[alien]

Alright, see if you can figure this out..

g16b (g13bb head) EFI sierra.

I've got a flat spot between 2000 - 3500rpm that's crazily intermittent. Sometimes the flat spot stretches out to 4000rpm as well, then it's like i've got a turbo that went on boost and have all my power back again. The only correlation i have, is that the zuk will idle super low, sometimes stalling when the flat spot is 'active'. So i can pull up at a set of lights and notice the idle is hunting around 400rpm, then when i take off i've got about half the power i'd normally have, until i pass 3500rpm when it surges away until the next gear change. I can then stop at the next lights and it's idling totally normally, and accelerates perfectly fine.

I can't replicate the issue on command, it's just far too unpredictable.

Things to note:
- Recently replaced IAC
- We've had more humid weather of late (and rain)
- It's worse when the engine is cold, but still happens when it's warm

My guess is potentially a failing (arcing) lead or faulty coil pack - but at no point does it sound like i've lost a cylinder (though the power loss is equivalent to missing one or two!).

Thoughts???

[watermouse]

alien wrote:

g16b (g13bb head) ...

My guess is potentially a failing (arcing) lead or faulty coil pack - but at no point does it sound like i've lost a cylinder (though the power loss is equivalent to missing one or two!).

Thoughts???

Interesting that you say that. If one coilpack goes down you lose two cylinders with the g13bb setup.

[jdk81]

Check the coils, plugs and leads.

I had a coil pack with a dodgy plug.
It'd occasionally arc out and run lumpy/poorly, usually at idle and/or under load, cruising was fine.

Was a tiny little crack in the rubber plug.

[alien]

Have checked everything is plugged in and nothing looks visually broken or corroded.

It does coincide with just having new spark plugs put in now that i think of it, so maybe one of the leads has been stretched / cracked / damaged being pulled out to do the plugs?

This looks like a go-er:
http://www.ebay.com.au/itm/NGK-IGNITION ... SwTapV3Una
and:
http://www.aliexpress.com/item/Set-of-2 ... 583575aaa9

Gets me all new coil packs and leads for under $100.

[hooki]

I would stick with genuine suzuki coils to be safe.

[alien]

mmm the cost of genuine really puts me off... i'll have a crack at aftermarket and see how it goes i suppose.

[alien]

Well, that did NOTHING.

Issue persists.

Ideas?

[MrRocky]

Aftermarket coilpacks are poo ive been down that road before they lasted 45mins and started to break down.
My money on throttlebody/tps possible even cam sensor or could it be your fuel pump on the brink of death/shit floating in the tank

[alien]

I've kept my old genuine ones just in case =)

Cam/TP sensor seems possible. Fuel pump is only about 6 months old and i've got 2 filters so unlikely to be that.

I'm just gonna dump it as Suzistore on Sat and make it their problem to diagnose & fix... lol, i'm over it.

[MrRocky]

Haha i reckon actual throttle body and tps they can do all sorts of weid intermittent stuff, do they have a new mech at suzistore or still mr 457

[alien]

Both - new guy who's swift specific but sorta kinda translates across, and still jake.

[alien]

SO my issues are resolved... combination of injectors and water temp sensor was the solution. Also a vernier gear used to adjust the timing back given the head's been shaved and timing was at around 20 degrees!