2001 tdi runaway compression results questions

Update a few threads down.


Greetings all! I recently had a short run away experience with my 2001 TDI beetle. Long story short I was coming home and I lost power and tons of smoke. I was really close to home so I pulled in the driveway and when I went to turn her off it started to rev but I stalle it out before it got over 3500 RPMs. there was a puddle of oil underneath and I knew that I'd obviously fried the Turbo. I pulled the intercooler and there was metal pieces in it.
I ran a a compression test after blowing all the oil out through the glow plug holes. I got 430, 400, 400, 405.
I'm super low on funds and need to get my car back on the road as soon as possible. Should I risk replacing the turbo and cleaning out the intercooler and running it? Or does it appear as if I have three bent rods? I did a search and found most people have a much greater difference in compression between cylinders. What is the next course of action with a tight budget considered? Thank you in advance.

Personally I think your good.
I would pull your intercooler, and all pipes off flush and clean them well.
I would redo the compression test again to make sure.
If any rods get bent it’s usually 2 and 3, due to the straight shot into those cylinders.
I’d find a good used turbo from someone on here, DO NOT get an aftermarket one off eBay.
Make sure it’s at least an oem one.

When everything is together be prepared to smoke out your neighborhood as any oil that made it to the cat and muffler need to burn off.
Your gonna need to do some spirited runs.

When my son snapped his turbo shaft in half, it took almost 30 minutes of hard driving to stop smoking, but then again he duped a lot of oil into th exhaust.

Your numbers are all close and within spec.

Yeah when I broke my turbo after cleaning everything up I had about a 10 mile run that laid down a huge smoke screen.

When it’s all back together pull the glow plugs to turn it over the first time so you can blow any residual oil out and not risk a hydrolock.

Thanks for the replies, guys. I was actually looking at a few different turbos on eBay. LOL I am trying to get an oe one if I can, not one of the China ones... As tempting as they are. I did a second compression test and the numbers were pretty much identical to the first test.

For turbos, oem will be a vnt 15 , idparts, metalmanparts, cascadegerman, fixmyvw, all have oem Garrett vnt15’s. You will also need a new oil feed line because it’s unlikely you’ll get the old one off without breaking it. I recommend a flexible braided line from cascadegerman, all 3 of my tdi’s have them now.

So much easier to install.

Stay away from eBay unless it’s one of those sellers, all of whom sell on eBay.

The Mahle vnt15 turbo is also an excellent oem replacement for a few dollars less than the Garrett......


https://www.idparts.com/vnt-15-turbocharger-038253019c-mahle-p-4608.html

Update:

Afraid its only bad news. I finally got the money to make repairs. Based on my compression test i decided to get a rebuilt garrett turbo. I installed the turbo over the weekend. I took my time, double checked everything, and got everything put back together today. Well, I went to turn the engine over for 10 seconds to get oil pumping through the turbo lines but my car didn't want to turn over very fast. Now, just to let you know, my starter has been acting a little funny before all this. It sounded a little weird when starting, and would slow crank often. Anyway, after it turned over 5 or 6 times really slowly smoke started coming up from the battery area I have no idea why from there, as i didn't do any work near there! I couldn't see exactly where it came from, but both battery post were warm. The negative side appears to have gotten hot enough to melt the tape around it. I reached under and the starter was pretty warm itself also. The solenoid was very cold. (working in 40 degrees). If it was bent rods, would that cause it to turn over very slow? I am thinking i might actually have bent rods, which made it hard for the engine to turn over, which overworked the starter causing it to overheat. Is that plausable? The battery was replaced about 2 months ago with a cheap walmart store brand battery.

I am stumped and at my wits ends, guys. My boss is pretty decent but if i can't get back to work this week i am gonna get fired. I am almost out of money to make anymore repairs or buy replacement parts. Any suggestions you have would be greatly appreciated. What might i have overlooked? thank you.

Charge the battery and clean the connections until they are shiny lead.
The starter cable also can corrode and need cleaning or replacement.
Last but not least clean the ground connections under the battery.

You most likely have bent rods. I know the same thing happened to my 2002 until the rod came through the block.

flee said:

Charge the battery and clean the connections until they are shiny lead.
The starter cable also can corrode and need cleaning or replacement.
Last but not least clean the ground connections under the battery.

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The battery terminal connectors are 2 months old with the battery, and are like new condition. The ground and connections were all redone as well. I just rechecked them to make sure, and the grounds and connections all seem to be within reason.

Curious Chris said:

You most likely have bent rods. I know the same thing happened to my 2002 until the rod came through the block.

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Thanks for responding. What do you mean same thing? slow cranking and you thought it was the starter? Did you get smoke from your battery/starter also?

Curious Chris said:

You most likely have bent rods. I know the same thing happened to my 2002 until the rod came through the block.

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His compression test looks pretty good, though. Usually if rods get bent in a runaway #2 and/or #3 are *way* lower than #1 and #4.

A bent rod or two also wouldn't likely cause slow cranking all on their own IMHO... in fact the lower compression should make it easier. After my runaway 2&3 were in the 100 psi range and she cranked over just fine.

My guess... apples and oranges. Starter (which sounds like it was acting strange in advance of this incident) has gone sideways, causing a larger-than-normal current draw which is overheating the wiring.

I suppose it's possible that the runaway did some other damage, but it sounds like it cranked over just fine before when doing the compression test?

Auto store can test the starter and rule it in or out as a suspect.

Vince Waldon said:

His compression test looks pretty good, though. Usually if rods get bent in a runaway #2 and/or #3 are *way* lower than #1 and #4.
A bent rod or two also wouldn't likely cause slow cranking all on their own IMHO... in fact the lower compression should make it easier. After my runaway 2&3 were in the 100 psi range and she cranked over just fine.
My guess... apples and oranges. Starter (which sounds like it was acting strange in advance of this incident) has gone sideways, causing a larger-than-normal current draw which is overheating the wiring.
I suppose it's possible that the runaway did some other damage, but it sounds like it cranked over just fine before when doing the compression test?
Auto store can test the starter and rule it in or out as a suspect.

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Thank you so much for your quick and thorough response, sir. Can the local auto stores run a starter test with the starter off the car?

Actually I just called and they can. I will take it in tomorrow and see what they say. I started to take the starter apart tonight to see if she needed some TLC. but i think i will just put it back together as is for better test results.

Most of them can with no problems.

I seriously don’t think you have a bent rod.

I think its either a bad ground or starter issue.

Simple test, pull the glow plug on each and do a leak down test, pressurized air and see where It comes from.
You can check for bent rods by doing the "rope trick". Basically with the Injectors out and the engine at TDC, use a rod (soft) like a braising rod or aluminum so not to scratch the cylinder wall, and have someone rotate it by hand at the crank, Mark with a scribe when its at TDC on each piston and same with bottom dead center. compare the measurements, someone here can do the math sand give you a accurate distance from the top of the piston to the top of the heads lip for the glow plugs. If it checks out and a leak down test is good, your fine. try and be consistent with where you place the rod, in the bowl vs on the top of the piston. Its at an angle so your going to have to be as close as you can, may take multiple attempts.
best to always turn it over by hand first

Get a multimeter and find the amp draw on the starter by clamping the amp loop onto the positive wire from the battery. If your over 80 some amps, your starter is TOAST. You should also have 10.9V MINIMUM when cranking, after a full charge and the lights on for a few minutes to take off the top charge.
If under 10.9v your battery is junk.
Id give you a 75% chance you didnt do any damage to the rods. you can always get a borascope and look inside the cylinder bore and see if any markings on the piston are present.
How big were the chuncks in the IC?

Check the starter it’s drawing to many amps. While the battery may be ok, its worth checking and fully charging.

My compression results were like 450 400 350 450. I threw a rod 6 months later.

Curious Chris said:

My compression results were like 450 400 350 450. I threw a rod 6 months later.

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If you had one cylinder doing 350, yea sounds about right.
His are not that bad though.

So I just took the starter to AutoZone and had it tested. It passed all tests except for the gear did not extend at all at the end. They tested it twice and it was the same both times. Now it's really boggling my mind now is that when I started to take the starter apart did I mess something up that cause the gear to not extend? It's just strange that it's not extending and that's the problem because the car will turn over. How does it turn over if the gear on the starter is not extending to hit the flywheel?

Curious Chris said:

My compression results were like 450 400 350 450. I threw a rod 6 months later.

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Yup, the tell-tale #2 or #3 being 100 psi below the top ones. #2 or #3 is where the liquid oil tends to collect and become ingested.

g0nefish1n said:

It's just strange that it's not extending and that's the problem because the car will turn over. How does it turn over if the gear on the starter is not extending to hit the flywheel?

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There's two parts to the starter... the part that turns (the motor) and the part that extends (solenoid and drive linkage).

Sounds like you've developed an issue with the part that extends.

You could mess around with finding out what and why and try to source specific parts (if available) or just source a quality replacement... either way you need a starter that's 100% before you go any further?

Or a degraded cable . . . he said the connections were potentially new, not the cables. Considering that this is a WallyWorld battery that may not be the correct one for a TDI, if cables were replaced, they might be too small as well. Remember, heat is due to current *and* excessive resistance . . . . starter current appeared to test fine, so wiring/resistance remains . . . (and he also didn't mention how longnhe cranked it . . .)

Well, the motor draws a lot more current than the solenoid, so if a degraded cable/connections/battery were the root issue I'd expect the solenoid to engage and the motor to stall rather than the other way round. Just my take, of course... stranger things have happened.

Another data point, if I understand the story correctly, is that it sounds like the solenoid is not working on the test bench either.

If the engine is not having mechanical issues, instead of a stall, the voltage drop will cause the starter to run slowly. Not sure on the VW starter specifically, but on most, the solenoid is also the switch for the starter motor, and if it won't extend, it won't get power at all (IE the dreaded "click" and no crank . . . ). Still sounds to me like voltage drop in the cables causing heat and slow crank . . . . Solenoid draw is trivial by comparison . . .

Thank you everyone for your feedback. We will find out later today whats going on. The starter will arrive today around 4pm. The ground cable didn't look too bad, but the terminal connector at the battery was only holding maybe HALF of the ground cable because it was too small. Someone had put a really cheap, shiny looking connector that was made for what looks like a 4 gauge wire? My stock ground wire appears to be a 2 gauge, but i can't confirm. Anyway, the negative terminal connector was too small to hold the bulk of the ground strap. I will check out new grounds and buy a quality terminal connector when i pick up the starter. A new starter, ground wire, connector, and cleaning all the grounds should tell us all we need to know this evening! Wish me luck! I will post back later.

More bad news, unfortunately.

I got a new starter today. Along with new battery terminals, and a new 2 gauge ground wire. I hooked everything up and she won't even turn over. The second i hook the battery up, the battery light in the car comes on. Nothing happens if i put the key in and turn it on, except the battery light gets a little brighter. I have no idea whats going on. I checked every single fuse on top of the battery, and inside by the drivers door. I am at a loss of what to do next. Any ideas?

At any point since you began to have starter issues was a battery connected backwards even briefly... jumper cables perhaps?

Vince Waldon said:

At any point since you began to have starter issues was a battery connected backwards even briefly... jumper cables perhaps?

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They definitely were never backwards. The short length of the ground would of made that impossible in this setup. I haven't used jumper cables on it. I had the battery out on a tender. Checked and charge it up today.

Ok, a backwards battery at some point is one possible explanation for how your BAT light is behaving.

Do you have a multimeter? If so check the battery voltage with the car turned off. Then take the red multimeter lead and put it on the stud at the starter.

The one the positive battery cable is hooked to. It should read the same voltage as your battery. If not your cable needs replacement, you’ve taken everything else out of the equation.