Ok, I need a sanity check on this problem.

Build Specifics:
2011 Camaro SS
ERL 427 11.5:1 compression
forged rotating assembly (Compstar/Wiseco)
ported TFS Genx 255 heads
ported FAST 102
ported LS3 TB
Tune by Pat G

The car fires and runs in open loop at idle. When it is up to temp and moves to closed loop it stumbles and dies. Looking at the logs, Bank 2 injector pulse width higher than bank 1 by a fair amount indicating I am fighting a lean condition. Also the NBO2 sensor on the bank is all over the place. I replaced that sensor with a new NTK NBO2. I am monitoring AFR with Innovate WBO2s and they are within .5 of each other stoich. Spark tester showed each coil firing on bank 2. Plugs seem to show a rich condition on cylinder 6. Cylinders 2 and 4 seem normal to slightly lean. Cylinder 8 looks as though it is not getting any fuel or not firing at all. The plug tip is clean, porcelain insulator is slightly browned, and the face of the threaded portion of the plug is shiny as the day I pulled it out of the box.

So I believe the issue lies either in the injector not firing or a severe vacuum leak at the manifold. Trying to justify why the WBO2s show ok conditions but the NBO2 on the bank 2 is jumping all over. My thought is since the NBO2 is in the header collector and the WBO2 is another 8-12" down the pipe the NBO2 is sensing the lean cylinder more if that makes sense. Thus contributing to the problems when moving to closed loop. What I don't understand is why I am not seeing any codes thrown.

My way ahead (feel free to critique):
1) Compression check all cylinders (plugs are already out so may as well)
2) Reinstall plugs/wires and check the manifold for a vacuum leak (specifically at the #8 cylinder port)
3) Check spark at each cylinder again
4) If none of that works, swap injectors and see if the problem moves
5) if that doesn't work, swap coils and see if the problem moves

Two logs attached and link to short YouTube video showing WBO2 readings during second log. Anyhow, feedback appreciated. Really anxious to finish this build and get the car on the road.



Travis

 

Hi Travis,

Test Idle (21OCT15).efi: what happened at frame 657...?
New Knock Sensor and plug wires (20OCT15).efi: what happened at frame 1653...?
at those frames some of the waveforms jump.

Both logs:
EXT.WO2AFR1/2 and EXT.WO2LAM1/2 look incorrect...
you have a LC-2 daisy chained to an MTX, right...?
can you reverse the order which they are chained (if possible).

Also, in addition to the pids you logged:
log this also: GM.ETCTP

( BTW: when logging for creating a tuning map, to increase sampling rate reduce the pid channel count to 24 (indicated at bottom of PIDs tab) )

 

Hi Joe,

First let me clarify the title of the one file should be new NBO2 sensor and plug wires. Not sure why I named it knock sensor other than being tired and struggling I suppose. So the file reflects a new NBO2 sensor on Bank 2.

I took a look at the spots you called out. Are you referring to the NBO2 bank 1 sensor reading? If so that is a great question. It is the stock NBO2 sensor that came in the car. It is a Denso sensor. The bank sensor I put in is an NTK sensor. I am putting a new NTK sensor on bank 1 right now so I have the same brand and model sensor in both banks.

I'll take a look at the PIDs to make sure I add the one you suggest and see what I can drop out to keep it at 24 or less.

WBO2s are LC2 into DLG-1 into FDV2. LC2 is connected to bank 2 and DLG-1 is connected to bank 1. Gauge reflects this so I would assume the output to FSV2 would reflect same should it not?

Plan of attack for this afternoon:

-Cleaned and reinstalled plugs. Complete
-Check resistance on plug wires. Complete all wires reading in right at 740 ohms.
-Dielectric grease all boots and reinstall plug wires. Complete.
-Change NBO2 bank 1 sensor. In progress.
-Start engine and immediately check for vacuum leaks with starting fluid.
-Use stethoscope to listen for injector pulse on all injectors.
-Check header down tube temps with IR thermometer (headers wrapped so a little harder to tell heat).
Reassess based on findings.

Was going to compression check but apparently my gauge has walked off.

Any other suggestions I am all ears. Thanks!

Travis

 

At those frames, several of the waveforms jump (for example, throttle is constant but MAP jumps up, NBO2's start oscillating, and some other pids jump too...).

I sent your logs to EFILive to see if they figure out why the EXT.WO2xxx data is wrong.

If you suspect #8 is not firing, swap it's coil with #2 and see where the no-fire ends up (it's easier to move a coil than it is to move an injector);

also check the terminal pins in the coil and injector connectors for good contact.

 

I have an E38 dash B (charts) that you can use (I have not populated dash A (gauges) for it yet)...

Unzip the attached file, copy its contents to the folder \Documents\EFILive\V7.5\VDash

then in scantool do this:
- go Edit-Properties->Startup->Load Defaults
- checkmark Always load dashboard file
- browse to and select the file \Documents\EFILive\V7.5\VDash\E38-1010.vbd
- click Ok (to exit Properties);

when you start the scantool it will display this chart (E38-1010)... if ever it does not, then on the Dashboard tab's toolbar you can click on the Open Dashboard button (icon looks like 3 folders opening) and specify this that file.

 

Ok, more questions than answers. Log attached. Still not sure why the WBO2 are not recording. They show on the FSV2 when I look there.

This log is from cold start after the battery was disconnected for about 20 hours. Here is what I did including what I said in the above post.

-New matching NTK NBO2 sensor in bank 1 installed. This makes both NBO2 front sensors new. Verified cable routing. Nothing laying on or near the header.
-Sprayed the manifold with starting fluid at each intake port area and no change in idle. No apparent vacuum leaks.
-Tried listening to injectors with stethoscope but valvetrain just too noisy to here anything else.
-Tried shooting header down tubes with IR thermometer but I couldn't get consistent readings with the header wrap.
-As a last ditch effort I tried disconnecting injectors on bank 2 one at a time while running to see if there was a difference in idle.

Cylinder 8 - no change in idle. Not pulsing?
Cylinder 6 - no change in idle. Not pulsing?
Cylinder 4 - definite change in idle. Definitely pulsing
Cylinder 2 - little change in idle. Possibly pulsing.

So what would cause one or more injectors to not pulse? This is factory ecm with factory harness and sensors in factory locations. Completely unmodified harness.

Why are the NBO2 spiking and dipping like crazy? You can see from the log the hold steady while heating then things get crazy. Starting about frame 2173 is where I am disconnecting injectors which seems to register on the NBO2 but again, I could tell no difference in idle except when I disconnected cylinder 4 and maybe cylinder 2.

Maybe this is a positive. STFT were more consistent between banks though they were adding a lot of fuel once they settled. Prior there was a 20-30 percent difference with bank 1 reading in the 5 range and bank 2 in the 25-30 range. Now they are both high once they settled in about frame 1500.

Injector pulse widths settled in better though bank 1 was firing less previously and now it is firing more but they are following each other more consistently and with .5 or so of each other.

So the NBO2s having extreme variances bothers me as does the now discernible change in idle when upplugging injectors. But the pulse width and fuel trims seem encouraging.

Tomorrow I'll have a noid light to verify the injectors are getting the signal to pulse at the connector. If they are getting the signal, I may try moving injectors to see if the problem moves with them. I'll also have a different spark test to verify spark performance through a variable gap.

Beyond this, I am at a loss. As always, input is appreciated.

Travis

 

Done. Thank you.

Travis

 

Ok I was typing a my latest and uploading another log when you posted. A lot of changes in that log so you might want to take a look.

Thanks for sending the logs to EFILive. I'm sure it's probably something I have done and can't figure out.

Not ready to move coils just yet with the results of the latest log. I will get the noid lights and new spark tester tomorrow and see what the results are with those then decide how to proceed. Feeling really stumped at this point and last thing I want to do is hurt the motor messing with it. Really appreciate your help again!

Travis

 

For #8, #6 and possibly #2:
check continuity from injector connector to ECM connector;
also check that connector terminal pins make good contact (inspect them, are they deformed);
also check that those injector connectors receive +12V.

 

The dips indicate a lean event which occurs when a cylinder fails to fire (the air is unburnt, so it causes the O2 to indicate lean, there is wet fuel in the exhaust which you might be able to smell).

 

Dips in MAP might be misfires...

 

Injector pins all looked fine as did the connectors. I run a continuity check this today to verify wires are good. I pick up the noid light set from NAPA this afternoon so I should get a definitive answer as to whether the injectors are getting signal. Also going to recheck spark at each cylinder with a different spark tester.

For those asking what a noid light is, here is a great demonstration.


So after I disconnected the injectors it seems this did effect the engine even though it was not noticeable from up front. Is it possible that things are getting where they need to be? I never ran the engine passed 160 ECT this time and assumed that because I could not tell any change from unplugging the injectors that I still had a problem. Looking at the fuel trims and pulse width things are more in line between banks than they ever were before. Thoughts?

All the dips are associated with slight increases in throttle (had my wife behind the wheel while I was under the hood). Would that not cause them?

I will post the results of the other tests this afternoon. I am hopefully optimistic this is moving in the right direction. Thanks.

 

Remove all spark plugs and see if they all look the same.

Also, from EFILive scantool, on DVT tab you can turn off one injector at a time... IDK if this helps to pinpoint (I have a chart somewhere here that maps A-H to 1-8).

Could be that it may need a tune.

 

I checked plugs and some cylinders look lean and some rich but this was before the last round of logging.

I'll check the use of DVT for disabling injectors. Going to verify signal with noid lights tomorrow first.

I've seen your post about injector, coil, and cylinder labeling on EFILive so I'll try a search for it since I know some of the labeling is goofy. I seem to remember some following firing orders rather than cylinder number.

Joe if you're available for a call tomorrow I'd like to discuss. Let me know via PM or call me at your discretion.

Thanks.

Travis

 

Yeah, it follows FO in reverse.

I'll call you in the early afternoon.

In DVT, you can also manilulate fueling/AFR to see how it runs.

 

Copy. I'm going to check injector and spark signal again this morning with the noid lights and spark tester. After that if everything looks correct I might run it up to temp and see what it does. I should have something to report by this afternoon. Thanks.

 

Ok tested injector signals on bank 2 and every injector is getting signal to pulse. Car stumbled noticeably every time I disconnected an injector this time. All injector connections were verified. No bent pins or problem connectors.

Ran fine until it hit about 150 ECT and then stumbled and died again. This really seems to be something with coming up to temp.

Both from NBO2s are new and read right at 450mv before car is running. No issues with connections and wire routing here either.

When my helper gets home I'll fire it up and run to temp again. If it does die at temp I'll cut off fuel and test cranking spark on bank 2 coils. Not sure if a dying coil would exhibit problems after it heats up but I suspect it could.

I keep getting this P0502 code even though the car has not moved. Not sure if it could be causing a problem or not. Double checked all connections on the transmission (6 speed manual) and nothing seems to be damaged.

Beyond that, back to being stumped. Only thing left to consider is a possible tune problem though I feel that is very unlikely since Pat G did the tune.

 

Ok latest round of diagnosis.

Car starts fine when cold. Gets up to ECT range of 150-160 degrees and then begins stumbling and dies. Then will not refire.

Checked the following:

-Battery 12.85 volts static and 11.18 volts load test. Battery is good.
-Fuel pressure is constant 58 psi. Fuel pressure is good.
-Injector signal checked with Noid Light. All injectors getting signal.
-Pulled valve covers and inspected valvetrain. All rockers in place. Springs look fine. No valvetrain issues.
-Checked for vacuum leaks at intake to head joint with starting fluid. No change in idle characteristics. No vacuum leaks.
-Pulled bank 2 plugs/wires again. Results as follows:
#2 Slightly rich. No timing issue prevalent. Gap adjusted from .045" to .040". Plug wire 754 ohms with no change bending/rolling wire.
#4 Super rich. No timing issue prevalent. Gap adjusted from .045" to .040". Plug wire 753 ohms with no change bending/rolling wire.
#6 Excessively rich. No timing issue prevalent. Gap adjusted from .045" to .040". Plug wire 763 ohms with no change bending/rolling wire.

#8 Very lean (possibly not firing at all or not after entering closed loop). Slightly too much timing though hard to know with lean condition. Gap adjusted from .045" to .040". Plug wire 761 ohms with no change bending/rolling wire.

Will do the same plug and wire checks on bank 1 though no problems have been evident on that bank.

Next step is button back up and move coils. Swapping bank one coils with bank 2 to see if the problem moves. If no change I will swap #8 injector with a bank 1 injector to see if the problem moves. If the problem remains in bank 2 then I've got to consider problems with a ECM, harness, tune or a mechanical issue (compression loss in that cylinder).

As always, appreciate any feedback. I know there are some smart folks here. Feel free to home in as I am running out of ideas.

Travis

 

All back together and the problem remains. Looks as though cylinder 1 and 8 are not firing. I'm actually able to touch the header wrap on those two cylinders while running. Moving coils did not move the problem. I'm thinking about reflashing the ECM with a full flash and see what that does. Then if that has no effect I might try reflashing with a tune from the old engine just to see if those cylinders start firing again. There has got to be a solution...

 

Ok, two logs attached Test Idle 6 is after completing everything above including moving coils and the problem remained in the same location. Test Idle 7 full reflash is a full reflash of the tune and verifying spark energy with kv gap tester at the #8 and #1 cylinders. I had good spark at both I am confident spark is not the problem. I am confident that injector signal is not the problem. I am now considering this is down to an injector problem, a tune problem, or a mechanical problem. Going to swap injector 8 with injector 4 and see what happens.