Main IndexAuto Repair Home Search Posts SEARCH
Who's Online WHO'S
Log in LOG

loss of compression on cyl's 4 and 6

  Email This Post

New User

Mar 31, 2009, 5:20 PM

Post #1 of 2 (754 views)
loss of compression on cyl's 4 and 6 Sign In

hello everything

1991 chevy Lumina, 3.1L with 240000miles

Question compression on cylinders 4 and 6 i have not yet checked the back cyclinders.

Car broke down on the highway at 75mph. towed home. did an initial compression check and found none on those cylinders except on cylinder 2. So i checked for spark, ok. Then i proceeded to check for valve action, None. OK I GOT IT NOW!! installed new timing chain and gears. AWESOME it should run now. But it dosn't. so i continued on with my tests and installed a compression tester on cylinders 2-6 and found #2 at 145lbs and #4 and 6 with absolutely Zero. Won't even flicker the guage. So i continued with a leak down tester. I put a 100lbs to it and hear a little blowby on the rings and nothing through the coolant or valves. Piston travel is definitely happening. Valves and timing are spot on. checked and rechecked the valve timing with two different sources of information. this engine is driving me bonkers and would like some input to as why this is happening. if i left any information out for your conclusion. let me know and i'll post it. thank you

Loren Champlain Sr
Veteran / Moderator
Loren Champlain Sr profile image

Mar 31, 2009, 6:47 PM

Post #2 of 2 (749 views)
Re: loss of compression on cyl's 4 and 6 [In reply to] Sign In

trevor; Did you do a wet test on 4 & 6? It's possible that they are just fuel washed. If still no compression, remove the valve cover and note rocker arm travel. This isn't an 'interference' engine, but it is 'possible'. 145# on #2 isn't anything to write home about, but enough to run. Will the engine start and run, at all? Might be interesting to get the other three cylinders' pressures, as well. With #4 & #6 next to each other, it 'could' be a head gasket, leaking between the two cylinders. Hope not.
SW Washington

loss of compression on cyl's 4 and 6

  Email This Post

Latest Forum Post

Hello guys. I have a big problem that local mechanics dont know how to solve. I ...

Hello everyone, I would like to now, witch part of your car, truck, bike ... you...

When I got into my car this morning, I found that most of the environmental cont...

Hello. We are working on a new OBD II tracker/scanner. Our device is almost fini...

Hi, I'm just trying to replace the cabin air filter on my 02 Hyundai Accent but ...

i had a small ticking at start of trip by time i had driven 200 miles, the ticki...

Feed Button

Automotive Forum Categories
AC Auto Repair
Auto Body Repair
Auto Insurance
Automotive Repair
Automotive Wiring
Automotive World
Brake Systems
Car Care Tips
Car Racing
Car Shows and Events
Car Stereo Repair
Car Troubleshooting
Engine and Car Noises
Engine Fault Codes
Engine Troubleshooting
Exhaust System Repair
Gasoline and Motor Oils
General Discussions
Motor Vehicle Inspection
Motorcycle ATV Repairs
Motorcycle Body Repair
Motorcycle Clutch Repair
Motorcycle Engine Repair
Motorcycle Repair
Motorcycle Seat Repair
Remote Control Cars
Steering and Suspension
The Bargin Bin
Traffic Ticket Help
Tricks of the Trade
Truck Repair
Truck Repair Advice
Truck Engine Repair
Truck Suspension Repair
Car Forum - Sitemap

Search for (options) Privacy

web statistics