1995 Cobra Ignition and Running Issues

[tsundave]

Hey guys, first time poster but long time lurker. Had an 88 GT with mass air that had been bad-touched in a lot of ways, and a lot of the stuff on here helped me set her straight before I sold her.

I recently came into a bargain on a pretty cherry 95 Cobra (rio red with a cloth saddle interior); previous owners definitely took good care of her, I've got a lotta records, even factory service and wiring manuals. Engine is stock, but chassis, suspension, and drivetrain have been modified (subframe connectors, caster camber plates, 3.73s, T2 diff, rear upper and lower control arms, etc).

The reason for the bargain was a couple known intermittent ignition issues. One where, after a short drive, it would crank but not turn over, and you had to let it sit for a couple hours. The other I caught on video here. This would usually go away after you stopped, turned off the engine, waited 10 seconds, and restarted. P.O. had thrown the parts bin at it; new coil, MSD cap and rotor, new TFI module, Walbro 255 fuel pump, resealed injectors, double roller timing chain, heads decked, obviously didn't solve the issue but was totally forthcoming about it.

Having gotten intimate with EEC wiring and its inner workings doing a Painless ECU harness install on the 88 GT, all of this lead me to believe something in the distributor was bad. Upon taking it out, it was hard to turn. I threw a Spectra in there to get me by (timed it, obviously) and it ran like dog. Returned it and bought Summit's house brand billet (using the MSD cap and rotor) and now a new issue has popped up.

It idles and pulls to redline fine when your foot's all the way in it, but bucks and stutters at part throttle and cruising. I thought it was a vacuum leak but couldn't find one. Took out the SPOUT connector and the issue went away. This is what's got me stumped. What and where else can I check? Are all of these issues related? Am I just unlucky and ended up with two bad distributors?

Thanks for any help and advice.

 

[Chythar]

Removing the SPOUT stops the computer from advancing the timing. Is the summit distributor a rebuilt one, or did they use brand new parts? Rebuilt dizzys re-use the PIP, and they rarely work well for long. I would check inside the dizzy for any gray powder or anything worn.

What brand are the coil and TFI module? MSD parts are usually crap for our cars, though purely mechanical parts like the cap and rotor are likely fine.

If you end up needing a new distributor and ignition parts, I personally recommend the Performance Distributors distributor and their Screamin' Demon coil. They work really well on my 94 Cobra.

Ford Hot Forged DUI – Performance Distributors

performancedistributors.com

 

[tsundave]

It's a Summit-branded billet. https://www.summitracing.com/parts/sum-850410/make/ford/model/mustang/submodel/gt Everything looked fine inside, the original one I pulled out had some gray powder build up like you mentioned.

TFI and coil are Standard Motor Product branded. I've still got the Motorcraft TFI that was in it and swapped it back in thinking that might be it, but the car ran the same way. But, I've heard from my buddy who was a Ford tech tell me he's had quality issues with parts-store aftermarket parts, so maybe you're on to something.

I came across those while I was looking for dizzys, they looked promising, thanks for the recommendation.

 

[Chythar]

Performance Distributors used to sell TFI modules for 94-95 5.0 engines; I have one in my Cobra now. Beyond that, I would recommend spending the money for a Motorcraft TFI. I took a look at the Summit page you linked to, and it appears to be a new unit. It's possible the PIP inside was a cheap unit and it's failing. You can rebuild the distributor and replace the PIP yourself, as long as you have a vise, some metal punches and a brass hammer. You have to press the bottom gear off, and if you don't have a press you need to pound that sucker off. The brass hammer keeps you from damaging the distributor. There are Youtube videos that can show you how to do the rebuild yourself, and this post walks you through it as well.

 

[tsundave]

Definitely planning on getting the Motorcraft TFI and the Screamin' Demon coil at the very least. The Summit dizzy looks like it uses the same pickup as the Spectra one based on the pigtail and wire cover, might've been unlucky and ended up with two bad ones. Irony of all this is for the price of a Motorcraft PIP and the dizzy, I could've bought the Performance Distributor, haha.

Thanks for the tips and write up!

 

[Chythar]

Glad to be of help. Please post back here once you fixed the issue, and what fixed it. It's always nice to know the end result.

 

[tsundave]

So after a couple months of poking around and leaving this thing be, turns out I've been barking up the wrong tree. I had the local dealer look at it, and turned out fuel pressure was falling flat under load. I did some of my own testing, and after driving around it seems like the Walbro cavitates if I drive for too long, the tank is too low, or I turn too sharply. I've never had experience with them, but apparently like this isn't an uncommon issue with Walbros. I have an Aeromotive 340 on the way. We'll see if that's the ticket.

I also won the distributor lottery, and had two bad ones in a row. I threw the original Motorcraft back in, and most of the poor running issues went away. Kept the Performance Distributor since I wanted to upgrade anyway, no problems so far.

 

[Chythar]

Thanks for the update, and glad to hear you've got things running better.

 

[tsundave]

Dropped the tank today, and found a couple things. Turns out the P.O. put in a Walbro 340, not a 255; more importantly, that 340 didn't have a fuel sock on it. I couldn't find one in the tank with my boroscope, thinking it might've come lose and floated around, so I assume it was never put on.

New fuel pump came in today as well. Put about 75 or so miles on it just running errands around town, hasn't skipped a beat so far! That Aeromotive is whisper quiet, too; can't even hardly hear it prime.