and eventually work my way down to the 7:1 to see if i can get my a/f to around 13.1 under boost. wish me luck