82 diesel rabbit problems

[cooguyfish]

I'll attempt to make this short. If this sub forum is inappropriate for this question please move it.

I just bought this rabbit. It ran well on the test drive but had a hard time starting up in the cold and idling. It smoked a lot and I figured it was related to the glow plugs being bad.

Fast forward to today, I put glow plugs on (the old ones were bad), but it still doesn't run right. It has a hard time idling, smokes a decent amount, and didn't clear up when it warmed up. It also has an occasional miss in it, mostly in the lower RPM's

Any input would be greatly appreciated.

Thanks

-Brandon

 

[oilhammer]

Timing. Compression. Pump. Injectors. Gotta check 'em all.

 

[cooguyfish]

Timing. Compression. Pump. Injectors. Gotta check 'em all.

How do you check compression on a diesel engine? and please don't say "pull the glowplugs." those things sucked to put on.

I will check the timing, that should be easy. How do you check the pump and injectors?

Thanks

-Brandon

 

[oilhammer]

On the IDI, I use an adapter that goes in the injector hole.

 

[Vince Waldon]

If it starts and runs really well when warm but is hard to start at cool or cold temperatures the glow plug system (relay, fuse, glow plugs, harness, temp sensor) is the first suspect. Troubleshooting info here:

http://vincewaldon.com/index.php?option=com_content&task=view&id=41&Itemid=28


Timing's #2 on the list... there's a checking/adjusting timing HOW-TO here... you'll need some jigs and a dial indicator:

http://vincewaldon.com/index.php?option=com_content&task=view&id=24&Itemid=28


Checking the pump is a job for a Bosch shop with a test bed... but it's last on your list of possibilities.

Checking the injectors requires a pop tester... diesel service shop. You will need a very deep 27mm socket to remove 'em and new heat shields when you re-install 'em... heat shields are single use only.

 

[joetdi]

Well I guess I will ask. Are you pulling out the knob in the dash all the way before you start the car? Also move the knob in and out and have someone check the lever on the pump to see if it moves with it.

And when you check the start of injection that knob has to be pushed in all the way.

 

[Joe_Meehan]

Are you pulling out the knob in the dash

I don't remember what years they had that cold start control, but if you are not using it, that would explain the problem.

 

[oilhammer]

When it is BITTER cold, you leave the knob in during cranking (this info is in the owner's manual). Crank until it starts to sputter, then pull the knob out. The knob advances the timing, and it is harder to crank against the super advanced timing, so it will crank slower. Get the crank spinning a little faster with the timing still as retarded as it can be until it gets a little heat and fuel in the cylinders, then pulling the knob to get it to fire off. Works great. My '91 (which is improved over the '82 even) started unaided after sitting overnight in -15F temps. It wasn't happy, but it started.

If the timing is way off, or if someone advanced it a lot to improve performance, cold starts can suffer some and will surely necessitate leaving the knob in during cold cranks even moreso.

 

[Tom W.]

Hard time idling, smokes badly @ idle? I would run a straight bottle of Lubro-molly diesel-purge. Cost you $10. http://forums.tdiclub.com/showthread.php?t=87948
I would also recommend you add in some Diesel-kleen w every tank of diesel, to improve the lubricity of the fuel.
I always do a compression test and an oil pressure test on any car I buy.
A dirty little secret w these old 1.6 idi engines is that they have a problem w bore wear. I've got 2 1.6 IDI TD engines sitting in my garage right now. Both are in good condition (fresh cyl heads, etc) except that the bores are so worn that they have low compression.

 

[oilhammer]

My 1.6L made it past 430k miles, and it STILL has no bore wear. I think proper care made a big difference, though. Heck, I just rebuilt it and the only thing in the lower end that got replaced was the piston rings, the wrist pin bushings, and the rod bearings... and the rod bearings actually still looked good.

 

[Tom W.]

oilhammer-don't you have a 92? What oil are you using?
My suspicion is that the VW block metalurgy got much better sometime around 1990-92. I've looked at a 81, an 82, an 85, and my curent project, an 86- they all had bore wear issues- talked to 2 fellow VW 1.6'ers, they've noticed the same thing on 86 and older 1.6 IDIs. Granted, all these engines had between 180-260k on them. Only one of the guys worked on anything newer than an 86- it was a 92 and he said the bore was perfect @220k(head gasket replacement).
I'm thinking of sleeving the 86 td, although I am only familiar with re-boring/oversize pistons. The previous owner had the head re-built on the advice of his mechanic in order to fix the low compression issue. When it turned out to be a worn cylinder issue, the PO sold me the car for $100. (Jetta D Turbo delux)

 

[oilhammer]

It is a '91, one of the last of the non-turbo cars. Castrol 5w40 Syntec, Mann oil filter, every 10k miles. It had a valve-job at 246k, mainly due to the head gasket starting to seep a little oil at the front of the engine. It started getting a LOT of blowby rather suddenly at around 430k miles, shortly after I ran it up to 95 for the first time ever (I really had to poop, and was still about 5 miles from home ). It started spitting the dipstick out from excess crankcase pressure, then a couple times on the highway I had a couple 1-second runaways, so I decided it was time to tear it down.

I found minimal piston wear, cylinder walls still clean and crosshatches present everywhere except some minor shiney spots near the top where the rings stop. A light hone cleaned that up, the rings themselves were pretty worn, and 2 rings came out in 2 pieces.

Still, 437k miles is not too shabby for a 52hp engine that spins nearly as fast in 5th on the highway as a TDI does in 3rd gear.

I suspect many earlier cars had bore wear issues from people cranking the timing way advanced to squeeze more power out of them, not sure. I rebuilt an '86 engine that had some, but both my '81s and my '82 just needed rings. I recently had an '82 in here, with an early '81 engine in it, that had severe bore wear, even had a huge lip at the top.