97 K3500 7.4l spitting, sputtering, backfires, and stalls

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1998_K1500_Sub

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I'm wondering what the service manual says about those ICM codes. The set of operating conditions which cause the codes to be set are usually quite detailed, and given in the manual. If someone was to study those conditionsi (from the manual) there might be some insight gained.

I would look in the manual myself but I'm on the road today and most of tomorrow.
 

454cid

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Manuals are here:


454 engine controls are in Vol. 4 section 6-2677

Just grab the 98 manual, since the 97 is not there. It'll be close enough.
 

Agibson

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Ok thanks I'll have to check it out. I'm almost to the point of put a carburetor on it.
 

Schurkey

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I'm new here so bear with me please. I have a 97 chevy k3500 pickup with 7.4l and automatic trans. It started spitting and sputtering backfires stalls out going down the the road it will shut off and start back on its own. I've replaced the distributor, plugs, wires, fuel pressure regulator, cps, fuel injectors, and ground straps that were missing. The crankshaft position sensor was the last thing I replaced it ran fine after I put in it in on the test drive. When I got in it the next morning same problems came back. I'm lost and need help please.
How old are the O2 sensors?

Ok I've test the voltage on power and ground wires. They both tested fine about 11.7 volts.
Moved the wiring harness all around while testing, to check for broken wires and all seems good.
How can the ground wire test at 11.7 volts? Is it broken or not actually grounded?

Is this with the engine running, or key on--engine off?

O2B2S1 .155 to .120
Hard to know if that's an O2 sensor problem, or a tremendously lean air-fuel mixture, or heaps of misfire.

I'd be looking at the misfire counters for each cylinder.

I'm almost to the point of put a carburetor on it.
That's insane. How do you plan to control the transmission?
 

Agibson

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How old are the O2 sensors?


How can the ground wire test at 11.7 volts? Is it broken or not actually grounded?

Is this with the engine running, or key on--engine off?


Hard to know if that's an O2 sensor problem, or a tremendously lean air-fuel mixture, or heaps of misfire.


That's insane.
I went from the ground wire on the icm plug to the positive side of the battery to see if I had ground. Key on engine off.

I have no idea how old the O2 sensors are.
I don't want to spend the money to change it over,but I have to get the truck up and running soon and that is an option.
 

BeXtreme

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I went from the ground wire on the icm plug to the positive side of the battery to see if I had ground. Key on engine off.

I have no idea how old the O2 sensors are.
I don't want to spend the money to change it over,but I have to get the truck up and running soon and that is an option.
11.7v when checking from the battery to the ground is VERY low. What did it read when you went to the battery ground instead? Getting a "voltage high" code when the voltage is reading that low is very suspicious. What was your knock count reading?
 
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