92 Mazda truck starting issues.

[CDX825]

Having issues with my 92 Mazda B2600I starting first thing in the morning. Once the truck is started it runs fine and can be started back up easily if its warm. But the first start of the day or after it has sat awhile it doesn't want to start without a bunch of cranking. I have spark and fuel pressure while cranking. Compression is good across all 4 cylinders. Timing is where its supposed to be. Spark plugs are newer and look good.
Someone had mentioned coolant temperature sensor causing a no start when cold or hot issue. Swapped it out and no change in behavior.
I'm at a loss as to what it could be especially considering that it runs good once started.

 

[D60]

I had TPS cause reverse symptoms on '95 F250 5.8 once. If you got it started cold, you were good all day. If you missed the cold start, it was minutes of cranking and fighting.

Maybe check TPS voltage and sweep to watch for consistent linear rise/fall.....? It's free to check

 

[CDX825]

I had TPS cause reverse symptoms on '95 F250 5.8 once. If you got it started cold, you were good all day. If you missed the cold start, it was minutes of cranking and fighting.

Maybe check TPS voltage and sweep to watch for consistent linear rise/fall.....? It's free to check

That half crossed my mind today as I was messing with it. I'm going to have to dig up the specs and what wires to probe for it.

 

[Puckrobber]

Love the older Mazda trucks. Wish they still made them.

 

[Rmay635703]

My 2001 Dodge Ram 1500 is that way but it’s a bad check valve, the longer it sits the longer it takes to prime the injectors

 

[Number_35]

These charts are from the FSM for a '90 Mazda MPV with the same 2.6 l engine, and show the status of the various sensors, etc.

I would look particularly at those columns wherein the cold-start conditions change as the engine warms up.

Check the engine when cold - look for a device that's giving hot rather than cold-start readings.

Good luck!

 

[andyd]

WAG, check valve in fuel pump is stuck open. Switch the key on for a second to get the pump to work. Repeat several times. This will get gas to the injectors. Now turn to start to crank engine over. Good luck