Just got my JY 5.3 running. Kinda. Been having trouble with it running super rich and finally narrowed it down to the #6 hole. I'm running a MS3 Gold Box and full sequential with plug and play wiring harness from efi source. All the plugs look good, except #6. Wet with fuel and its bad enough I get fuel out the exhaust.

Running Siemens Deka 80lb injectors.

Swapped injectors with hole #2 and the problem remains at hole 6.
Coil pack is working and swapped with a known good to verify.
Did a compression test and leak down test and both checked out.
Lifters are moving valves full range of motion.
I put a light in the injector plug and verified it is pulsing.
Checked the pinout on the ecm and verified continuity.

When idling, AF/R is out of Range on my AEM Gauge to the rich side. I can unplug #6 injector and AF/R moves back to the targeted AFR at 14. When I pull the plug and clean it, it will Idle at the correct AFR for a few seconds until the plug fouls and I lose spark.

I'm not sure what to do next? I just downloaded megalog veiwer and am going to data log tomorrow night and see if the PW are different on #6. I went through and cleaned up all the grounds on my motor to chassis and and motor to megasquirt and made sure everything is tight.

What am I missing?

 

This aspect makes no sense.

Are you monitoring lambda on each bank, or in a combined collector for all 8 ?

It should be idling at your desired target, 14 etc, or close to it. If you unplug an injector it should go very lean. It should almost never be able to achieve 14.0:1 unless it was idling around 8-9:1 in the first place.

 

I have the wideband sensor in my downpipe off the turbo. i'm guessing the the raw fuel coming out of #6 is skewing the AFR reading, and when the injector is unplugged the ecm is able to correct it to the target.

I called efi source today and he wants me to send in the MS3 box so he can take a look at it. The other thing that is strange about this is at first, I kept pulling fuel from the VE table to lean it out and when it was making much differnence I started pulling plugs to see what was going, the left bank (odd injectors) where gray (lean) and the right bank was plugs were black and sooty.

And finally, when I load different tunes it doesn't seem to change the VE Table.

 

Raw fuel will not affect the sensor. Air/oxygen will

 

Ok, Sent the MS3 in and it check out perfectly. There has to be something going on with the motor. What would cause a misfire on one hole and still keep a good compression and and leak down test reading? Maybe an intake manifold gasket leak?

 

Poor valve sealing.

In theory yes a compression test should show, yes in theory a leakdown test might show ( well probably not ), but neither are tested are engine operating speeds and oil pressures etc.

But an intake gasket leak is another possibility and certainly easy to test for.

 

When I bought the motor someone had broken one of the mounting holes for the top cover out of the intake and epoxied it back together. I really didn't think to much about it at the time. Guess I will pull it and investigate. The motor has always had an "airy" sound to it. If that turns out good, guess i will pull the heads and look at the valves.

 

I didnt say the issue could be the valves...I said valve sealing.

That can be anything relating to the valve opening/closing.

ie valves, lifters, pushrods, cam, pre-load, valve seats etc etc

Removing the heads means you cant inspect a lot of that.

I would ensure lifter preload is within limits on that cylinder, that the lifters can bleed down and arent locked open, check installed valve heights are all similar.
You can do all these before removing the heads.

As for intake leaks, no idea what it's called over there, but an aerosol product like Easy Start, or carb cleaner is handy. Spray this around the suspect area, if you hear an rpm change then that's a good sign of an intake leak.

 

You can check for an intake leak with a can of brake clean but i would pull that intake and check it out sounds light you might have a restriction

 

I think your right, it would explain why the left side runs more lean than the right side if there is a rag or something blocking hole 6 and causing overall less airflow to the right bank.

 

So I pulled the intake off tonight. All the intake ports are grimey and have a light coating of oil, which I assume is from the PCV system. Except for #6. It is dry as a bone. You can see where at one time it was oil/grimey like the rest, but it is very differnt from the other 7.



This is a shot of the right bank. Left side of the Picture is the front of the motor. You can see the difference between #6 and the others.



Closer shot of #4 and #6

I forgot to snap a pic of the intake, but it is the same way. It's almost like the #6 hole hasn't been pulling air into the cylinder for quite some time.

 

I turned the motor over and ensured the intake valve was being opened and closed. Also, I put pac 1218 springs in before I installed the motor. Also, put in a trick flow cam. I did not personally run the motor before i got it, but the junkyard claimed they did and also compression tested it.

 

Looks to me like #6 is "clean" from the extra fuel that has been going through it washing the port walls...

 

I should have grabbed a couple pics of the intake. It's the same way. I guess dry would be a better way to describe it. If I run my finger on the inside of the intake I'll get a little bit of grime/oil from the runner. On #6 there is nothing, it's dry. Almost like it's been burnt off.

 

Clean can suggest water ingress ( obviously not here, as there should be no way water can get in there ). Clean can suggest fuel washing it clean. Whether excessive amounts of fuel or no air.

Given the intake design, unless something is stuck inside the port runner, it would be hard to imagine a no air scenario.

On the other hand if no air was getting into the cylinder due to valve not opening...same deal.

 

Ok start from the top have you done a compression test? If yes and its good is it possible you swapped injector plugs on 6 and 8 injectors ive done it before on the other side with 5 and 7 only caused a miss on 5

The head is clean from extra fuel intake might be cleaned from the same thing

 

Ok here it goes from the start.

Bought Supposedly good running motor from Junkyard.

I installed PAC 1218 Valve Springs, 80lb Seimens Deka Injectors, and TrickFlow Cam. http://www.summitracing.com/parts/tfs-30602001

Ordered an EFI source MS3 Gold Box and Plug and Play harness.

I have a total runtime of approximately 10 minutes. From the first start of this motor it has run very rich, 10.1:1 AFR. No matter what I did to the VE table it was rich. Pulled the plugs and noticed the right bank plugs where considerably more black than the left bank, and also #6 wasn't firing. At this point, the motor would smoke and blow raw fuel out of the exhaust.

I suspected a stuck injector and ordered a new one. I put it in and same thing, wet plug on 6. So I checked for spark, and even swapped coil packs with a know good one. Same result. I then swapped that injector with a know good and the problem stayed with #6 hole.

Frome there, I suspected the MS3 box was haywire. So I plugged a light into the injector harness and watched the pulses. It seemed to be fine, but I sent it in to be checked out anyway. Mike @ EFI Source confirmed it is working properly. I moved on to the wiring harness and checked continuity, and that it was pinned correctly in the harness.

I then checked compression. 150#'s on #6. Then I did a leak down test and it was identical to cylinder #2. Measured the rocker arm movement and it was the same as other cylinders.

With the intake off, I turned the motor over and physically verified the valve is opening and closing. There is no blockage in the intake.

 

If you are making changes to the fuel table correctly, there is no possible way you would not see a change on the wideband. Unless of course the wideband is not working or set up correctly either.

Really...given the amount of unknowns, bringing in someone with some experience would be helpful

The simple fact you said earlier unplugging that cylinder brought the AFR's displayed to near 14 means the overall tune is horrendously rich...again if the wideband is working and set up correctly.

IMO whilst you are chasing a problem with cyl 6, you are also chasing multiple other problems here. Whether the ecu install, wiring, tuning etc.

Add that on top of a completely unknown engine...which you then also changed stuff like cam etc.

If you only have 10mins runtime with this engine, I would struggle to believe that inlet port was cleaned in that short time, which would imply there are issues with the motor to start with.

So when you changed the cam, did you measure and install correct length pushrods ?

 

First and foremost thank you for taking the time to help me out with this.

While this is my first FI LS motor, I have spent considerable time building and wrenching on diesel motors that do not have plugs to foul. I work at an ag equipment dealership and have gotten some of the mechanics involved with this project and it is definitely not a cut and dry case.

I 100% agree that most of the confusion here is the massive amounts of unknowns. But here is what I do know:

I am using a LS1 turbo tune from Mike @ EFI source so I am at least starting with something that runs other peoples motors. Also, since my build is almost and exact clone to denmah's first Farimont 5 motor, I loaded that tune and had the same results with the fouling plug on #6.

I pulled all 8 spark plugs tonight and did another compression test with the intake off.

1. 183# 3. 185# 5. 160# 7. 170#
2. 170# 4. 185# 6. 170# 8. 185#

When I pulled the plugs, yet again all the right bank plugs are reading more rich than the left bank plugs.

I did not check nor install new pushrods with the cam as it is supposedly compatible with stock pushrods, I reused the ones that were in the motor. The cam was installed dot to dot.

My wideband sensor is set for gasoline, and I understand that 10:1 is 0 volts or the bottom of the scale? So my theory on this is something mechanical is causing the right bank to run very rich, maybe much lower than 10:1. So when I changed the ve table, it is actually pulling fuel but not enough to get actual AFR above 10.1. I can hear the motor change when I pull fuel, and I had gotten it to idle at around 11, but at that point with a missing cylinder and little fuel was having a hard time keeping it running.

I am running a single wahlbro 400 in tank pump with a 12V power supply. This runs through a high flow filter to the stock truck fuel regulator. I thought this was an accepted way to run the fuel system, but I have not checked fuel pressure. I would have thought that a fuel pressure problem would have followed the injector and not stayed with the cylinder.

 

You are using a tune from a different engine, it's a huge assumption this will be correct for you.

You are not using his wiring loom...so again an assumption here the two are identical.

You are assuming all your sensors are calibrated correctly....again this should always be verified with any new install regardless of where a base map came from. It's basic set up and diagnostic, as well as plain old common sense before starting.

The wideband may display that, and assuming you are feeding this info to the ecu, you would need to confirm what the ecu is seeing from it is correct and sensible. Again, back to basic setup stages to remove assumptions things are correct.

You mention only one, so I presume you only monitor lambda on either one bank, or after a collector for all 8 ?

Monitoring both banks is very helpful.

It is unlikely fuel pressure is the problem.

Uploading a datalog may help, but IMO it probably wont reveal enough.

And one cylinder down would have negligible effect on the engine running. I could pull 2 or 3 cylinders and the engine would still run fine.
You could run a V8 at idle with a dead cylinder and struggle to even notice.

The tune is mega rich, the wideband will not be reading correctly if there is a cylinder pumping air onto the cylinder, which means the tune is far far richer than the wideband is even displaying.

Really, there are multiple problems here and you need to got back to basics and work through as a new install.

Compression is good, you would hope valve timing is correct, you need to ensure all wiring is correct, and the tune including all sensor calibrations must be correct.

Remove all assumptions.