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Discussion Starter #1
hey guys, Wrap yer brains around this and lets figure it out....91 gt, 351, efi, all stock ignition except for a 140amp alt and a performance distributors tfi module. I have a comp cams extreme energy cam with a 532 lift/ 232 duration so it's fairly lumpy. When all is right the cam is very noticible even at 950 rpm and the engine revs freely to red line with good throttle response. Now, when all is not right, start the car engine will still fire quickly, but the idle is smooth and it settles quickly at 800 rpm. hit the gas and it sounds like its under a load (in neutral) and will not rev past 3500 rpm. try and drive it and it will fall on its face and some times backfire through the intake. not hard but it's noticable. The best way to describe it is it sounds like the timing is set at - 30 degrees! NOW the fun part...go down the road and just "flick" the key from on to off and back on....while in gear so the car will just refire when the key goes back to on and it will rev like normal and run like the timing is set back to 20 degrees advanced. all with the "flick of the switch..this started out of now where. no changes to the engine or accessories. I drove it one day and it was fine, the next day it was doing this. it is TOTALLY random. it may happen the first start or not at all for a week. Once it does do this and you flick the switch it WILL NOT do it again until you shut the car off and start it back up. I've checked/changed the dizzy three times, tfi module, all the wiring in the engine harness, reseated the eec harness, salt n pepper shakers, changed the MAF re-ran all new larger cables from the battery to the starter to the alt checked all the grounds and ran new heavy gauge ones for extra coverage. checked and replaced any suspect wires on the igniton harness on the steering column. I'm down to swapping out the eec for a different one but I dont have a spare and I'd hate to spend 150 on another and still have the issue. Any thoughts? even showed it to a friendly tech at the ford dealership and he was scratching his head. NO CODES on the eec either. Open to any/all ideas...if I've tried it I'll tell ya!!!! link to videos gotstang.com - Mustang Videos for GTNBY2
Thanks in advance...
Brad
GTNBY2
 

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Discussion Starter #3
I would think so also...like volumetric effeciency tables, fuel tables and such but I;ve ran this motor with this eec with no mods or chips for 5 years. The problem just rose up a few months ago. I'm thinking I've got a bad eecreading concerning the electronic advance and when I flick the switch it reaccquires the signal and reads correctly..I just don't know why its doing it. I need a data logger and a full set of sensors so I can figure this out. I have eliminated all the simple solutions I think so now its time to go into things I no nothing about...
 
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