What's wrong with my engine?

[nextelbuddy]

The ZHP swap I put into my wagon at 184,000 miles and some change. It was running perfectly fine in the donor car before it was pulled as I drove that car so I know.

Now that it is in my wagon I'm having issues with a misfire cylinder 5 very consistent and it only happens if I go wide open throttle above 3,500 to 4,000 RPMs...

I can tell when it's going to happen because when I go wide open throttle there is a loss of power and a very audible noise that sounds like a rattling or pinging. I'm inside the car The sound like it's coming from directly in front of me in the intake manifold area.

if I keep pressing through and letting the noise occur then the misfire will occur and the car will idle roughly until I turn the car off turn the back on.

If I drive the car staying below 3500 RPMs just cruising around it's fine. And idles perfect it even passed emissions because I was able to complete the drive cycle in about 30 minutes because everything is kept blow 3,000 RPMs.

Things that have been changed on the engine before I swapped it in are:

CCV system
Intake manifold gaskets
Throttle body gasket
Oil filter housing gasket
Valve car gasket and spark plug gasket set
6 brand new NGK iridium plugs gapped .32
M3 fuel pump
New mann fuel filter
Lower intake boot


It was at this point that when I got my swap done I passed emissions got my drive cycle done and then when I wanted to go for a spirited drive that's when I figured out the problem.

I pulled the iridium plugs and saw that cylinders 1 2 and 3 look perfectly fine..cylinders 4,5 and 6 look rich with 5 and 6 being the most carbon deposit heavy.

I pulled both pre-cst O2 sensors and bank one looks just fine but bank too looks very white as a there's a lien condition.

So I'm not sure why bank 2 cylinders 4,5 and 6 spark plugs look rich but the associated oxygen sensor for that bank looks extremely lean or white maybe fouled out

Also I fired up INPA and check to the lambda short-term and long-term trims and saw the bank to lambda was sitting at a -8 value and never moved..

Things I've done so far that if not helped and I still have the same exact problem are:

-Change to another known good fuel pump
-Change the fuel filter again
-Swapped in 6 good coil packs from my S54 engine which are the same coil pack part number as m54
- installed six brand new NGK double platinum plugs
-installed two known good PreCat O2 sensors and bank 1 and bank 2
-Pulled the disa valve verified the pin was still there the flap was good there was no play That's functioning properly Even resealed it with some gasket sealer to see if maybe there was a small leak somewhere...
-cleared every single adaptation value using INPA

After all that said I'm done put everything back together and does the same thing. Same exact thing no change.

My attempt to do a compression test tonight and that didn't go the way I wanted to. I purchase a compression tester from O'Reilly's that was a Bosch unit... And the unit is defective. As soon as the needle goes all the way up to 160ish needle starts dropping down all the way to zero and it's not holding pressure. went to a friend's house to borrow his compression tester in his was broken too The needle wouldn't even move.

So scratch the compression test for now until this weekend I'll have to get another tester.

So right now in my mind I either have what I think is a very bad intake leak somewhere maybe a crack and take manifold or a pinched gasket maybe...

Or I think bank 2 catalytic converter is clogged possibly.

I know it's a lot to read I'm going to post some pictures below of my spark plugs my O2 sensors before they were swapped and my screenshot from INPA showing my field trim

Maybe some M54ZHP gurus can give me some more direction or their thoughts or maybe confirm what I'm thinking.

In the pictures of the spark plugs the order of cylinders is 1 through 6 left to right. 123 look good 456-Rich.

In the pictures of the oxygen sensors the dark one is bank 1 and the white one is bank 2.



https://uploads.tapatalk-cdn.com/20190822/50f4b796557ffb6f1e72e671c4a64c7a.jpghttps://uploads.tapatalk-cdn.com/20190822/81032bb5ccd59f3b8819440530b2abb6.jpghttps://uploads.tapatalk-cdn.com/20190822/9f13f677c2b21d1aff5e68f422c02ac6.jpghttps://uploads.tapatalk-cdn.com/20190822/204589c448cb9853082ff6fa7a1f63a9.jpghttps://uploads.tapatalk-cdn.com/20190822/1310e948771166ae11e116ba0835a328.jpg

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[Stigissimo]

The fact that it’s the same cylinder every time gets me thinking ignition, but you’ve gone down nearly every path in that system.

Have you checked the DISA? I’d put money on it being that. Could also explain the rattling and pinging.


Edit: just reread that you did check the disa. Puzzling. So you checked the pin, but did you check to make sure the vacuum pot worked correctly? All of those symptoms point to the disa, especially the 4-6 plugs being rich

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[nextelbuddy]

The fact that it’s the same cylinder every time gets me thinking ignition, but you’ve gone down nearly every path in that system.

Have you checked the DISA? I’d put money on it being that. Could also explain the rattling and pinging.


Edit: just reread that you did check the disa. Puzzling. So you checked the pin, but did you check to make sure the vacuum pot worked correctly? All of those symptoms point to the disa, especially the 4-6 plugs being rich

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I didn't, I'm an S54 guy so I'll have to look at some guides on checking that.

FYI update from this morning. What do you think?

Ok so both pre cat o2 sensors were replaced with known good ones I had from another car.

Reset every single adaptation in INPA including lambda adaptations.

Issue still remains but now I get 2 errors when the misfires occurs...

P0305 - misfire cylinder 5 of course
P2197 - bank 2 sensor 1 o2 sensor stuck lean.

Searching shows that typically the P2197 code stems from a vacuum leak in bank 2...

So maybe that's why spark plugs show Rich on bank 2 but O2 sensor shows lean/white?

Looks time to smoke test intake manifold. Just have to find a smoke tester unfortunately

[Stigissimo]

Yeah it’s a simple test and easy to reach, might as well give it a try - pull the DISA, use one hand to fully open the flap, then cover over the little hole with your finger near the vacuum pot. When you release the flap with your other hand, it should spring back to maybe 1/2-3/4 open and hold there.


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[nextelbuddy]

Yeah it’s a simple test and easy to reach, might as well give it a try - pull the DISA, use one hand to fully open the flap, then cover over the little hole with your finger near the vacuum pot. When you release the flap with your other hand, it should spring back to maybe 1/2-3/4 open and hold there.


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Actually I did do that lol I was playing with the flap and I heard a wooshing sound and saw the hole and used my finger tip to cover it.i noticed the flap didn't close all the way until I lifted off the hole however on mine it closes a good amount with the hole closed. I figured it would at least stay open most of the way. I would say it only stays open 25% with the hole closed and releasing it lets it close that last 25%


Thanks a lot for taking the time to respond, I really appreciate it. Guess others don't really have any Info.

[Stigissimo]

Actually I did do that lol I was playing with the flap and I heard a wooshing sound and saw the hole and used my finger tip to cover it.i noticed the flap didn't close all the way until I lifted off the hole however on mine it closes a good amount with the hole closed. I figured it would at least stay open most of the way. I would say it only stays open 25% with the hole closed and releasing it lets it close that last 25%


Thanks a lot for taking the time to respond, I really appreciate it. Guess others don't really have any Info.


No problem mang! I may be misremembering and the flap may close halfway-3/4 rather than stay open that amount. If ya get what I’m saying.


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[holyc0w]

That sounds right.

Maybe unplug the DISA connector and see if anything changes?

[nextelbuddy]

this morning i decided to unplug the MAF.

the results are still overall its down on power just as before but this time when i go WOT, it no longer has the loud rattle/misfire CEL.. instead of goes to redline, slowly but you can hear the rattle very lightly but no misfire and no chugging/hesitation like before.


i know unplugging MAF causes DME to go RICH.. so would this mean that i have a lean condition aka manifold leak somewhere and by DME running RICH, its compensating with extra fuel to hide the leak somewhat.

going to make a homemade smoketester after work and see what i can find but im really thinking something under the intake manifold is leaking or unplugged or cracked...

[DeathTrap]

Did you ever get this sorted?

[racer2086]

Did you examine your exhaust manifold and gasket? Since you did a swap, that was one point in the chain that was disturbed from before and would explain why you have rich plugs and a lean O2 sensor if air was entering the exhaust system before the O2 sensor. It would also explain why bank 1 is normal, while bank 2 is wanting rich and reading lean if cylinder 4, 5, or 6 was leaking. It also makes sense that if you have a small exhaust leak, it would get worse as the RPMs rise, as it is a venturi effect with the faster flowing exhaust drawing more air in from the leak. Smoke test the exhaust and see what you find.

The misfires you are experiencing are a symptom not a cause of your issues. Those cylinders are being injected pig rich, while the car is reading lean on the O2.