2003 350 Z Engine misfire. I think chain jumped timing.
 

Go easy on me , I'm on here for my son's car I bought him.
Car now has 175.000 miles on it and was running great for 2 years . It threw a random misfire code and since the car is old I figured it was in need of a tune up. Replaced all the usual stuff, coil packs, plugs ,cam and crank sensors. Timing solenoids, injectors. I believe the chain has jumped time. Chain feels llose through access plate and I hear a grinding noise in the front maybe plastic tensioner guide broke laying in there.

Car still runs but feels like its running on 4 cylinders.
My question is can I still do a compression check or is engine blown from interference? Is there a chance I can just replace alll the chains etc and be fine?

Thanks , Appreciate any help!

You’re good Tommy -

First and foremost are you 100% sure that you hooked up coil pack #4 and #6 correctly? Nissan made these two counter intuitive and many people mis-match them and the car still runs but runs out of sequence…If you are not sure and cannot make heads or tails you can reference the wire colors of each coilpack connector.

You’ll need the factory service manual with is usually available on NICO and make sure you get the right year.

You want to reference Section EC and usually the ECU pin tables is right around page 100-110. On my 2003 Ignition Coils are ECU pins 60-62 and 79-81.

Also, ignition coils on cylinders 1 and 3 are on a subharness off the main engine bay harness…double check that you plugged this subharness back into the main harness. If you did not than, yes, you are only running on 4 cylinders


If you need further help with this let me know

It would be wise to take the front timing chain case off and see what’s going on … the chain should not be loose. This is a pretty big endevor for anyone that doesnt have engine rebuilding experience but can be done. The work isnt necessarily in the removal of the timing chain case cover or the internal trouble shooting and rectification but to put the timing chain case cover back on (and so it doesnt leak and assuming you keep the engine in the car) you need to drop the oil pan, which means dropping the front subframe, which involves supporting the engine from the top (with a hoist or engine bay bar) and also means about 2/3rd of the front suspension has to come off too. It can be done but it’s rather involved.

To answer your question - yes, you can still do a compression test if you think that you are only one or two teeth off. These are interference engines but people run them with a tooth off without damage.

If the engine is currently running (or has run) then thats a good indication that you are within the safe limits (or you’ve plowed a valve into the piston head already, lol)

Yes - assuming no damage you can buy a replacement timing chain kit (which is wise at your mileage), take everything off, set cylinder 1 to TDC, set the intake and exhaust cams accordingly and re-string the timing chains. While you’re finding the Factory Service Manual for Section EC for the wiring, download Section EM and there are instructions on how to reset timing from square one.

Also happy to help with this…

Let us know how it all goes -

Coils were done one at a time so I don't think mixing up coils was possible. I come from Corvettes and Vipers so the overhead cam engine is new as far as working on. So the engine timing cover can't be removed with out jacking engine to remove pan?

My plan was to remove radiator with fan assembly and all components on the front in the way?

I discovered the access cover on the drivers front . The timing chain is broke. I'm going to assume a new engine is needed . Can I pull the engine from the top?

Attachment 454940 Chain slipped off from broken guide?

Can anyone make anything form this? After a second look it appears ok ....

That tensioner is extended quite a bit. With 175k miles, the chain is past it's service life anyways. I'd pull the cover off to inspect everything. Plan on replacing the chains, guides, tensioner and water pump.

I'm assuming that's what the loud noise is at start up. At this point I'm trying to get the car to run right. Doing the chain is a big job.I can do it but limited on time and it's my son's car.

Also is the tensioner faulty or the guide faulty causing the tensioner to over extend?

Usually, the guide. That's why the cover needs to come off. If it was just the tensioner, it could be replaced through the inspection cover.

Yes - you can pull the engine from the top …

I would do just that and dont try to diagnose this from the replacment windows

Replace the timing chain components, water pump, tensioners, etc and get a fresh start.

I got one day a week which will take me a while. I called some shops, they didn't want to mess with it. Maybe a Nissan dealer will do it probably $2,500 .Might be cheaper to get a used engine-JDM $1,800 or so with 60,000 miles. Don't know I have always went with rebuilt but very expensive.

If you decide to use the FSM for guidance in removing the engine, there is alternative source. It's not free but, it is on physical media (CD) as a PDF.
Rock Auto has listing under the literature section for each year of the Z.
When I got mine, if I remember correctly it was $20.
Probably the best thing I've purchased for my 07.
BTW, when I had problems with oil pressure, it cost about $3200 parts and labor at an independent shop not a dealer. Replaced everything that you really should when you're in there because of all the work and the labor oil pump water pump you name it maintain auxiliary change sensors guides actuator the whole thing it was a good investment. Happened at 160,000 miles, car now has 250,000 no oil pressure problems no other problems at all.

Good luck,
Please let us know if you need anything else. And how everything works out.
E john

Ok made some progress.#6 coil connection was bad. Car runs much better but now it has the TCS slip light on and it idles a tad odd and a little high bit much better. Car is now drivable. . Seems like a vacuum leak to me. Been reading about the ECM relearn process. Not sure if that will do anything.

Can't find a leak , best place to look?

Has the intake plenum been off? Were the gaskets reused?

Yes. For the replacement of fuel injectors and coil packs. New gaskest when valve covers were replaced. They looked like new so reused them.Been trying to find a leak with carb cleaner. I guess I will get some new gaskets and try again.

So car is getting a PO147 and PO300. Son took it to a shop and said to replace the passenger side O2 sensor. MAF is new. O2 sensors are only a year old and everything has been replaced. I did the intake gasket set again and can't find any leak. checked the fuel pressure about 50lbs consistent

Is there anything else I could be missing ? Going to change the O2 sensor and if that doesn't fix it a compression test....

I didn't read this whole thread again, so did you do the coils? Have you checked to see if they're wet with oil? If they are, replace the valve cover (whole thing, not just the gasket) and the affected coil(s).

Valve covers ,coils injectors,crank, cam sensors, timing solenoids, intake gaskets top and bottom. Spark plugs. Pulled the passenger front o2 sensor. It had soot on it .Cleaned it with MAF cleaner. Going to try another o2 senor ...