Somebody Who Knows What They're Doing: Help!!

JRizzle

New Member
Jul 4, 2015
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Hi everyone. I've been subtly searching this site ever since I purchased a 1995 GT 5.0 5 speed. It is not a Foxbody, but not a 4.6. Anyway, I'm stumped.
The car has a serious miss. The guy before me replaced the whole ignition system trying to track it down, all but coil which I had checked. I checked compression, I tried the KOEO KOER balancing tests but it just spit out crazy numbers that don't even make sense. It also would ONLY do the KOEO test & would not progress to the following two; KOER or balancing. It ran halfway alright when I got it, if I opened her up it would run normal for about 3 seconds. At idle/low speed it runs like :poo:. Well, now I can barely get it to go around the block. It misses so bad it jerks. I guess in 95 they also put obd2's under the dash - tried that w/ three different scanners all said the connection was bad. All of the tests, on top of the fact that one day it runs alright & now it runs like crap seem to me like a bad ECM. I took the intake plenum off, raised the fuel rails & watched the injectors while being turned over & they all spit fuel. I thought it may have been an injector...anyway, I cannot find an ECM online...I've tried searching 17 different ways & just cannot find a refurbished/new one for a 95 5.0 5 speed...any opinions, advice, or anyone who can point me in the direction of an ECM &/or tell me what years will work if I happen to get lucky at a junkyard would be helping me TREMENDOUSLY. Thank you all.

P.S. VIN is 1FALP42T1SF117356

And...obviously, I need to complete this mission as cheap as possible. I just want it to run right.
 
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Well, first off the 94-95 5.0's have OBD1. The OBD2 port under the dash does not work on the 5.0's. Ford tried to save money by putting the exact same dash in all the 94 and 95 Mustangs, and they sell more 3.8 V6's then 5.0's. The OBD1 connectors are behind the passenger shock tower.

Figuring out a miss can be tough, there are a lot of things that can cause it. You could have several things wrong that together cause the bad miss you are experiencing. Let's run through a few things.

When the car runs at Wide Open Throttle (WOT), the computer runs the engine based on its internal data tables. But when running at partial throttle, the computer uses the O2 sensors to figure out if the engine is running right. Does your car have O2 sensors? When were they last replaced?

Running rough can be caused by a bad or dirty MAF. The MAF is inside the air box just behind the filter. You can take out the sensor in the box and gently clean the wires with q-tips and rubbing alcohol. If the q-tips have dirt on them, the sensor may not give the computer the right readings.

A vacuum leak can cause the car to run rough, as the computer won't be adding the right amount of fuel for the air in the engine. Check the rubber hoses for cracks or leaks. If a hose is flaking or covered in cracks, it's likely leaking. Also, some of the hoses on the intake can get old and stiff. If any of the hoses aren't tight on their fittings, they may also let extra air in to the engine. You can replace most of the hoses with bulk hose from many auto parts stores.

Check all that out, and let us know what you find.
 
It does have O2 sensors. I see now why the one didn't work at the parts store, but it still doesn't explain the crazy numbers the ect was spitting out on me, then when the KOEO test was done the KOER or balancing tests wouldn't initiate. One other thing to mention...the guy before me hacked the egr hose and welded it. But I think the car has ran right since then...idk. I hate the idea of replacing o2 sensors: its hard as hell to get them out, & the ones in it are not stock. They have red wire covers and are half stripped so I think that was done already. I used ether to do the rpm vacuum leak check hillbilly style no results. The miss just progressed to being so bad its literally not drivable from being drivable before. I figured out how you look up the ECM by the part # on it so that's the next thing I'm going to price check and, since the o2's look fairly new or at least have been replaced, I think the ECM is the way to go. Rarely have I ever experienced a bad computer in a vehicle but I feel that I've literally done everything else to the best of my shade tree mechanic abilities. I will see this thread thru to the solution also
 
What were these crazy numbers the ECM was giving you? Unless you can borrow a used ECM and try it out, that's probably not in the price range of things you just replace with a guess if you're looking for new -- better off taking it to a good mechanic or the dealer and have them tell you what's actually wrong with the car. You're going to want one for a 94/95 unless you're up for a more substantial project.
 
You need to post the trouble code numbers. As mentioned in another post the code port is in the engine bay passenger side on the strut tower. There are different ECUs for for these years depending on gearing and transmission configurations. O2 sensors are critical and must be the correct ones. There are only 2 O2 sensors and are mounted before the cats.
 
I don't do mechanics. The intro-net will teach me all that I need to know. I fix things, appliances & vehicles, for a living. This stang jus had me stumped. I work on more GM stuff...anyway! It was the arcing spark plug issue, on top of the fact it needed a coolant fan-turn-on sensor & an alternator but as soon as I found the fried up wire & replaced it, it was all good. Something so freaking simple...stumped for a week..
 
Oh, and the engine light only comes on now after 5-10 mins of driving. I believe that the weak/going out alternator is doing that. It may well be responsible for the fact that I got half a sheet of paper of random numbers. They didn't match up correctly to be codes plus I had a guy w a Bluetooth obd tester have a go n it wouldn't read them. Maybe still issues w the ECM but, for now, it runs correctly.
 
I have half a sheet of #'s. Yet, now the ECT light goes off then on after driving. I can't tell u what they r w/o doin it again but it won't go beyond the KOEO test....KOER & balance doesn't initiate. It runs good enough now but still needs an alternator. That could be the whole reason that the ECM is acting funky. Oh, and nobody can read it w an obd1 scanner. Tried 2 diff ones at O'Reilly & a Bluetooth 1. But, like I said, the major issue was an arcing wire. I'm not taking it to a mechanic. Hell no. My goal is to make $ on it & I'm already ******* deep.
 
I've never seen a Bluetooth OBD-I tester so are you sure you're checking the correct port? Your car is OBD-I, the test port is on the rear of the passenger strut tower. The one under the dash doesn't do anything on the 5.0. If you don't want to spring for the $25 tester, you can google for how to use a jumper and read the codes from the CEL flashes, or use a multimeter. If it still won't go into test mode, it's possible you do have a bad ECU.

The alternator's not typically going to set a code, or set off the check engine light. You'll get the battery light, and possibly cause some problems with the air bags if the voltage gets too low. But if it's throwing out bad voltage, it could definitely be causing problems. I agree, get that correct first (also make sure your grounds are in good shape) and see where you stand.

I understand not wanting to go to a mechanic, I don't let anyone else touch my car either, and I'm cheap. But if you're in over your head, unable to read codes, and considering randomly replacing expensive parts, sometimes it's smarter to consider it.