Started LQ4 swap for first time and runs really rough, long term fuel trim way off

[ja_engineer]

I have been working on my 1980 Camaro/LQ4 restomod for the past several years and I finally fired it this weekend and it is running really rough. First fire I was getting P0200 code which ended up being a damaged injector pigtail (injector 6) so I repaired that but I am still having a problem with bank 2. I checked remainder of wiring and it appeared good and noid light shows all injectors pulsing. I have attached my tune and two quick logs that I took. At this point I am guessing it is either clogged injectors or bad o2 (but they are brand new ac delco), but I was hoping someone more knowledgeable with Gen III tunes/logs might be able to spot something that I am missing. I really want to take this for a drive since the car hasn't moved under power for around 10 years. Any help is greatly appreciated!

Equipment/Mods:
Stock LQ4 - 2003 Express 3500 donor
Speartech reworked harness
85mm truck maf
long tube headers
segment swap auto to manual

[joecar]

It seems to me that your injectors have problems.

[joecar]

Do you have the FPR that came with the LQ4 (i.e. at the fuel rail)...?

Did you connect the reference hose from the FPR to the intake manifold (vacuum side)...?

Did you measure rail pressure (with FPR manifold-reference hose temporarily removed)...?

[ja_engineer]

Do you have the FPR that came with the LQ4 (i.e. at the fuel rail)...?

Did you connect the reference hose from the FPR to the intake manifold (vacuum side)...?

Did you measure rail pressure (with FPR manifold-reference hose temporarily removed)...?

I do have the stock regulator and the vacuum hose is hooked up but when I checked pressure at the rail I am getting about 80 psi so I may have s bad regulator.



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[joecar]

80 psi may mean that the FPR is not able to dump fuel back into the return line (is return line clogged...?).

[ja_engineer]

It is a new line and I ran some air through it to blow it out after assembly. I will check in the morning if it has gotten linked or something. I recall one of the bends going over the axle deforming some when I bent it but I don't remember it being that significant.


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[ja_engineer]

80 psi may mean that the FPR is not able to dump fuel back into the return line (is return line clogged...?).

I figured out the fuel pressure issue, the regulator on the rail is adjustable and I was able to adjust it down to 58 PSI which smoothed out the car some but it is still running rough. Also if I give it any throttle it starts to surge and stumble and LTFT is still 8.6 on bank 2. I have uploaded two logs. The first one is when I was dialing in the fuel pressure regulator and the second is after I got it adjusted and a gave it a little throttle. I am still thinking injectors but I might try to switch 02's from side to side to see if the issue changes banks. I was looking at the 02 voltage and wondering if it is switching correctly but I am not really sure what it should look like for this engine. Again your help is much appreciated.

[joecar]

Did you adjust the FPR to 58 psi with the reference hose temporarily removed (i.e. FPR exposed to BARO)...?

[joecar]

BTW: you don't have to log that many pids (too many pids reduces the sampling rate).

[ja_engineer]

Did you adjust the FPR to 58 psi with the reference hose temporarily removed (i.e. FPR exposed to BARO)...?

Last night I set it exposed to atmosphere the first time and when I hooked up the vacuum reference it dropped to like 47 psi so I reset it with the reference line hooked up. I didn't expect it to drop that much but after doing some research that appears to be correct. Tonight I reset it based on being exposed to atmosphere and I started unhooking injectors to see the effect. Two injectors on bank two had no effect when being unhooked. I checked with a stethoscope and one of the two was not firing and the other had a faint tick. I Then checked those two connectors again with the noid light and they were both getting pulse signals so I am pretty sure I have a couple bad injectors. I have attached the logs from tonight.

Thanks for your help joecar!