1st Gen R53 Cooper S Most liked posts in thread: P0300 Error (random mis-fire) and limp mode

Well... one bullet dodged and one still in the air.

The leaking coolant was from bad shaft seals on the waterpump... the one that I bought new from MINI last fall (and is still under warranty, as is the labor to replace the defective part). Yea for the compulsive receipt keeper! That was gonna be an expensive fix.

The dealership wants to fix the coolant leak and then diagnose the P0300 issue. Will see what happens on that front next.

 

OK... just heard back from the dealership. They fixed the water pump under the part warranty. They then checked the codes and couldn't find any evidence of the misfire (except for the P300 code in the memory). They drove it over 15 miles (and it should have done it at least once if not 2-3 times given my recent history), so perhaps the water pump problem was somehow causing the misfire issue. Either that or the Techron I added to the gas tank just took a couple of extra days to clean the injectors.

They mentioned that the foam airfilter appeared to be over-oiled, but I haven't touched that for over 6 months, so I seriously doubt that is the issue. I'll give it a cleaning this weekend, just to be safe. Hopefully my new supercharger boots will be here, so I can update those, put in the new fuel filter, replace the performance coil/wires/plugs and get Jango back to normal!

Jango is ready to be picked up and there is no bill due for the service! I'll owe a bit to Enterprise for the loaner while they were working on the car (EDIT: Nope... MINI covered the rental as well! Total bill = $0), but in the grand scheme of things, it all looks good!

Thank you for the professional and attentive service, MOD (MINI of Dallas)!

 

I remember throwing a SES light back when the car was under warranty (don't know what code). I had put on the intercooler only 3-4 months earlier and was using the stock boots. My dealership replaced the throttle body under warranty but politely suggested that the poor fit of the stock boots w/ the GMRS intercooler could have also been the culprit and suggested a heavier aftermarket boot should be applied. I ordered the Alta boots when I got home and put 'em on a week later. The code never came back.

New Alta silicone boots are on the way, as is a new fuel filter (it's time anyway and it won't hurt to get a good look in there and see what's up).

 

Strange things afoot this morning...

- I found about 1/4 cup of coolant on the garage floor (may be un-related as I topped up the coolant earlier last week). I had noticed some spotting under there over the week, but it's summer here in TX... I had marked it up as AC condensation drippage. This was definately sweet blue coolant, though.

- right after I swapped the plugs and wires, I took the car out for a test drive. It went into limp mode about 1/4 mile from the house. I let it sit overnight and then drove 20+ miles to the office this morning without a hiccup!

 

I'm liking the idea of that homemade boost leak tester. I can't see the pics from the office, but I think I can rig something like that up, especially given my DDM intake.

 

Hmmm... well, it went into limp mode again as I drove off to lunch.

I think I've got another set of injectors on the shelf (the stock MCS pieces... I'm running JCW injectors w/ Jan's tune right now). Would it be worth swapping these back in for diagnosis? Would I run a risk of going too lean (just for daily driving... not going to the track like this).

On the overheating front, I've never seen the temp gauge go above normal and I've been keeping a close eye on it with the 100+ degree temps we are seeing and the code being thrown regularly. Is there a gasket failure or cracked block explanation that might tie the P0300 code and the coolant leak together?

Looks like I'll be under the car this evening, trying to see where that coolant leak is coming from.

 

I crawled under the car to get a good look when I got home tonight. Coolant was dripping off of the front edge of the oil pan fairly quickly (2-3 drops in 10 sec). I couldn't see a source from the hoses, thermostat or radiator... Maybe the water pump or the flanges that lead to it.

Unfortunately, i don't have time to deal with this right now. Will probably break down and call the dealer tomorrow.

 

Yep... poor Jango is at MINI of Dallas now. I hate taking him in, but I just don't have the time to go digging (even if I had the requisite skills or knowledge) anymore and I don't want to risk possible damage from continuing on myself.

 

I dropped by the dealership this morning to flash the original receipt. They already had the waterpump work scheduled for today, so I might hear something on the misfire issue tomorrow morning.

I'm always leery of having service done at the dealership, but so far it has been a pretty good experience... they got me in for diagnosis the same day that I called 'em and happily took the warranty work on the water pump once I emailed in a scan of the receipt. Keep it up, MINI of Dallas!

 

Oh yeah... I'll try to remember to pop back on this thread in a week or so to let you know if the misfire is really gone.