This is topic Help with stalling / hesitation / stumbling problem in forum Tech Talk at Northern California Ford Owners .
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Posted by BCINGUU (Member # 2397) on
:
I have the following symptoms on my 90, anybody know what might cause this? Engine dies when slowing to stop, tries to die while idling, hesitates and medium throttle acceleration and stumbles like its falling on its face while backfiring through the intake under hard acceleration.
Datalog shows timing slams fully negative (-32 degrees) under acceleration, wtf. This is making me focus on possible timing related causes.
I have tried the following:
KOEO and KOER tests, no problems. (KOEO initially showed a code 22, replaced the BARO sensor and the code went away)
New ECU computer (third one I've tried)
Removed aftermarket chip, same behavior.
New coil, plugs, wires
Swapped distributors
Here is my combo:
347 Engine
Trick Flow Twisted Wedge Heads
Comp Stage 1 cam 221/225 .525/.530 112LSA
MSD Ford Blaster TFI ignition coil OEM-style
93 Cobra MAF calibrated for 24# injectors
Ford Motorsport 24 lb./hr. fuel injectors
FMS Cobra upper and lower intake
Cold air intake, K&N filter and MAF in fenderwell
180 degree high flow thermostat
BBK Long-tube 1-5/8 inch ceramic-coated headers
BBK Shorty H-pipe with hi-flow cats (CARB E.O. D-245-5)
Spintech side-exit Mufflers
TwEECer programmable EEC-IV tuner chip
Posted by 92stangLX (Member # 3252) on
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Are you running lean? It kinda sounds like the computer is purposely pulling out a bunch of timing for some reason.
Do you have any codes?
Posted by BCINGUU (Member # 2397) on
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No codes any more after I got rid of Code 22.
I'm thinking of going Code 7A myself later today though.
Posted by BCINGUU (Member # 2397) on
:
edit.
[ March 06, 2007, 04:25 PM: Message edited by: BCINGUU ]
Posted by BCINGUU (Member # 2397) on
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Here is the resolution in case anybody finds this in the archives and wonders. Dirty MAF wire. Cleaned it and everything is fine now. And, the car just passed smog!!!
Posted by CA FiveOh (Member # 7429) on
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Did you put the 93 cobra MAF transfer in the Tweecer? I know you said the wire was dirty, but a poor transfer function will cause that also. Just curious.
Posted by BCINGUU (Member # 2397) on
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Yes, I have copied over the MAF xfer function from the X3Z on my 93 Cobra, which should be close enough I hope. I have also tuned my injector offset and slopes so my KAMRF correction factor is about 1%.
And, I passed smog yesterday! So it must be working right.
Posted by CA FiveOh (Member # 7429) on
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Damn, if you're at a 1% correction factor than your tune is pretty spot on. Cool!
Posted by BCINGUU (Member # 2397) on
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Yeah, I've spent a lot of hours tuning several cars over the last 5 years or so, and got pretty good at getting those 3 parameters to line up.
"Laptop tuning" isn't considered all that strange any more...
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