GrayZ28

All,

It is a 94 Z28, T-56 and bolt-ons to include the MSD LT1 distributor in place of the opti and just under 99K on it. The best way i can describe the problem is to put it in a scenario so here i go. I wake up and drive the car to work in the morning and park it around 0745 at work. During the day i do not drive it until time to go home and everything works just fine. But, if i drive it to lunch or to run errands at lunchtime and park it again, say between 12:30 to 1:30, on my way home around 4 to 5 o'clock the car will die on me. If i am sitting at idle it will just die like the key is turned off. If i am driving the RPMs will drop, climb, go back to normal for a second and then the car will die smoothly. I get no SES light but i do get a check gauges light. Everything looks on the up and up when this happens. When it dies if i sit there for 15 to 20 seconds or more it will start right up and do fine on the way home. Any ideas? If i drive it at lunchtime the temp gauge will barely be off the peg when i drive home but i wouldn't see why that would matter. Could it be a fuel pressure/pump issue? It is still operating on the stocker. It doesn't really smell rich or lean in the exhaust but my fuel mileage at my last fill-up was down and i don't remember stomping the pedal much at all. Please help as i am out of ideas and tired of pulling over on the interstate or the side of the road when i drive home. Thanks to those that provide inputs.

Garry

Guest47904

Does that mean it stays dead cold or it is pegged hot????????

SPARK
FWIW, my 94 would never start on a real humid (lot of dew) morning. I had to wait until the warmer part of the day. The opti was getting condensation in it. Maybe the warmth and getting cold during the day is causing the same thing for you. I never did scan mine when it was doing it but I would think if the low voltage side of the opti was the problem with condensation, the PCM should still throw a code. Remember, one of them will not set an SES. Give it a try.

FUEL
If you were having a problem like the vent valve to the tank not allowing enough air into the tank, you should see it no matter when you drive. However, let's suppose you drive a short distance to work and a short distance home (since we don't know). With the added miles during lunch cruises, you may see the problem. In any case if it is fuel related, a fuel pressure gage taped to the windshield would show the potential fuel problem when it occurs. Try that.

Injuneer

Sounds like its possible the t'stat may be sticking open. Low coolant temps will reduce fuel mileage. Low coolant temps will prevent the PCM from operating closed loop.

GrayZ28

Speedy,

Sorry for the confusion. If i drive it at lunch by the time i drive home the engine is still kinda warm. The temp gauge arm will be just off the peg on the cold side. We don't get alot of humidity here but it is higher in this season so maybe it is getting some condensation. I'll look into that. And i drive about 15 miles each way for work. And i do hit traffic since most of my commute is on I-40 and I-25. Maybe the fact that it lives in a garage at night would cause less condensation build-up if that is the problem. And for the fuel pressure gauge, i would throw it inline before the fuel enters the fuel rails or somewhere else? Right about now i am willing to try just about anything short of sticking a lit match in the gas tank. And Injuneer, thanks for the T'stat suggestion. My next weekend project on this thing does involve me changing out the stat amongst pther things. But that weekend project is now on hold since some doucher got the numbers off my debt card and bought a bunch of stuff up in Michigan. So if anybody lives in Sterling Heights, Michigan please find these people and thrash them accordingly. But i digress. I'm going to use my regular CC to order up a new fuel pump, stat and buy new plugs and wires as well as new header gaskets and collector gaskets. Seems i destroyed the collector gasket on the passenger side again!!!!! Stupid lowering springs i put on the car!!! So thanks for the tips and please, if anyone else has something let me know. I'll try and keep everyone posted on my progess, or lack thereof.

Garry

mrmint69

There is a schrader valve to connect directly to. I would use that to check the fuel pressure. I bought mine at the auto parts store for only $25. Much easier and you can use it forever unless it breaks because it only $25. Do you know if its the vented MSD pro billet distributor?