Another Surging Idle Problem Please Help

[daniel93gt]

Hello everyone. I know this subject has to have been brought up in here a million times but none the less I need some help. What I have is a 93 mustang gt. I have taken the engine out of the mustang and put it into an 88 f-150 with and automatic. The engine fine ran at first with no problems, but now at idle I have surging problems( typical of head and cam mods), and I need help on smothing it out. I engine is a 302 bored .40 flat top pistons, ported e7te's, truck upper and lower intake, truck tb, stock 19lb injectors, truck computer, and an e303. I have terrible surging problems at idle and cant seem to get it smoothed out. Also the engine dies when I first put it in gear and also when I pull up to a light. I have the timing set at 10deg with the spout connector out and the computer advances it to about 14 with the connector in. I thought about using the mustang parts and converting the truck to mass air, but i am not real sure what all it you have to do. The mustang computer I have is an a3m1 which is a mass air computer for a 5 speed. If I do the conversion will the computer work with the automatic? Would a stall converter help the surging and dying problem? The harness in the mustang is butchered but I think I can do the conversion with just the wires going to the maf meter right? Can the conversion be simplified if I just bought another harness? If so which harness would work, any chance of plug and play? Any and all help will be appreciated. thanks
Daniel

 

[Scorcher2005]

i always thought maual stang computers were A9L's....? What is feul pressure at? What bout turning in the idle screw on the TB? Also clean you IAC, check TPS voltage etc. Heres a link w/ more info: http://www.muscularmustangs.com/iac.php

Also, check out the sticky at the top of the forums.

 

[daniel93gt]

You are correct a9l computers are for manuals but the a3m1 is identical to the a9l but has a higher rev limiter. I tried screwing in the idle screw, I will try cleaning some of the sensor and see what happens.

 

[Scorcher2005]

you screw out the screw to make the idle go down. screwing it in makes the TB open more at idle and creates a higher idle rpm

 

[stang99x]

I had serious idle issues on mine, most likely related to all the EGR and vaccum lines I removed, but when I bought that cheap EGR simulator off ebay, ir ran without a single glitch

 

[jrichker]

See the Sticky "Help me create the "Surging Idle Checklist" at the top of the forum.

In the "Help me create the "Surging Idle Checklistst", Ranchero50 posted some very good information on fixing idle problems on engines with other than stock cams. You'll need to read a lot of the other posts before you get to his post, it is pretty far down the list.

 

[daniel93gt]

well I have done almost everything on the list except for converting to mass air. I cleaned the tb, iac, act, and all their connectors still no results I set the timing at 13deg and the engine pulls a steady 19psi vacuum when the engine isnt surging. When it is surging at idle it fluctuates from 15 to 21 and when I hit the throttle it drops to about 5psi and then back up to 19 when i let off. My tps voltage is .95v closed and 4.53v at wot. I tried to reset the base idle with the computer as it tells me to on the modular mustangs website and the engine wont start with the iac disconnected as he instructed. I have raise the idle by screwing in the idle screw but it doesnt seem to help, only seems to give me surging at a higher idle. The truck stalls when I pull up to a light, but I can keep it running If i slowly stop and then pop it into neutral. But If i quickly stop it will stall in either neutral or in gear when I get stopped. I dont believe i have any vacuum leaks but i havent check all of them I have eliminated all of the smog equiptment except for the egr valve, and I am just using the smog pump as a pully until i can get another belt. Im thinking that since it stalls when the engine is slowed down quickly and at a light maybe having a stall converter might help. The transmission says metric on the pan. Any thoughts?

 

[daniel93gt]

I just wanted to add that my exhaust seems to smell really rich but my computer hasnt thown any codes. Im using the truck speed density computer. does anyone know if I convert to mass air if My a3m1 computer out of my mustang will work with an automatic even though it was made for a manual? any good harnesses to use for the converstion without having to dice mine.?