dmontzsta

heh, my 270,000+ engine had better results

Erik, engine shipping soon...

MrGone

iTrader: (30)

Well I've been having some issues with my car, just kind of a high idle, and you can hear a clicking sort of noise in the exhaust (when you stand at the muffler) it sounds like it belongs to just one cylinder, or so, if that makes sense. The idle came down to normal today, just a few days ago when I was tinkering with the car it wouldnt go below 1100rpm.

Cylinder:
#1 170PSI
#2 175PSI
#3 160PSI
#4 167PSI
#5 160PSI
#6 170PSI

The other thing I found is that cylinder #1 had a Bosch +4 in it, while all of the other ones have Bosch Platinums (just the single ground).

I used a 6 turn count aswell, I was thinking about going 7, but didn't.

The other thing is the plugs are all carboned, not clear or small hint of yellow like they should be. and the threads all have oil on them.

Tommarrow I am going to pickup some NGK Coppers and see how it goes.

What do you guys think?


MrGone

oh yeah, just for clarification, this is on my 92 SE 5spd, so VE.

Ramius83

That sounds great. You won't physically notice a difference with the Copper plugs, but your engine will (with the better/stronger spark).

I just compression tested me engine yesterday and I yielded the following results:

#1 - 190
#2 - 190
#3 - 182
#4 - 187
#5 - 190
#6 - 187

When you did the test, did you make sure that your engine was run before the test and it was up to regular operating temperatures? And did you hold the gas pedal down during the test? You have to do both to yield the "true" results of the compression test. But regardless, great numbers.....

MrGone

iTrader: (30)

The engine has 127k on it. The car was at regular operating temp, but I didnt hold the gas pedal down. I took out all of the spark plugs (my autoshop teacher told me once that it helps in getting a true reading).

About the gas pedal thing, My shop teacher said that you do that so the car wont try to start, I believe it cuts the gas, but only works on a majority of EFI cars. Oh wait, now that I think about it, is that so the engine can breath easier?

Also, how many times do you crank the car before you take your reading?


Since there isnt really a "dead" cylinder, I think the reason why my car was acting up was because of one of the spark plugs. I didnt purchase the car too long ago, and havent really been able to drive it yet (insurance) but I found that cylinder #1 had a Bosch +4 in it, while the rest had Bosch Platinums (just the single ground). In the exhaust (standing at the muffler) I could hear a ticking noise with each RPM, so I'm thinking that could be the problem. Plus the car would studder here and there. Unfortunately past experiences tell me it really isnt that simple, but we can all hope

Ramius83

The reason for holding down the gas pedal is to let the engine breath while you are performing the test. It also still allows the cylinders to pull in air during the test to "simulate" real conditions on the intake and exhaust valves. And you were right about removing all the spark plugs. Some other people don't always do that, but when you have the factory FSM, Haynes manual, and Chilton's manual all telling you to do so, then it is best to remove all the plugs lol.

After I heated the engine up and removed all the spark plugs and coil packs, I turned the engine 6 times for each cylinder for EACH reading. However, it built up the pressure on the first crank, which yields GREAT readings on the engine. If it takes atleast all of those cranks to build the pressure up, then something is up with the compression and you need to get it looked at.

FYI, my engine has almost 174k miles on the engine, yep, you read it right, almost 174k miles.......

MrGone

iTrader: (30)

I think I'll redo the test tommarrow (today) just for good measure. I'll let you guys know how it goes

Kashoggio

iTrader: (11)

ok to do this the right way you have to do a dry test and a wet test ( if its needed) . The dry test is done when the engine is cold and hasent been run for a while. The wet test is done putting a small amount of oil in to your cylinder that your testing ( this will seal the cylinder) . Make sure your fuel pump fuse is out. When you do the testing dont trun over the car more then 4 times, after the 4th time you will get the most accurate readings. The first puff (stroke)should be 75% of the total reading for that piston. When you compare the final reading make sure all the cylinders are in the same range, no more then 10-15& difference between the highest and the lowest. Noramlly if your readngs are low you would do a wet test, if you notice that your reading have a significant jump up in compression... you are in trouble. This usually mean a bad piston ring but to be sure you would do a cylinder leak down test. This is done by getting the piston in TDC of the compression stroke and with a leak down guage putting in 100 psi of air. The reading of this should be again no more then 10-15 less then a 100 psi. If the pressure is falling inspect the: oil dipstick, exhaust , intake. If air is coming out of any of these at a significant rate then you found your problem.

Beldin

And don't ever put Bosch +4's in. These plugs will do nothing but damage the tops of your cylinders. The run too hot.

ivelweyz

All the cylinders should be within a range of 10psi right? or was it 5???

max83

My compression test was all around 125. I took my car to the track shortly after and ran my fastest times.

MrGone

iTrader: (30)

turns out the problem was because one of my injectors was bad. I just finished replaceing it alittle while ago, and the roughness has completely gone away.

meccanoble

iTrader: (22)

anyone in NJ have the parts necessary for a compression test? think i can do one on my car?

Ramius83

Mecc: You can get the compression tester for about 40 bucks from your local auto parts store.

BigDogJonx

iTrader: (7)

Or borrow it from someone who has one

Ramius83

I was just definitely