Have a ‘02 R53 with about 127k mi. on it, with the following relevant mods:

Rebuilt and ported & polished head (w/in last year at 116k mi.)
2006 Supercharger (had 20K miles on it)
Craven 15% Supercharger Pulley
Craven 2% overdrive lightweight crank pulley
Alta Cold Air Intake


While driving in to work this past Friday (11/25), maybe doing 40-50mph, I felt the car ever so slightly start to sputter. Hoped it was just a passing hiccup, I continued on. It wasn’t a passing hiccup and, within about 5 miles, the car got worse. It went from slight to full sputter/shaking, big loss of power when trying to accelerate. Threw a CEL with a P0303 code (“cylinder #3 misfire”).

When it happened, I was running the OEM Ignition Coil Pack. Over the weekend I swapped in the MSD Ignition Coil Pack, cleared the code and after about 2 minutes of running I get the same result (code P0303).

I inspected the plugs and cylinder #3 is definitely not like the others:

Cylinder #1:





Cylinder #2:





Cylinder #3:




Cylinder #4:





.
If it makes any difference, the plugs are NGK Iridium, BKR7EIX.

Actually, a P3030 code is how my last big issue with this car started. Less than a year ago it burned a couple of exhaust valves and had to have the head rebuilt (at about 116k mi.). During the rebuild, I also had the head ported & polished. I posted about what precipitated that rebuild in a thread back in December 2015: https://www.northamericanmotoring.co...-at-150-a.html

As I've mentioned in other threads, my Indy shop is about 100mi. away (200 round trip). To get my R53 to my Indy shop I have to rent an auto transport trailer ($$$) and haul it up there using the thirsty v10 Excursion ($$$). So, to the extent this is something I can look at, try to fix, troubleshoot, narrow the possible issues, etc. ... and avoid the trek to the Indy shop, I’m all ears.

So, any ideas or other recommendations? Any idea what could be the problem?

Thank you in advance.
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it looks wet. perhaps the coil pack or ignition cable? try a compression test too.

 

Bad injector? (Stuck open)

 

1. Compression test
2. New ignition wires

If you get past those steps then you've got bigger problems, but cylinder 3 is fuel washed like that because it isn't firing, these cars don't shut down injectors with misfire conditions like the 2nd gen cars do.

 

Ignition wires were replace by Indy shop on August 25, 2016 because of a prior P0304 code ("Cylinder #4 Misfire"). I suppose #3 wire could have gone bad ... but sheesh.

As I mentioned, I also swapped Ignition Coil Pack and had the same results.

Even assuming little compression in #3, wouldn't the plug still burn off the fuel or at least look more similar to the other three plugs?

Outside of swapping wires (and assuming both coil packs can be bad on the same plug) what else might cause cylinder #3 to not fire? ECU?

 

A bad DME could cause misfire problems, but I would rule out the cheaper and quicker to fix problems first.

Low compression will not contribute to a clean burn, so no, it isn't going to clean that plug.

If the vaporized mixture isn't compressed during ignition it more or less is just like lighting a fart, you get a quick flame and no power.

 

I burned a set of valves also. But before that, like you I replaced the coil and wires with no change. But I did also change the injectors and the issues have resolved.

It's a cheap way to go before you need a new head again.

///Rich

 

Yeah, if I had to rebuild the head again, in less than one year . . . I'd rather take the car around the back of the shed and just shoot it. I'd rather not be the guy who starts a conversation with "So, how many miles per head rebuild do you get on your R53?" instead of how many miles per gallon.

Going to pick up some ignition wires today. Will keep you posted.

So, up until now, I haven't had any justification to buy a compression tester. I like to buy decent tools, but not ones that will have a "Snap-On" effect on my wallet. A quick search yielded this one:

http://www.promini.com/product-exec/...earch_model/99

Anything I should look for in a compression tester or any other recommendations?
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If you're looking for quick ball park numbers a Harbor Freight compression tester will get you by.

I do agree that a quality gauge is always nicer, but many of them are made by the same manufacturers, (not to say the HF is the same as the Snap On). A manual pressure gauge isn't that hard of a product to get right. (Unless you're Glowshift...)

 

Swapped out the #3 ignition wire with a new one and cleared the CEL. Still runs ruff and throws a P3030 code.

It was pouring rain last night, so I didn't test for spark to eliminate the DME. Will try tonight.
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Just following up....


... I had an opportunity to do some more diagnostics on the car.


Cylinder #3 plug (as well as all others) is getting plenty of spark.


Did a compression test on all four Cylinders.

Cylinder #1 = 115 psi
Cylinder #2 = 105 psi
Cylinder #3 = 0 psi
Cylinder #4 = 90 psi

My understanding is 150 psi is standard in the R53, correct?


I haven’t done a leak down test yet. Not sure I want to spend the $$$ on the testing instrument if the indy shop is going to do it anyway. However, I’d be willing to bet money that it’s the exhaust valves again.

In less than a year of having the head completely rebuilt, how does that happen?
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There are a couple of reasons but it is time to change the injectors for sure.

One last question is does your car have an aftermarket pulley? If so, what size?

///Rich

 

Ugh! Should I change the injectors before or after I file the Mini-induced bankruptcy?

I do have aftermarket pulleys:
15% sc pulley
2% od crank pulley

I had the same setup the first time when the exhaust valves melted ... and the Indy shop said they had no idea what could have happened ... and just "drive it like stole it" was their only advice after the rebuild.

If all that was needed to avoid another future valve meltdown was bigger injectors, I'll be a little peeved.

​​​​​​​So, what size injectors should I be looking at?
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With extra boost you need to be sure you don't go lean. I have no idea which injectors to get but sounds like at least the JCW ones are the way to go.

I have no pulley and had the stock injectors and still burnt the valve but it took 130,000 miles to do so. And put in a set of stock injectors taken from a friends mini when he went larger.

It's a delicate balance with these cars. And with so much boost, and no tune, you are on the edge.

///Rich