Suburban 99 Vortec 7400 swap 0411 missfire issue (RESOLVE)

[ali32109]

I'm facing issue after 0411 swap, engine seem to run only on 3 cylinder 1 , 2 & 8 only.
i did follow Lextech pinout sheet and i follow step by step Lawrence LT Tolman on youtube.

it's very rough and there is black smoke out of exhaust, my flow rate is 22.2 lb/h but black smoke will disappears if i increase flow rate to 31 lb/h. but still run very rough.
when try to press gas rpm rise slowly

i did know that only 3 cylinder working by disable one by one injector on VCM scanner, and only 1 , 2 & 8 when disable notes different, also tried to spray water engine header to check which one still cold and i was right only 1, 2 & 8 was hot the rest not.

i did pull some spark plug and it has spark.

maybe fuel issue or timing issue? however before swap i change the distributor and was perfect timing at CMP 0

Any tips on finding out where the problem is?

 

[yevgenievich]

Trace out injector wires to verify correct and check for power on injector plugs. Also check to see if get gnd pulse on injectors. Then there is a firing order and verifying spark.

 

[ali32109]

i tried today but no use.
injector wires: Check it.
power on injector plugs: Check it.
firing order on HP Tuner, i think i did it right.

I attached my file Maybe i did something wrong

 

[ali32109]

Maybe this information is also useful, I have an check engine light
P0452
P1689
P0449
P0740
P0785

 

[yevgenievich]

I did not see a file attached. For hpt file, have to change extension to txt or something else that forum accepts for upload.

Codes not necessarily indicating something specific that will not make it run, but possibly some wiring issues. Bad connections or shorts. Might have to double check your pinout change and retrace all steps. (After verifying tune is correct for application)

 

[ali32109]

sorry didn't know i can't upload this format, i uploaded on google drive

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[yevgenievich]

I don't have access to any google services at the moment. Will check back later if nobody else gets a chance to take a look.

 

[Road Trip]

i did know that only 3 cylinder working by disable one by one injector on VCM scanner, and only 1 , 2 & 8 when disable notes different, also tried to spray water engine header to check which one still cold and i was right only 1, 2 & 8 was hot the rest not.

Greetings ali32109,

I was looking for failure patterns in what you've shared, and although it might be coincidence I see something interesting?

The firing order of your 7.4 is: * 1-8-4-3-6-5-7-2 *

If I look at your engine from the crank rotation perspective,
#2 > #1 > #8 are firing, followed by the remaining 5 cylinders not firing?

I won't have a chance to look at the DTCs until this evening, but the only thing
that comes to mind at first glance is that I would take a close look in the vicinity
of the CKP? Is the gap between the sensor and the reluctor correct? Is the reluctor
spinning true, maintaining the same gap throughout the 360° of crank rotation?

For what it's worth, on the Vortec motores the CKP signal is The Reference signal,
timing-wise, for everything in the VCM (now 0411) ...so any goofiness here is more
than just a minor nuisance.

No guarantees, just something to keep in the back of your mind while sorting through
the DTCs and reviewing your pinning to the new 0411 computer.

Best of luck --

 

[ali32109]

i want to add one thing i did, i only pull OS from my old 0411 which was for Tahoe 2002 then i did the changes on the file. is this right? or should i download stock express van 5.7 and change what need to change and use that?

 

[BeXtreme]

Maybe this information is also useful, I have an check engine light
P0452
P1689
P0449
P0740
P0785

What is the base tune you are using from? That P1689 code is a traction control system code.
https://www.corvetteforum.com/forums/c5-tech/2888122-p1689-code-on-2000-vette.html

Its possible the PCM thinks that it needs to engage the traction control and cut injectors to reduce

i want to add one thing i did, i only pull OS from my old 0411 which was for Tahoe 2002 then i did the changes on the file. is this right? or should i download stock express van 5.7 and change what need to change and use that?

This is your problem. It thinks you have a 5.3 with traction control. It thinks you have coil packs. The engine tune file is completely different, you have to start with an express van tune.