Enduro

Awhile back I did a compression test on my 99 max with ~92k on it and here WERE the numbers reading from left to right starting at the front bank:
#1-205 #2-210 #3-215 #4-220 #5-210 #6-210

At ~94k I took it to the dealer for a charging system problem and they said I have too much carbon deposits and wanted $90 for cleaning. I took sugestions from DBM and others and tried the fuel system cleaner first.

I used a total two bottles of Chevron Techron Concentrate. First one with a tank full of gasoline, skipped one tank, then a second bottle filled with ~12 gallons of gasoline.

Today I redid the compression test, using the same gauge as before, and here are the numbers again reading from left to right starting at the front bank:
#1-202 #2-198 #3-205 #4-198 #5-200 #6-205

The psi numbers definitely lowered overall, still high but I spent a total of ~$12, definitely better than the $90 dealer wanted. Yes I'm a happy man Money well spent indeed!

Micah95GLE

I have always used Chevron Techroline exclusively in my Maxima. That stuff rules.

theblue

I use it also... I think it helps

bangster2k

When do you suggest using he ceveron stuff?

CandiMan

iTrader: (1)

Wouldn't the ambient conditions affect a compression reading, if someone did a compression reading at 12pm with the sun blasting and another test at 9pm when the air cooler wouldn't the reading be different. Regardless of how slightly it might be different, there's a possibility the readings would be different. Basically I'm trying to find out were all the variables the same when doing both test, i.e. weather, battery/starter condition, testing methods, etc. Speaking of compression testing, isn't it best to remove all the sparks plugs and keep the throttle plates wide open when doing the test?

BigDogJonx

iTrader: (7)

I though higher psi numbers are better? The more pressure the better the compression ratio is? or do I have it backwards.

Anyways, what should the numbers really be? And how did you test the compression psi in each chamber? With what tool?

Matt93SE

iTrader: (44)

well higher numbers are better, but only to a point..

when they start to go above factory specs, tha's usually a sign that there's a lot of carbon buildup in the cylinders and on the pistons..

i.e. the carbon deposits are large enough to take up a measureable amount of room inside the combustion chamber, so your compression pressure goes up because of it...

clean the gunk out, and the pressure will go back down some- hopefully back to within factory specs.

Eric L.

Too high of a compression can cause detonation, or ignition of the gasoline from pressure alone, not from the spark of the spark plug. Hence, it is best to maintain as close to factory compression as possible.

I've tried many different fuel injector cleaners, and I must say Chevron Techron concentrate is the only one I've had success with. Good to see others have it working for them too.

BigDogJonx

iTrader: (7)

When would you say is the best time to use this cleaner, I mean I know I dont need it now since I got a tad over 4k miles on my car now. But just wondering

Enduro

If you want to use it then wait til your car has at least over 10k miles and use just a bottle or two once a year. Then again I don't see the point of using it unless you suspect build up of carbon deposits. If you use low-grade/quality gasoline and just want an extra cleaner now and then, then I think Chevron has a less concentrate bottle for that purpose.

High compression is good for power only if that's how it was designed from factory or produced in a controlled manner, ex...forced induction, but definitely not from left over gunk from the combustion process.