New fox owner, idle issues need some advice

anorth93

Member
May 15, 2020
83
10
18
florida
hey there, new to the site, have been reading things on here for awhile but this is my first time posting.
So here it is and im sorry if this has been asked 100 times. A few months back I bought a 93 lx Efi, and I got it home to realize it had some idle issues. It wouldn't stay running at all, rpms would drop low and it would die. So first thing I untagged the MAF, ran better. So got a new one idles much better but still not right. Did some research and thought maybe the IAC. So I got a new one and it worked abit better. So now here is where I'm racking my brain. I go out to start it and it just turns over and over. Finally when it does crank it drops to about 500 rpm and dies. After doing this two or three times I can rev it up to about 1k rpm and let off and it stays and idles perfect from there out. Any ideas on what's causing this? Any help would be greatly appreciated!
 
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Here is a good place to start. It saves you from being a parts changer, and pinpoints the problem. Thanks to member @jrichker

 
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Thank you guys working on that now. Also not sure if you can help with this, I just got my car back today got the AOD rebuilt. I know should have went with a C4 but the rebuild was cheaper right now with the craziness in the world. So before I got it rebuilt I would have to let off the gas just alitte bit for it to shift to second. But the 3rd gear was burnt up. So now the new tranny is in just dove it and it does the same thing. I can floor it hit about 5k rpm and have to lift alittle then it shifts to second. Is this normal for the AOD. Or is mine just junk? It runs great and shifts all the gears good but. It won't shift from 1st to second without me letting off the gas.And thoughts would help . Thanks in advance !
 
Also its like it has no first gear power. It will hardly spin the tires. The tires are 255/60/15 the guy I got it from said it has 3.73s but there is no way. If the gears are stock would that tire size be to big to where it won't hardly spin the tires?
 
Dump codes sticky

Look at the top of the 5.0 Tech forum where the sticky threads are posted. One of them is how to dump the computer codes. Codes may be present even if the CEL (Check Engine Light) isn’t on. You don’t need a code reader or scanner – all you need is a paper clip, or if your lady friend has a hair pin, that will do the job.
I highly suggest that you read it and follow the instructions to dump the codes. http://www.stangnet.com/mustang-forums/threads/how-to-pull-codes-from-eec4.889006/
 
Sounds like your tv cable on your trans is not adjusted properly. If you run it too long out of adjustment you will fry that newly rebuilt AOD.


Chris
 
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Ok so ran codes got koeo code 82 and 15.and my koer code was 12. I'm fixing to do the smog delete so that will take car of that. but I don't see why it doesn't have any low end power. It feels horribly slow, and there is no way it'll do a burnout. Not sure if this would make any codes come up or power loss but when I run my ac and everything my voltage drops horrible low, can a bad alt cause power loss like that?? I'm sure some of these questions sound stupid. But this is my first fox and jsut trying to figure it out
 
Ok so here is my car its mostly stock but has a few upgrades.
93 lx 5.0 efi automatic AOD with shift kit
Has full flowmaster exhaust, bbk headers
Msd distributor, cap and igniton coil.
Bbk cold air intake
New Maf
New iac

So here is the problem. I got the car with a bad tranny, had it rebuilt and now it shifts great. But it has no first gear power. I thought it was because the tranny was blown but now its freshly rebuilt and thats not the problem. When I floor It will hardly spin the tires. The tires are 255/60/15 the guy I got it from said it has 3.73s but there is no way. If the gears are stock would that tire size be to big to where it won't hardly spin the tires? Also from the tail pipes I smell strong gas so its running really rich, and I'm not sure why. Also when I have the AC and everyone on my volts drop really low. I think the alt may be bad. If it is can that cause that much low end power loss?

Ran the codes got koeo codes 82, 15
Koer codes 12, 91

Any thoughts or advice would be greatly appreciated!
 
I second the above two comments. A bad sensor could be why to the running rich. Which could also make your car sluggish. Retarded timing would also make it sluggish. I would probably go through the surging idle checklist, verify timing (I might even throw a new harmonic balancer on it to ensure accuracy), and do a compression test.
 
Well didn't quite get all I wanted done but got the smog deleted. Previous owner had it all tore apart so I just took it off. I don't have cats anyways. But found a broke vaccum line to the charcoal canister and the tps isn't right so just ordered a new one. Going to set timing and idle tomorrow night. Also ordered the one o2 sensor that was bad.
 
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Also I noticed when I start the car there is vaccume at the Egr for about 10 sec then goes away. I know there shouldn't be at idle. But not sure if this is normal for a few sec then goes away. Building me a smoke machine this weekend to so I can for any leaks I can't see
 
Ok did the base idle reset and got my tps set right but this is the weird thing I can back the idle screw up to about 600-750ish thats all. I can back it all the way out dang near take the screw out and it won't die. Get the idle to about 7 750 plug or unplug the IAC no changes at all. Im getting so lost with this car. And now that I have messed with the idle screw it doesn't want to start and stay running. So I idle it way back up to like 1k maybe abit more and it will start. Any ideas?? The IAC is bran new.
 
Ya i did but I will try it once again. Seems like when I idle it down to far it won't even start so I gotta idle it up back higher and it'll start but still takes a few tries. It'll turn over try to start then Sputter out and die. After a few times of that it'll finally start. And I've just noticed when it does finally run if I press the gas and rev it up the rpms drop fine till about 1200-1500. Gets stuck there for about 5 sec or so then falls back down to idle.
 
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My voltage also drops really low it seems
 
Put a volt meter on the battery to get a true reading. Good idea to do a load test while you are there, check volts at idle with nothing turned on then turn everything on and compare the readings.
For the proper procedures on adjustments and see if you have a problem go through the surging idle checklist in the tech/how to forum.

Lots of good stuff there.