Driving to work yesterday and got about 2 miles from home and my 93 Formula just quit. Would crank fine but wouldnt start. After about 30 minutes it started and I got it home. Last night I put a fuel pressure gauge on it and let it idle for 20 minutes and it ran fine. Took it for a drive and it ran great. Put about 10 miles on it with no fuel pressure drop. Drove to work this morning and as soon as I pulled into the shop about 12 miles, it quit. After about 1.5 hrs it finally started and seemed to be fine. Fuel pressure never dropped so I believe the fuel pump is not the problem. I left the car at the shop not wanting it to leave me stranded on the side of the road and it was running fine when I left. Here are the things I have done to it in the last month:
52mm TB with bypass
new cap and rotor
Magnecore wires
Pro magnum 1.6 rr
flow matched and blue printed 24# injectors
new fuel filter

It has a Crane hi6 with a ps91 coil. When it first quit I unhooked the crane box and went back to the stock ignition/coil, so it did this with both coils. Any help would be greatly appreciated.

Dave

 

No other symptoms when it quits? Dash lights don't go out or anything?

Actually, fuel pumps can act up when they get hot and then work again when they cool down (maybe 30-60 minutes later). What you need to do is check for pressure when it won't start. Keep your test gauge with you.
If fuel pressure is ok at that time, check for spark.

 

Shoebox, No symptons at all, just quits. I have a fuel gauge on it that has the long tube on it so I can lay it on the windshield while I drive it. It never moved when it quit. Even after it stalls there is still normal pressure. It will crank over fine but no start. No SES light or anything. The first time it quit I was going about 35mph and today I was almost stopped to turn into the parking lot and as soon as I touched the gas it started to pick up RPM's and just died.

 

Sounds ignition related then. Opti and ICM are a couple things that come to mind that can act up when they get hot.

 

Thanks Shoebox. I was thinking the ICM but wasnt sure since the opti was just inspected and cleaned. It was suprisingly clean for having 90K on it. Will get one and try it first. Thanks again.

Dave

 

Have someone wiggle the wires leading to the map sensor(black thing on top of the manifold.)Had mine replaced because my car wouldn't start before I had these replaced.Hope this helps.Also,make sure the map sensor is installed properly with gasket.My02(corrosion,bad crimp job with the wires,crappy connector to the map.My02)

 

Before throwing parts at it, it would be nice to be sure it was actually not getting spark when it dies and won't restart. Maybe you could troubleshoot a little more so you don't waste your money on something not needed. Even wiring can go open when it gets hot.

 

My problem kinda sounds like his, cept mine just don't start at all. Turns over but no start. And I know shoebox already has tried to help me with mine. I checked and I'm not getting spark but I don't know if thats gonna be the opti or the ICM causing that?

 

Just had the same problem. Just kept getting worse and worse. It would shut off at around 180* but would shut off sooner everyday. New optispark solved the problem. I also replaced the icm before I did the optispark and that didnt work for me. Might want to try the icm since your opti looked ok. I couldn't return the new icm I bought since it's an electronics item and once it's opened, it yours. I have my old one I could give you for a cheap price ( I have a '93 as well). Shoot me an email if your interested.

 

Well it did it again after I got it home so it is sitting in the garage. I was just sitting in it after the 12 mile drive and would give it a little gas and then let it idle. I repeated that several times and then when I went to hit the gas it just quit. Good fuel pressure and NO spark. Had a new icm ready to install so I put it on and still no spark. Opti bad?????

 

Sounds like opti to me. My car dies on the highway last year, similiar symptoms. A few weeks earlier it had been the fuel pump.

 

Where is the best place to get an opti? I know the 93's are higher $$

 

Dal Slabaugh: 877-448-5451
email: lockitup@bright.net
VanDevere Buick/Pontiac/Olds Akron, OH

Jason Cromer: 877-726-8295 or 850-243-8826 (direct parts dept)
email: gmparts@samtaylor.com
Sam Taylor Buick/Cadillac Ft. Walton Beach, FL

Take a look at the plug in at the opti and the other end of that harness that is on the side of the intake manifold. Just a good idea to check that before you put money on a new opti.