10
Dec
Checked compression have 150 psi 1 3 5 7 145 psi 2 cylinders 4 6 8 all 0 psi. A dropped valve seat damaged valve spring a damaged valve and a dropped valve can all lead to no compression in one cylinder.
The head gasket connects to the cylinder head at the top of the engine.
No compression in cylinder 6. Here are the results of the compression test. Cylinder 1-6 ordered left to right readings in psi 150 - 152 - 135 - 145 - 137 - 050 The test shows cylinders 35 are low. What really concerns me is that cylinder 6 holds no pressure at all.
When the engine is cranked the meter jumps to 50psi and doesnt hold. You will want to do a cylinder leakage test. This is where you put the piston on TDC put about 50 PSI of compressed air in the cylinder and then check the intake exhaust cooling system and crankcase oil fill cap for air escaping.
This will tell you where the air is coming out which means this is where your compression is escaping. No compression on cylinder 6. Jump to Latest Follow 1 - 10 of 10 Posts.
VR4Thunder Daily Driver. Joined Dec 8 2004 76 Posts. Discussion Starter 1 Jul 9 2006.
So the engine was running fine then just sputtered a bit stalled and was difficult to start. When it started it ran very poorly and struggled to stay alive. I did a.
So basically cylinder 6 isnt sealing correctly. There are a number of possibilities a broken valve spring a bent push-rod a brokenbent rocker arm a collapsed lifter a bent or cracked valve a blown head gasket a cracked head a badbroken piston ring scored cylinder etc. If I had to bet I would guess a bad lifter.
Took it to mechanic 1 they determined there was no compression in cylinder 6. They quoted me 1200 dollars to tear down the engine for an accurate diagnosis and then from there they would tell me if its fixable or not. So I had it towed to the dealer who is quoting me 1850 to tear downdiagnose and that payment would go towards either.
Still has 20 psi oil pressure at a hot idle. So it could be bad lifters causing the compression issue or a fault in the AFM assembly causing an internal oil leakbypass to the AFM lifters to clyinder 6 and causing them to partially collapse and drop compression. If its bad rings on cylinder 6 then there are bigger issues here.
There are several causes you can eliminate if your cylinders are losing compression. One possibility is a blown head gasket. The head gasket connects to the cylinder head at the top of the engine.
If there is a problem youll notice a gap between the cylinder and the head and gas will escape the cylinder leading to low compression. I have a 60 in my wifes 34 ton Suburban. While pulling a trailer down to the in-laws the service engine light started to flash.
I eased off of it and pulled over. At an idle the motor ran really rough. We limped it the rest of the way and took it to the shop.
They compression tested it and it had NO compression on one of the cylinders. No Engine Compression In All Cylinders Broken Timing Belt or Chain. Every car engine needs a timing belt or chain.
To keep the camshaft in correlation with the crankshaft. When these parts fail the camshaft stops turning. Which causes the intake and exhaust valve not to open and close.
Without the camshaft rotating the engine cannot make compression. The usual cause of no compression in all cylinders is incorrect testing. Cant get full compression sucking on vacuum.
Do not test one cylinder and then replace the spark plug it reduces cranking speed. Diesel you need to remove injectors or glow plugs fit adapter with a heat shunt. Nice and shiny looked as though it was freshly cleaned parked up off road in front of a house on the way out to the M4.
LMB KDCDont think its anyone on here but you never knowAlso spotted today in the same road an e39 with M5 style wing mirrors pretty certain it was a da. Had a diesel mechanic come and check out said had less than 40 PSI compression on 6 cylinder. Listed possible causes as.
1 Bad injector not sealing up and causing loss of compression. 2 Bad rocker arm not closing valves. 3 Hole in piston caused by bad injector or bad tune over fueling cylinder.
When you apply compressed air in the cylinder and the valves are closed and it does not hold air– there is a leak. With the air applied remove the oil cap and listen for air to excape– then listen in the exhaust pipe– then the intake– when you hear the air excaping through one of these that is the problem. Jumped timing chain no compression on 3 cylinders - GM 36.
If playback doesnt begin shortly try. What causes a cylinder to have no compression. Most cylinders heads are made of aluminum and expand at a different rate compared to the metal valve seat.
This variance in expansion rate can cause the seat to fall out of the head. Once this has occurred the cylinder will have no compression as the air escapes into the valve port. There is some stress fracturing and cracks but nothing to justify the loss of 90 of my compression.
I have since bought a stud kit head gaskets and new piston with rings. While out I tested the valves on the head by filling the ports with paint thinner and no leaks. I lifted the engine in chassis removed the oil pan and removed the 8 piston.
Maybe thats what they did but I am just curious as to no compression on the back cylinders on 2 different banks. Btw 4k is great Last engine I did was a 47l given it was a mopar reman engine with 0 miles on it but it was 95k out the door. No compression in all cylinders is also caused by a broken timing belt or a broken camshaft while low compression in all cylinders can be traced to damaged piston rings.
A dropped valve seat damaged valve spring a damaged valve and a dropped valve can all lead to no compression in one cylinder. No compression would indicate zero psi and that is unlikely unless the piston has the top blown out or one of the valves is held open significantly. Loosening the rockers to release the valves and then connecting air pressure to an adapter at the spark plug opening should isolate the cause of the leak.
Replaced engine controll computer and readjusted all the valves at this point it would start but it ran extreamly as if it was out of time. To make sure it wasnt off a tooth still no sucess. Checked compression have 150 psi 1 3 5 7 145 psi 2 cylinders 4 6 8 all 0 psi.
Could this be from a timing chain issue. A cylinder with no compression would indicate a failed set of piston rings VERY expensive to fix or possibly a blown head gasket at that cylinder. Not quite so expensive.
Id be interested to know what they want to do exactly. Cant say it as particularly driving with no compression in one cylinder. At technical terms the called it as cylinder deactivation mostly this is followed in V6 V8 engines.
To improve the fuel efficiency they Isolate or deactivate two to four cylinders where the full power from the engine is.