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Yes my name is Holden
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Discussion Starter · #1 ·
Greetings Guys; On my way home a few days ago, engine started loosing power. 5 miles later I'm home & it barley made it into the garage, but it didn't go into Safe Mode. I Scan & code P 0172 shows, Rich Bank 1. Replaced 17 year old 47,000 O2 Up-stream sensors & check down stream O2's. Car barley starts & pops out the Driver (Bank 1) side exhaust? Won't idle. I had pulled the fuel relay, unplugged the coils & turned it over with starter listening for mechanical problems. Sounds good on starter motor! Disconnected battery for a bit, fired it again & pop, pop pop. What next, suggestions welcome. Oh I put a FAST 102 on last year all torqued to spec. I'm to the point of pulling the intake? Ole' Bob. Ps the offending Bank!
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Yes my name is Holden
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Discussion Starter · #4 ·
Hi Guys; Coolant temp was just calibrated & seems correct. Knock wire I'll double check in 10 minutes, I have shorties. Fuel trims?? And no I haven't checked the response, above my tech level. THANK you ever so much guys. I'm headed to the shop, Later, Ole' Bob.
 

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Discussion Starter · #5 ·
Good Evening Fellas; Well my computer friend came by, HP novices we are! He looked at a data log from a pervious test cruse run-blast. Then we ran the engine for 4 long minutes missin' & spittin' @1500, NO codes. But comparing the data logs the only reading he could find was the MAP sensor reading were way different? We haven't eliminated a FI nozzle yet either. Oh, I had relocated my MAP to the rear of the FAST out of sight & reach! And yes it has shined the one of the aluminum tubes back there. I'm on a path to pull the intake to remove the OE MAPS as the bracket I made to hold it in screw location is impossible to get with intake ON. Plug hole, mount new AC Delco MAP I ordered Saturday up front. YUK Ugly, but serviceable. Oh fuel pressure, 60 Lbs & oil PSI 70 cold 45 warm. Wish me luck, Ole' Bob
 

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Yes my name is Holden
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Discussion Starter · #7 · (Edited)
Greetings; No Good news. Back four Cylinders 5, 7 & 6, 8 aren’t firing, cool header tubes. FAST intake base port partially collapsed (1 or 2%) into the flow. High heat & lots of vacuum, new gaskets & back on! During our latest test run, noted the intake cover was very warm above a few runners?? This all started with lost power & code PO172 (Rich Bank 1). So far, New (AC) Up-stream O2’s, bench tested Down-stream O2’s, Checked good. New MAP (AC) & relocated up front. With it running on cylinders 1, 2, 4 & most of the time #3, it popped codes PO172 & PO173. Both Banks Rich? Engine still sounds good on the starter, no unusual noise. 75 PSI of oil pressure cold, 45-50 luke warm, coolant 135*F. Fuel, 60 PSI running. Spark Jumps out of the plug wire, but if ya up-plug the coil the engine doesn’t run any worse? Same if ya un-plug a fuel injector. All this on the back four cylinders. Now if ya start un-plugging coils or injectors up front cylinders 1, 2, 4 & 3 is the odd ball the engine will miss & spit even worse. Oh spark plugs on bank one looked excellent. This info came off a GM Tech II hand held unit. So before I turn one more screw I’m looking to anyone that has experience similar problems. Thank you for your thoughts, Ole’ Bob.
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Yes my name is Holden
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Discussion Starter · #9 ·
Yup #8 Monday for sure, as that is one of the cold exhaust tubes & easiest to get at. What isn't making an sense to me is how can 4 coils or four injectors all fail at the same time. Or four melted pistons, four anything all at the same time. One of the fellas mentioned that he had similar problem but it affective all 8 cylinders. Including slow to respond starter & run on at key Off. I have same issue, fresh starter working perfect before miss-not firing popped up. I would except some run on with to Rich & I have that in ace's. And both banks are reporting PO172-73 codes?? Oh the fella replaced the ECM, his engine went back to normal behaver. Thank you, Ole' Bob.
 

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the intake warpage just looks like overtorquing. Even correct torquing. FAST's seem prone to that.

it is possible some injector drivers pooped the bed. maybe use a noid light or backprobe the injector connectors to see if they are firing.
 

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Discussion Starter · #11 ·
Hi Not Farnsworth; Interesting on the FAST. I'm a small guy that usually errors to the light side of Torque. Spec 70-89 inch Lbs. & I had pulled them to 77 & dated the day I did that. But then you already know that I'm a bit....? In my case I think it was heat? Yesterday my young friend came by with his GM Tech II unit & his electrical engineer bother & the had their way with my sweetie. He works at the local dealership & was planning to do some research Monday. Thank you I will show him your post-suggestion as it's past my tech level. My Ole' brain keeps coming back to how can 4 of anything all fail at the same time? Ole' Bob.
 

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the intake warpage just looks like overtorquing. Even correct torquing. FAST's seem prone to that.

it is possible some injector drivers pooped the bed. maybe use a noid light or backprobe the injector connectors to see if they are firing.
It probably is firing as he is getting rich bank errors. Causing the unburnt fuel to go out
 

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Discussion Starter · #14 ·
HI Rich & all; We talked about the crank sensor & concluded if it was bad why would the front 4 cylinders fire & run? And nothing came up on his Tech II indicating it was not within parameters? Please keep in mind the back four tubes stay cool during a three-four minute test run. And the front four get Hot with the exception of #3 as it just gets very warm. Thank you again for all the thoughts & I'll get back after I compression test #8 & pull the rocker covers. Ole' Bob.
 

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Yes my name is Holden
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Discussion Starter · #16 ·
Good Morning Guys; After my young friend (GM tech) came by with his Tech II hand held unit we only know that I'm rich on both banks now & rear 4 cylinders are not making fire. Couldn't find anything else wrong. So this morning after conversing with you guys & the FB crowd I'm back at BAD Gas. I plan to take a sample after I finish this post. Suggestions for taking sample? And possibly emptying the tank. My first guess was bad gas, as I had just filled up 4 miles earlier. But why would it only affect the rear cylinders? Hobby shop is calling, Ole' bob.
 

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Yes my name is Holden
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Discussion Starter · #19 ·
Since I was driving at 50 MPH @ around 1900 RPM when the power lose first happen. The wires weren't wrong then. So those little gremlins under the hood switched wires while I was drivin"? And I'm not buying into broken parts as I have no bad banging noise's. Just misfiring & pops. I hope to take sample off the fuel rail port, soon.
 

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Since I was driving at 50 MPH @ around 1900 RPM when the power lose first happen. The wires weren't wrong then. So those little gremlins under the hood switched wires while I was drivin"? And I'm not buying into broken parts as I have no bad banging noise's. Just misfiring & pops. I hope to take sample off the fuel rail port, soon.
ok, i didn't catch that you were driving when it happened.

but, bad gas would effect the whole engine, though.

maybe your ECM did crap the bad. not sure how it handles injector or coil driving, but each injector and coil is controlled individually.

not sure what other way the engine would run as you described.

perhaps a failed injector driver just holds the injector open. back 4 are dumping so much fuel that they run cool. but why the back 4?

this issue is just odd.

what type of injectors are you running?
 
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