LS1 Swap Issues

pushrod36 said:

You mentioned moving coils.  Have you tried moving injectors?

I would but since the misfire detection is turned off due to the large cam tune, I dont know which (if any) cylider is the culprit. May need to get HPTuners just so I can turn this back on temporarily. 

No Time said:

In addition to the grounds, I'd take a look at some basics:

-fuel pressure check under the following conditions:  not running, running at idle,  throttle tip in, gradual throttle application, and at higher rpm where you said it seems more responsive. 

- compression check warm and cold

- if you have cats installed, try unbolting the joint in front of the cart or removing the O2 sensor in front of the cat and running it to see if the tip in problem improves. Clogged/restricted cats can cause the bog at tip in, but the engine will accept gradual throttle application. It could also mess with O2 readings causing rich condition. 

- you can also use the propane torch to richen the mixture into the intake to check O2 sensor behavior and if the signal is real or default. 

Will do on all the above aside from CATS, nothing back there to get plugged :-)

Finally getting some time to delve in deeper. Also bought HP tuners so I can start to diagnose with more accuracy (hopefully). Does something seem strange with how B1S1 is reacting with both of these charts? I am sorting through an issue where the car bogs down heavily under tip-in and has a misfire I am trying to track down. Swapped O2's between these two logs and including screen shots. Tune is amazing and car ran great for a few years until started to have some misfire issues. Next step is to try to turn misfire detection back on and see if I can locate the trouble cylinder. All sorts of new plugs, wires, sensors thrown on this 3 year old build to try and correct. Any input appreciated!

Rather than moving injectors or coils have you tried going one by one and unplugging them? If one of them is the problem there should be minimal change in how the engine is running when you unplug that specific injector/coil.  The good coils and injectors when unplugged should upset the idle pretty good.

Yeah, that B1S1 signal is weird. I've never seen one look like that. If this was an oscilloscope, I would say that signal is undersampled and it looks like the software is interpolating, but I don't know if that's even possible in HP Tuners. I also don't know whether that would be related to your problem at all. Does it only run crappy in closed loop? Maybe try disabling the O2s altogether and drive it around in open loop for a while to see if it makes a difference.

The tuner has set it so it runs 100% on open loop. On unplugging injectors, it really didn't help to narrow down. The cam is pretty damn lumpy and the car is INCREDIBLY loud, so its really hard to notice one cylinder down. I actually could unplug 3 of them before it really got rough enough to notice lol.....

obsolete said:

Yeah, that B1S1 signal is weird. I've never seen one look like that. If this was an oscilloscope, I would say that signal is undersampled and it looks like the software is interpolating, but I don't know if that's even possible in HP Tuners. I also don't know whether that would be related to your problem at all. Does it only run crappy in closed loop? Maybe try disabling the O2s altogether and drive it around in open loop for a while to see if it makes a difference.

I am going to log it with the O2 unplugged on each bank to see if the voltage holds around 450mV when unplugged or if that may show the B1 sensor shorted somewhere. Wondering if the B1 sensor heater circuit has an issue with it being so strangly mapped. 

Olemiss540 said:

The tuner has set it so it runs 100% on open loop. On unplugging injectors, it really didn't help to narrow down. The cam is pretty damn lumpy and the car is INCREDIBLY loud, so its really hard to notice one cylinder down. I actually could unplug 3 of them before it really got rough enough to notice lol.....

Use a heat gun on each exhaust port to detect "down" cylinder?  (probably need to start from a cold engine)

Olemiss540 said:

The tuner has set it so it runs 100% on open loop. 

Uhhhh just at idle right? Even that is a little lazy.

Indy - Guy said:

Olemiss540 said:

The tuner has set it so it runs 100% on open loop. On unplugging injectors, it really didn't help to narrow down. The cam is pretty damn lumpy and the car is INCREDIBLY loud, so its really hard to notice one cylinder down. I actually could unplug 3 of them before it really got rough enough to notice lol.....

Use a heat gun on each exhaust port to detect "down" cylinder?  (probably need to start from a cold engine)

Tried that and didnt see any LARGE differences sadly. Going to turn the misfire detection back on with HPTuners to see which one is misfiring most. I dont believe the misfire is causing the LEAN voltages on both O2's but I believe that is the next thing to troubleshoot. Wondering if the Ceramic Coated headers is what caused the O2 issues (lean readings possibly due to lack of heat)????

In reply to Olemiss540 :

Ceramic coating doesn't do much for controlling heat it doesn't make the exhaust gas any colder and still makes the headers unpleasant to touch.

I know you said new plugs and wires but have you confirmed that none of the plugs were damaged.  It's not hard to crack the porcelain installing them and can have you chasing tail for a while.  Just trying to check the basics here.

RacetruckRon said:

In reply to Olemiss540 :

Ceramic coating doesn't do much for controlling heat it doesn't make the exhaust gas any colder and still makes the headers unpleasant to touch.

I know you said new plugs and wires but have you confirmed that none of the plugs were damaged.  It's not hard to crack the porcelain installing them and can have you chasing tail for a while.  Just trying to check the basics here.

Yes, it actually on its 3rd set of new plugs/wires. Dont ask how frustrating that has been thanks to trying a shop for once.

Based on my logs, looks like IAC valve is at zero while idling, so that would point to a vacuum leak which would explain the VERY low O2 readings of showing lean while idling.  

FINALLY PROGRESS! Figured out how to turn back misfire detection on the PCM (turned off due to aggressive cam) and started swapping parts around to watch its effect on misfire counts and O2 voltages. O2 drivers side was consistently pegged around 28mV with passenger side a bit higher and actually fluctuation on throttle stabs. 

Swapped ign coils bank to bank, nothing. Pulled injectors and swapped them bank to bank yesterday and BOOM. Now drivers side O2 reading higher and fluctuating with passenger side O2 sitting dead lean 28mV.

Ordered a new 42# Delphi injector and when it arrives will try to swap it out with the one I suspect is bad. 

After 2.5 years of spuddering and a few grand to E36 M3ty mechanics, may be finally making progreess!