CEL Codes, and a misfire.

[1952Chevy]

I have been positing in my build thread, but might need some help here. Build Thread

So I replaced the motor in my 99 Suburban K2500. 7.4 Vortec. Everything is stock. I took the motor from a parts truck, and replaced all the seals/gaskets etc.

During the install I had the distrubutor 180 out. Got that fixed, but now I'm plagued with a misfire, and occasionally a P1345(cam crank offset code). I have pulled the distributor out multiple times, and I'm 99% sure it's in exactly like it's supposed to be. It idles fine, but I get a miss at around 2k RPM under no load, and miscellaneously under load at multiple RPM ranges.

Along with the P1345 I have
P0140 - EGR
P0137 - O2 Sensor
P0154 - O2 Sensor

EGR Valve is new, I do have an exhaust leak from where I cut the exhaust out. I put a flex pipe on for now, but it's not a good seal. I am not sure if that would cause the EGR code, but I'm sure that could cause the O2 sensor codes.

Without more codes for the misfire, what can I do to get this ironed out? I would love to have it all back to perfect.


New items are:
Injectors
FPR
Spark Plugs(gapped to .045)
Cap/Rotor
Plug Wires
Oil Pump
Gaskets/seals

The only thing that wasn't installed on the old motor were the plug wires, and it ran fine then(besides the rod knock, but no codes).

Is it possible that I still messed up the distributor install? I watched probably 10 different videos, and read more write ups than I can count. They all had the same info, and I followed that to a T. Rotor pointed towards the "8" arrow after being fully installed with #1 cylinder at TDC compression stroke.

Any help is appreciated

 

[1952Chevy]

Forgot to add, I have a code reader, but not with the ability to read cam/crank offset.

 

[yevgenievich]

Forgot to add, I have a code reader, but not with the ability to read cam/crank offset.

Need one with the function of displaying live data to get that set. Maybe using a piston stop and verifying true tdc might get it close on setting the distributor.

 

[1952Chevy]

Need one with the function of displaying live data to get that set. Maybe using a piston stop and verifying true tdc might get it close on setting the distributor.

I had never heard of such a thing(I thought I was very tool literate). Just looked them up, and that might be my best option without a better scan tool. I guess I just trusted that the balancer mark would be correct. We shall see.

 

[81nascar]

You really are going to need some type of scanner to get some sensor values. Even most of the cheap ones show data.. That's what leads to figuring out what's going on.. The data is important. DO you actually have a misfire(like codes?)or just feels like it's missing? Scanner data would show you that.. and help eliminate or confirm that guess/concern.. The O2 codes could be related to the poor exhaust seal if the leak is before the O2 sensors.. After a install like all of that, if you get a bunch of codes it's best to go over the work you did. Check connections , make sure things are tight and in place and check any grounds and wires you may have disturbed or pinched.. Don't take any of them for granted.. Grounds are like the number one thing when getting a bunch of things happening at once out of the blue if all was right before.. What was the condition of the replacement engine? Did you use all of the sensors from it or your old engine?? It's possible it could have had an existing condition/problem/sensor issue?? Gotta ask yourself what changed with the swap..

After all of that..... doing what was suggested with a piston stop would be very helpful to determine TDC on the balancer just to be sure.. You my even be a tooth off. It happens.

 

[AuroraGirl]

You really are going to need some type of scanner to get some sensor values. Even most of the cheap ones show data.. That's what leads to figuring out what's going on.. The data is important. DO you actually have a misfire(like codes?)or just feels like it's missing? Scanner data would show you that.. and help eliminate or confirm that guess/concern.. The O2 codes could be related to the poor exhaust seal if the leak is before the O2 sensors.. After a install like all of that, if you get a bunch of codes it's best to go over the work you did. Check connections , make sure things are tight and in place and check any grounds and wires you may have disturbed or pinched.. Don't take any of them for granted.. Grounds are like the number one thing when getting a bunch of things happening at once out of the blue if all was right before.. What was the condition of the replacement engine? Did you use all of the sensors from it or your old engine?? It's possible it could have had an existing condition/problem/sensor issue?? Gotta ask yourself what changed with the swap..

After all of that..... doing what was suggested with a piston stop would be very helpful to determine TDC on the balancer just to be sure.. You my even be a tooth off. It happens.

mind you misfiring is only coded if its obd2 important you can technically have a misfire under threshold of damaging catalyst and it could pass by but its not super likely. i would look for thingsl ike motor mounts, basically, before misfire if there wasnt a code.

also, using a sealer or tape on the threads of knock sensors could de-sensitize them.

 

[81nascar]

mind you misfiring is only coded if its obd2 important you can technically have a misfire under threshold of damaging catalyst and it could pass by but its not super likely. i would look for thingsl ike motor mounts, basically, before misfire if there wasnt a code.

also, using a sealer or tape on the threads of knock sensors could de-sensitize them.

Ok I've been working on cars for 30 years. You are going to have to explain to me how a motor mount is going to cause these codes or any on a 7.4 ..

 

[AuroraGirl]

Ok I've been working on cars for 30 years. You are going to have to explain to me how a motor mount is going to cause these codes or any on a 7.4 ..

didnt say it would.

I said, i would look for thingsl ike motor mounts, basically, before misfire if there wasnt a code.

As in, someone may incorrectly perceive something they call knock but it wasnt knock.

 

[1952Chevy]

Thanks for all the replies. Here's more info. Motor came out of a 97 K2500 Suburban, 180k miles. Ran like a top other than lots oil leak(like every imaginable gasket/seal). No codes, or miss at all. I used the majority of sensors from the motor that was originally in my truck minus crank pos sensor, and knock sensors(they stayed installed on the motor).

It is 100% a misfire. I also hear popping from the exhaust on deceleration. I am going to probably look at the timing chain. I forgot I messed with it(did not replace). I removed the cam gear to look at the teeth and the chain. Everything seemed ok, but a little sloppy. I should have replace it, but there were none in stock in town and I was trying to press on. Maybe I am off a tooth on the timing chain. That would also explain my not being able to get the cam/crank offset correct.

Any recommendations for a scanner that will read what I need? Are the Bluetooth readers and apps any good?

 

[81nascar]

didnt say it would.

I said, i would look for thingsl ike motor mounts, basically, before misfire if there wasnt a code.

As in, someone may incorrectly perceive something they call knock but it wasnt knock.

You should reread what you wrote because that is what it implies.. You didn't define it.. and where is the whole knock thing coming from?? Since when is misfiring a knock? A broken mount is not going to bang around and KNOCK during idle a bunch of times and at a steady acceleration.. Only when you put an initial load on it does it move. Again he has codes, misfire or not. A scanner would help diagnose it in the pids and graphs .. Even a subtle movement would show before a code was set or pending.. Anyway on to the problem .. We can agree to disagree..