... another no start puzzle

[greg lousy]

I've got through a number of no starts without posting here but this one is getting to me. My 86 turbo jetta had run great since I bought it... great cold start, got me through a hell of a winter... compression felt great when turning by hand, smoke free, etc. it recently had some hard starting which turned to no starting.
I did the usual checks, bottle feed (no difference), tweaked ip timing, checked stop solonoid. IP has no leaks and pretty sure no air (i was looking through lines that were once clear but are pretty murky).
then when I got the timing covers off I noticed that my belt was worn to crap - one side was stripping away, and I knew it had all happenned very recently, as I had looked at the belt a month or two ago. then i found that the intermediate shaft pulley was wobbly and found that the inner ring of it was falling apart, like it was screwed on with that little key slot not fitting, or the little key jacked around, or something seized. Luckily, the timing was still right on so i dont think anything disasterous happened. I was thinking the thin belt may still be messing with the IP timing, but today I got things put back together with new belt and intermediate shaft pulley and now the car has no signs of being even close to starting, cranks fine, no fire, not even smoke. I lossened an injector line and rechecked stop solenoid just to make sure it was getting fuel because there was so little happening. yep, getting fuel at least. Then I double checked the general timing, as I had just got the belt on. Timing was on.
This is my first turbo and Im pretty ignorant. I tried undoing the big hose from turbo to intake, no difference. Could a failed turbo choke the exhaust? ... thinking about air because I dont know what else to think of. Engine still feels good cranking by hand. intermediate shaft appears to be tracking well with new pulley. I'm open to ideas.

[TylerDurden]

I'd check the compression for two reasons:
1) no start... combustion requires fuel, compression and timing. Seems you have verified two out of three.
2) if the belt was slipping, the oil pump may not have been supplying adequate oil pressure and additional wear would result.

Some new clear lines would be a good idea too.

[82vdub]

If you have a block heater, plug that in for a couple hours before trying to start. A warm/hot diesel will start easier than a cold one, and this kind of confirms or rules out good/bad glow plugs. You didn't mention that you checked them, and voltage at the plug is not a proper test. You need to verify the amp draw, or that they physically glow. Otherwise, I would say that the timing is off. If you timed it by a dial gauge, I've never had one start or start well doing this myself. I've always had to advance it after I used the dial gauge to get it to start/run properly.

[greg lousy]

no block heater. sorry, forgot to say that I did check the glow plugs when the hard starting began, they're fine,... physically took them out and jumpered them to glow, and with the summer temps I would expect at the very least a threat of firing with bad plugs.
I didnt use a dial gauge. I am used to getting it in the ballpark and setting by ear but in this case there is not even a threat of it firing at any point in the whole range of the IP... I went bit by bit back and forth, thats whats throwing me off.

This may sit for a bit as I'm sick and now I have to fix my golf first to get around. I have to do an IP swap on that one, but was hoping to get the jetta going so I could get into the engine of the golf.

When I get back to the jetta I plan on doing compression test, put the injectors on backwards and look at the spray, maybe use dial gauge to make sure I'm not way off for some reason. I think theres something atypical here, or at least atypical to me.

I'm also thinking about the broken intermediate shaft pulley. I never noticed any loss of vacuum on my brakes, so I the oil pump couldn't have been completely failing, but thats a good thought. I'll get back to this in a bit.
thanks, always appreciate it.

[greg lousy]

I put the injectors on backwards, did a cold compression test, took a look at glow plugs in their natural habitat. Glow plug system good. injectors producing good looking spray, still can see no air in lines. Compression looks to be the problem, something like 300 200 100 300, cold, of course, with cheap harbor freight tester, but still... 100... damn. I put some oil in the 100 cylinder and the compression shot up in a way i've never seen with this test... got around 400. I kept testing and the reading slowly worked its way back down as the oil dissipated.
So it looks like the rings are shot. I hadn't done a compression test on this engine before, but, judging from the general signs (turning by hand, cold starts, clean, smooth starts and running) I think this happened fairly quickly. If this was in fact the result of inadequate oil pressure, would a rering do it, or do you guys think there would be any additional damage?

I'm trying to figure out my situation, trying to figure out where to put my money and time (golf also needs help and 81 dasher hatchback may come into picture)

[Fatmobile]

With that range of compression values you should have a good idea of how good compression should feel when you turn the crank by hand.
Some of the cylinders must have turned quite easily.

Hard to tell how well a rering will work until you see the ridge on the cylinders and grooves on the pistons.

[air-cooled or diesel]

I put the injectors on backwards, did a cold compression test, took a look at glow plugs in their natural habitat. Glow plug system good. injectors producing good looking spray, still can see no air in lines. Compression looks to be the problem, something like 300 200 100 300, cold, of course, with cheap harbor freight tester, but still... 100... damn. I put some oil in the 100 cylinder and the compression shot up in a way i've never seen with this test... got around 400. I kept testing and the reading slowly worked its way back down as the oil dissipated.

your pretty crazy to try this,, and with a cheap compression tester, works on gas motors, in a diesel its live, and you kept on cranking, your lucky the oil in the cylinders didnt combust, you can do this if you dont mind losing a compression tester,,but never have anyone anywhere near or in-line-of-sight-to tester, boom and your in the hospital, you ll make a mess and then some, like shrapnel,

[greg lousy]

Thanks, I've done this test four or five times and never thought about accidental combustion, though it would make sense to. I thought I got the idea from Bentley, and out of curiosity I just confirmed that. Just a few cranks with the glow plugs disconnected probably would have been a wiser move.

Yes Fatmobile, my engine has become a great example of how an engine should not feel when hand cranking. (Though I think I was just turning through this stroke without even realizing)

[greg lousy]

finally getting into this. I haven't pulled the pistons yet but the head is off. ridges in the cylinders seem about what I would expect, though I have only seen the inside of one other engine. No obvious failures in the gasket or cracks in the block. Moving ahead with rering, as this is about as far as I'm going with this car even if it would technically need to be rebored... see where it gets me, hopefully down the road

[greg lousy]

for the sake of someone else not making the same mistake, I started to ream the ridges with like a 3 to 5 inch reamer. it barely fit and when i put the blade in the scoring position, I think it pushed the reamer off center... started to scratch the cylinder under the ridge. Since the scratch is much narrower than the ridge, I'm hoping the ring just moves over it smoothly. For now I'm just gonna leave the ridges and see how it goes, which, after researching here, is what I probably should have done in the first place, damn

[greg lousy]

The rings on two of the pistons were very obviously shot - visibly thinner, huge ring gaps. Interestingly, these did NOT corrospond to the cylinders with crap compression (well, one did, and one of the cylinders with shot rings was strangely ok)

Anyhow, I'm having trouble getting the pistons back in with the ring compressor. I'm using a generic compressor that goes all the way up to like 7 inches, so I think its just not getting a good uniform squeeze. I also tried to mess around with hose clamps, same thing. I can see its real close... may even go if I ream the ridges but I'd rather not. I'm planning on buying a more suitable compressor, one with less excess sleeve, or one of those plier - style ones.... unless there some trick or idea that I don't know about.... any advice?

.... and yes, I did check to ensure the new rings fit on their own. They seem right

[82vdub]

They seem right

Are they? It makes a difference. Did you lightly hone the cylinders so that the new rings will seat properly? A smaller ring compressor will work better than a larger one.

[greg lousy]

yes, I honed. I put the rings in by themselves to check the fit. To my uneducated eye, they look good, which just means that they fit in the cylinders by themselves and leave a small gap. I will measure the gap and check the bantley specs to make sure. Then I'll probably get a better suited compressor.

[greg lousy]

I got a smaller, better ring compressor (the plier type). It gets the rings into the cylinder. I got the middle ring into the cylinder, but then it got tight, tight enough that I wasn't comfortable forcing it. Im gonna clean the ring grooves again, and see where I'm at., maybe ream or sand the ridges if I need to. The rings do seem to fit through the ridge, but only barely (gap appears completely closed when by itself in ridge area). I think the ridge and maybe some leftover gunk in the grooves is making it a tight fit, which is why I couldn't even get them in with the last ring compressor

[82vdub]

You'll need to make sure the rings grooves are clear, and what size rings did you get for your standard bore size? You using oversize rings or standard size? Check the end gaps of the rings towards the bottom of where the rings will be when the piston is at the bottom of the stroke. You need to verify that the gaps are correct and that your rings were boxed correctly from the factory.