Weird cruising misfire, DAM = 0.2, but no FKC/FKL

[xt2005bonbon]

Do the OCV swap first. It should be fairly easy. Don't need to wait for the crush washers. But yeah, IIRC from your logs, it looks like one of your OCVs is lagging a bit at times.

[Infosecdad]

If you replace an OCV, please go OEM; we have seen aftermarket fail out of the box.

 

Honestly, if you can swing it, replace them as a pair.

[lagwagon]

Ok, I swapped the OCVs and did another initialization but things went pretty different. I followed the same procedure - cold start for 1 minute, hold 2000 rpm for 1 minute, hold 3000 rpm for 1 minute. I also replaced a PCV hose that literally exploded when I pulled it off.

 

The first time I did this (last week), the car started with 0° avcs both sides and initialized when I held 3000 rpm. Duty cycle went up to ~45% and advance went up to ~15°.

 

This time, the car started with 7-8° advance at 9.41% duty cycle and didn't seem to initialize. I am hoping this is a result of having the battery disconnected and the car going back through a full relearn, also, I have not pulled the 1° of timing yet.

 

Datalog4 - 3000rpm avcs initialization is the log from last week where it seems to have initialized properly but still shows a mismatch in advance for the same duty cycle.

 

Datalog10 - swapped ocvs initialization is from the cold start today where it doesn't seem to have initialized. ACVS stays mostly at 7-9° and duty cycle stays at 9.41% the whole time.

 

I guess I'll try again tomorrow, or after some driving but I'm a bit worried that the car is starting up with advance that doesn't seem to match what that duty cycle should get. All my other logs show 0° advance at 9.41% dc.

 

Other than that, not sure what's going on.

datalog4 - 3000rpm avcs initialization.csv

datalog10 - swapped ocvs initialization.csv

[lagwagon]

Drove around to get through some learning from the battery disconnect and did a quick log reving to 2000 and 3000. Left side lagged very slightly, but nothing like the test before the OCV swap. Might be the difference between doing this test on a cold vs hot engine.

 

I think the issue in the previous log was no oil pressure in the OCVs after the swap.

 

I'll do another cold test tomorrow morning and post it up to compare apples to apples (hopefully!)

datalog1.csv

[xt2005bonbon]

Have not checked your logs; but I know on my 05 OBXT, when I reset the ECU and start the car cold right after, the AVCS angles get 'stuck' at a pretty high angle in my case, like 14 deg I think. It stays there until she warms up and I driver her around a bit. Then, it'll go back to zero when not under load and behave normal. I can't remember if it does the same thing after an ECU reset and a warm engine start.

[lagwagon]

Have not checked your logs; but I know on my 05 OBXT, when I reset the ECU and start the car cold right after, the AVCS angles get 'stuck' at a pretty high angle in my case, like 14 deg I think. It stays there until she warms up and I driver her around a bit. Then, it'll go back to zero when not under load and behave normal. I can't remember if it does the same thing after an ECU reset and a warm engine start.

 

I think the valve must hold some pressure causing that to happen after a reset.

 

No log yet from the cold start but neither side responded to the idle-2000-3000 steps this morning. They stayed at 0 until several minutes into the drive. I'll post the log tonight to see if there was any difference in synchronization when they did react. Maybe it is too cold in the mornings now to do this.

[xt2005bonbon]

What is your current DAM?

[lagwagon]

What is your current DAM?

 

It's back up to 1 after the reset and a couple short drives.

[xt2005bonbon]

OK. Just to be sure, have you also verified that there is nothing loose around the engine, like exhaust heat shields? I just noticed that I had a couple loose heat shields and was registering FKC left and right. I tightened them up last week and now it is better. A trick I use is hit the intercooler with my fist on its upper right corner and listen for anything vibrating.

[lagwagon]

OK. Just to be sure, have you also verified that there is nothing loose around the engine, like exhaust heat shields? I just noticed that I had a couple loose heat shields and was registering FKC left and right. I tightened them up last week and now it is better. A trick I use is hit the intercooler with my fist on its upper right corner and listen for anything vibrating.

 

I have one that rattles near the O2 sensor (it's tight, but it touches the manifold and is rusting away). My plan is to get a cut off wheel for my dremel and cut away the part that is touching (it's only about 1 square inch that needs to be cut out).

[lagwagon]

Next log, lol.

 

This one shows that the problem did not change sides when I swapped the OCVs left to right, so there is low pressure getting to the left OCV, duty cycle is going up to compensate during transient driving but not quite getting there and the difference in advance is as high as 9°. This log also has a knock with the car fully in gear, but very low rpm. It still is making a correction though.

datalog3.csv

[xt2005bonbon]

You can see that the left side is lagging a little. I believe left side is driver side. Have you checked/removed the banjo bolt filter behind the timing belt cover? Can't remember if you mentioned it. Pain in the butt to access without removing timing belt cover. But there is a way.

 

 

Also, I am just surprised to see you still have AVCS advance even when your AFR is 21. I need to check if mine does that, but I only recall in my case AVCS advance under load and rich AFR.

 

 

 

I would also log boost and load, so it is easier, at least for me, to see when/how much you are pushing the car.

[lagwagon]

You can see that the left side is lagging a little. I believe left side is driver side. Have you checked/removed the banjo bolt filter behind the timing belt cover? Can't remember if you mentioned it. Pain in the butt to access without removing timing belt cover. But there is a way.

 

 

Also, I am just surprised to see you still have AVCS advance even when your AFR is 21. I need to check if mine does that, but I only recall in my case AVCS advance under load and rich AFR.

 

 

 

I would also log boost and load, so it is easier, at least for me, to see when/how much you are pushing the car.

 

I can add boost and load but I’ll need to take some off the list or it just fails the log. I’ll probably take off cylinder roughness again.

[xt2005bonbon]

Yeah. Looks like you're free of misfires, which is a great thing btw.

[lagwagon]

Well, I removed roughness and added boost and requested torque and it won't log at all. I can watch live data but I press the button to start logging and when it is initializing it loses communication...every single time. I guess I'll try again later.

 

Likely related side note: while my AP reads data and the mechanic/dealer hasn't had any issues, my larger scan tool won't connect and the previous owner also reported to the dealer about not being able to connect his tool. Seems to have started sometime in 2012. I assume he bought the AP in an attempt to scan but I haven't asked him.

 

EDIT: I see in some lists there is calculated load, but I don't see that in my list on the actual AP. I haven't removed anything from the monitors list so not sure why it wouldn't be there.

Edited December 9, 2021 by lagwagon

[xt2005bonbon]

What are all the variables you can view on your AP?

 

 

Also, have you ever removed that banjo bolt filter on the driver side?

[lagwagon]

What are all the variables you can view on your AP?

 

 

Also, have you ever removed that banjo bolt filter on the driver side?

 

I found calculated load after running through the list several times, I must be going blind(er). I haven't removed the banjo bolt filter(s) yet, or checked to see if they are there.

 

I took off a/b/c/d fuel and was able to get ONE log to work yesterday but I ran out of time to download it and review it. It seems to be logging boost that causes problems. As soon as I take boost off the list it seems to log normally (or as normal as it ever does for me).

[lagwagon]

I got a couple of logs with calculated load and boost logged.

 

2nd gear pull - this is a short steep uphill section so acceleration is more like a flat road section 3rd gear pull. Same hill I logged a 2nd gear pull earlier in this thread.

 

Uphill - long uphill at highway speeds 100/110 km/hr. I did four similar pulls today but this one was the steeper uphill section and includes a speed change from 100 to 110 so boost is actually hit and was held for a reasonable portion of the hill.

 

Everything looks pretty good in all these logs, to me at least. Even the ramp up of left advance looks not too bad but I was probably purposefully driving smoothly getting into the 2nd gear pull would is probably masking the asynchronization of the left cam. I know a wot pull should be hard on the throttle but coming around the corner rpms drop too far to go straight to wot. Just the reality of driving in the city.

datalog13 - 2nd gear pull.csv

datalog1 uphill.csv

[lagwagon]

Bump from the dead. Car was alternating between A/F Learning 1A at +15 and -10 over the winter, with stalling pulling up to stops. I adjusted the idle to +200 rpm to compensate for the stalling.

 

I finally had the rebuilt and flow tested injectors installed, along with the PCV hoses from both valve covers. A/F Learning 1A is now at ~0 and I've backed down the idle to stock. One of the hoses was completely plugged with waxy residue.

 

I haven't had a chance to data log yet but I'm thinking that the increase in pressure in the head could've caused issues with the OCV solenoid opening properly. This depends on the oil circuit and the direction the valve moves to open - with, or counter flow. It will be interesting to see if there is still lag in the left advance or if it has evened out.

 

When in doubt, check for blocked hoses!