The Hidden Engine Health Test in Ford EEC-IV PCMs that you need to know about. 

That’s a legitimate diagnostic even on a carb equipped car. Thanks for the feedback and thanks for watching!

@@davelowets If it's efi, chances are flood mode is implemented and you can perform your compression balance test without opening the hood.

I'm surprised how many guys I see trying to diagnose problems with their Fox that don't even go as far as pulling codes, but I would be willing to bet that MOST of the guys who do pull the codes don't know that you can activate the cylinder balance test that is built in to the EEC-IV and find a dead or low contributing cylinder. It's such a powerful test when it comes to determining overall engine health or narrowing problems down to a particular cylinder!

Thanks Matt! I also have the same tester, it’s old like me and it still works fine haha! This video was an excellent review and very helpful 👍👍

Of course, and it isn’t supposed to be a secret, but I would wager that your average enthusiast watching this didn’t know about it, and that even when these cars were contemporary it wasn’t well known amongst owners.

@@tecmotiondyno I hear ya. Pure dumb luck that I stumbled on it to be honest.

Thanks for watching!

Thanks for the great feedback!

Good feedback!

Good score.

The cylinder balance test is documented but people don’t read the manual and some of those that do don’t recognize the power of this test! Sometimes you get codes on a modified car that just don’t apply.

There are headlight restoration kits, but I have never used them. LMR sells new lights for reasonable money. I have used them in the past and they can make a real difference in how the car looks.

You’re welcome. Thanks for watching!

Thanks for your supportive comments. If I get a rear end removal job I will film it, but if your objective is just to do the gear change and you are hiring someone to do it, it will be simpler and less costly to do it in the car. If you are changing everything - control arms, shocks, weld on housing ends etc, and you more or less have to remove the housing anyway, it makes sense to do the gear swap with the housing out of the car and on jackstands, otherwise I think you are just making extra work. I usually book three days with the car for a gear swap because of interruptions and contingency, and the only step I usually do on the third day is to put the fluid in it because I prefer to let the rtv cure overnight. In bigger shops where the mechanic can just work on the car and doesn’t have to answer the phone and deal with walk in’s and all of the other little daily distractions, an 8 hour day is usually enough for the job, so you don’t generally have to give your car up for an extended period of time to get the gears changed.

@@tecmotiondyno thank you so much!! 🙏biggest reason why I wanted to pull the rear out and take it to a shop was because I hate leaving my car at places unattended. Figured it be easier to take rear out car take the new parts and whole axle to a shop and say call me when it's done. I see what you are saying though! Thanks

On a professional OBD2 tool, a similar test can usually be found under engine functional tests, and should be called something like Cylinder Balance or Power Balance. I can't speak to your specific application, but that is where to look.

There are also 5.0 Ford setups that are batch fire. I have never personally tried the cylinder balance test on one of them.

I have seen them unable to test where the sig return line is blown on the PCM, but that should prevent the KOEO test as well. With the older style tester, you do need to start the car, then switch the tester from HOLD to TEST in order to initiate the KOER test, just in case you accidentally missed that step. Sometimes these weird problems are very hard to diagnose in person, never mind over the internet! Thanks for watching.

Yes, most OBDI Fords have these tests. Some codes have unique meanings on trucks though, so pay attention to the notations on the code list.

Could be, or a computer fault. Could be oxygen sensors too. Try the cylinder balance test to see if the problem is limited to one or two cylinders.

Bad temperature sending unit.?

The first thing that I would be looking at is a bad pcm or blown sig rtn trace on the pcm caused by an incorrect loop back on the o2 sensor harness. Fuel pump running constantly is a typical symptom of a bad pcm or corrupted chip on the pcm.

@@tecmotiondyno thank you !

No big deal. The only thing you lose is the 1-2 second prime cutoff at startup. I prefer constant run, and wired mine direct instead of through the computer. It's been fine for 28 years as is.

I totally agree with you on this.

You are welcome. I hope it helped out!

This used to be the version you bought, but mine was made when the Fox Mustang was contemporary. Innova 3145 is the modern day successor and should have all the same capabilities but displays the codes on an LCD. You might pick up an old one on eBay.

Hey, do you have the model number of yours, I can’t see the screen on the a nova one.

@@Olds_Pwr thank you

@@Olds_Pwr just found one on eBay

Mine was $7 on clearance 20 yrs ago when they became digital.

No, it is an injector cut only.

I would say that the better part of them were SEFI including all the Mustang engines, but you are right, some of them are bank fire. I am not 100% sure how this test works on a bank fire version, but it could use a spark cut.

@@tecmotiondyno FWIW in my understanding, the earlier versions of efi were speed density because maf sensor technology was in it's infancy. My '95, '94, '90 Fords use speed density but california (CARB) versions were for '95 used maf. I'm not sure exactly which engines or when Ford first introduced maf, but those were all sequential injection as far as I know and speed density (MAP only) were all bank fire injection. In the case of '95 maf, ignition wasn't DIS, as far as I know. Thus I'm pretty sure if the ignition is dis, this will also be sequential injection. Then we have all the different versions of ecm's, parts availability (discontinued parts?), on and on... ;)

Pretty well all of the speed density cars were SEFI - Mustang, T-Bird, Cougar, Mark VII, Crown Vic, Grand Marquis, etc. These will go back as early as 1986 in some cases. MAF was first introduced in the Mustang in California in 1988 and nationwide in 1989. The speed density trucks and vans were mostly bank-fire. MAF equipped trucks like some 93 E-Series vans were SEFI.

@@tecmotiondyno 1990 2.9 V6 Bronco II federal emissions? 1995 Bronco 5.8 Federal emissions? 1994 F250 460 Federal emissions? See electrical schematic, 8 injector channels or bank fire?

I don't have the 94 460 schematic or the 95 Bronco schematic handy. The 90 V6 Bronco is a MAP controlled vehicle and is batch fire. In most cases I think the MAF vehicles were SEFI and the cars were SEFI regardless of whether they were MAF or MAP, as I said.

Search for ford obd1 on Amazon. There is an updated version on there for sure. I would guess that you can pick it up at lots of parts stores too. NAPA, O’Reilly, maybe Harbor Freight. When I looked on Amazon Canada it was a ready to ship item.