Extremely helpful again, many thanks!!

Sure enough the pin for the cyl 4 injector is grounded and the others are not (key off).

I guess I'm shopping for a computer.

Thanks again!

 

I see different parts numbers all associated with 07 Fits. Mine is 37820-RME-C14

Is there any way to know if others would be compatible?

 

Canada and the USA are different; M/T and A/T may be different (so I'm guessing there are 4 part numbers already and not sure if sport and base are the same either). Not sure if it's possible but can you open the cover and take a picture of the board (if lucky you may even see a damage). I've never had opened PCM from Fit yet (only from late 80-s)
BTW the badly wrecked car had no blood inside but plenty of glass fragments inside (so wear safety glasses or goalkeeper's mask while driven on freeway) therefore I cannot open PCM from there. May do it on the different yard later this weekend (injector drivers are the same, but I have no idea if it possible to un-solder them easy)

 

I read somewhere that the 3 digits in the middle go location-transmission-version. So I'm assuming R is Canada or north America, M is Manual and the E likely doesn't matter.

I don't see anything visually on the board. Going to start calling wreckers when they open. I see one on Ebay that is an exact match but shipping time won't be fun from the USA. This is the first time I've had both cars down at once and living at the end of a dirt road in the middle of nowhere suddenly has a downside! Driving my mother in laws car for a couple of days.

 

Is there a way to flash the ECU without the dealer? Local dealers are backed up 2 weeks!!

 

Just talked to a few local dealers. They are all backed up several weeks. Also, they want the whole car there... so I'd have to drive the car there on 3 cylinders, then replace the ECU in the parking lot??

Anybody want to buy a fit?

 

OK going to get an ECU after work. Went to the dealership and gave them my sob story they will fit me in on Wednesday. Fingers crossed!!

 

They have to input your key code and mileage into the PCM; on the image I cannot even identify injector driver(s) the electronic package perpendicular to the bar code may look like either ignition coil or injector driver

 

Looks like as close a match as I'm going to find!

After my sob story the dealer agreed to look at the car Wednesday. I need to reinstall the old computer to drive it there (40 minutes). I'm afraid that this will cook my new injector. Should I disconnect it? Another injector is a third the price of a tow truck so I'm willing to take the gamble.

 

Shorted out driver will cause injector to spray continuously (will be running rich with black smoke); open driver (or disconnected injector will simply cause an engine to run on 3 clinders

 

I unplugged injector, drove to the dealership and plugged it back in. I was afraid that the computer would fry the new injector.

The dealer was very skeptical and did not want to do the computer. The first person I spoke to said it would be 3 weeks for them to fit me in. However when I showed up with the sob story a second person said they would fit it in in 2 days. The computer has to be an exact match (for the top numbers).

The new used computer fixed the misfire. To be honest I don't feel a noticeable difference from the valve lash adjustment, but I also haven't driven it in over a week.

Hue thanks to all who helped and especially Doctor J for the insight and drawings!!

 

No probs this is what is forum for!
At my earliest opportunity I'll pull one or two injectors from the wrecked car and section it open; I don't care if injector fails [electrically] open but it's disaster when it shorts out!
BTW (off topic) if you are getting ABS and brake idiot lights right after engine starts in cold weather which goes away after few brake applications, it's a time for a new battery!

 

A note for anyone who runs into this or winds up replacing a computer for another reason:

A newly installed computer might not know your spare key. The unrecognized key will allow the starter to turn the motor, but the car will not start. You may notice a flashing key light on the instrument panel.

Do not start frantically checking fuel or ignition components. Do not go get a heat gun and start warming fuel lines, nor buy any fuel line anti-freeze. These will all do you no good. Just go find your other key.

Is there a way to program a spare key without going to the dealer?

 

You need software to do that; here in California a licensed locksmith can do that but the price is not much cheaper compared to the dealer. PS my former neighbor managed to get into the car but was not able to clone a key or copy a key code (he used counterfeit software given to him by someone else). The cops came and ended his efforts and seized his laptop an key making machine

 

Bahaha... I suppose I will run back to the dealer when I get a moment.

 

To the original poster did you smell unburnt fuel before or after the check engine light started blinking for the misfire?

I’ve had the exact same issue on cylinder 4 (2008 Fit Sport Manual) completely dead 4th cylinder and I’ve checked the coils switching them around and the plugs as well and they’re not the problem, Cylinder 4 is not firing no matter what.

I also have a parasitic battery drain, it’s a six month old battery, but I have to start the car every 6-8 hours or the battery is depleted. I thought this may point to the ECM being shorted as well.

I’m leaning towards thinking it’s the exact same problem you had shorted out fuel injector on cylinder4 which fried the switching transistor or perhaps other parts of the ECM.

The thing with my 2008 fit though is I’ve had a slow leak in the radiator which dribbles out the top occasionally and at that time when the radiator starts leaking I can hear air bubbles in the system gurgling while driving or idling. So I’m thinking it could be HEAD GASKET BUT could a failed HEAD GASKET also cause a completely dead cylinder on cylinder 4?

That issue could be separate, just a compromised radiator and/or some other part of the cooling system allowing air in, it’s a 200,000 mile old radiator. I can see where the radiator is leaking from the very top (occasionally) through a couple small holes in plastic looks like they were designed for that but not sure?

So I think I have the exact same ECM and fuel injector problem on cylinder 4, and that my radiator may be a separate issue, not Head Gasket?

Unless I have three issues and parasitic battery drain is from the ELD (electronic load detector) or audio component or some such..

I’m not well-versed in performaning electrical tests and do not have the equipment except for basic tools which I used to switch around plugs and coils, both fairly new.

thank you for anyone who takes the time to chime in on what I should tell a mechanic as far as tests to perform.

I’m in Massachusetts near Vermont and I don’t have a regular mechanic, I’d like to tell them what specific diagnostic tests to perform, but not sure of the proper Termanology.

 

Hey! Huge thanks to MagicalSeats for reviving this old thread. I'm happy to say that my 07 fit is still purring like a kitten, with huge thanks to doctor J!! Unfortunately salt has turned it into a rust bucket and it needs to make its way to the scrap heap soon. This issue was over 4 years ago and I haven't touched the motor since (other than oil changes). Car has been running 4 years with 50lbs compression difference between cylinders... and I red line every shift! hahaha...

I'm confused by your post as first you say you have a spark issue and then you say you think it is the injectors. I don't know how a spark plug could ground itself out without having visible mechanical damage, but if the spark plug was buggered you could move the plug and the loss of spark would move with it, which should be easy enough to spot if you just ground out the plug and crank the engine... but you said you've done that. If you have spark on all cylinders I'm going to go out on a limb and guess spark isn't your issue.

I'm pretty sure a head gasket could kill a cylinder if you've got coolant leaking into it. You should be able to tell that from the spark plug though. Also just cranking the engine over with the plug out should also be a sign.

My thoughts are that you should test compression and fuel injectors. Compression is easy but requires a tool. I think mine was like 40 bucks and everything is more expensive in Canada so it should be cheaper for you. If compression checks out you should dig down to your fuel rail and do a check on your injectors. Just start the car, hold a long screwdriver on the injector and press it up against your ear. You'll hear a click on each revolution if the injector is trying to fire.

Good luck, and thanks for the trip down memory lane.

 

Sorry I mis-typed it should’ve read “I think I have a shorted out FUEL INJECTOR on cylinder four (same as you) The same as your situation. Which then fried the ECM which is now causing a parasitic drain on my battery in addition to a dead cylinder 4

I have done the compression tests with car off (just cranking) and all cylinders test between 150 and 200.

I really think I have the same exact issue that you had but….. Also I have a slow leak in my radiator and some gurgling bubbles from time to time.

So my friend thinks it’s the head gasket since the air is getting in the radiator somehow from time to time, but I really think it’s just the old radiator (200k)

I was wondering if you have any other clues that might point me towards the ECM without running all the electrical tests that I don’t know how to do or have proper equipment for.

Thanks for your reply, would appreciate one more if you have any further clues, glad to hear your fit is still chugging along. Are you interested in selling it?


Would love to hear any of Doctor J’s suggestions as well.

As to how I should proceed with tests should I tell the mechanic to test the fuel injector and ECM first?

Or is a leakdown test in order to rule out head gasket?

I’m leaning toward being the exact same issue you had so would like to test the electrical side first the fuel injector and ECM to avoid opening any more holes up atm with the pressurized test…

 

I would definitely check on your injectors before jumping to the conclusion that the ecm is fried. You might just have a blocked injector causing the misfire. It wouldn't explain your parasitic drain issue but the two aren't necessarily linked. The injector test doesn't require fancy equipment. You can test it with a 9 volt battery as described in this thread. If you want to check resistance across it you just need a multimeter which is like 15 bucks up here in Canada. Same for the ECM diagnostics.

 

Thank you part of the problem solved.

What happened was I switched around the coils myself which made no difference.

I didn’t have a spark plug socket so I brought it to my friends, I then had to attend something else and he told me he would switch the spark plugs around apparently he did not because I told him to be careful since cylinder3 has helicoil (previous owner).

I forgot to double check with him whether he had done it and he did not - he decided not to lol

so when i switch the plugs around myself, plug 4 was loose it was threaded all the way in but hardly any resistance when I went to loosen it…And when I got it out it had so much carbon deposit it was not able to spark. Ceramic part totally clean.

Replaced with new spark plug no more misfire and check engine light is not blinking but solid with PO420 which has been ongoing.

For various reasons I’ve been idling the car far more than normal lately so that might’ve increased the carbon buildup, along with the fact that it’s prob been running rich for a while now trying to track that down. I’m pretty sure a loose plug on its own wouldn’t cause that much carbon buildup.

Still have parasitic battery drain so that is a separate issue I believe.

Could a faulty air to fuel ratio sensor pre-cat cause excessive carbon build up to a degree that the spark plug would stop firing? could malfunctioning fuel injectors alone cause that much carbon buildup?… Or more likely blow by?


By the way I bet you if you run your compression test again and do it like five or six times on each cylinder you will get vastly different readings that’s what happened to me.

I would crank it the same amount of times each time but I’d get 150 psi sometimes and other times I would get closer to 200 psi.

i’m not even sure if that indicates a problem may just be the fit tests like that for some reason I don’t know but I bet If you test each cylinder multiple times you will get readings that are significantly different although still within decent spec.


and lol @ redlining it every shift 😆 Probably not a big deal this little engine seems like it keeps going and going even with multiple issues.