Hi Folks
Have a 1985 190D which had more problems than what actually worked. Solved most of them but the MOST critical one remains unsolved. I must have read what seems like thousands (slightly exaggerated) blowby problems forum discussions on the topic but nothing seems to be exactly my problem or else I too dumb to recognize it.
Here tis the situation (1985 190D, California version, 5 speed stick shift):
1. Extreme blowby-If I plug the PCV valve with my finger, the engine will die within a few seconds. So much pressure that I had to bypass the oil distribution hose on the Intake manufold and run a plastic line from the PC Valve to the rear of the car - mounting the plastic tube just under the end of the tail pipe.
2. Very little if any smoke from the exhaust pipe at any speed but the makeshift plastic blowby pipe looks like a jet engine spewing out oil and oil vaper at any speed.
2. Engine has great power
3. On a round trip of roughly 130 miles, the car throws out almost a GALLON of oil. I think most or all of it is expelled from the PCV thru to the end of the makeshift plastic tube.
4. Had to wire down the oil dipstick because the blowby will blow the stick almost out of the dipstick tube.
5, No apparent loss of antifreeze.
6. Get real good fuel milage (lots of power for a non-turbo 4 cylinder-so I wouldn't think I have a ring(s) problem.
Now, I understand that the engine breather assembly in the Valve cover which helps in reducing crank case pressure. Is there any way to test the breather system to see if maybe the diaphram failed? Or what do you think are some possibilities?
Oh, by the way, I don't know if PVC valve is the correct terminology or not but it looks like one
Thanks in advance for any help you can give me.
George
We found the fuel sending unit. Put in in and didn't work. Took it apart and discovered that one of the two resistance wires was broken in two pieces. Unfortunately, the break was in the middle of the wire and can't be repaired.
These two sets of tests proved not to be a whole lot of fun to do.
The compression tests were performed while the engine was hot. I reinstalled the glow plugs and restarted the engine to obtain operating temperatures for the leak-down tests but by the time I worked around corners installing the tester equipment the engine went from hot to medium hot (warm).
Although I had the air compressor output set at 95 psi, The Harbor Freight leak-down tester seems to works on a incoming air pressure of 12 to 15psi –anymore incoming pressure causes the percentage gauge to go past the zero calibration mark and can damage the gauge. I question whether 15 psi is enough to test a diesel engine (although, I’m wrong on just about everything).
I did run a cold engine Leak down test on Sunday using higher pressures – the results were pretty much the same except that there air noise coming from the dip stick tube as well as a louder air noise from the valve cover bypass valve. The cold engine compression tests showed cylinder 1 having an average of 246 psi, cylinder 2: 340 psi, cylinder 3: 377 psi and cylinder 4: 340 psi. However, I did not disable the injector pump – with all the fuel washing down the cylinder walls and being a cold engine could account for the poor results.
I was surprised to find out that today’s test with a hot engine (and using a new Leak-down tester) that the engine tests were so much better – suspiciously better. All the blow by pressure/noise came from the valve cover and nothing from anyplace else – maybe if I adjusted the leak-down tester to accept a higher incoming pressure, today’s results would be more like last weekend’s tests (but using higher pressures around 30-40 psi blew the percentage gauge last Sunday-got a new one yesterday).
The strange thing I noticed today while warming the engine was that with each rotation of the engine the intake ports were puffing out rather hi amounts of air. Almost makes me think that the intake valves aren’t closing soon enough before top dead center. ANY IDEAS or is this the way it suppose be?
Here comes the results:
Compression Tests & Leak-Down Test Results
BARS PSI
From To From To
Good Compression 24 30 348 435
Minimum Comp 15 218
Max Cylinder Variance 4 58
Above info was taken from the Mercedes Manual & converted to PSI
Tuesday, Sept 13th Compression Tests Results-Hot Engine
Test 1 Test 2 Test 3 Average Variance
Cyl 1 325 320 320 322 -36
Cyl 2 320 320 320 320 -38
Cyl 3 345 345 345 345 -13
Cyl 4 358 358 358 358 0
Note: While engine was running, strong puffs of air continuely shot out of the Air Intake ports:Cylinder 1 blew strongest - 2,3 & 4 ejected puffs with slightly less pressure than cylinder 1.
Tuesday, Sept 13th Cylinder Leak-Down Test Results-Less Than Hot Engine
Valve Cover Dip Stick Intake Exhaust Adjacent Anti Freeze Percent
Air Noise Air Noise Air Noise Air Noise Cylinders ReservoirLoss
Cyl 1 Loudest None None None None No Bubbles 30%
Cyl 2 Loud None None None None No Bubbles 10% Cyl 3 Loud None None None None No Bubbles 24%
Cyl 4 Loud None None None None No Bubbles 30%
* All Cylinders registered in the "Good Compression" Zone of the Gauge
Man - the charts above shure doesn't look like the ones I sized down for creating in the "Quick Reply" box.
So attached is the same but in EXCEL format.
Sorry,
George
Update on the Harbor Fright Leak-Down Tester-Model 94190
So concerned over getting a good percentage score on all of the cylinders knowing full well that at highway speeds the block pressure blows the dip stick halfway up the its tube that I contacted technical support at Harbor Freight (also noting to them that the tester passes only 13 psi when zeroing the percentage gauge - I think the pressure going into the cylinder should be a great deal higher).
The guy at harbor Freight researched the tester and got back to me with the results. Apparently, they know there is a manufactors defect and are taking them off the market and orders when returned to give full refund wih NO replacment. To his knowledge no replacement model has been discussed.
Think the compression tests numbers are OK.
So, guess all my info regarding leak-down testing is garbage.
George
Timing chain jump is one of the things I considered - the puffs of air were coming out of all the air intake openings.
Regarding the blowby or high crankcase pressure, I read in one of the forums (someplace) that 4 or 5 percent of all Mercedes diesels up to around 1993 had gasket that would blow/rupture between cylinder 1 and the timing chain well. Maybe that might be one reason the crancase is blowing the dip stick up its tube.
When I wiped out the 1st tester over he weekend, I forced about 30 psi thru the tester. Not only did the valve cover roar with air noise but so did the dip stick tube (to a lesser degree but there was still plenty of pressure coming out the tube - rings or maybe oil drain passages in the head.
Don't think the Harbor Freight tool tells can tell much with only 14 -15 psi input into the cylinders - believe more pressure is needed to tell the actual conditions of the rings (as far as blow by is concerned).
Next step I think is to remove the head & see what's there. Need my son, Donivan (master mechanic for the Ford Motor Company) to take a vacation at my house. Not sure I would recognize all the ins and outs of diagnosing head or head gasket problem by myself.
Thanks or your help.
George
Have you actually checked the engine timing marks? All that requires is removing the valve cover - might be worth doing before you pull the head and incur the considerable cost of a gasket and head bolts.
I haven't personally seen a 2.2 leak between cyl 1 and the timing cover, but i have seen a 2.5 turbo do so, and the engines are fundamentally similar so it's a possibility. As the engine temperature increases and metal parts expand and fit better together, this problem may alleviate itself a little bit. Is the blow-by as severe with the engine warm as cold?
As for the cylinder leakdown testing, I'd certainly rather use more pressure, but feeling airflow can still be diagnostically useful. Remember that air coming out of the intake can also indicate loose rings on more than one cylinder - if you're applying air to one that has loose rings and another cylinder has an open intake valve (as one always does at any given time), you may be feeling air that's made its way into the crankcase then back into another combustion chamber and into the intake that way.
Try retesting cold compression with a (small) amount of oil in the cylinders showing lower compression (one at a time - and don't go heavy on the oil, you don't want the thing to start up and run on you). If the compression improves, it would more definitively indicate weak or broken rings.
Oh, and cheers to your son. I was a Ford Diesel Master Tech myself, worked for them for quite a while. Good people to work for, and a pretty damn good product.
No I didn't actually check the timing marks - couldn't find them. What I did was I noticed where Cylinder #1 rocker arm position was relative to the oil filler cap - which I can peak through to see when rotating the engine. With the leak down tester hooked up and knowing when #1 cylinder was on the fuel intake cycle (can hear cyl 1 sucking air thru its intake port) I slowly turn the engine until the percentage gauge gave the best reading. Then peeped thru the oil filler on te valve cover to make sure the rocker lobe way perfectly verticle. Ran thru a couple cycles and kept checking for the best reading on the percentage gauge just to make sure the procedure was correc.
Knowing the firing order, I went to clinder 4 and did the same thing, twh #2 and so on.
I figure the best prcentage reading stands a good chance that the piston in TDC on the firing stroke.
Yea, kinda proud of my son - took his advanced Ford training in Pittsburgh but only get a chance to see him a couple tims a year. You two need to form a club together.
Again, Thanks,
George
Will try the wet test tomorrow. When I did a dry test lat Saturday with a cold engine, the average out of 4 tests was Cylinder 1: 246psi,cyl 2: 340psi, cly 3: 377psi and cyl 4: 340psi. The hot engine compression tests on Tusday were a whole lot better. I did not do a wet test cause I wasn't sure how much oil to squirt in the glow plug openings.
I will check out the engines you mentioned in your message to me (none of the junk yards around here have Mercedes Diesels). But quite frankly, the old monthly Social Security check couldn't take it without vommiting.
On your crankshaft pulley, you should see a series of timing marks and some sort of pin coming out of the block. With the valve cover off (you may be able to see the mark through the oil filler cap, not sure on the 2.2) you'll see that the cam bearing caps have a small ridge on their aft side. The ridge on the #1 cap is the only one which is relevant to you. As you turn the engine over, you'll see a groove cut into the very front of the cam, just behind that bearing cap. Line that groove up with the line on the bearing cap, and that's cyl 1 TDC (top dead center) on the compression stroke. The cam lobes for cylinder 1 should both be fairly vertical; one might describe their appearance like "bunny ears." With the cam lined up, check where the timing mark reads on the crankshaft. Ideally, it should be exactly at TDC or zero degrees. More likely, it will read two to four degrees after top dead center (ATDC). This is due to slight stretch in the timing chain over time, and is not a significant cause for concern. More than four degrees of timing retard would indicate excessive stretch or possible jumped timing.
If you want to check wet compression, use a small oil can and give a single shot of oil down the cylinder in question. Or just measure out about a teaspoon.
Pulled the valve cover and the chain tentioner pulley and found the following:
With the timing marks in alignment (cap 1 with timing sprocket) the engine block pin points to about 14 degrees BTC (not ATC). That is to say rotating the crank clockwise, the 20 degree mark comes up first then drops down to about 14 degrees - at that time the cam shaft marking lines up with the bearing cap. TDC mark on the crankshaft pulley is still to the left of the 14 dgree mark (TDC mark hasn't got to the block pin yet).
What's the best thing to do? Take the chain off and reset the crank to TDC on the compression stroke and align the cam shaft to the compression stroke? Run the engine thru five or six complete turns and recheck the cam to crankshaft pulley alignment.
Or is this even a good idea.
With crankshaft pulley indicator pointing to 0 (zero) TDC mark (see pic), cylinder #1 (nearest to radiator) should be at Top Dead Center, with both intake & exh valve lobes vertical, pointing up.
If timing is off, you'll need to remove the camshaft and reset it for cylinder #1 at TDC position.
OK: Here's what I did. Don't want to slap the engine back together & start her up without first checking with you:
Just to recap the other day, I rotated the engine until the intake valve (2nd from radiator) began to close and brought the cam shaft on up until the cap score mark match the cam shaft score mark. Then I checked the timeing mark on the crank shaft pulley which read about 14 degrees BFTC.Just a a footnote: the two lobes are no where near being verticle - each one is at an equal angle just a little above a horizontal position when at TDC - a little like your bunny ears except more flattened toward the horizontal.
Today, I removed the timing chain tensioner and moved the chain clockwise one link - which moved the cam shaft counter clockwise one tooth. Then replace the chain tensioner (body first, then spring, etc.).
After rotating the engine five or six times & the intake closing, I rotated the crankshaft a littlte bit more until the score marks on the cam shaft & bearing cap lined up.
The new reading on the crankshaft is now 5 degrees after TDC - meaning while rotating the crank, the TDC mark came first and and continued until it stopped at the 5 degree mark on the crank pulley. I"m going into great detail because I want you to know exactly what I did.
Now, based on what you previously said, I am guessing 5 degrees after TDC is better that 14 degrees before TDC. Or am I wrong?
If what I did is correct, do you think this might solve most of the blowby problem (with all thee air puffing from intake ports) ?
Am anxiously waiting for your input.
Thanks for your help.
George
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