engine compression question

528 Views 6 Replies 1 Participant Last post by Zerosoul, Sep 18, 2001

Discussion Starter · Sep 18, 2001

I have the following questions about engine compression, see if anyone can help me out here:

according to supra repair manual, difference between each cylinder shouldnt be more than 14psi. does that mean all 6 cylinders should be within 14psi difference?

also, how much HP would the engine loose if all 5 cylinders are in good condition except 1?

Lastly, according repair manual, I should also disconnect Camshaft position sensor...but its a PIA to reach it, would it effect the result if I were to leave it connected?

going to check mine soon, hope everything works out.

thanx
Jonas

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Grant

· #2 · Sep 18, 2001

Zerosoul said:
Lastly, according repair manual, I should also disconnect Camshaft position sensor...but its a PIA to reach it, would it effect the result if I were to leave it connected?

No, just pull the EFI fuses.

I'd say if your happy with your car's current performance, it doesn't really matter what your compression is, so long as its not completely FUBAR. But judging by the EGTs you posted earlier, it won't be so great.

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Discussion Starter · #3 · Sep 18, 2001

Grant,
I am still trying to figure out the EGt issue. I am running NGK6097 and I regularly getting 750c doing hard pull up end of 5th gear.
I checked my compression and they are all within spec thought a bit low (130.000+miles on the clock)

#1 155
#2 150
#3 145
#4 150
#5 145
#6 150

my plugs seem fine..little looks a bit hot with slightly white color on the tip. I just bought a HKS AFR and dial more fuel in and see if that will help. keep in mind, all CA supras are running shitty 91octan, so overheat should be very common here if any supras wre to keep boosting around18psi. I really dont think its my fuel systems problem since I ran much coolor (710c max) when we still have 92octan.

Jonas

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Discussion Starter · #4 · Sep 18, 2001

EGT's Seem Low to me

Sorry to interject, but aren't those EGT's a bit low? I am used to DSM's where I have my EGT probe 1 inch from the head, so perhaps you guys run an EGT probe farther away from the head to account for the cooler level. So, how far away from the head do you put the EGT probe on a mkiv?

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Discussion Starter · #5 · Sep 18, 2001

I have my EGT probe at top of downpipe.

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Grant

· #6 · Sep 18, 2001

Jonas, maybe you want to get in on the group buy for the OBDI display thingy. It can tell you timing advance, in other words if your knocking or not. Chad ([email protected]) is doing it. I'm willing to bet your car is knocking like a mofo with that shitty gas. I've never seen over 680 at the top of my DP. Just turn down the boost man.

Black95TT, its very difficult to tap the stock manifold with the turbos still on the car.

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Discussion Starter · #7 · Sep 18, 2001

yeh I will get one. I know my EGT is dangerously high, so its 15psi for me now

thanx for the advice.
BTW, is the OBDI display the same as the one bidding on ebay with a small LCD screen?

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