[BoomBoom4216]

Hi guys - first post with a bit of a story behind it...

Have a 2006 Zook Jimny M13A with a few bugs it seems. For the last 2 years its been a bit blippy for the sake of the word, missfiring and carrying on like a drunkard over a good number of years as I had no time or care to look into the issue - a more recent OBD scanning showed missfiring on 1, 2, 3, 4 cylinders with fault codes Fault: 05, Pending: 06 and PO301, 302, 303, 304, 300, 301P, 302P, 303P, 304P and 300P - so the time came for a decent clean up...

The plugs that were installed were Bosh Platinums with a fair amount of sales pitch at the time thrown in for durability and reliability, however when they came out after 2 years in the engine cylinder 3 & 4 platinum electrodes were eroded well into the ceramic posts! I mean GONE you could see the electrodes had dissapeared down into the ceramic posts - and thats a platinum tip!

So a big service was done before christmas, engine & filter, gearbox, centre box, rear diff, front diff, knuckles, both fan and alternator belts with some issue with the tensioner idler pully bolt not wanting to budge even with 106kgs of meat behind it... I guess 10 years of a bolt sitting idle will happen...

So the new plugs went in NGK BKR6 something or other and were gapped to 1.0 / 1.1 mm as per Jimny manual. I found that the car ran horribly and couldnt cilmb the hill here I was servicing at, without the cars engine missfiring and I really had to give it its all to even get home. I let it go overnight to sleep on it, the next morning I attacked the issue by removing the plugs and gappng them down to 0.9 mm and reinstalling them.

Well how did the car run after the regapping - perfectly, some issue with blipping intermittantly, however didnt have my OBD scanner to clear any residual codes with me as I was also servicing another car and forgot with all the other tools I brought.

Driving around to test the Jimny I found that the engine responded differently, not only being more responsive but at 3200 RPM there is a notable difference in revving noise and feel of the engine, almost similar to a VVT 'kicking in'? I could always hit this point (where the enigine really revved harder & vibrated more) on every gear change and it was always the same at 3200 RPM no earlier or later. Worst part is driving at highway speeds where it kicks in at 100km's or near enough and it stays there... But the accelleration performance from 60 km/h on the on ramp to 100 km/h and further to say to 140 km/h is very welcomed in regards to its previous performance and fuel use now, especially on the highway run.

I did a water misting (on the day of regapping the plugs) through the inlet by squirting a stream / mist of water through . Since that I put in half a tank of BP Ultimate 98RON and noticed a notible gain of 'buzz box' performance since...

Yesterday afternoon I again after warming the engine to very hot as it was a stupidly warm day, performed a misting (avoiding the AMS sensor this time, as the first cleaning I managed to soak the AMS sensor and it was near impossible to keep the engine alive untill it dried out, got sucked through) through the engine with water and just kept the revvs up to 2000RPM to blow any carbon through for about 3 minutes - no steam or black deposits were on the concrete this time. Went for a drive and the changes were very noticable again, 0 - 60 and pickup in 3rd and 4th gear are unlike its ever been before. Rescanned with the OBD scanner and no codes - so far so good!

I rang a local suzuki specialist and yeh it was hot so he must've been peeved with someone on the other side just asking questions willy nilly about the VVT and its controller - but he didnt know much about it and what it kicked in at. But it seems that the forums may be the place to ask if anyone has experienced any fair gains from their M13A without the need to install other options but just toying around with them?

With the blipping issue, yeh its still there very very very mildly / intermittantly, however not there when I applied power say to take off in first gear or in lower rev ranges of other gears as it usually did when I had the Bosh plugs in. Its a completely different car by feel it seems? Before the car would kangaroo jump from the blipping before and was pretty embarasing, you couldnt safely traverse a intersection from a standstill if you had to gun the accellerator!

Any ideas or could it be something else like a lead set going, a EGR becoming clogged or something else that someone has experiencedand rectified with their own Jimny???

Fair bit of write up but would like to hear any experiences or thoughts?

Thanks.

[Gwagensteve]

At a guess the misfire is being caused by faulty leads, coil packs or plug boots.

The misfire will be killing plugs, so I wouldn't blame the plugs for failure.

It's unlikely you'll see "fair" gains without an increase in engine capacity or replacing camshafts etc, which will most likely reduce the engines effective rev range - unhelpful for a relatively heavy car with a small motor.

Steve.

[alien]

100% replace coil packs and leads. Cheap on eBay, about $120 i think?

Also check the fuel pump.

[BoomBoom4216]

Coil packs and leads are my guess at this point also - wish I could test them to decipher which actual one needs replacing.

There is a review post with the issue with the Bosh plugs eroding into the ceramic post here

http://mkrd.info/articles-on-fixing-car ... eview.html

When I mean gains, I mean gains... Not like its gone from 62kW to 90kW however the engine is far far far far superior than its ever been in my memory of driving the car.

I think the water fogging through the engine has done something with the inside to the point of allowing efficient operation.

[Gwagensteve]

A possible clue is that gapping the plugs in tighter than factory spec made the car run better - this implies that spark energy is below specification.

The effect of RPM and spark energy is interesting. The highest load on the ignition system is at high load/low revs and , ironically, idle. Once revs increase demand is lower, so your comment the car seems to come alive over a particular RPM is consistent with ignition issues.

I wouldn't expect problems with the fuel pump to make the car behave this way.

Just to be clear, obviously increasing cubic capacity won't reduce usable rev range. I was referring to more aggressive camshafts/cam timing etc.

Additionally, any substantial (I don't know if this is the same as "fair") gains will require an ECU remap which can get pretty cost prohibitive

[shep]

Try repco for the coils. I bought a spare one for travelling and it was $40ish.

[BoomBoom4216]

Gwagensteve wrote:

The effect of RPM and spark energy is interesting. The highest load on the ignition system is at high load/low revs and , ironically, idle. Once revs increase demand is lower, so your comment the car seems to come alive over a particular RPM is consistent with ignition issues.

There is no effect on RPM as such, the car runs smoothly and seems as if all the torque has miraculously could easily back, what I thought was standard for a 1.3L was what I lived with...

Now the rev range is spritely and plenty of grunt per se... With the rev range as mentioned there is a definable change in engine noise in the rev range at 3200 where I am assuming the VVT controller switches in now. The power that comes in at this point is negligible but the car feels more spirited at this point where it wants to rev out to red-line easier than ever before?

Not sure if the VVT oil pressure galleries was blocked or the car was retarding due to the plugs and that's why I was getting higher than normal fuel usage, but at the moment, I've got about 90km from $20 (little under 1/4 tank) of 98 Ultimate and I've still got 1/8th a tank left...

shep wrote:

Try repco for the coils. I bought a spare one for travelling and it was $40ish.

They're the clowns that gave me the run around with the fan & alternator belts being the wrong lengths... Quiet a crap job riding 30km's on a freeride bike in the heat to exchange a belt for one that I shouldve got straight up.

I will give them a call in the morning at $40 each thats a steal! Wonder how long they'll last, as I was last quoted $150 each coil and $65 per lead.

[MrRocky]

Aftermarket coils are all garbage only genuine cut it but they are $$$ as for plugs just use the reccomended plug no gapping is necessary. Bosch plugs have always been 2nd rate

[BoomBoom4216]

shep wrote:

Try repco for the coils. I bought a spare one for travelling and it was $40ish.

Just dropped into Repco.

For VDO coils as a pair I am quoted $160. Additionally for a set of leads I'm also quoted $89 - total of $$249.

Going genuine coils and leads... I'd rather just buy a new car

[BoomBoom4216]

Well after the run of good luck I thought that I would pull the plugs out and have a good look. Plugs are in awesome condition with what I have been doing, saturday night again for a haul along the highway, easy again to hit the limiter, something I couldnt achieve before...And fuel use was negligable... But the persistant but lesser felt tick was still there while ideling.

Got the digital vernier callipers out and measured the gaps of the plugs, most ranging from .58mm to .62mm - not the .90mm I thought that I had gapped them... Mustve been the hot and delirious day...

Anyhow, regapped them to .87 / .90mm now and reinstalled.

Checked the leads and coils, coil No.1 was ok it seemed values on 9.4 to 16.90 on the Ohms setting, coil pack No.2was another story... Dead, no values whatsoever at all on the screen...

Rebuilt the car as was and drove down to Repco, and the car stuttered and spluttered especially taking off from the lights, I was back at the origional state of the engine, however taking off at speed showed no change, still got that change in engine noise at 3,200 rpm and that feel of it all coming out.

Before left homeI took another vid of the coil No.2 and it was making like a high discharge ''TICK''.

Paid my $149 for the coil set, said bugger it I would just change both at this point and keep the origional coil No.1 as a spare just in case.
Changed the coils out there and in the blisteringly hot car park with a bloody sizzeling engine and sun roaring down, after that went and put another $20 of Ultimate 98 in the tank.

The drive home was nothing short of remarkable, engine was quiet, still have that engine note change at 3,200rpm so still thinking that its the VVT hitting at that spot.[color=#FF4000]Can anyone vouch for any change of engine noise at 3,200rpm with thir M13A jimny???[/color]

Anyhow seems all fixed at this point.

[BoomBoom4216]

And after trying to live with this vibration at the engine speed noted and speaking to another Jimny owner, I crawled around the engine only to find a missing bolt from the AC pump, the single bolt down the bottom gone. So when revving the engine past that point the AC would vibrate against its backing plate to the engine.

Now the whole engine rev range is smooth upto 6500.