Anyways, they did the compression test, and said it's 255psi on all four cylinders. Spec'd min according to Bentley is 276, with 'new' being 360-450psi. They also said the pump timing could not be set because the pump was worn out (noisy).
Full Answer
What is a compression test on a VW TDI engine?
This article shows how to do a compression test on a VW TDI engine or Audi TDI engine. A compression test will tell you the compression of the engine. It is not to be confused with a leakdown test, which puts air into the cylinders and measures the rate that the air leaks out.
Why does my VW Passat have low compression?
Excessively low engine compression can be piston/cylinder wear, bad valve, bad head gasket, or a cracked engine. Diesel fuel is an oil so the pistons and cylinder walls don't wear out as fast a gasoline engines with the accumulation of mileage. For the VW Passat TDI compression test, see this article.
What is a bad compression reading for a diesel engine?
Keep in mind that high altitude will also lower compression test readings. For example, VW diesel engines have a spec of 360-450 psi with new engines. It is only considered a bad engine if the reading is below 276 or there is a difference of more than 73 psi between cylinders.
How much compression should a gas engine have between cylinders?
To put it in perspective, gasoline engines typically can have no more than 15 psi difference between cylinders on engine compression of about 125-180 psi, depending on the car. If you need more detailed information about the condition of the engine, then a leakdown test or a better compression tester is recommended.
What should my compression test be?
A compression test reveals the condition of your engine's valves, its valve seats, and piston rings and whether these parts are wearing evenly. Healthy engines should have compression over 100 psi per cylinder, with no more than 10 percent variation between the highest and lowest readings.
What is good compression on a diesel engine?
275 to 400 psiWhat is good compression on a diesel engine? Good compression on a diesel engine falls in the range of 275 to 400 psi. You typically don't want to have a variance of more than 10% between cylinders. Keep these two things in mind and you should be all set!
What is the normal compression rate?
Compression ratios usually vary between 1.05–7 per stage; however, a ratio of 3.5–4.0 per stage is considered maximum for most process operations. Quite often, the temperature rise of the gas during the compression dictates a limit for the safe or reasonable pressure rise.
What should compression be at idle?
Comparing measurements between cylinders is important. Running compression at idle should be 50-75 PSI (about half cranking compression).
How much compression does a diesel need?
Generally, each cylinder should have 300 to 500 PSI, and all cylinders in a single engine should measure within 10 percent of each other. If the compression in the engine is too low, too high or deviates too drastically from one cylinder to the next, you likely have internal damage to your engine.
What is the minimum compression ratio for diesel?
First, combustion chamber is adapted in order to reach low compression ratio (CR 13.7:1).
What is a good compression ratio for Turbo?
9 to 9.5:1If you're going for a higher boost on the street, you'll want to stay lower on the compression ratio to avoid detonation. However, if you're contemplating a mild boost of say 7 to 10 lbs, a static compression ratio in the range of 9 to 9.5:1 may prove to give you better all-around drivability and off-idle acceleration.
Is 200 psi a good compression?
Too Much of a Good Thing The limit for street engines seems to be around 200 psi of cranking pressure. Numbers higher than 200 psi create excessive cylinder pressure at low engine speeds, which turns the engine into a detonating monster.
What PSI is 10 to 1 compression?
For example, if the static compression ratio is 10:1, and the dynamic compression ratio is 7.5:1, a useful value for cylinder pressure would be (7.5)^1.3 × atmospheric pressure, or 13.7 bar. (× 14.7 psi at sea level = 201.8 psi.
How do you fix low compression on a diesel engine?
If you discover you do have low compression, the only solution is to replace the leaking part whether it's the piston, piston ring, camshaft, head gasket or valves.
How do you fix a compression back on a diesel engine?
there is only option to remove from the back compression is overhauling. or if the only piston rings are found wear out. then we need to change the piston rings only. but first of all, we need to check up the pistons and piston cylinders.
What is considered low compression in an engine?
As a rule, most engines should have 140 to 160 lbs. of cranking compression with no more than 10% difference between any of the cylinders. Low compression in one cylinder usually indicates a bad exhaust valve. Low compression in two adjacent cylinders typically means you have a bad head gasket.