Help!!
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From: Maricopa, AZ
Thread Starter
Teching In
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Ok guys I hot the truck scaned this morning. It threw a bunch of codes. Here they are. Engine coolant sensor, o2 sensor, exhaust gas recirculation flaw, air injector switching valve, shift/timing solenoid, evaporative small leak, fuel pump circuit malfuntion
TECH Addict
Joined: Dec 2010
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From: Maricopa, AZ
The coolant sensor will cause issues along with the fuel pump. You'll need an ohm meter to check the coolant sensor, and a voltmeter to check it's wiring. You'll also need the voltmeter and ohm meter (multimeter will work for both) to check the fuel pump wiring. But the fuel pump issue might be just that the wiring isn't set up for the pcm to see the fuel pump. Is check fuel pressure (you need a fuel pressure gauge for that).
Listen, to SSRRR, the missing O2 sensors will NOT make it run bad, or "confuse the PCM". It should run fine in open loop. You have something else wrong. Throwing all those parts you mentioned at one seldom fixes them. It could be as simple as the valves miss-adjusted, with would take valve cover gaskets at worst case, but more likely none at all. You need to have somebody knowledgeable diagnose if for you.
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I took it to a shop today and they put it on the lift. Once they got a look underneath it they wouldnt touch it. They said the wiring is a total mess underneath. Couldnt even find the wiring for the o2's. Im looking for a shop in ohio that has plenty of experience with these motors/swaps that I can just take the truck to. Possibly throw a stand alone wiring harness in and fix whatever else may be wrong.
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PM Mike Harris. Screen name "1FAST94" on impalassforum.com.
I'm not sure if he's active on this forum; I believe it's the same screen name.
He's on the northeast side of Dayton and does just about everything with LT1's
I'm not sure if he's active on this forum; I believe it's the same screen name.
He's on the northeast side of Dayton and does just about everything with LT1's
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Teching In
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Take some pictures of the back of the intake manifold near the firewall, some of the exhaust manifolds and one of the front of the engine where the pulleys are.
Like with the maf we can tell a lot from pics. If it had egr and air/smog delete we can tell. If no egr block of plates were used that could be why it runs poorly.
I say get pics loaded up since its free and people can at least notice anything major.
I was thinking speed density until I saw the pic of the maf lol.
I'm curious what the fuel pressure regulator looks like. If the vac lines are not hooked up you will get poor gas mileage, and the weird starting issues. Mix that with pirate air from no egr block off plates and your going to have a very odd running car.
I would also trace plug wires and make sure none are melted, the right plug wire being burnt can make a lt1 seem almost normal, it will idle fairly smooth and drive ok if your foot isn't in it, but it's running on 7 cyl. Some cylinders not fireing are more distinguished then others I've notice.
The o2 problem is weird. You cod start by getting a pcm pin diagram and see where the wires go from the computer.
Makes me curious about the knock sensor too.
Like with the maf we can tell a lot from pics. If it had egr and air/smog delete we can tell. If no egr block of plates were used that could be why it runs poorly.
I say get pics loaded up since its free and people can at least notice anything major.
I was thinking speed density until I saw the pic of the maf lol.
I'm curious what the fuel pressure regulator looks like. If the vac lines are not hooked up you will get poor gas mileage, and the weird starting issues. Mix that with pirate air from no egr block off plates and your going to have a very odd running car.
I would also trace plug wires and make sure none are melted, the right plug wire being burnt can make a lt1 seem almost normal, it will idle fairly smooth and drive ok if your foot isn't in it, but it's running on 7 cyl. Some cylinders not fireing are more distinguished then others I've notice.
The o2 problem is weird. You cod start by getting a pcm pin diagram and see where the wires go from the computer.
Makes me curious about the knock sensor too.
Last edited by trilkb; Mar 3, 2016 at 07:44 PM.
Thread Starter
Teching In
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Take some pictures of the back of the intake manifold near the firewall, some of the exhaust manifolds and one of the front of the engine where the pulleys are.
Like with the maf we can tell a lot from pics. If it had egr and air/smog delete we can tell. If no egr block of plates were used that could be why it runs poorly.
I say get pics loaded up since its free and people can at least notice anything major.
I was thinking speed density until I saw the pic of the maf lol.
I'm curious what the fuel pressure regulator looks like. If the vac lines are not hooked up you will get poor gas mileage, and the weird starting issues.
Like with the maf we can tell a lot from pics. If it had egr and air/smog delete we can tell. If no egr block of plates were used that could be why it runs poorly.
I say get pics loaded up since its free and people can at least notice anything major.
I was thinking speed density until I saw the pic of the maf lol.
I'm curious what the fuel pressure regulator looks like. If the vac lines are not hooked up you will get poor gas mileage, and the weird starting issues.
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Joined: Dec 2010
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From: Maricopa, AZ
That's actually not that bad. Hell, that's better than most mid 80's WTF stock vacuum web of **** that manufacturers had. All you need is some time, zip ties, electrical tape, and beer. Make that **** all neat. Well, from the top anyway. How bad does it look from underneath?
What you need to do is start eliminating possible causes of the problems. Checking fuel pressure for example. If you check fuel pressure and it's good, the you know you need to verify the wiring of the fuel system, assuming **** was installed right the first time. Checking the Coolant temp sensor (on the water pump), if that's reading the correct resistance for the temperature than you need to look at wiring, if not replace the sensor.
Personally, I'd do a OBD1 PCM swap to get the awesome data logging software available, and re-wire the whole truck if I needed to. But, that's me and you may not be able to do all that.
Can you read a schematic? It would be time consuming, but you could trace every wire from the PCM to what sensor (or light, solenoid, gauge, motor, etc) it should be going to. Then once everything is in the right place, you can zip tie it up and mount it all pretty like.
What you need to do is start eliminating possible causes of the problems. Checking fuel pressure for example. If you check fuel pressure and it's good, the you know you need to verify the wiring of the fuel system, assuming **** was installed right the first time. Checking the Coolant temp sensor (on the water pump), if that's reading the correct resistance for the temperature than you need to look at wiring, if not replace the sensor.
Personally, I'd do a OBD1 PCM swap to get the awesome data logging software available, and re-wire the whole truck if I needed to. But, that's me and you may not be able to do all that.
Can you read a schematic? It would be time consuming, but you could trace every wire from the PCM to what sensor (or light, solenoid, gauge, motor, etc) it should be going to. Then once everything is in the right place, you can zip tie it up and mount it all pretty like.
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From what the guys said at the garage the wiring was a total rats nest underneath the truck. I have a buddy that is an ace when it comes to the ls1's hes installed them in everything he owns and several other vehicles too. He suggested the stand alone wiring harness and reflashing the pcm. He will install the harness and make sure everything is hooked up and ran where it should be and make it look like it came factory. Once thats done and we know the electrical out of the way then I guess we can start addressing any other issues
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Joined: Dec 2010
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From: Maricopa, AZ
Sounds like you have a plan with your buddy. At least after all the wiring is straight, you can eliminate that as a problem.