fl1a

From time to time I have had problems with the engine cutting out momentarily after warming up. the tach will drop and the engine pulls. It has gotten much worse in the last couple of days, when the engine gets warm the tach drops and the ammeter will sometimes drop below center at the same time. I have gone through and cleaned and retorqued all the ground points under the hood and seem to have no problems with other systems in the car. I have cleaned all of the positive tie points I can find under the hood, and all of the connections have been clean and corrosion free except for the 2 ground tie points closest to the battery over the headlight on that side. I cleaned those and reattached them and far from improving anything it has gotten worse. Any Ideas?

7 UP Mustang

Check fuel pump pressure and make sure you have some good gas in the tank. Is this a DD?

fl1a

It's a daily driver, the fuel is good. This seems to be an electrical problem.

wbrockstar

I can't think of any correlation between a cold engine & warm engine that would cause battery draw.The ecm moves from open to closed loop during that time,but nothing related to that change should cause excessive electrical draw.The fan kicking on,if its doing so would be one possibility or maybe some type of heat soak issue with the alternator.A short in the fan or its wiring could cause excess draw.Resistance increases with heat and the more resistance there is,the harder it will be for current to travel. You could put a multimeter on the battery posts and see what voltage its putting out when its cold then warm.It should have 12.5+ volts key off/engine off.13.5+ volts key on/engine running. 13.5-14.7 volts at 2000rpm.You can also let Autozone test the battery & alternator while theyre still installed. Try turning accessories on(AC,blower motor,headlights) to see if voltage recovers after the accessories are switched on.It voltage drops when theyre turned on and doesn't go back up where it was before,the battery or charging system is suspect.
Th ccrm in the 94-95 models can develop issues to,but I Dont know if it would cause the issue your having or not,just from a cold to warm engine? ?

Urambo Tauro

I don't want to lead anyone on a wild goose chase, and you certainly shouldn't go throwing parts at it, but FWIW I could see the CCRM as a possibility here (I had to replace the one on my '95 earlier this year). It houses relays for the PCM, fuel pump, AC clutch, and cooling fan. On these cars, it's mounted near the radiator, but on later models Ford tucked it behind the fender. I wonder if they did that to combat temperature issues...

If you pull the CCRM, you can carefully drill the rivets out and inspect for bad solder joints. If it looks good, that doesn't necessarily give it a clean bill of health (mine looked ok but was bad). But if you do spot a clear problem, that'll save you from having to diagnose further. At which point, you can swap a replacement in, or perhaps attempt to solder it back together yourself.

fl1a

I appreciate your responses, I have had 2 CCRM's go bad, One was there when I bought the car. the fan failed and took out that circuit. I replaced the fan motor and then the ccrm. a couple years later I had to replace the radiator and later found the ccrm's connector had cracked and that one failed. The one in it now is working fine. This problem starts when I can see a small deflection in the ammeter and I can also see a corresponding drop in the tachometer's reading with the engine dropping rpms momentarily with momentary engine braking. It has an automatic and I once thought it might have been the transmission unlocking, but after 2 trips to the transmission shop, they assure me the transmission is not the cause. I have also put 2 new TFI's in it and now have 2 spares.

Buck Sergeant

fl1a, I am not great at auto electric, but I agree with the boys about the CCRM being a prime suspect.The ground wire for the CCRM is one of the wires coming out of the factory ground harness that connects to the battery pole. It's one of the bigger black wires...not the biggest obviously. If it isn't the CCRM, I would look for a broken/disconnected ground wire. I know you have already done this, but I am convinced it is a grounding issue. Let me know what the fix is.

wbrockstar

You can set the meter to read ohms then connect a multimeter lead to each end of the ground cable/wire. The meter should read 5.0 ohms or less.If not,the cable is broken or corroded internally.

fl1a

This weekend, I went through and cleaned 2 other grounding points and in addition, cleaned the termination on the block grounding cable. It hadn't been touched since the replacement engine was installed. when I removed the nut holding things in place, there was a helical lockwasher under a self washered nut on top of a support bracket tie point then a stud in the block. I cleaned the stud base, put the ground cable on it contacting the block and not a piece of sheet metal sandwiched between. Put the bracket on top of that and the nut holding all down tight. I then got the standard ignition TFI from the car, and the two Motorcraft TFI "spares" together and took them to be tested. The Standard was marginal, one Motorcraft was bad, and the other good. I put it in the car, and it has been doing a lot better. I can see smaller pulldowns on the ammeter, but they appear to be the fan turn ons. Thanks again for the suggestions.

Buck Sergeant

Fl1a, it's great when a problem has been solved. Enjoy your ride.