? About Compression Check

[We Gone]

I changed my plugs this weekend and did compression check. 91 46K miles..by the way did it cold. as I was changing plugs..

200 205 215 205
200 210 205 225

? is about the 225???

[Jeffvette]

Test needs to be done with the engine warm... or at operating temps. Numbers are supposed to be in the 150-200 psi.

[We Gone]

what kind of differance will I see warm vs cold?

[We Gone]

Test needs to be done with the engine warm... or at operating temps. Numbers are supposed to be in the 150-200 psi.

OK at Temp....195

228 230 226 230

225 228 225 230

[Jeffvette]

LOL, seems like the book numbers may be off. They are all within acceptable range of each other.

But high compression numbers can lead to detonation.

[We Gone]

Thanks that is what I have been having issues with detonation. went down 2 heat ranges on the plugs and it went away with the stock prom....Can't run the SGC prom with out getting 1 to 3 knoxs as I roll ito the throttle.

[Zr1 Destroyer]

If you really wanna put your motor to the test do a leak down on it!:thumbsup:

[bradslt5]

I agree . a leak down is really a tell all . summit has a good unit for just under a c note

[We Gone]

I'll check them out...thats the one tool I don't have...yet :mrgreen:

These are from the snap-on scantool before plug change AC Rapid Fire #5 about 30K miles on them

Hot Chip
INT..L...129 R...128
BLM..L..128 R..136...only ran at temp for about 10min. no more than 30mph
MAP..1.12V Hg 9.2
TPS Closed...54
BPN L..3.8 R..4.0
O2..L..93 to 677 R..106 to 646
IAC..30
Spark Adv. 10-11 @ idle 900rpms the most adv I got was in the low 20s
Lots of ping & Knox

Stock chip
INT...L120-124....R120-124
BLM..L125....R131 about the same run time
MAP 1.24-1.26 hg 10
TPS closed.54
BPN.L4.0 R4.0
O2 L115-655 R155-668
IAC..20
Spark Adv. 8-10 @ idle 675rpms most Adv. 18-20
Some ping & Knox



After plug change NGK BKR7EIX

Hot Chip
INT..L...129 R...129
BLM..L..130 R..130... ran at temp for about 100 miles
MAP..1.12V Hg 9.2
TPS Closed...54
BPN L..4.0 R..4.0
O2..L..93 to 677 R..106 to 646
IAC..30
Spark Adv. 10-11 @ idle 900rpms the most adv I got was in the low 20s
1-3 knoxs & still some ping on throttle roll in

Stock chip
INT...L-128....R-128
BLM..L125....R125 about the same run time
MAP 1.24-1.26 hg 10
TPS closed.54
BPN.L4.0 R4.0
O2 L115-655 R155-668
IAC..20
Spark Adv. 8-10 @ idle 675rpms most Adv. 18-20
No knoxs on throttle roll in

I'll stick to the stock prom until I have time to get another tune.

[bradslt5]

corey henderson has some cool tunes for a basicly stk motor (210)867-6286.