I have a 2005 blazer 2 dr 4x4. It throws code p0300 when climbing most hills at and above 2000 rpm .
ive replaced dist , wires , plugs , map and maf no change .
the other day i took the tech 2 out and noticed that when it does this bank2 fuel trims go -15 but bank 1 stays around +3.

No cyl codes get set but misfire graphic shows cyl 6 as the culprit , did fuel injector and power balance .

will injector balance fail to see an injector that sticks at 2200 rpm vs 600 rpm .

when this occours i get the flashing cel and definite misfire .

 

Which fuel injector balance test did you do? Do you have a recent compression test?

George

 

I used my tech2. And did the fuel injector leakdown test with fuel gauge and also did the cylinder balance test. , with no findings

I know i should do a compression test and will asap .

With my fuel trim on bank2 at -15 , and the misfire graphic showing cyl 6. Could an injector be sticking on too long at higher rpm but act normal at idle ?

the fuel trims go opposite when the misfire starts around 2000 rpm on cyl 6. Until the cel flashes .

 

Many possibilities. Injector malfunction, mechanical problem in the cylinder(s), O2 sensor/wiring/power, ignition problems. What does the B2S1 O2 sensor look like in graph form during this problem?


This must be bank 2 air fuel problem month. lol.

George

 

 

What are the conditions during the period where the O2 sensor pegs rich? Do you know the frame rate?

George

 

Not sure how to determine frame rate , but what happens is ... I start climbing a hill at about 80kmhr (60mph) and as the load increases the misfire graphic shows cyl 6 rise and max out til the cel flashes and power reduces until i let off throttle and gradually it comes back as i crest the hill .

also happens on the highway above 110kmhr rpms 2100 to 2300 rpm. Or if i acelerrate hard it pulls fine until 2000 plus rpm .

 

Tell me what happens with fuel trims during this. We need all 4 numbers:

https://blazerforum.com/forum/2nd-ge...-trims-102906/

Also. can you measure CMP retard?


George

 

Short term bank 1. +6 %
short term banl 2. -14
Long term bank 1. +3
long term bank 2. -4

Cam retard was at -5

 

Ok so bank 2 is perceived to go rich under a load and needs reduced fuel delivery to lower emissions, or so the computer thinks. Here are the possibilities:

1) The O2 sensor or its wiring is faulty. What does the graph look like at idle? A simple test is to swap precat O2 sensors and see if the problem follows.

2) Engine mechanical problems. The compression test will help us here

3) Ignition problems. You may have a weak coil or faulty ICM or the power/grounds to those items may be marginal. I would start with measuring power/grounds. Your CMP retard should be closer to zero but 5 should not cause these problems. Try misting your ignition components with water in the dark at idle and 2500 rpm and look for arching. Pull the #6 plug and compare it to the others during the compression test. Look for carbon tracing under the distr cap. Make sure all of the ignition wires are properly seated. Swap plugs and wires at #6 and see if the problem follows.

4) Faulty injectors. You did a balance test and got a normal result so I would hold this for last

This should keep us busy.


George