[P1399] Engine misfire, what else to do?
 

Hi all,

Been having engine problems lately and am looking for some pointers on what to do. Running out of clues myself.

I own a December 1999 S2000 with ~196K km (little under 120K miles) on the clock. In January this year I had some maintenance done to the engine, after which issues slowly started building up (or so it seems). What was done at the time was the following;

1. Replace TCT for a OEM refurbished one
2. Replace valve retainers with AP2 ones
3. Changed oil (5W40 full synthetic, Kroon Emperol) and OEM oil filter
4. Adjusted valve clearance

After the maintenance, the car ran fine. Had a good drive home and was ready to have fun with the car again. Upon a sunny day somewhere early March I took the car out for a spin and went for a longer drive. Waited until the engine oil was at operating temperate, as of course I wanted to listen and feel VTEC kick in (don't we all ;)). As always, the car happily revved up to 9000RPM and I had a big smile on my face. After that, the engine started running like shit. I immediately noticed that the engine sounded raw, especially going over ~3500RPM. Drove home very slow that day and parked the car. The next day, I started the engine and it sounded fine. Revving up, it sounded a bit raw. Letting the engine run idle, I waited for it to warm up and I pulled up to the highway. In 4th gear, the CEL light started flashing. Slowed down and after a while it came on steady. Long story short...

Got a ODBII reader and red the DTC's. Turned out to be P1399 and P0301. Obviously I contacted the person that did the maintenance, who has been every so helpful! Got loads of great suggestions and helped assist with a couple of things. Additionally used some of the misfire threads here on the forum.

What was done to fix/diagnose the issue?

1. Swapped spark plugs (current ones are OEM NKG, in for 7000km) and replaced them. > No change.
2. Swapped coil pack cylinder 1 to 4. > No change.
3. Adjusted valve clearance. > No change.
4. Injector cleaner in my tank. > No change after driving ~200km.
5. Changed oil for 10W40 full synthetic (Kroon Emperol). > Engine runs smoother, other than that no change
6. Swapped TCT with different refurbished OEM. > No change.
7. Swapped injectors of cylinder 1 and 2. > No change.
8. Did a compression test > 185 cylinder 1. ~195 on cylinders 2 through 4.

What are the existing symptoms?

1. Engine runs 'raw' at higher revs (I'd say Subaru like sound) after 3000~3500RPM. Guessing sound of misfire
2. Ticking (guessing TCT) coming and going at idle and low revs. Video with sound
   here
   . Was better after oil change, video with sound after oil change
   here
   .
3. Before changing the oil from 5w40 to 10w40 I did a check on oil level. Noticed that the car drank quite a lot of oil. It didn't do that before?
4. Flashing CEL under load (you can clearly hear misfire).
5. Today, after warming up, the oil light lit at idle. It's actually flickering. Reving the engine makes it go. > This is what scares me.
6. When warn, trying to start the engine, it turns over difficult.

The car has no problem going into VTEC (obviously when warm) and doesn't hesitate whatsoever. I can't feel any performance drop. Should mention that oil level is ok, full. I always check oil before I go for a drive.

My maintenance guy suggested that it could be;

1. Bad oil pump.
2. Damange to the bearings (guessing rod bearings).

Before taking it back to him and pulling the engine apart. What else can I do, or what could it be?

In case of any trolls, yes I didn't change the blinker fluid. ;)

Small update. Started the car again last night (engine was cold).

Fired up instantly, no problems turning over. Sounded ok, not rattle. Waited for the car to go off the choke, after which I slowly increased the throttle a couple of time. CEL lit up, so I read the values

1. P0300, P0301 and P0302. > This is after it ran extremely shitty earlier today and after I switched the injectors in the morning.

Could my coils or spark plugs be fried? In the above I mentioned I swapped them, I didn't replace them.

Sparkies are new; try finding a local with known good parts and swap the coil packs onto it from theres and see if it changes.

If it is drinking a lot of oil (smoking a lot), this can cause misfires as well....did any of your plugs have oil on them?

Thanks, appreciate the response! I'm not too sure about the oil now. It actually doesn't smoke at all! I check my rear view mirror when revving up, not a puff. Actually ordered a pack of brand new coils today, will pop them in when I get them later this week. This is weird stuff. Will post an update.

Did you guys check your coil packs closely too see if they were wet with oil? If your spark plug hole gaskets have never been changed inside your valve cover then they will definitely flood oil into the coil packs chambers causing misfires and killing the coils. Change them out with OEM replacement ones and swop the coils with the new ones to see if that cures the problem - I'm sure it will unless that oil pump really has gone bad...

Good suggestion! The seals have been replaced with the same maintenance in Jan, just checked the invoice. I will check when replacing them, if the coils are wet with oil and report back.

Cool!

Every single time this comes up people say plugs and coil packs. Inevitably the OP responds that the plugs are new or new-ish. So they swap coil packs around and/or buy new ones - and that never works either. I think it's injectors. Why doesn't anyone ever try new or rebuilt and balanced injectors?

Plugs and coils come up because it's one of the basic steps. As you can see I've already fiddled around with my injectors. I have those on my list as next item as well. I've found a part number for the injectors, however can't seem to find the OEM manufacturer. Any pointers? :)

The oil light flickering at idle and the hard start after warm-up is the 1st problem I'd chase. Check your oil pressure with a mechanical gauge and crankshaft end-play (thrust washers?) Before doing anything else.