Figure this out

[DeltaCub]

The compression being too high still intrigues me. I believe this engine has a cast iron block with an aluminum head.

[J-Mech]

WOW! You guys are on it!! Some good guesses! But, with your guess I want an explanation. Remember, this isn't my car so I'm not just going to go tearing it apart for no reason, or throwing parts at it. I can guess better than anyone, but guessing costs someone money, and it's usually me. Customers don't want to pay for guesses. If you think I need to open the motor up, convince me, because that's expensive.

OK..... Let me see if I can address these. Yes, for the record I already solved the puzzle. I put it up here so I could use it to teach, because this is perfect example of problem where knowing engine basics solved the issue, and why I said we could compare it to a cub.


To all who said cam timing..... you are correct.

I can't believe no one addressed the misfire first or suggested spark plugs!! (EDIT: as I'm typing this I went and looked at new answers and Bill finally said address the plugs. Good job Bill!) That was the very first thing I did. High miles, old car.... must need a tune up! So, new plugs and boots. Old ones were shot, and I'm sure it did it some good, but didn't fix it. So.... I moved on to making sure that the miss was across the board, not just one one cylinder. It was consistent in that is was a random misfire. No one cylinder more than the other. Next, I did a compression check. That's when I found the 225# cranking. Holy crap that's way too high!!!! So.... low vacuum, high cranking compression.... I went for plugged exhaust/cat converter. Dropped the pipe at the manifold. Ran exactly the same. No change other than now it's really loud. So exhaust goes back on. Sooooo what causes low intake vacuum, high compression, random misfires and the computer can't see??? Cam timing. All the computer reads is the intake cam. It only looks at it at starting, so once it's running it doesn't care about that sensor anymore. If the intake cam is out of time, it would have had a cam/crank correlation code. It didn't. Exhaust cam is back there all by itself and has no sensor. I suspected that the exhaust cam was retarded because that would cause the symptoms. So... I pulled the cover and guess what?

IMG_20150328_104807.jpg


Now the point here is that even with computer controlled motors.... sometimes the computer doesn't know what's going on, and the codes it presents are just symptoms, not problems. I had to rely on a basic knowledge to find the problem. If it had been a cub.... 2182 for example, it would have presented a slightly different set of symptoms because it is a single cam motor. I didn't jump straight to cam timing right off the bat for several reasons. 1.) typically belt driven cams get out of time easily, chain (or gear) driven, not as often. 2.) going "exploring" is always a last choice for me. Takes time, and costs money and all too many times I found nothing. I like to have a very good reason and know exactly what I'm looking for before opening up a motor. 3.) at the beginning there wasn't enough info to support that claim. Every test gave a new answer of what it couldn't be which eventually led me to the problem. They were easier tests and didn't require opening the engine. I approach my stuff just like I do my customers..... don't go exploring, don't guess high dollar repairs until all low dollar ones have been explored, test until you find the problem..... DON'T GUESS!

That was fun guys!! Thanks to all!

[Sam Mac]

Any idea how the cams got out of time?

[Alvy]

Originally Posted by Sam Mac

Any idea how the cams got out of time?

I'm "guessing" someone had put it back together wrong as new timing cover gasket was seen

[J-Mech]

There was one other thing that I found that I didn't disclose.... I found the cruise control cable had been tightened to bring the idle up. After I loosened it, it made the problem worse. Way worse. My assumption is that the water pump went out, and when it was replaced whoever did it didn't realize it jumped time and put it back together. I really think the previous owner had been driving it that way for quite some time. Had the intake cam moved..... it would have thrown a code a may not have even let it start because the computer would have seen that the cam and crank weren't in time.

[cubby102]

I shoulda been more specific on the timing set being installed wrong:/ I had a similar problem on a 1.8 ford the FIL had... good that ya got it figured out though. Wish I had all the gadgets to work on these new computer controlled things. Well done

[zippy1]

Great quiz Jon, and good example of finding the problem before "just" throwing parts at it and hoping it sticks.

[J-Mech]

Originally Posted by cubby102

I shoulda been more specific on the timing set being installed wrong:/ I had a similar problem on a 1.8 ford the FIL had... good that ya got it figured out though. Wish I had all the gadgets to work on these new computer controlled things. Well done

You did fine! I kind of ignored your response because it came so early and I wanted to give others time to read and come up with ideas. I figured some would come to it, and others would just enjoy watching. Thanks for participating!

Originally Posted by zippy1

Great quiz Jon, and good example of finding the problem before "just" throwing parts at it and hoping it sticks.

Thanks Todd!

Anyone can guess. But guessing is expensive, whether it's on your own machine, or someone else's. My point was that it doesn't matter what your working on..... car, truck, tractor or your cub, you should take the time to test and come up with a "theory" if you will, then test your theory to see if it's right. A knowledge of the "basics" is key and important. Sometimes even the most difficult appearing problem has a simple solution. I admit, this one kind of puzzled me, but only because I had no "patient history". Gear/chain timing seldom is off. Had I known that it had been into before, I would have made it to the solution faster. Sure I was pretty aware that the cover had been off before, but the car is a '98. It would be silly to assume it had never been worked on. But to me it was sillier to think that the PO had driven it with that issue. For all I know at this point, it may have been the reason they sold the car! It's fixed now. Thanks everyone for "playing along".

[EricR]

Boy I remember when I worked for a chevy dealer back in the 90's towing a bunch of those duel-over-head cam engines, kept me busy, lol.