Ok like the title says. My buddy traded a SRT4 for a 2006 110k mile Z. The kid that sold it to him basically scammed him. The motor was throwing a misfire code but he said all it was was a MAF sensor.

Said the motor was "replaced with a new motor that was freshly rebuilt". We've looked and clearly the lock has never been opened past the injectors.

It's throwing a random misfire code and a Bank 2 code.

Exhaust sounds like crap, it's in limp mode, pops and crackles out of the intake box.

Mods were a back end exhaust delete, pod filter intake.

I've already given him my stock air box. No fix.

I've given him my old working injectors. No fix.

He's replaced the coil packs, spark plugs, injectors, intake.

He's taken it to several shops who tell us different things and are just guessing beyond what we have done.

We compression tested it and all cylinders are 150+...

We're thinking timing? VVT sensors?

What else could this be? We seriously don't know where else to go beyond what we've done and think. He's already spent $400 on parts that haven't changed anything.


Any ideas boys?

Edit: We pulled the plugs again today, and his bank 2 (passenger side) plugs were white, his driver side plugs were black. Normal ish build up.

 

harness to injectors in correct sequence? apart from checking grounds that all I have.

At lease compression is good.....

 

Yea he said he checked that already.

 

Make sure that the 4 & 6 coil plugs are not switched. The way they lay, they all the time get swapped around after doing plugsz

 

Traded a dodge neon(essentially garbage) for a 350z.

Sounds like your friend did the scamming.









(it's a joke I know the neon's hold their value wayyyy better than the 350z)

 

Do you know what code it's throwing ?

 

He does. I forgot the exact number but it was Bank 2 and random misfire.

Edit: asked him he said it's only throwing P0300. Now. The other code went away after we reset the ECU the last time and he hasn't checked it since.

 

As others have said, make sure the coil pack wiring isn't flipped. These can be easily screwed up. If the wiring harness isn't too baked, there should be some labels for the cylinders on it. I used an auto paint pen on my plugs to number them because these labels were flaking off like dust in the wind.

Elsewise, my only other thoughts are cam position censor or possibly crank position sensor, but I believe you would get a different code for those.

Hope the wiring harness wasn't hacked!
-Icer

 

Nope they are connected correctly.

He has already changed the CPS's. That's one of the things the mechanics said it was. Didn't help.

We are thinking it's the VVT sensors and sylinoids. Cause it idles perfectly fine. But as soon as you get past 3k it starts getting shitty, then at 4K it start misfiring like crazy through the intake and exhaust.

 

Check the ground wiring for the coil packs.
Make sure the coil packs are not blistered.

Had a similar issue once and it was due to bad ground wiring.
Random misfire, misfire bank 2,4.
Fixed the issue

 

Solved.

Blown cat.

Bank 2 had a 209 psi back pressure return. Gave him my old cats and it runs strong.

 

I need new cats, My honey comb is all blown out and now its rattling.

 

Whoa! Glad you found the issue! I'm curious though, with the blown cat, were there no obvious signs of it being the cat? No rattle can noise coming from it or change in exhaust note? Definitely something to keep in mind going forward.
Thanks for following up on the resolution! All to often people don't update.
-Icer

 

Well his Z has seen some better days so there is a few rattles.

But his biggest thing you could hear was his terrible exhaust node since only half his cylinders were firing and exhausting. But appariently blown cats with limp mode is common. I came across a lot of blown cats sending cars into misfire/limp mode while we were looking for issues on the internet.

I told him to check early on but he said no way it's a cat lol

 

I'll look into buying some used cats or maybe some rest pipes then. ��

 

My buddy should be selling his he just bought since I gave him mine if you're interested.

Not sure if they are new, or new refurbished.

 

Test pipes or cats?

 

Seen some used ones on Craigslist for 50 bucks.

 

Cats.

That's not bad. He found and bought some the other day for $80 on CL.