1996 K1500 Suburban shifting funny / cutting out

[ak diesel driver]

Probably better said but I'd run it for a bit and maybe wiggle the wires to check it for intermittent/poor connections

 

[jrsavoie]

Ok I would like to jump in and reword what AK is saying -no offense, I think it is just getting complicated.

To do the test. It will be hard to start, may take 15- 20 start. Once it starts and revs up, turn it off- no test drive needed. Any misfire afterwards is irrelevant.
1. Tell them unplug the cps and try to start it.
A. If it doesn’t start, the optic sensor is bad.
B. If it starts the optic sensor is working.

2. Plug it back in. Unplug the optic sensor.
A. If it doesn’t start, the cps is bad.
B. If it starts the cps is good.

Thank you much. That maDe it clear to me!!

 

[jrsavoie]

Sounds like the engine is cutting out and this can cause a downshift. At the minimum the TCC will unlock and then lock back up when the engine is running ok again. Fishbite is the term you are looking for for a single miss that you feel.

It's possible you have air in the fuel system, gelling fuel... What's the lift pump PSI at the water drain now, how old is the fuel filter, and is the fuel heater working? Water at fuel drain? Fuel smell like gasoline?

I did run some fuel out the T drain. Looked good. I never got a fuel pressure gauge on that vehicle yet.

Fuel filter gets changed with every oil change. Oil changes have been at 10,000 miles since I switched to the super cheap Mobile 1 5w40. But when I run out of that stuff, I will be switching back to Amzoil 5W30 signature series diesel engine oil and going back to 20,000 mile oil changes.

Not cold enough for fuel jelling.

I did open the T drain with the Suburban running. Seemed to run fine.

I will tell them to do the clear return line test also.

 

[jrsavoie]

Ended up being the injection pump.

A new injection pump and the set of injectors I had here for the Tahoe fixed it up.

 

[MrMarty51]

Good to hear another story of success.

 

[jrsavoie]

Not a success yet. LOL

We still haVE TO BLEED THE BRakes again and make sure the softness in the pedal is do to lack of proper bleeding.

Are there any tutorials for solo bleeding?

I have reverse bled with a lift pump before. And have done the bottle full of brake fluid with a hose in it.

I do have a Mighty Vac.

Monday when I messed with it. It was very tight the first time I stopped after bleeding. After the 2nd and 3rd stop, it was back to the same.

I have not tried unhooking the wires going to the anti-lock and trying it that way yet. I have not gotten any anti-lock action yet.

 

[jrsavoie]

https://www.google.com/search?clien...j33i22i29i30k1j33i160k1j33i21k1.0.9cpNPfSZAYw