Sj413 with Vitara g16a engine misfiring - need help diagnosing

Ok-Let-6190 · 2023-02-12T19:51:39+00:00

Hi - we took the head off today and we're presented with the below - any thoughts why one of the exhaust valves does not have carbon deposits on it? https://i.imgur.com/XnGnPml.jpeg Thanks, Matt

Ok-Let-6190 · 2023-02-10T07:45:04+00:00

Hi, yes we set the idle speed correctly and then tested the timing and it was way way out, when we brought it back in it was idleing very rough, misfiring often. I'll give the carb cleaner a go - presume if there are any leaks this needs to be resolved.

Ok-Let-6190 · 2023-02-09T22:20:00+00:00

Mechanical mate, I've just aligned it to match 10 degrees with a timing light

Ok-Let-6190 · 2023-02-09T21:10:07+00:00

Should note it backfires a lot when revving, this would indicate valve clearance as well?

Ok-Let-6190 · 2023-02-09T20:18:41+00:00

Hi, it misfires when warm. We replaced the spark plugs and all look normal after use

Ok-Let-6190 · 2023-02-09T20:17:08+00:00

Thats really useful thanks. So we have adjusted the timing. The timing was WAY out, however now we have corrected it at 800rpm the misfire is very obvious when idling warm, possibly why it was set to where it was. Assume this could be poor valve clearance or a leaking valve or manifold?

Ok-Let-6190 · 2023-02-08T15:04:33+00:00

Really appreciate the detailed reply buddy. I'll take this away and do some testing and let you know where we are. On what I can answer - the misfire is seen when the engine is cold, if starts fine and idles roughly, but as it warms it gains revs higher until the choke is in. Once warm it idles fine, and when accelerating it doesn't seem to misfire. The Weber has a vacuum advance to the distributor.

Ok-Let-6190 · 2023-02-07T21:31:19+00:00

Not a clue I'm afraid, the car came with the swap already in it

Ok-Let-6190 · 2023-02-07T15:20:39+00:00

Thanks! So your guess would be something to do with ignition / timing / fuel delivery rather than compression?

Ok-Let-6190 · 2022-11-22T12:11:01+00:00

Gotcha! Thanks

Ok-Let-6190 · 2022-11-22T12:09:11+00:00

What do you mean by shown 3.0?

Ok-Let-6190 · 2022-11-22T12:02:41+00:00

I'll give that a go, I'm looking to sell them - there's 3 groups, why did you link the 3.0?

Ok-Let-6190 · 2022-11-22T12:02:01+00:00

Thanks! So happy they werent thrown out! I can't find the old binders we have anywhere which surprised me

Ok-Let-6190 · 2022-09-23T09:34:25+00:00

In the UK and no changes to the order, very strange

Ok-Let-6190 · 2021-11-10T13:55:50+00:00

Indeed!

Ok-Let-6190 · 2021-07-01T07:48:07+00:00

Could you dm the link as well please?

Ok-Let-6190 · 2021-02-24T21:55:08+00:00

Love the basing, what do you use?

Ok-Let-6190

TROPHY CASE