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Odd compression on new 2.3 engine

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Sam's GSX

5+ Year Contributor
394
54
Jun 10, 2018
Hohenwald, Tennessee
I've got a couple of problems that have popped up, 1 is small and the other is, I did a compression test after my second drive of the engine, and it came back
1 172
2 145
3 127
4 177

These 2 things I can think of, I'm not surprised cylinder 3 is the lowest (although that's much to low) because I gapped the softer ring slightly to big, 0032 (or 33, its written somewhere, I'll check tomorrow)
I believe.
The other thing is the break in seating of the rings, on my first drive I got into 15 psi and dropped the gas at 5500, i would have gone higher but my afr was 17-1, i couldn't predict the maf comp with it being the first drive.
I did 2 more pulls going to 5000 and decel.
So hopefully i just need to rev higher and decel from 7k or so.
Everything is new, and the engine is acting great overall.

The second problem is when I'm coming to a stop and put the car in neutral, or hold the clutch, the idle will climb from 1500 to 2k before it cuts, drops back to 1500 and repeats. That ones not a huge deal, maybe someone knows something about it.
Any help is appreciated, thank you

I've got a couple of problems that have popped up, 1 is small and the other is, I did a compression test after my second drive of the engine, and it came back
1 172
2 145
3 127
4 177

These 2 things I can think of, I'm not surprised cylinder 3 is the lowest (although that's much to low) because I gapped the softer ring slightly to big, 0032 (or 33, its written somewhere, I'll check tomorrow)
I believe.
The other thing is the break in seating of the rings, on my first drive I got into 15 psi and dropped the gas at 5500, i would have gone higher but my afr was 17-1, i couldn't predict the maf comp with it being the first drive.
I did 2 more pulls going to 5000 and decel.
So hopefully i just need to rev higher and decel from 7k or so.
Everything is new, and the engine is acting great overall.

The second problem is when I'm coming to a stop and put the car in neutral, or hold the clutch, the idle will climb from 1500 to 2k before it cuts, drops back to 1500 and repeats. That ones not a huge deal, maybe someone knows something about it.
Any help is appreciated, thank you
I believe it was only happening while rolling, when I stop it sits high (2k ish) without bouncing.
 
Last edited by a moderator:
An hour is up.....:p :hellyeah:
Just giving you a hard time Sam.
 
ok, here is the log from yesterday, at 1097 seconds a did a little pull to 4500 i think, to check if my maf adjustment was good and to see if the stock injectors could keep up, (i didnt decel because i thought i covered that on the first drive) my tru boost if off, and it runs around 16 psi, the injectors did get up to 117% duty /: (i plan on switching to the 1450cc after i do some harder decel later today
 

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i did forget to hold wot, but when i remembered, we redid them all
(my process was: tried to do it right when i stopped, but i was counting on someone to help so about 10 minutes after the enginr was off, remove all spark plugs, unplug cam and crank sensors, do test)
 
Ok, I've done a lot today, I did a hard pull to 7k and decel in gear to try to seat the rings better, but...I was still on stock injectors, and when I went to 5500rpm before, it used 117% duty cycle, this time, it used a whopping 161.7 duty cycle, and was at 17-1 afr by the end of it.
I have since switched to my 1450cc and dialed them in, took me 3 hours, but it took 2 weeks last time and i never got them running properly.
Air flow per rev is .25
CombinedFT is basically 0
And afr is normally 14.7

Also I've not really got the climbing idle while rolling anymore, so that's not a problem
 
I have been getting some knockRet while normal acceleration (mostly in 3rd gear, sometimes a little in second)

I'm hoping this is just phantom knock because I dont have balance shaft, or it's a 2.3 so the stroke is longer.
Minimal knock while doing a pull, like 1.7 retard max, I'm on water meth so I don't think this is real, especially at only 16psi, I'd prefer to get rid of this so I can have my timing back, but not a huge deal as long as it's not hurting anything
 
Did compression come up after your driving Sam? How did the car "feel". Gas will still limit your timing, is it a custom timing map or a 1g or 2g or Evo map?
 
Yes I had driven it 20 miles to get gas,
It's a custom mad from Jed, one of the members on here,
So I should find the spot on the map where it was knocking and pull it some? I'll try that
 
Well, it feels great!! It could be because I haven't driven a fast car in months, but I hope not, I'll do another compression test in 3 days when I get back
 
Ok, I'll check that but it pretty much is gone now, the injectors were changed to 1450 yesterday, and tuned quite well, maf comp is adjusted, afr are good everywhere.
Only problem is the knock at the moment
 
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