Some of you remember I had some engine issues that have been repaired and then I set off for MTTS in Indy and then to MITM. I've had some new issues since the fix. For a recap of the previous issues please see http://www.motoringalliance.com/forums/cooper-s-engine-drivetrain/3073-p0301-driving-me-nuts.html On the way from Dallas to Indy a code was thrown, P0420, turned out it was not a big deal, probably means that my Random Technologies cat with ~50k miles is starting to go south. Not surprising. When in Indy with just about 1000 miles on the "rebuild" the oil and filter were changed. I only provide that info as a data point. Outside temps for the majority of this drive were a bit warm with upper 90's and even low 100's seen quite often. Octane levels for the most part when outside of Dallas and Indy were 91. The car was tuned with 93 octane fuel. The vast majority of the driving was with the cruise control set between 75 and 90. Always tried to purchase fuel from name brand places that looked busy enough to have fresh fuel. About 1770 miles into the trip while in Nebraska I pulled in for fuel. After filling up with Shell branded 91 Octane I fired up the engine. It started on 3 cyl, gave me a flashing CEL and shut the DSC off. Shut the car off, read the codes. P0304-misfire cyl 4 and the P0420 again. Cursed a bit, reset the code and fired the car up again, now running on all 4. There was no perceived drop in power as I continued my drive, but I did have a CEL again. --- Some observations: When cold car fires up with no issue, runs on all 4. Once driven for a time long enough to heat soak most everything subsequent restarts the car fires on 3 cyl but if the throttle is goosed when turning the key it starts on all 4. Problem was less obvious in CO Mtns where temps never got above ~80F When driving around town if throttle is lifted abruptly and car put into neutral as when coasting up to a light the engine stalls with AC on or off. If coasting up to a light in gear till ~1000 rpm and then into neutral no stall. ---- Since returning to Dallas the tank was run almost dry and took 13.5 gallons of name brand tier 1 93 octane fuel. Subsequent trips around town for the next few days were logged using the beta version of the Bytetronic logging tool. This past Wen when starting the car cold the CEL did not come on. Drove around a bit running a few errands and only experienced the stalling issue. Outside temps on that day were 75-80F with a light drizzle at times. Log results didn't really show anything untoward, there were a few random misfires but they were single incidents and did not involve cyl 4 at all. Certainly not enough to throw codes. Thurs and Fri the outside temps were in the low 90's. Both days I experienced the same codes directly after the same activity. There is a nice wide 1.5 mile straight bit of road near the house. Both time I was on that road I was on the gas taking it to near redline of 8K in 1st and 2nd. Codes were again thrown both time and then cleared when back home. Boy am I glad I posted an article with all the ECU codes in the library, it has proved invaluable to me. P0304 - Misfire Cyl 4 P0313 - Misfire Detected with Low Fuel P0420 - Catalyst System Efficiency Below Threshold I've spoken to more than a few people detailing all this out and getting opinions. As not to muddy your thoughts I'm not going to add them at this point. So what does the M/A brain trust think and what are my next steps in resolving this issue?
This mornings drive: P0420 and in pending... P0108 Manifold Absolute Pressure/Barometric Pressure Circuit High Input Outside temps are about 85F and the there is an air quality alert for the D/FW Metroplex. Code was tossed as I was entering highway on a long ramp where I had to lift abruptly sine a motorcycle pulled off the shoulder right n front of me. Valentine One was also going nuts so there were shenanigans going on from my part.
I am with k here and questioning the ignition system: coil, wires, connection points, etc. And yeah, the cat sounds like it is on it's way out as well. The stalling is primarily tune related as I believe you have some large injectors. Get a fresh custom tune with specific attention paid to low rpm injector duty cycle.
How old are the injectors ? A clogged or failing fuel injector could be causing this, could it not ? Maybe have them tested at the very least. Outside of that, i am on the ignition bandwagon.
Bummer Nate... so the wires/plugs/coil are easy to test, swap out some that are lying around and see what happens. Injectors? One can move them around and see if the misfire moves... I don't know why a tune that was good would need changing, if the injectors aren't flowing well, then the right thing to do would be clean the injectors. Unless the engine has never run well at idle since tune. If it hasn't then that might be an area to look at. Anyway, this must suck big time. Just did a lot of engine work and still have gremlins under the hood. Total bummer..... Have you checked the basics? compression and leak down? Matt
Probably unrelated, but, there was a similar problem on the 2001 Jeep Cherokee. It was heat soak in the #4 injector. Wrapping it in heat reflective barrier fixed it for cheap.
P0420 Nathan, I was able to get around the P0420 issue using an O2 simulator. I'm not sure when I finally get a tune if the simulator will create an issue for their readings or not? I had a similar stalling issue. Where unless I watched the vacuum gauge drop and wait for it to start to rise before I'd depress my clutch it would stall. Mine was related to the header tubes being too small for the BVH ports. I'm not sure if this is something that a tuner could work out or not? Karl
Back on the stalling and your custom tune. Another simple thing to have the tuner adjust is the idle rpm. A modified MINI with items, like larger injectors, a cam, or even a BVH, could have some low rpm idle issue that need to be addressed in the tune via a few different means. The factory setting of an idle rpm at 800 may not be sufficient for a modified car, 850, 900, and even 1Krpm is not uncommon for a highly modified and tuned MINI like yours. BTW, I think an idle of 1Krpm is more for a car with a big lopy race cam, so that would likely be excessively high for you. The uber high Ta conditions we get down here coupled with the AC load seem to make stalling more problematic. So, do nothing and I bet it will not be stalling in 3 months.
I've been logging data but my trips have been quite short. I really need to go a for a good long drive and collect data as the car heat soaks. I have ordered a fuel filter. I'm thinking that might be a good place to start and at worst just be a maintenance type item. With all the little towns I've bought gas in over the years it is quite possible that may a needed change.
Couple thoughts... while the fuel filter won't hurt anything, restricted flow from clogged filters is more of a problem at high fuel flow than low. It will kill the top end before it kills the bottom. Data logging is somewhat usefull, but it gets messy fast.. There are so many variables and so many use cases, that it's easy to generate tons of information that can be more confusing that helpfull. With any engine problem, start with a couple of the basics and also check whatever was worked on last time. For you, this is the whole physical plant! Kind sucks but do the basic diagnostics to make sure that everything checks out before you start playing whack-a-mole with parts and fixes. So, compression and leak down. Look at oil pressure as well. Check resistance on plug wires and coils... Make a list of what was worked on in your last dance with repairs, and make sure that is all sound. Based on what you learn you will probably get a good hint about what is sound and can be crossed off the list, and where to spend more time. Matt
misfire on hot start, but not cold i would check for a leaking injector flooding the cylinder. after a drive shut the car down for a 10 mins pull the spark plugs and see if any cylinders are noticeably wetter with gas then the others. Or you can find someone with the rig to leak test injectors the real way. the stall on decel is most likely a combination of things. it seems to happen with a light flywheel, a bigger cam, a higher flow cyl head and header. the car goes into fuel cutoff on decel and on some cars with that combination of parts the RPMs drop too fast for the dme to catch at idle. Maybe your tuner can adjust the fuel cut in decel? I fixed my car with the same problem by trying a few combinations of header/cam until i found one that worked for me. but first check all the basics, fuel pressure, vacuum, compression...
A follow-up here would be a good idea. With a few 1000 miles since the rebuild these have gone away. I do still get the P0420 at times. I'm sure that is related to a cat that is probably on it's way out. 50K miles on an after market race cat is probably pushing it. Also the wires for the O2 sensors are extended and the car was running very rich at startup too. The rich mixture at startup has been dialed out. My thoughts are the engine just needed to run in for a bit to mate all the new parts.
Well, great to see that things are settling for you on the engine rebuild and the codes. I am battling a P2096(lean) these days, and have been through a few cycles of diagnostics. So much fun.
Nathan I had a weird issue with misfire on 2 and plug grounding strap errosion on 1 back in October. What I ended up doing was buying new plugs and wires. That didn't do it. So I checked the coil pack and sure enough it was on its very last leg if not dead causing so extremely erratic activity. Once I got a new coil on it and adaptations cleared the car performed perfectly fine. If you coil looks like this on the underside its DEAD. A brand new where you see white on the dead one it will be black.
The rich mixture is what's killing the Cat-con. If you aren't running too rich cat-cons live for 200-300k miles. Even high-flow race cats. I don't know if you've ever killed one but it will suddenly sound like small pebbles rattling in a tin can with any throttle input. Sent from my Droid using Tapatalk