96 burb 7.4 misfire after 5.0 injectors

[mehcs]

Hi BeXtreme,
I'm using the Dash command app with Veepeak OBD2 scanner. The banks 3 and 4 threw me off too. may try to reset the pids but I'm assuming the values are meant for 1&2.
so the vacuum side is interesting and am thinking the same. Kind of.. This may throw for a loop but I'm going off the fact that what I'm about to explain were already missing from the truck and ran fine in that state. I actually posted this prior to making any of these changes but I'm missing this test port. The line from the canister was hanging. Also missing one on top of the plenum.. This is a CA emission truck.


PLEASE NOTE THAT i CONNECTED BOTH OF THESE ITEMS WITH VACUUM HOSE WHEN i REASSEMBLED BUT TOOK BACK OFF TO HAVE TRUCK IN THE SAME STATE PRIOR TO TEARING APART AND HAVING ISSUES.

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This is the other item. The actual hose is missing the right angle boot is there and yes today i noticed it sucking air. There's a broken plastic line that comes our from the passenger side of the firewall that I'm guessing it came from.

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Also, the plugs, wires and distributor were not changed. only FPR and injectors.




Regarding the test. Do i test this around the plenum where gasket meets lower intake or lower intake? (This question may sound dumb after what I just explained the missing hoses lol).

 

[mehcs]

Grease was included with injectors and used on both o-rings as well as swab in the injector bores.

 

[Orpedcrow]

I’m still not 100% certain on how to decipher fuel trims, but, they don’t look good lol. Sounds like a vacuum leak to me.

 

[mehcs]

I'm also curious about the "Ignition timing advance for #1 cylinder" at -29deg. Also the spark advance. Can anyone tell me if this is normal range?

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[RichLo]

Something isnt happy. Have you tried disconnecting the battery for 15+ minutes to reset to factory tune? I would try that and immediately data log those suspect parameters to see if they start trending that direction again. Then if they do, start data logging other sensors that could effect those like MAP sensor, o2 sensors, TPS, ECT, MAF, etc. Find something that is telling the computer to go wonky.

 

[mehcs]

I had the negative terminal off yesterday and back on before starting and pulling recent data. I read somewhere that you pull the positive off and touch the two cables together to reset?? Or is negative off sufficient?

 

[smokymtn65]

do you have a vaccuum gauge if so whatsbit reading?

Can you cycle injectors on and off with scanner you are using to see if one is the issue?

 

[mehcs]

do you have a vaccuum gauge if so whatsbit reading?

Can you cycle injectors on and off with scanner you are using to see if one is the issue?

No I don't have one but would get one to test. Where is the best place to tap into to test vacuum and what kind of numbers am I looking for?

The scanner that I have is the basic Dash Command app with blue tooth OBD2 reader. I don't think it has that function.

 

[mehcs]

Something isnt happy. Have you tried disconnecting the battery for 15+ minutes to reset to factory tune? I would try that and immediately data log those suspect parameters to see if they start trending that direction again. Then if they do, start data logging other sensors that could effect those like MAP sensor, o2 sensors, TPS, ECT, MAF, etc. Find something that is telling the computer to go wonky.

I'm not replying to these correctly. sorry...

I had the negative terminal off yesterday and back on before starting and pulling recent data. I read somewhere that you pull the positive off and touch the two cables together to reset?? Or is negative off sufficient?

 

[smokymtn65]

Has it set any codes or did i miss that?