Okay guys and gals,

I have had it up to here (Place image of person holding hand above head here) with the misfire thing...

About a month and a half or two ago I got a misfire code P0302. I was driving down the highway and the MINI went into limp mode. Thinking maybe its just a freak occurrence, I turned the car off and when I started it back up, it was fine. At that time I was at WOT in 6th about 4000RPM.

Now I have tested it and it will happen in 5th and 6th gear only, ~at 4100RPM, doesn't matter if its WOT or not. So, now I stay away from the higher speeds.

I looked at the plugs that were there at the time, and they looked "OK" OEM, I swapped #2 with #1 and then #2 with #4, and no avail. Since then I have replaced them, wires, and coil. I am tired of just throwing money at it to try and solve this. I also took off the intercooler and throttle body, cleaning both of all oil/dirt/grime.

Any ideas?

Addison

 

When you swapped the #2 and #1 plugs, did you get the same code and Limp mode?

Questions:
- what plugs did you replace them with?
- did you clear the codes after the parts were replaced?
- did you check your injectors? swap it out with #1 and see if you get the misfiring code in cylinder 1...

mike

 

1. I honestly don't remember. I want to say Denso Iridiums.
2. I did clear the codes, I have the Scangauge II.
3. I did not check my injectors. I will try that tonight. Is there anything special I need to do to remove them?

Would there still be a random-ish problem like this if the injector was bad? Wouldn't the problem be consistant? Or am I wrong in that assumption?

Addison

 

wear mechanics gloves for sure

 

See this thread:
https://www.northamericanmotoring.co...ll-how-to.html

 

Thanks guys! so far. I did the switcheroo. We'll see what happens.

Injector 1:



Injector 2: (proposed bad one)


Injector 3:


Injector 4:



I'm going out for a test run. Hopefully the misfire changes to CYL1

 

I had the same code on a different car. After checking plugs and changing plug wires, I finally traced it to the fuel injector electrical connector not making good contact.

 

Nope. That didn't do it. Still got the code at 4300RPM on Cyl 2.

 

Reverse for me. It's cylinder 3 kicking the misfire for me. Are you getting any othe codes too. I've got a P0108 code and I'm going with a bad MAP sensor. Good luck and keep us posted.

 

Mine was doing it a couple of months back and went away after I cleaned and greased coil and spark plug terminals. But I know you're both past that. Misfires are a bit hinky to diagnose on these cars...

 

The only other code that I got p1688 which from what I can gather is "Electronic Throttle Control Monitor Level 2/3 Mass Air Flow Calculation"

I'm not sure if they are related or not.

 

I had the same code and changed all the same parts and more. Finally flowed the intake manifold and found it flowed 17-20% more on cylinder 2 than any other cylinder.

 

I'm not sure I understand what you mean. How did you test and what does that mean?

 

We put the intake manifold on a flow bench, it should that the volume of air that in #2 cylinder was much high than the others. So if the same amount of fuel is applied to each cylinder the ratio of fuel to air is really different in one cylinder. In my case it was more air than fuel which had one cylinder really lean and hot.

 

Ok, thank you for the explanation. How can we/you/I fix that? Is there a way? Can I test that anyway here?

 

You should do a compression test. I went through this same thing on the same cylinder and ended up having a bad valve. A few months later after getting it all fixed up, we were having random misfires and fixed it all and picked up almost 40 more whp by changing both MAP sensors and the wiring harness. It has been running perfectly now for almost a year. So I would say that there are three more possible fixes for you. Good Luck

 

UGH. That sounds expensive....

 

Well, I just ran a compression test:

CYL1: 155psi/155psi
CYL2: 160psi/156psi
CYL3: 160psi/160psi
CYL4: 161psi/161psi

These are test1/test2. both run "dry".

 

Compression is good then. Our number 2 was only hitting 80 and all the others were where you are at. You may want to try replacing the MAP sensors especially if you are throwing that p1688. There are two, one right in front and the other is right next to the throttle body.

 

If you are having the same problem I had the only way to check is to remove the intake manifold and take it to someone with a flow bench. I am not sure if anyone wants to take the time to machine the stock intake to make them even. At the time I had search here and a couple other website and found others that discovered there could be a large difference between the parts, they had suggested maybe Mini had more than one factory making the parts and there were differences in the molds. I ended up going with a aftermarket intake. Just for your information my car has been tuned on a Mustang dyno, at 195hp I burned a valve seal, 210hp I blow a hole in the head. During the tune if we had the A/F about stock the tubes on the exhaust would begin to glow, so the A/F was set to the rich side to avoid this happening. Since everything was measured from the tail pipe we did not know that is was one cylinder running so different. After putting the hole in the head we starting measuring everything and that is when we found the the problem. I did have my rev limiter up to 7800 and both problems happened at high revs. Not sure if this helps you are not.

 

Well, I don't know what to do.

Today I got two more, different codes, P0123 and P0222.
P0222 Throttle/pedal position sensor/switch 'B' circuit low
P0123 Throttle/pedal position sensor/switch 'A' circuit High

 

take it to Vista and ask to have greg work on your car....

 

Hi guys i changed almost everything, plugs, coils, injectors, fuel pump and still getting the P0203 misfire code.
Any advice for next step????

I notice today when fuel in the tank is less than half i get P0302 more often, i fill the tank and i drive it 75 miles without P0302

Please anyone with great idea shoot me a email at suysal@optonline.net, i am sick and tired throwing money to this problem, i am at the stage where i will drive the car to one steep clif and let it go

 

I don't know what to tell you... I ended up swapping Injectors 2 & 4 again and used some 3-in-1 oil on the O-ring, I don't get the code anymore. So, I am thinking it was a bad seal.

 

Ever since I pulled my engine for my 6 speed swap I have been getting misfire codes at random. Whenever the car feels like it. All throttle settings. And the misfire codes would be different. So you ask yourself. What is in common? Well...the pack for one. Changed the plugs, pack and wires. Still happened. And its not an injector because I have multiple cylinder misfire to along with individual cylinders. I know its a loose ground or the main injector harness connector because of the engine pull....I just dont really care to fix it right now. Well...I havent had my car for like 4 months...but thats a different story.