-1.25/+3.25 corrections cylinder 4. Worn plugs? Something else?

[DieselMech]

Thats what concerned me, knock and negative corrections decelerating or at 5psi of boost :|

I don't know what the threshold for knock is before its dangerous - as far as I know, any = bad.

How about wot logs?


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[Clint Beastwood]

How about wot logs?


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Wot logs generally clean, every once in a while a knock on cylinder 4.
I flashed back to Cobb stg 0 until my new plugs come in

 

[DieselMech]

at least in the mazdaspeed platform which is similar in it being direct injection pt knock was a value that could be all over the place and generally wasn't a indicator of engine problems. As long as wot logs look good overall I would say not to worry. Have you tried a gallon of E85 on a 93 tune to see if eliminates the knock? If not try it, if it goes away with E85 then it's a true knock issue and the tunes needs to be adjusted. If it remains then you are getting false knock from something in the engine bay most likely making noise

 

[Clint Beastwood]

I'm trying to run without the engine cover. I found a place on the corner of the ST engine cover that it was tapping against the 2jr intake on deceleration (it was a little shiny spot - about 0.5" between the engine cover and the intake pipe). I'm wonder if that tapping on deceleration was maybe enough to trigger a single knock when letting off the gas. I'm still running cobb stage 0, a new set of plugs from whoosh should be coming in today, then I'll flash back to dizzy and see wassup.

 

[DieselMech]

I'm trying to run without the engine cover. I found a place on the corner of the ST engine cover that it was tapping against the 2jr intake on deceleration (it was a little shiny spot - about 0.5" between the engine cover and the intake pipe). I'm wonder if that tapping on deceleration was maybe enough to trigger a single knock when letting off the gas. I'm still running cobb stage 0, a new set of plugs from whoosh should be coming in today, then I'll flash back to dizzy and see wassup.

I would definitely say that is a likely cause, maybe try putting weather stripping on the cut out section of the cowling if anything to stop the intake from hitting and rubbing.


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[Clint Beastwood]

I would definitely say that is a likely cause, maybe try putting weather stripping on the cut out section of the cowling if anything to stop the intake from hitting and rubbing.


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I was just going to take one of my wood rasps and reshape the corner of the engine cover

I have a bunch of dryer-duct insulation (foam with aluminum foil on the back) that I have inside the cowl area, but I am hesitant to install the stuff much closer to the engine - I do not know the thermal characteristics of the underlying foam. Do not want to create a fire hazard. I went 18 miles with no negative corrections on cobb S0 (in early morning 80 degree and raining(yes really) weather) so I'll flip back to dizzy tomorrow and see if any negative corrections come back. I'll still install new plugs, 50 bucks for peace of mind is worth it to me.

 

[DieselMech]

I was just going to take one of my wood rasps and reshape the corner of the engine cover

I have a bunch of dryer-duct insulation (foam with aluminum foil on the back) that I have inside the cowl area, but I am hesitant to install the stuff much closer to the engine - I do not know the thermal characteristics of the underlying foam. Do not want to create a fire hazard. I went 18 miles with no negative corrections on cobb S0 (in early morning 80 degree and raining(yes really) weather) so I'll flip back to dizzy tomorrow and see if any negative corrections come back. I'll still install new plugs, 50 bucks for peace of mind is worth it to me.

Yea I would be too, that’s a lot of heat near fiberglass but with a stock heat shield in place I would think you’d be ok. I’m OCD about engine maintenance so I feel your concern and would definitely be buying plugs too. Hopefully the new plugs sort everything out for you.


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[Clint Beastwood]

Yea I would be too, that’s a lot of heat near fiberglass but with a stock heat shield in place I would think you’d be ok. I’m OCD about engine maintenance so I feel your concern and would definitely be buying plugs too. Hopefully the new plugs sort everything out for you.


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Thanks duder!

 

[Clint Beastwood]

I’m OCD about engine maintenance so I feel your concern and would definitely be buying plugs too.

Last time I was in for service one of the techs was asking about my 2jr intake, then he said "I don't mean to be rude, but the outside of the car is *so* dirty, but under the hood there wasn't a spec of dust, anywhere, not on the battery, even the oil dipstick was spotless - what's up?" lol.

If only the outside of the car was as shielded from concrete dust as engine bay was lol. (lots of nearby construction, I gave up on washing the car because concrete dust becomes... concrete, when you wash it).

 

[DieselMech]

I just got lazy and pay a local car wash a monthly amount to wash my car 3 times a week and then I detail it every now and then. After five years my paint is starting to show its age. Under the hood though is as mint af lol

 

[Clint Beastwood]

I just got lazy and pay a local car wash a monthly amount to wash my car 3 times a week and then I detail it every now and then. After five years my paint is starting to show its age. Under the hood though is as mint af lol

I was, but my car's average "time until dirty" is standing at about 45 minutes. WITH GOSH-DARNED POWDERED CONCRETE.
I can't wait until I finish the move into our smaller house. Simpler life, here I come!

 

[Clint Beastwood]

Plugs swapped. The electrode looked pretty worn when compared to the new ones

 

[MRX330]

“Spark plug tech” by Peloton
Do a search on here

 

[Clint Beastwood]

“Spark plug tech” by Peloton
Do a search on here

I read through it, I didn't realize anyone bothered indexing plugs on a FiST, I haven't done that in a looooong time. SO TIME CONSUMING.

 

[Clint Beastwood]

I grabbed another data log. Is it possible I get the negative corrections because I am torquing through from ~3000 rpm instead of downshifting? This is easily the smallest-engined turbo car I've had so maybe I just need to break the torque habit and downshift more. There are positive corrections as it advances timing, then a knock (3300rpm @ 12.9psi of boost) and boom - negative corrections. I generally get one knock/negative correction every time I drive the car. The more I read the more it sounds like I am well within "safe" with that low number of knocks, but I'd like to hear a little positive confirmation before I just call it "ok".

https://datazap.me/u/clitbeastwood/dizzystage2randomnegcorr?log=0&data=4-7

 

[MRX330]

I read through it, I didn't realize anyone bothered indexing plugs on a FiST, I haven't done that in a looooong time. SO TIME CONSUMING.

Not really. That wasn’t all that was in the thread either.

 

[Clint Beastwood]

Not really. That wasn’t all that was in the thread either.

I think I'm on page 4, gimme a little more time it just takes me back to indexing plugs in my old plymouth duster. Thank god they were like 80 cents.

 

[MRX330]

I think I'm on page 4, gimme a little more time it just takes me back to indexing plugs in my old plymouth duster. Thank god they were like 80 cents.

I’ve done it with NGK’s which are more expensive obviously but the guy at the parts store was ok with me returning the ones I didn’t use

 

[Clint Beastwood]

I’ve done it with NGK’s which are more expensive obviously but the guy at the parts store was ok with me returning the ones I didn’t use

I think we wound up using them in a bunch of 10 foot long spud guns. So surprised we didn't die.

 

[Clint Beastwood]

Not really. That wasn’t all that was in the thread either.

I think that my takeaway is that I might be way too knock sensitive, and that I don't necessarily need the 1-step colder plugs.

On the knock sensitivity, I'm coming from some old school turbo tuning where you generally knew you had knock when you holed a piston. The FiST does a pretty good job of scaling things down. A few negative corrections are fine, as long as the OAR doesn't drop, right?

In my old GN and Omni GLHS, any knock you could detect was bad, but the FiST seems to auto-correct really well.

Since most of my knock seems to be at part throttle/low RPM I guess maybe I just have to get used to downshifting more. I'll make the adjustment and see if it curbs some of the knock.