2002 Grand Am GT losing power

[fastback4]

I did some drag racing there myself, not to mention the Frisches Main Liner. Firefighter huh? Most of use run away from flames, you guys are drawn to them like mosquitoes to light. Thanks ahead of time....

Thanks Tom, I have been following yours and a few other threads looking for similar info.

I'm 49, Cincinnati Firefighter/EMT FAO (driver) for 21 years, and living in NCH, OH. Hey I lived with my grandfather on Shepherd Ave for about 3 years right after high school. I could see GE from my front door, lol. Our local drag strip in the 80's was Gate 17 to the bridge.

Axe

[Rootie524]

sounds like a compression check is needed like you said. that will be able to tell you the problem, or allow you to eliminate a lot of potential things. a car in good standing should be about 160-180 psi on each cylinder. if you see big fluctuation between cylinders..then bingo.

talk about a PITA though..transverse engines are a read hoot for taking out spark plugs and doing a compression test. and guess what..a compression test involves taking out spark plugs!!! YAY!

[Axe_1]

Thanks Tom, we all have to do something and this was the easiest way to make enough money to live that I could find, lol.

Thanks Rootie, yeah I've done compression tests before but normally on V8's. I've changed these plugs and even yesterday pulled each plug wire to test. They aren't horrible to do just hard on my back. I may jack it up and throw some stands under it like suggested earlier. At least for the odd number cyls.

Still easier than on a V8 Third Gen F Body! Thank Jesus for swivels and extensions, lol.

I did want to ask though, I haven't done a comp test in years and was wondering if it's better to do with all the plugs out, or just one at a time as I test them? I really want to replace the wires as I go also. These look like possibly originals. They are all numbered like Packard sets.

Thanks again,

Axe

EDIT: Forgot to add that the Alternator looks questionable. I'm also planning to drop the S belt for a minute to see if the front bearing is bad. It's black around the front vents and was hot, hot after running for 3-4 min. I'd love to be able to throw a bearing in it, or worst case, replace it altogether.

[Azrael]

For a comp. test all plugs should be out, fuel/ignition systems disabled and the throttle wide open during cranking.

[fastback4]

I did not know that .Interesting, schooled again!

For a comp. test all plugs should be out, fuel/ignition systems disabled and the throttle wide open during cranking.

[Axe_1]

For a comp. test all plugs should be out, fuel/ignition systems disabled and the throttle wide open during cranking.

Thanks Azrael, I wasn't sure about the plugs and a reminder about the rest never hurts. I dug around the basement and brought up my Comp Tester about 5 min ago. I keep a few things all in one plastic case: Comp Tester, Vacuum/Fuel Pressure Gauge,Torque Wrench, Gear Pullers & Slide Hammers, Analog Timing Light, etc.

Axe

[CNCguy]

P/S I'm 30 miles south of Cinn. Ohio in California, Ky., 58, Work at Generous Electric Evendale, 32 years...

I think that could be a tough drive in the winter. You must have hired in a couple of years before they were running all of those "help wanted" radio commercials (maybe 1980??). At the time I was working for a company that was doing some work for the rocket case division and several of my coworkers went there. I applied and interviewed for a position in EM&R but didn't have enough formal training. They offered an interim position as machinist while I finished some classes but I declined. Looking back at it now (always easy to do) it was probably a mistake to not take the job. Perhaps life would have had less stress.

[fastback4]

I did in fact, 1978..You leave early in bad weather and take it slow. I know plenty of EM&R's and most of them have difficulty with a breaker switch, not kidding! We all fake it till we make it. Never look back, unless she's looking back!

[Axe_1]

Well the CFD way is to promote to your own level of incompetence!

I think I'm there!

I knew a guy that worked at GE. I think he was one of the upper echelon but we were family friends. J. Frampton?

My wife and I knew that kid that got taken out by a moving piece of machinery in the 80's. I can't remember his name right now but we lived a couple doors down from them at one point.

Axe

[Axe_1]

OK, back OT for a minute.

I found the time to get a compression test after it cooled down this evening. The results are not good! The good news is that every cylinder looked about the same. The bad news is that the needle flashed to about 125 psi (+ or -) but immediately released the pressure. I mean it was down to zero within 2-3 seconds. While it was releasing I hit the pin a couple of times to make sure it wasn't stuck but you could hear it release. I don't think it was the tool. It was a KAL Compresion Tester I bought back in the late 80's/early 90's but I've taken good care of it and the "O" rings felt good.

I did oil the threads on the tester, but I've heard of some people putting a small amount of motor oil in the cylinders before testing. That seems like it would give a false reading on the riungs so I didn't do it.

No water or milk in the oil.
No steam out of the exhaust.
Runs good at idle and revs good without a load.
Bogs down when you ask for power while driving.
Top speed about 35 MPH.

I'm thinking it jumped a tooth off on the timing.

Someone with more experience on these engines please tell me if you have anything else. I'll try to round up a way to check the timing for tomorrow.

Axe

[walterdude]

After getting a low compression reading you can squirt a little oil in the cylinder and see if you get a higher number and if it holds.. It gives an indication of if it's the rings or valves that are bad.. The oil will seal up the rings (enough for a test) but not valves....
Hope this makes sense,,,
Tom...

[CNCguy]

The bad news is that the needle flashed to about 125 psi (+ or -) but immediately released the pressure. I mean it was down to zero within 2-3 seconds. While it was releasing I hit the pin a couple of times to make sure it wasn't stuck but you could hear it release.Axe

Sounds like a problem with your compression tester. The gage should only go up and hold steady until the pressure is released through the valve. Perhaps the check valve in the gage has gotten dirty or the rubber is getting hard and not sealing. Quite a few compression gages use a standard Schrader valve which is easy to replace. A bad gage is better than rings, valves or other mechanical issues.

[Axe_1]

I don't know man, the O rings feel good. I even pulled them off and they're plyable. The schrader valve is working b/c if I hit it before the pressure goes all the way down it releases the rest immediately. You can hear and see the difference.

This is a running engine. I had it up way over 120 MPH about 3 months before this happened with no problems. (registers 150mph)

It ran great then one day m wife said it was losing power and about a week later it started this bogging down.

I give.

Axe

[robertisaar]

during a compression test, a tester doesn't continuously read pressure in the cylinder... it has a check valve that causes the highest pulse of pressure to give you your reading. after that, it doesn't know or care what the pressure is inside the cylinder(which should be close to nothing anyway, since there is a good chance it was always land with either the exhaust or intake valve open.

a leakdown tester reads continously though, but that's due to you having to rotate the engine so that the cylinder you're testing is at TDC, then you pressurize it, and see how long it takes to leak a certain amount of PSI.

[Axe_1]

Gotcha robertisaar. I'm mechanical minded, but have been away from automotive work for over 10 years due to a back injury. I see that you guys are right. I have a check valve or something stuck inside the Compression Tester! I was feeling so down last night that I just cleaned up and took my helper (Son) to Arby's. I'll play with the tester and try again today.

It didn't feel or sound like it was leaking at the threads but I'm sure it's inside the quick connect or the gauge its self.

Thanks for not letting me give up on it today.

Axe