N00b Mechanic with a couple of stumpers

Maintenance/Repairs
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1

Greetings everyone!

I was recently gifted a 1994 Jetta GL 5-speed with about 70k miles on it. Previous owner had blown out the clutch (thanks to an original auto-adjust cable), and had just left the car to rot and I, needing a basic bit of transportation that parts were plentiful and cheap, have rescued it.

After replacing the clutch (as well as a new shifter) and new brakes, the car runs like a champ…until it began to hesitate on acceleration. After reading about the problems across the Net about the auto-adjust clutch cables and how they go bad around 70k miles, I went ahead and replaced the old cable with a manual adjust cable.

I didn’t have any hesitation on the test drive, but a new problem (or problems) has emerged as I was driving it around with the new clutch cable…

When stopped at a red light, the car idled wonderfully at approx. 1000rpms. Car purred like a kitten. After about a minute of sitting at the light with the car in neutral, the car began to lose power, rumbled, stuttered, then regained power and idled normally. After another minute, the car - again - began to lose power, rumbled, stuttered, and then stalled out completely.

On restarting the engine, putting the car into first gear and going, the most horrible smell wafted through the passenger compartment.

I noted the smell again after starting from a dead stop at another red light, but without the stall.

I had experienced the smell previously, always when in first gear, always from a dead stop, and always in first gear. I had assumed that the smell was due to the auto-adjust clutch cable was bad and eating another clutch, hence, my replacement. But when it happened after replacing the cable and, ensuring the cable was adjusted properly (that is, it lets out the clutch entirely), it still happens.

So, it looks like I have two issues, and I’m not sure they are related or not, but they have me stumped:

  1. The car, when warmed up, will lose power when the transmission is in neutral, and will occasionally stall.
  2. The car, when coming from a full stop in first gear and accelerating, will emit the most horrific smell. It doesn’t really smell like rotten eggs, but its definitely NOT good.

I am banging my head against the wall here.

I could really use any and all help with this. So, c’mon Car Talkers, let’s solve this!

2

If the smell is similar to a rotten egg smell, it could be a catalytic converter going bad. A bad catalytic converter can cause a blockage in the exhaust, causing the engine to slowly stumble then stall. If the engine cannot blow out the exhaust, it cannot breathe in enough air.

A 1994 ODB system is probably not smart enough to know if the cat is going bad. A 1996 or newer ODB-II car would probably have set a trouble code.

3

Well, the smell isn’t all that similar to a rotten egg smell. Smells a lot more metallic.

Having found the receipts from the repairs, it looks like I did - indeed - have a new exhaust system and catalytic converter installed. Could a new exhaust system have a brief smell on acceleration, like, burning off some sort of film or something (that is, breaking in the cat)?

4

Metallic smell? Like burning brakes? Now I’m thinking something IS wrong with the clutch. I’d consider having it checked out.

5

I’ll do that; that’s what I’m worried about too, since it’s a new clutch as well. I haven’t had any hesitation on starting, and the clutch doesn’t seem to be slipping or coming out of gear. It doesn’t really answer the question about the stall, but its a start…

6

Does this car perchance have synthetic motor oil in it? Synthetic oil burning on the exhaust can smell metallic or like burning plastic.

To check for blocked exhaust, put your hand by the opening of the exhaust pipe when the car is idling. You should be able to feel the individual bursts of exhaust easily at the tail pipe. If it is just a smooth blow, the exhaust is blocked. Blocked exhaust generally manifests itself under load rather than at idle.

7

When sitting idling at the light, is the trans in neutral? Is the trans in gear and you are holding down the clutch petal? I don’t the clutch is adjusted properly and it is not completely disengaging. That would account for the feeling of lost power (drag), then as the clutch heats up it fades out (like old drum brakes) and it seems to have more power. The smell is likely coming from the clutch and you get it circulating in the cabin when you start moving.

8

A blocked exhaust or catalytic converter will not generally show up at idle unless it’s very severely restricted. Then you will have severe drivability problems as well, like bucking, jerking, and practically no acceleration at takeoff. It will worsen at higher RPMs. I’m kind of with UncleTurbo in thinking the clutch may be dragging when you have the pedal all the way in. I think the shuddering/stumble may be a different problem. It’s a almost 20 year-old car. Check for cracked vacuum lines, a failing sensor, etc. Is the check engine light on? Has the car had a tune up with new plugs, wires, etc?

9

Wow! Some great responses :smiley:

When sitting at the light, I have the transmission in neutral. Force of habit - this is the fifth car I’ve owned with a stick, so, I’m pretty well used to driving a manual. Now, yesterday, I put in a new clutch cable, thinking that it was the old self-adjusting cable that was the problem (something the 1992-1997 Jetta’s were known for), and, on first drive around town, stopping at stop signs, there was no smell at all. It was only when I stopped for an extended period of time at the stop light that I noticed the smell on launch.

I don’t have any CEL lights, and, in fact, the shudder/stumble happens so fast when it does stall that the car just dies. Let me go through the receipts and see what all had been done to it before I got it. At the very least, I know it has an entirely new exhaust system and a new clutch. If the clutch is dragging, and I have a manual adjust cable, I assume that means I have the cable too tight and need to loosen it?

10

This is strange…if you are in neutral with the clutch disengaged…then you arent using the clutch in any way…if you were in gear with the clutch depressed THEN …we wonder if the clutch was able to fully disengage or not…but thats not in the equation any longer with what you are doing.

I was going to initially say the same exact thing as Busted said…but now, I dunno

It may be possible that the car is running out of fuel and then regaining that fuel flow…when you near run out of fuel it can generate some nasty smells before it dies…OR its got a misfire condition that creeps up and goes away…this may get much more pronounced in time…if it DOES it certainly will NOT be the clutch as a suspect…it may be an ignition component like a coil or distributor cap n rotor…

.This is a strange one on me…Wish I could sit in the car with you…IF that were possible, I’d be able to tell you A LOT more as there may be other clues you are overlooking bec you are so focused on the clutch and trying to blame it…or at least its in the forefront of your mind, you know? Its kinda hard to diag this way…I will have to think about this one a bit more…lol

Blackbird

11

Well, here is some more fuel for thought:

Went out today and found a disconnected vacuum hose, a vacuum link in another hose, and found a conduit that was running from the engine to the intake box that had also been disconnected. I reconnected hoses and fixed leaks and, now, having driven the car around town for an hour or so, no stalls, no loss of power, the car didnt even stumble.

So, maybe that’s fixed, because, even when warmed up, the RPMs never dipped below 750.

BUT, the smell still persists.

Now, I noticed that the smell occurs when driving around, the following:

  1. On occasion (I’d say 1 in 4 or 1 in 5), when attempting to accelerate from a dead stop and putting the car in first gear, it would hesitate until I disengaged and re-engaged the clutch, and the car would accelerate fine, but that smell would occur.
  2. On occasion (Out of the 5 times I put in Reverse, it happened three times), there was definitely a rumble or grind when putting the car into reverse.

So, I’m getting a sneaking feeling that something is wrong with the clutch (not the cable).