This is topic Fuel system issue, or tune issue? in forum Tech Talk at Northern California Ford Owners  .


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Posted by Reloaded83 (Member # 8647) on :
 
My '04 Mach 1 currently has a "break in" tune using Sniper. The car is going to a dyno (as soon as I figure out who I'm taking it to) to be tuned, and I'll be switching to SCT. I want to make sure that the car is ready to be tuned. The car takes about 3-5 seconds of cranking in the morning before it actually starts. Also, with a mechanical fuel gauge hooked up, the car was idling around only 29 psi. It would drive fine out of boost, but lean out (17.1 or higher) if you stabbed the gas or if you went into boost. So I changed out the fuel pump as the Cobra pumps that were in there were used and I've had them for a year. After that, the car reacted much better. You could gas it without it leaning out like before. I took it out for a drive yesterday, and if you roll into the throttle, I could get it up to about 8-9 PSI with an AFR of around 12-12.2 But if you stab the throttle or go WOT from a roll, it would lean out the same way. Needless to say, the car hasn't been driven much due to the lean issue. And though the engine does have a warranty, I'd prefer not to have my car down for another few weeks while another engine gets put in. My question is, do I have something wrong in my fuel system? Are my injectors too large for the fuel pump setup I'm running? I've been advised that at this power level I should be fine with what I have and I personally know a Cobra running almost my exact setup (I think he has a 4lb lower, same upper), and making 480something on pump gas to the wheels with no problems.

Basically I want to make sure that it's just the current tune that is the problem so that when I do send the car out to be dyno tuned, I know it can be. I'm sure I'll leave out some important info, so I'll try and answer any questions as best I can.

Mods on the car currently:
'04 Cobra longblock
Mach 1 PCM
2.76 pulley
JLT high boost intake
63lb injectors
Cobra tank/NEW Cobra pump assy. as of two days ago
Boost-a-Pump (40 amp)
Sniper MAF
LFP heat exchanger
NGK TR6 plugs

My old set up was a stock Mach block with a 3.40" pulley and 39lb injectors with the used Cobra tank/pumps/no BAP. I never had a problem of leaning out before. Under WOT I was always around 11.8 and it started right up every time.

I'm still not totally sure where I want to take the car to get tuned, but I have heard a lot of good things about AED and I believe someone from that shop is here on the forums? So I may be getting ahold of them to see if they can take care of the car for me. Thank you for reading my novel and any help is always appreciated.

[ May 15, 2009, 11:23 AM: Message edited by: Reloaded83 ]
 
Posted by 92stangLX (Member # 3252) on :
 
1st off, I wouldn't go under boost until you get a proper dyno tune. It sounds like you "should" have enough fuel. I would talk to a tuner about your fuel system setup and if they say it's cool then get it to the dyno and have it tuned before you blow your motor.
 
Posted by Reloaded83 (Member # 8647) on :
 
Trust me, I haven't driven it in boost since it has leaned out. And the car has been sitting for about a week while I figure out where to take it. I definately understand that the engine could easily let go if I drive it while lean. [Smile]

Thanks for the reply.
 
Posted by SHOalex (Member # 7720) on :
 
Who ever you decide to get the tune from ask them first they should be able to steer you in the right direction for sure

[ May 15, 2009, 05:27 PM: Message edited by: SHOalex ]
 
Posted by 427 StRoKeR 94 GT (Member # 8722) on :
 
A.E.D. IN SAC [patriot]
 
Posted by Duncan Motors (Member # 7045) on :
 
ive been using aj's tune shop in napa, dude is awsome and way helpfull way knowlegable on many systems 707 812 4195.he aint happy unless your happy type of person.
 




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