My 1993 Mazda B2600i starts perfectly in the morning. Runs for 10 minutes and stops. It will not start again until the next day morning, again for only 10 minutes or so and so on. I have spark at ignition. I checked #1 and #2 plug wires. There was spark there as well even after it quits running. The fuel filter by the firewall at passenger side at the outlet had a good flow rate although I did not check the PSI. It filled a 2.5 cup glass in roughly 30 seconds. I listened to the injectors with a screw driver at my ear and I hear the clicks. There is a half a tank of gas in the gas tank and yes I did remove the gas cap to let air in the tank. When it runs for that first 10 minutes every morning before it quits, it runs very well, with no glitches. To me it seems that the issue is warm engine related with a fuel starvation problem. I also tried to clean the 4 Dist. Cap points and the rotor a little bit.

Can any one help?

 

Does it sputter to a stop or just quit? It sounds like something is going wrong as it enters closed loop mode. Will it even start the same day but ohhhhhh 8 hours later? Or is that also a no go? Do you smell fuel?

Welcome to the forums!!

 

It just shuts down. When you try to crank it it may even catch on first few times but never continues. Especially after releasing the key. It stops. I did not time myself about the eight hours but my impression is, for a relible start you have to wait until the next day morning. I don't smell the fuel.

 

I am not sure what a moderator does.

 

A Moderator is another term for GOD. If you cross him, he writes to you in RED letters!
Currently he's writing to you in black letters. He generally knows a lot and makes sure you follow the rules. He doesn't like people that come on here to advertising their website which sells NFL Jerseys and the such. And right on cue, 6 minutes after posting this a Spammer has posted advertising NFL Jerseys.
Your problem is weird. Your car may be possessed and God can't help you then!
Normally at start up the car is suppose to run a bit richer and then lean out when warmed up. Your car may be running richer as time goes on. You could have leaking valve injector seals. I am far from certain though. Do you see a lot of black smoke coming out of tailpipe?
Could also be loose ignition, electrical.

 

We could have a massive intake leak as the metal parts warm up causing the car to lean out so bad and die but it should refire and run still and this leak would have to be so massive it would be obvious.......at least I think it would be. Will the truck run longer if you unplug one/all of the O2 sensors? This might/should keep it in open loop IF this is the problem, if it dies after you do this I think were looking at something other than an open/closed loop problem, this does not mean your O2 sensors are bad just something in the process of closed loop. Is the check engine light on at all? Ditto to what Noggin said about loose electrical, loose connections get hot and can become even looser or increase their resistance to the point where they may as well not even be hooked up. Double check/wiggle check all wiring connections that seem suspect.

 

However, I am quite sure that ignition electronics are in tact. I will check the oxygen sensor idea. The problem is duplicated exactly the same way each time. This for me eliminates the posibility of electrical short. That would be too random of a problem. I keep thinking that it is some kind of fuel shortage or a computer issue. Tomorrow I am going to run it until it stops. That is about 10 minutes. Then I will disconnect the O2 sensor as you recommended. I do not know the concept of open and closed loops.

 

I forgot to add that there is no black smoke. In fact the tail pipe shows a lot of water vapor when you first start it but that goes away as the car warms up. and soon after that it dies.

 

Open loop is when the computer is running the engine from a set of data tables with very minimal input from sensors, the engine runs but is not at peak power, minimal emissions or maximum response, this is due to some sensors (O2s) needing time to heat up (some models use heated O2s to shorten open loop time), open loop is when the most fuel is consumed because of this, once the computer detects the engine is sufficiently warm it goes into closed loop mode, in this mode the computer uses all available inputs to run the engine, in this mode it uses the O2s to set the fuel trim either richer or leaner depending on how the engine is running, there are also times when it will open certain valves now depending on what is being called for, as an example (not saying this is your problem) the computer could be calling for full open EGR at idle by mistake once you hit closed loop and your engine is just breathing in its own exhaust, it could be many things but to rule out an open/closed loop issue its best to keep it in open loop and see if it runs. Have you replaced the battery lately or jump started anyone?

 

How can I over ride the computer to put my truck on open or closed loop condition? And if that happens to be the issue do I replace the computer or some other component?