99 yukon warm engine stalling

[Name]

Hello all, I have a slight problem with my 99 yukon, 5.7L 4X4.

The codes that I am receiving are P1345, and P0300, but only when the engine gets warm. The CMP retard is showing 0.4 degrees at 1200 rpm. It has a new distributor, new cam sensor, and new crank sensor, but I never performed a cam/crank relearn.

Recently the head gasket was done, both heads polished by machine shop, and valves were adjusted to 175 psi compression when the engine was cold. When cold, The car will start first crank, and idle nicely with no notable issues... but if I drive for more than 10 miles, the engine starts to run pretty rough, to the point where it will stall right when I come to a stop. After this "WARM ENGINE STALL", If I try to start it right after it stalls, It feels as if the starter gets frozen on the first crank, and all you hear is a really long crank, and eventually the engine will catch on and start with a little gas pressed, but at this point the engine is running horribly, and will stall at every stop. Also when the engine warms up, it will still drive on the freeway, although the acceleration is very sluggish once the car get warm, whereas it has full power on acceleration when its cold.

I am now thinking that I may have adjusted the valves a little too tightly while the engine was cold, and now when the engine gets hot, it cannot hold compression. I have not checked compression yet, while the engine is hot, because I have been too busy throwing parts at this thing. When the valves were first adjusted, it was showing 175 psi for all cylinders, but again the engine was cold. Fuel pressure is good. The list of parts that I have put in this thing eliminate a ton of possibilities.

The new parts include :
Swapped out the Spider injector unit with the New Delphi MFI Unit
AC delco Distributor
cmp sensor
CKP sensor
map sensor
both pre-cat o2 sensors (delphi)
new delphi fuel pump and fuel filter
New ECT sensor
New egr valve and PCV valve
New MAF sensor
New IAC sensor
New TPS
New ICM
New COIL
New ACDELCO spark plugs and autozone brand spark plug wires
Throttle body and upper intake is sparkling clean

What do you all think ?

 

[SunlitComet]

If you have P1345 then your dizzy is not installed correctly. You are allowed a CAM_RETARD reading of 0.0°+-0.2° which you are outside of. Fix that issue and it may resolve some others. As for the valves you can do it cold there is just a specific procedure you must follow. You do not adjust them to a psi. Go over your coolant temp sensor circuit for proper operation and dump any house brand parts like your wires and go back to delco or delphi.

 

[Name]

Interesting. I thought there was a tolerance of + or - 2 Degrees. That would have left me well within range. Alldata and mitchel are both saying plus or minus 2 degrees also; which is why I was confused with the p1345 code. Only if I drive for long distances and the engine gets really hot, it will start to run rough and trigger a p0300 code.

I had gotten rid of the p1345 code in the past, but after checking the cam retard, it was at -6.8 and the p1345 code was not popping up. I recently advanced the distributor from -6.8 degrees, to the current 0.4, and I got the p1345 code once since then, when the engine was running horrible; as I have been driving it for 2 days now, mostly short distances, and the p1345 code has not appeared, nor has the p0300.

I think the p0300 and the p1345 codes are being triggered because I had not completed the cam/crank relearn. In alldata it's saying that anytime the CMP/CKP sensors are replaced, or distributor, you must do a crank relearn or else you could detect false misfires and incorrect correlation between the two sensors. I have replaced all 3 of these items and never done the relearn, although I am not getting a p1346 code.

I will go over the temp sensor circuit though, that may be worth while.

Thanks for the suggestions.

 

[SunlitComet]

The case relearn and CAM_RETARD are two different things. You may not see the case code for a long while but until you perform it it can cause incorrect data or misfire history. You do have that tolerance. Tolerance from 0.0°. So any where between -0.2° to +0.2° is acceptable. YOU HAVE FAILED SIR! Give it another shot. And get the case relearn done. Amazingly quick to do with a proper scanner but how it is done can make owners really nervous. If you have the scanner to initiate the procedure I can tell you what to do. You only do the case relearn if the crank senor is replaced with another. is it the CAM_RETARD that has to be done if the dizzy is disturbed. Alldata should have resistance values for the coolant temp sensor mounted on the thermostat housing that feeds the computer. If not let me know. I have to ask something tho, why did you throw parts at it when you have resources like the forum here and especially the factory service data from Alldata? You may have wasted a lot of money. Especially if you did not use Delco or Delphi parts. Some aftermarket parts just don't meet the tolerances of oem specs.

 

[Name]

If i have a 2 degree tolerance from 0, that would be -2, to 2. ( -.2 and .2 are "two tenths" of a degree from zero, not Two degrees.)

I checked the resistance on the ECT sensor itself, and it is showing about 1600 ohms at 70 degrees, which is within specs.

When I checked the resistance for the ground on the ECT connector (the black wire), it was showing 1.2 ohms. From what I know about ground wires, a good ground should have zero resistance. could this be a possible fault?

Thanks.

 

[SunlitComet]

Sorry I am getting decimal happy again. -2° to +2°.

If that number is in Fahrenheit then 70°f around the 3300-3400 ohm range.
If in Celsius that would put you at about 467 ohms.

Unless I goofed again, what chart are you using? I am looking at the one for the temp sensor on the thermostat housing that feeds the computer. Being as the range goes from 70 ohms to 100,000 ohms 1.2 should not hurt at all.