Progress Thread Matt's 93 Lx - Running Issues

Hahaha I love all the B cam videos and sayings. I think that made that decision for me!

Wow I can't believe I haven't updated this thread since May. Jet ski racing takes up most of my time over the summer, but drove the stang a ton, and managed to get a few things done on it. Finally got tints all the way around and had it detailed. Long road of buying 17" chrome cobras to find out that the front two were cracked. Bought two new front 17x8 ones from AM and ran the older rear ones for a bit. Couldn't stand that they didn't match so ended up buying two 17x9 from AM a few weeks ago. Also fixed the ashtray door.

Finally tracked down my favorite mod so far! Gen 1 GTS solar wing! I had been searching for a while and it turned out there was one under my nose two towns over. Luckily found it on a local forum.

I think i have everything i need for the H/C/I swap which will be going down in 2 weeks (have to take some days off before the end of the year so it worked perfectly). GT40 3 bars, TFS1, Edelbrock performer 5.0, 1.6 roller rockers, adjustable FPR, new BBK shorties. If some of you were following before, I bought a short block to build up but i'm putting that on hold in the interest of time. While I have the heads off I have to de-rust the strut towers , potentially add some steel, and seal back up.

Also found a sweet fox matchbox at a swap meet!

Thanks! Is that why they are 6 digit? I thought at first it was because it was a later car but I've seen other 93s with 5 digit too. They just threw in the 24s so it ran like crap. No you don't have to swap the compressor. I think you are supposed to swap the pressure switch to a 134 one but I was having issues with it so I just put the old one back in and it's been fine. It does seem to cycle on and off a lot but I rarely use the AC anyway. Nice! Where are you on LI?

Ok guys, all finished with the H/C/I swap. Well, it has been for a while now but i'm still chasing issues. Long story short, the injectors that I had were no good so I had to swap back to the old ones. I'm running stock 19 lbs. Since I put it back together I've had a miss down low, and a lean pop sometimes. It would clear up after about 2500 rpm and fell pretty strong, but not what it should. All of the ignition and fuel components are the same as before the swap except for the FPR. The other day I wanted to check the compression to make sure all was good with the heads. I put the pedal to the floor when cranking so it wouldn't flood. 145-150 psi all around. Put the plugs back in, fired it up and it ran very rough and a minute or so later died completely. It wouldn't restart, and sat like that for a few weeks. I dropped in a whole new distributor to try, and nothing. Fuel pressure is fine, and stays consistent while cranking. Before it wouldn't run I disconnected the PCV because i was having issues with that. I was messing around with it this past weekend and it finally fired up, but with the same misfire down low. It died after a few minutes and wouldn't restart. That's where I left it. Couple of things that I noticed that could be wrong:

- Fuel pressure is constant while cranking, but bleeds off very quickly. One small squirt and the pressure is gone. When I bled it to put the gauge in well before the swap, it took a while to bleed off. FPR is an adjustable one, and rail is stock. Both were used though. All other fuel components are the same as before.
- I'm getting spark at all plug wires but if you take off the wire closest to the upper manifold, it will arc to it. All plugs are new. They were a little wet when i pulled them after the car wouldn't start.
- There were no codes.
- There seemed to be a vacuum leak when I first finished the top end. I pulled off the hose that goes from the oil fill tube to the TB, and there was a ton of vacuum coming out of there. I plugged the PCV and the idle came way down. PCV valve and grommet are new. Am i missing something here?

Any other thoughts on what I could be overlooking? Thanks!

All of the vac lines are new, and I suspected a slipped gasket too but when you unplug the PCV, the vac in the crankcase goes away. I had a vac gauge on it when it was running, it was a little low but not bad. I also checked for an air leak in the back of the intake manifold but nothing there either. Timing is at about 14 degrees right now.

It only arcs to the manifold after I remove the wire from the closest post on the cap. Is that normal? I painted the intake manifold too, does the distributor need to be ground to the manifold?

Forgot to mention - the other odd thing i found is that the burn marks on the rotor and cap are at the edge of the post and the edge of the rotor. That mean anything?

And yes, I've been through the no start checklist many times. The thing that's getting me is there's spark, compression, and fuel but still not starting.

I should also add that I have voltage at at least two of the injector plugs. I also checked the 10 pin connectors, very clean inside but i added a little dielectric grease in there anyway

Ill double check the list again, but i already have spark and fuel pressure/power at injectors. Don't forget it did fire up for a few minutes the other day and then died. Something intermittent then, of course.

Pretty sure I put back that harness ground, and i have a nice big ground from the motor to the firewall that I put when i did the 3g conversion.

Ok found some time to do a little work to the car today. Checked and cleaned all the grounds. Went through the checklist and the coil itself has a nice spark, but when it goes through the distributor it's weak. found that I only have 10v going to the coil. Stock setup, no ignition box. Thoughts?

Also, if I probe the red on the coil, and ground to the battery it's around 12v

Ok forget the 10v thing. It's 12v if you check it from the red to ground. I followed jrichkers checklist below for weak spark. 12v at the TFI as well. I'm starting to think the MSD coil is bad. Thoughts?

https://www.stangnet.com/mustang-forums/threads/ignition-coil-wiring-91-lx-5-0.890672/

Thanks guys. This one was on the car when I bought it and served me well for 2 years

Fixed it! I plugged in a borrowed coil and it fired right up. Seemed like the off idle bog was gone too, but I'll have to drive it for a while and see. I'm going to pick up a Motorcraft coil tomorrow. Thanks guys!