make sure to keep maf connected during test.

 

I don’t see anyway to perform this test while having the maf connected.

also, my PCV seems to be faulty. Any idea how to replace that? Hummer here in San Antonio says it’s just a valve not a valve cover replacement.

 

if thats a hole on the flex pipe then thats probably your issues right there

 

no holes. I pulled everything off. Seems pretty airtight.

today I took the diablo trinity tune off and returned the PCM to stock. I also set it to watch my fuel trims.

on bank 1 short fuel trim stayed at 0.00%.

im gonna follow that up tomorrow.


I also pulled the TB, it was a little dirty but not near as what I was expecting.

there is a very little bit (maybe 1/4 teaspoon) if that inside the air tube. I’ve certainly seen more in my Jeep.

 

LTFT?

 

fantastic video.

im gonna take a long drive and record the live data and look at it tonight. The bank one stft was at idle in my driveway. So it wasn’t under any type of load or anything.

 

fuel pressure regulator? Fuel filter?

looks like you covered the basics.

 

Ok so this week I have had some time to do some testing.

I did find a hose that connects to the plastic piece for the intake that was cracked and replaced it. Also the hose that comes from the airbox to the intake was warped all to hell, there's no way air was getting actually to the intake. After fixing those two points I got DTCs for 2270 and 2271. All of our problems are due to bank one, so i relegated my testing to bank one except for the fuel injectors. I had the entire fuel rail off so I checked all of them.

Ill not my findings here after all the testings done.

Fuel Pressure at the fuel rail is at 52 PSI. Spec is between 55-60 according to alldata

Fuel Injector OHM Readings.
AllData Specs state between 11-14 Ohms at 50-90 Degrees Fahrenheit
Heated Injectors to 190 Degrees Fahrenheit.

1. Cold-12.7-hot 15.3
2.cold 12.6 - hot 15.6
3.cold 12.7 - hot 15.5
4.cold 12.3 - hot 16
5.cold 12.7 - hot 14.3
6.cold 12.6 - hot 14.3
7.cold 12.7 - hot 14.9
8.cold 12.7 - hot 15.5

Compression test results on bank 1

Cylinder 1 - 152
Cylinder 2 - 148
Cylinder 3 - 148
Cylinder 4 - 150

Cylinder Leak Down Test Results

Cylinder - 1 - 0% loss - intake valve sticking. Burped 2x at 50-55 PSI then built up to 70 PSI and held for 60 seconds.

Cylinder - 2 - 2 PSI loss at 70 PSI after 60 seconds - Air Loss was heard at the muffler.

Cylinder- 3 - 0% loss at 70 PSI for 60 seconds

Cylinder - 4 0% loss at 70 PSI for 60 seconds

Note: cylinder 2 spark plug was loose barely finger tight.
Note 2: Since all tests were done on bank 1, Cylinders 1,2,3,4 refer to cylinders 1,3,5,7 respectively.

One thing I did was switch the sides of the fuel injectors over to Bank 2, if my problems change banks then I'll know there is an issue with the injectors. Aside from testing the spray patterns and ohms of each injector I don't really see anything wrong with them. But time will tell.

My wife notes that today before she went to run her errands that the temp gauge went straight to half from a cold start. She also took a video, I need to find out how to get video from her phone to here. But it showed something unusual, I'm certain I've not ever seen this before.

I did replace the coolant temp switch in the last week. The temps are incredibly much better. running between 199-205. Before was running around 215-220.

I included a pic of the spark plugs. From left to right are cylinders 1,3,5,7.

 

Skip to 0:50 for what she caught. I’ve never seen this. She’s says she didn’t goose the gas peddle, that the engine revved up on its own.

 

Check that "coolant temp switch" you recently replaced!