Hi all,


Since fitting my engine back in the car, after a short drive she developed a misfire on cylinder 1 and 2. I thought coil packs were bad (I made these up with my original coil pack top and stems/stalk from another car since a pair of mine cracked) so these two were replaced with used OEM. Started up and idled pretty much perfect, took her for a drive and seemed quite powerful, no sign of any issue. After maybe 15 miles a misfire developed at idle which probably took the slightest feel of power away. This got worse around 20 miles to where I stalled out stopping at a red light.

Since putting the car together I just through in some plugs I had, 4 bosch from a maxima and two ngk-r lrf5a. I figured this was probably the source of the issue so I bought a set of bosch platinum as recommended by the advance auto nearby. Started up, idle great for a minute or so, as the car warmed up I could hear/feel a slight intermittent misfire. Went for a drive, made it 4/5 miles before misses got real bad and eventually stalled very erratically (like going from 5/6 cylinders to 3/4 then to 2 and 1) and wouldn't start back.

I replaced all 6 with used NGK-R LFR5A, 4 were lightly used and 2 used more from the original engine. Had a slight mis again a couple minutes after starting but I managed to drive home without stalling. Idled on the drive as though one cylinder wasn't firing but didn't stall at all - although there were a few dip in revs. I unplugged the right bank front coil pack thinking it was dead again, but it was working, so unplugging it stalled the engine.

What's weird is before the overheat (Reason for engine out) she was running smooth on some very worn NGK-R LFR5A plugs. Then the new bosch ones stalled the engine completely. Only single thing which changed before and after engine repair is that the compression is now (minutely) higher since planing the cylinder heads and decks. Could the increased compression be causing my problems? Would I need colder plugs (NGK-R LFR'4'A) like the boosted guys use?


All help is greatly appreciated
Brad

 

I would suggest picking up a new set of ngk and resetting the computer before restarting with the new plugs.

 

Probably the ECM is not liking the changes?

I would suggest following the troubleshooting steps in the FSM

http://forums.nicoclub.com/fsm-list-...g-t525067.html

Especially chapter EC

Good luck

Telcoman

 

Thanks guys, new plugs are a definite.
I had a look around again this morning, disconnecting each coil pack. Middle driver side bank one was out, swapped for another spare and she idles better.
The idle is definitely slightly rough but when I give it some revs becomes pretty smooth.
The engine pulls very strong and revs smoothly whilst doing so without stuttering.

I cleared the codes and rescanned to get:
P0328 Knock sensor high input Bank 1
P0462 Fuel Level Sensor A circuit low input
and most importantly
P0345 Camshaft Poition sensor Bank 2

My VDC and slip light are on (no brake) and she takes 3/4 seconds of cranking to fire up.
These lights and starting issue wasn't there before so I suspect now is just a dodgy wire/plug to the camshaft sensor since I've been moving wires around diagnosing the coil packs and plugs.

I'll check the camshaft sensor, connector and wires and update you guys.
I'm still shocked that the new bosch plat plugs took me 4 miles before stranding me........


EDIT: Do you guys think I should go for the colder (LFR6A) plugs because of slightly higher compression or are those only really for turbo engines?
Could the car perform worse with colder plugs or is colder always better?

 

Update:

Bank 2 camshaft sens was unplugged, connector was broken so have to tape it together for now.
VDC and slip lights off. Still a slight unsteadiness to the idle which seems to go away with revs.
I have a code for intake over-advanced. This is probably because of the change I made to the timing when reassembling the engine with the planed heads and decks.

So far the only unusual behavior is the unsteady idle which sort of shuffles the car forward when you release the brakes just enough to let the car move in drive. Also, if I rev the engine a little, when the revs drop back down they don't just fall back to idle. It dips below idle (like 500rpm I think) and then goes back to around 600rpm, I think, and steadies itself there. Once or twice it has just died from the revs dipping to low after a rev.......

I'll look at putting some new plugs in and see how much better the idle gets. Maybe check through the coil packs, although I checked the first time.
Will have some videos soon.

 

you might want to check your timing out. If you remove the cam sprocket covers, you can see how far off you are with this neat tool. If the timing isn't right, I don't think you can expect the engine to perform properly and may cause all types of symptoms.

http://www.jimwolftechnology.com/wol...c_template.pdf

If you don't mind, post a picture with the template in place.

 

This might have a lot to do with the changes you did when replacing the timing chain. If I recall you shifted over a few teeth on the chain because you thought it was too loose. You should fix it and set it properly per the FSM.

Also, hunting idle can be caused by a vacuum leak. If you're having issues like sensors unplugged/damaged, then (and I don't intend to sound mean) you shouldn't trust anything you've done up to this point and should go back and verify every little thing. The coil packs could be plugged in wrong, it's fairly easy to flip them. I doubt it's a spark plug problem right now, it's some other problem with the engine.

 

Yeah, I did have an over advanced intake camshaft code when I scanned it. The problem was the heads were closer to the crankshaft which made the chain 'loose', so I set the crank and camshafts to tdc as closely as I could using the teeth available on the chain. I'm trying to get the idle as best I can, and I know the idle can be better because I've heard (have video as well) the engine idleing very smoothly. I am running two old plugs and four slightly used. On Tuesday I started her up after swapping coils and plugs to the current setup and she idled smooth. Little later there's the sound of one cylinder missing at idle which I can't detect with revs or under heavy load. I'll get some videos up asap.

Really I'm just trying to find the possible sources to the unsteady idle because I know the engine as it is now can idle pretty smooth.....
Thanks for the suggestions guys. I still have a plug connector which I haven't found where it connects too.