Swole Ignition coils, blowing fuse and big problems on my Jazz

[Dwight]

Hello everyone,

I have some issues on my Jazz and it's driving me crazy because I thought I fixed it, but I haven't, and now the problem seems to be deeper than what I initially thought.

For context, the car is full stock, very well maintained and serviced (by myself, I have a lift) and I've had it for about 10 years-ish. For those 10 years the car has been running on e85 (bioethanol) with no modifications, I mix it about 40/60% with normal gas in winter to avoid rough starts, but it goes up to 100% e85 (bioethanol) when it gets warmer, so half of the year. Been doing this since I have it, no problem at all, beside the engine light always on because of the ethanol, and no modification, so the engine probably runs a bit lean. As soon as I'd put a full tank of normal gas into it, the light goes off after a couples of kms. So all has been good on that side and I don't really suspect it to have anything to do with my problem.

So sometimes in the last month, the car randomly would stutter in 3rd gear or start to run janky and all. I thought that was weird, but since the weather goes from super cold to warm-ish and rainy in a matter of days, I assumed my engine had some trouble adapting to my gas/e85 mix sometimes. Sometimes, turning it off and on again (while driving) would immediately fix the issue and it would run ok again). Happened overall maybe 5 or 6 times and I use the car everyday.

However last week, while idling on a parking (it was coldish and rainy, needed heat inside) the car started running like hell, clearly misfires and all. I thought "Damn, this is terrible and getting worse, I'm gonna scan it real quick while I'm at it".

I have a small ELM 327 OBDII plug sort of thing that you find on Amazon for cheap that usually does the work with a carscanner app to read DTCs. So I turned off the car, checked the DTC and I had:



-  P0303 Cylinder 3 misfire detected -status: temporary

-  P0304 Cylinder 4 misfire detected -status: temporary

-  P0351 Ignition Coil A, primary/secondary circuit malfunction -status: confirmed

-  P0357 Ignition Coil G primary/secondary circuit malfunction -status: confirmed[/li]

(Also had some P0171 system to lean on bank 1 but I'm sure it's related to my fuel mix and what triggers the engine light in other normal days when the car runs great, so I doubt it's related here)

So I thought it was weird, and I would investigate later, but turns out when I started the car again, it now ran on 3 cylinder, possibly less (I'm sure it wasn't 4) and the engine light started blinking, which never happened before) and the idle went down and down and car just stalled...forever.

Yep, car wouldn't start at all after that, cranks, but no start. Managed to get the car towed to my workshop and I investigated the ignition coils first, since the last and only scan I had about the car talked about this.

Sure enough, wasn't a pretty sight, out of 8 coils, 4 were showing signs of overheating, including one with severe signs of heating, I'm talking about the flat "top" of the coil being cracked like a wall because it swelled, when the other ones would show swoling on the sides...

Anyway, thought it was the issue, because spark plugs are "only" 3 years old. I ordered 8 brand new ignition coils and installed them today.

Car didn't start, I was about to shed a tear, when I checked for fuses and relay and what not and everything seemed clear, until I stubble upon the fuse number 24, on the inside fusebox, located on very botton line, on third from the far right. It's a 15A fuse and it was blown, and according to the internet, it's a fuse related to the ignition.

Changed it, and boom car starts flawlessly, runs on all fours, no engine light, it's a miracle, I'm about to shed a tear of happiness. I let it run for a few minutes, and I'd say about 5 minutes in, it starts to have a few misfires, then it start to idle weird and run like hell again, about to stall again... I turn it off, thinking meh I'll drive it to check.

Turns out I can't, I started it, and managed to do less than a kilometer whilst clearly running on only 2 or 3 cylinders maximum before it died on me again (engine light blinking), checked the Number 24 fuse: blown. I had spares, tried to put a new one in to a least go back home, couldn't even do that, it blew in a few meters. Tried another one, blew almost instantly after starting...

Since it was getting worse, I thought I wouldn't try my luck anymore and just tow it back home, which I did.

So here we are, I have absolutely no idea what's going on. I'm not the best when it comes to electrical issues, I only know the basics, so right now my understanding doesn't go beyond the fact that something makes this fuse blow and my engine dies...

Now I'm hoping one of you guys can help me make sense out of this mess...

What do you think? Sorry for the long read, figured I might as well give the full story, maybe some details are important.

Thanks 

[bill888]

I think we need to find a wiring diagram and understand purpose of fuse no. 24.

I could only find partial wiring diagrams for pre-2004 L13A and post 2006 L15A engines but neither go far as listing fuses on google images.


The coil packs receive a timing signal from the ECU to trigger.  The coil packs likely receive a separate main 12v supply (not from ECU).   This 12v feed may or may not be served by fuse no. 24 ?

On assumption the 8 new coil packs are not defective (partial short circuit), I can only speculate you may have a damaged wiring loom or corroded connector.  eg. may be a partial short to ground causing higher than normal current to flow through fuse no. 24 when ignition is on.  When engine is running, it makes things worse.

I wonder whether or not fuse 24 would eventually blow after a few minutes if you were say to turn on the ignition BUT do NOT start the engine ?


Or fuse 24 has nothing whatsoever to do with ignition and replacing the spark plugs and coil packs did not really resolve the unrelated fault....


As stated above, this is just pure speculation on my part without seeing full wiring diagram.


UK spec interior fuse box (forum image from UKjim posted many years ago):

[Dwight]

Hey, thanks for your detailed answer.

So about that fuse, according to some video about the fuse and relay assignment and location that I found on YouTube, the 24 fuse is "Ignition Coil N°2". So I would assume it really has a power over the 12V supply of ignition coils.

I would also like to point out that previous ignition coils whilst showing overheat signs, were at least a decade old, if not stock parts. So I would assume the overheating came gradually or not, damaging those coils over time.

I would assume what damaged those coils over time got worse and worse, to a point it now makes the coils acting up and the car running like hell, and eventually blow out the fuse.

Now to find what is this problem...

I can try to put another fuse in and let the ignition on without starting for a solid 10 minutes to see if it blows up at some point, doesn't cost nothing.

I also think I'll sadly have to investigate the wiring harness I suppose, eventhough you can't really see much unless you unwrap it, which implies rewraping it later...

The only "weird" thing I noticed on that harness, is that absolutely all the connectors (the ones that go on the ignition coils) have their little plastic tab to lock it broken. So basically no connector seems to be locked fully, eventhough since there are seals on those connectors, you have to push them in quite deep to plug them to the ignition coils, and it seems to stay there and not move back. And all 8 of them are like this, and probably have been like before I even bought the car. So here again I could only assume it's not the issue here since it was working in that state correctly before.

[bill888]

fwiw, to avoid unravelling the wiring harness to visually inspect it.   Perhaps with ignition off and/or battery disconnected, you could use a multimeter to measure the resistance between the pins on each of the 8 plugs and car's chassis ground/earth/0v.

One of the four? pins will probably grounded btw.

 

[CRC]

I've attached some wiring diagrams that you may find useful with your problem ..... gleaned from the internet and I have created a 20 page pdf with all the wiring in it, but I'm not allowed to put pdf files in the post, so here are three of the pages.

I'll have a look, but thought you might find these useful for now, as the Haynes manual doesn't seem to show these.

[CRC]

This gets confusing ... the StartmyCar website shows fuse details for all the Honda Jazz models, and I've attached images for 2002, 2003 and 2004 cars.

2002 and 2003 look very similar with fuses 7 and 9 on the coil packs, while 2004 shows a marked difference, with no sign of any coil pack fuses?

None of the fuse boxes seem to suggest that anything for fuse 24??

Your profile says the car is a 2004 model, just wondering if it was registered in 2004 but was actually a 2003 model?

[Dwight]

Thanks guys for all those answers.

I would assume those wiring diagrams are absolute gold in that situation, if I knew how to read them... lol. I'm sorry I just know the bare minimum about electronics and those schemes are hieroglyphs to my eyes 

About the car, I'm pretty positive that it is a 2004 model and not a 2003, since it was registered in august of 04'... 

[bill888]

fwiw, the schematics uploaded by CRC looks like the same one I found earlier. I think they are for the pre-2004 facelifted model though.  2004 cars received new front bumper and steering wheel etc.

15 Amp fuses 7 (front coils) and 9 (rear coils) seem to serve the two banks for 4 coil packs/spark plugs for pre-2004 cars.

For post-2004 cars, the image uploaded by CRC shows fuses numbered up to no. 33 (ignition coil). But there are only 29 numbered fuses....   Perhaps the schematic is for a different variant such as the 1.5 or for different market. There is a reference to Canadian model for one of the fuses.

[bill888]

Stating the obvious, but have you looked in the Car Owner's manual?

I found a YT video for a 2005 1.4 Auto
https://youtu.be/EMRGac_kHmI?si=aWXvFgtoFemG4v_u


It shows Fuses 2 and 24 serving the two banks of coil packs.

[CRC]

I've attached a graphic showing just one of the coil packs on the car.

Essentially, each coil pack is switched on and off directly from an ECU pin (no fuse) as the switching is done inside the electronic module marked ICM on the graphic. This operates the primary winding on each coil pack and as this goes on and off, it induces a high voltage in the secondary winding that has enough poke to cause a spark to jump across the spark plug.

The information so far suggests that the rear 4 coil packs are fused by a common fuse, and the front 4 coil packs are similarly fused together by a common fuse.

If either of these fuses was blown, logic would dictate that you would lose all 4 rear or all 4 front coil packs together. 

In the really old days, there used to be one coil, switched by a mechanically opening set of points that generated a high voltage and this was sent to the right spark plug by a rotating rotor in the distributor. Everything had to be set up mechanically, points eroded away the system needed pretty much continual messing with .... even the vacuum operated advance system that would mechanically move the points base round depending on the vacuum conditions.

I think I would start to fault this based on the saying "never ignore the obvious", and there are two things that can cause untold problems.

1. Earth connections - from the battery (-VE) post to the chassis and from the engine to the chassis. In both cases there will normally be a braided lead with a nut/bolt tab connection. Clean them up.

2. Pull apart every electrical connector you can find, squirt with a decent contact cleaner and push them back together a few times. You mention that a lot of the locking tabs are missing .... I have seen on Youtube a method of using small cable ties to solve this problem.

You'd be amazed how often this simple approach can solve problems ..... it is possible to spend way too long going down the intense detail rabbit hole when just a dodgy, intermittent contact fault is the culprit.

 

[CRC]

And just to confuse us all even more, the Haynes worshop manual (apparently for 2002 to 2008 models) shows a fuse box with 29 fuses in, and strangely, Fuse 24 (15A) is shown as "ignition coil 1" and Fuse 2 (15A) is shown as "ignition coil 2".

This seems completely different from all the other fuse box information gleaned from the internet, so I have no idea which one you have.

If it's the Haynes version, you should see a rectangular fuse box, with 21 vertical fuses on the top row (starting with F1 on the top right and finishing with F23 at the top left), and on the second row down, you should see 8 horizontal fuses, starting with F22 at the top right and F29 at the furthest left point before 4 relays complete the second row. On the third row down, there are 8 relays which then completes the fuse box.

I've attached a file showing the layout of the Haynes manual fusebox ... does that look familiar?

[CRC]

Sorry, slight mistake on the diagram ... corrected version attached

[CRC]

Thinking about it all, I'm starting to think that your Fuse 24 is important, so I've attached a graphic with a suggest method of trying to pin down  where the issue is.
Just a logical, test one thing at a time approach, which sometimes is the only way .....

Good luck

[Dwight]

Guys...

I really appreciate your help on this, and because all the ressources, schematics and whatnot you pulled for me made me desperate enough to search for something stupid that I've missed, hoping it's not as complicated as it seems, and surely enough I think I've fixed it...

I thought there were only one fuse in the interior related to the ignition coils, and one additionnal thick one in the fuse and relays box in the engine bay.

Turns out there are two fuses in the interior, as you guys probably noticed while searching for the correct fuses schematic.

So fuse n°24 AND fuse n°2 are BOTH related to ignition coil, and I would assume one for each bank.

I was so focused on fuse 24 thinking it was the only one related to IC that I missed checking my fuse n°2 which serves the same purpose, and guess what: it was blown out too...

Changed both of them, car started smoothly, and runs perfectely. Took it for a spin, did about 15 kilometers, no problem so far. Runs great.

So yea... You'll understand why this is embarassing, it was literally just another blown out fuse which I would have noticed, would I have opened up my car user's book and look for the fuse locations and purposes. I guess what really put me off was the fact I found my ignition coil in such a bad shape.

So my theory, and correct me because I'm probably wrong, is that my previous ignition coil were stock, through time they started getting worse and overheat, which apparently would be normal on Honda Fit, it's not the first time it's mentionned that after some time they just go bad.

So I guess they just went worse, but significantly worse this last month, explaining misfires and weird idling. I assume when I was waiting on that parking lot the other day, they just went bad enough to the point of making fone of the fuse melt, it explains why with only one fuse, I managed to start it back but it was running very weird, just like yesterday when I changed only n°24 fuse and took it for a short spin, it ends up blowing the sole surviving fuse and then it completely shuts down because there's no ignition coil running at all anymore.

So yesterday when I changed fuse n°24, it still was short of another working fuse, the fuse n°2 that I've missed.

I guess it's "that" simple and "that" dumb. Or at least I hope so.

Morale of the story, don't be lazy like me, and check ALL your fuses. 
 

[CRC]

Glad to hear that you've got it all sorted by the sounds of things.

Time will tell if there is an underlying, intermittent wiring issue in there that may show itself in the future, but if it does, at least you'll have a clue about how to find it now.

Looking into these issues is good for the future, as our 2003 Jazz is still running on its 23 year old coil packs, but one day ....