Repairing your own car

[kaffeemitmilch 1,294]

Hey, thanks. I would love to have had this before I bought the wheels and tires because I actually wanted the cheaper 13s. The FZS has the 14s on there, hence my girlfriend's insistence that I get those. Not too much more expensive, though. All in all, this discussion has been very helpful. Y'all ain't too bad.

[kaffeemitmilch 1,294]

Having car problems. Hope someone here has an idea.

 

A few months ago (I wasn't around, so this is all over the phone), the car had problems starting. It took a while, and then sputtered, then revs went high, up to 4k, all without going into gear yet. If the revs were low, and it was put into gear, unless the revs were kept high, it would die. Revs stayed high a while, even when driving. The car would sometimes also sputter when driving, as if there was fuel starvation. Then, they would go back to normal mostly, but sometimes just shoot up. At the light, they came up sometimes too. Apparently, when the weather cooled, this didn't happen. It also didn't happen sometimes when the car had rested for a while.

 

Once, she took it to the mechanic. They checked it out, cleaned the throttle, "fixed it" (I don't know what she meant by this) temporarily, and suggested getting a new or used one online and going back to them. They also said it could be the ECU.

 

She bought the wrong throttle on eBay! I specifically asked her to look at the engine code, but she couldn't find it BTW, I only see WWO. Is that a code for a Lupo?

 

Anyway, it ran fine MOSTLY for the past month, but then suddenly a couple of days ago (warmer weather?) it started again. I looked under the hood, opened the airbox to get to the throttle, and it was full of oil. Not flooded, but it has a substantial amount of it, also around the throttle opening. The airbox sits on top of the throttle, so the opening is flat, and goes down into intake. I'm used to seeing them sideways, with the valve plate sitting vertically, so this is different for me. The was also oil in a little tube running into the box from an exhaust recircling tube. I'm wondering if there's a sensor in there that's clogged. Probably, eh? Might have to get a new sensor.

 

I couldn't really find anything wrong with the throttle. It's not catching at any point, and with the engine started, and slightly revving, it doesn't stay open while the revs are high. So, a vacuum leak somewhere? I sprayed starter fluid around a few hoses, but nothing jumped. I might have missed a hose or two, though. What about other sensors? I take it the one coming back into the airbox is an exhaust sensor. Something else I haven't seen in the States is a pipe coming directly out of the exhaust manifold and into my air intake hose, with a sort of valve that never fully closes, controlled by a copper piece (might be broke, I'm not sure). What's that?

 

Anyway, the MPG is currently at about 30, which is a bit low for a Lupo with only 150,000 km on it, I think. I hope y'all can give me a few pointers here. Cheers.

[2B_orNot2B 8,451]

Some of the possible causes (and solutions) are;

 

• Intake manifold-to-head leaks (replace gasket)
• Blown head gasket - check for evidence of coolant/oil mixing - although it may not be blowing between them. (replace gasket)
• Worn timing gears,chain or sprocket (replace)
• Worn camshaft lobes (replace camshaft)
• Overheating engine (check cooling and heating system for leaks, air-locking, function of temperature sender unit, thermostat, radiator cap and fan switch)*
• Blocked crankcase vent valve (remove restriction or replace valve) My money's on this already btw.*
• Leaking EGR valve (repair leak and/or replace EGR valve) My money's on this already too btw.*
• Faulty fuel pump (replace pump)
• Vacuum leaks -These take time to locate. Refer to the workshop manual (I recommended up-thread) for the vacuum layout and, where you suspect a leak, apply a little bit of thickish washing-up detergent and watch for it being sucked in. (replace cracked or leaking tubes)

 

***"suddenly a couple of days ago (warmer weather?) it started again. (Hints at engine running too warm) I looked under the hood, opened the airbox to get to the throttle, and it was full of oil. Not flooded, but it has a substantial amount of it, also around the throttle opening. (Points at crankcase vent valve) The was also oil in a little tube running into the box from an exhaust recircling tube. I'm wondering if there's a sensor in there that's clogged.( Suggests EGR valve) Something else I haven't seen in the States is a pipe coming directly out of the exhaust manifold and into my air intake hose, with a sort of valve that never fully closes, controlled by a copper piece (might be broke, I'm not sure). What's that?" ( sounds like a Winter/Summer hose - in winter should be set to draw some warm exhaust gas in to the air intake - in warm weather that pipe should be turned to the front of the car. If it's in the wrong position or if the intake is 'breathing' insufficient fresh air that's also a possible cause of overheating.)

 

Have you examined the condition of the spark plugs yet? I think you may find they've been getting fouled up with oil. Be sure to note which cylinder you take which plug from as they can provide many clues (valve oil seals leaking - head gasket blowing -ignition or valve timing faults, etc.). Note the exact condition of each one (colour, spark gap, etc.) then clean them, reset the gaps and replace.

 

The workshop manual lists the specs for the temp sensors, thermostat, radiator cap and tells you how to test them too.

I'd start by eliminating the least expensive, and most obvious, causes first and (if you and your better half have been good) you'll hopefully soon get it sorted.

 

Unfortunately, it could be any one (or more) of a number of causes. Which is why the mechanic who "fixed it" could only have been sure to find and fix the fault/s if he'd been told he had an unlimited time and money budget. The ECU is a possibility, but that's also a make or break option - may work - may not. Many shops have a handful of used ECUs for the most popular cars their customers own. Look here if you need one or for any other used parts you might need.

 

HTH

 

2B

 

ETA: If some, or all, of your spark plugs do look oily, burnt or heavily carboned up then it'd probably be worthwhile having a compression test done. That may not prove the head gasket condition, but should tell you if there's any problem with the valves, camshaft, timing gear, piston rings, etc..

[kaffeemitmilch 1,294]

Thanks 2B. I forgot to mention a bit of smoke coming through the oil breather hose coming into the airbox. That sounds bad... I searched a bit for the oil issue, and I'll be looking for other vents that are clogged (how many should there be?). Just ordered a Haynes manual 4150 for a Polo. Should be right. Will check EGR, check for more vacuum leaks, and will do a thorough cleanup of the throttle. The oil doesn't look like it has coolant in it. Engine temp is completely fine too. Will also replace spark plugs and note their condition. I was going to get them, but I couldn't find a plug socket to take them out. About the compression, the car shouldn't run fine a lot of the time if there's an issue in the combustion chambers, should it?

 

This is a pain in the ass as we're driving between FFM and Giessen every day looking for a bloody apartment! Perfect timing.

[2B_orNot2B 8,451]

The smoke coming through the crankcase vent does suggest you may well have a more serious issue. It could be that sticking or worn piston rings are allowing a mixture of exhaust gas and oil mist to be force fed up into the airbox - especially if the air filter is oiled up too.

 

You'd be surprised how long a car can run relatively well with poor compression on one or two cylinders. The problem very often isn't evident to the driver if it's a gradual diminishing of performance over a longish time frame. In cold weather oil is thicker when starting and that can mask poor compression issues. Paradoxically when an engine warms up, although the oil thins out, the metal parts expand which can also hide fading compression. A compression test will tell more than virtually any other test about the condition of older or higher mileage motors and, for a mechanic, the results can be a very good indicator of probable cause and potential cost.

 

If you've tried all the simpler solutions and still not got any improvement then the quick'n'dirty alternative to an engine overhaul or swap is to go shopping (where I told you in Giessen) for an engine-cleaner-in-a-can (or 3). Look for products with words like Miracle, Magic, Wonder in their name and, as the ones with any repute will be expensive, buy some cheap oil and a filter. Ask the guys you buy it from where you can go to flush the motor out (must be a shop with an oil-separation system) and do it thoroughly. Sometimes you might have to do it twice over a week or two, but if the rings are gummed up or the valves are sticking freeing them up can sometimes add tens of thousands of miles to the motor's useful life. Be sure all your levels are always correct (not too much!) and avoid hammering down the A5.

 

2B

 

ETA: Heavy carbon deposits on plugs can be a sign of an over rich fuel mixture or oil (from leaky valve seals or piston ring blow-by) being baked on. These carbon deposits glow red when hot which can cause pre-ignition. Engines affected can be running too hot without actually overheating to the extent that you'd have problems with the cooling system. Engine loping or hunting, which is what you described, can be caused by an accumulation of many minor faults which is why any long distance diagnosis can be no more than guesswork.

[kaffeemitmilch 1,294]

Damn.

 

Ok, well to start off, I got some fuel injector cleaner and threw that into the gas tank. I'm headed to FFM this afternoon so I'm hoping it'll do some cleaning. Compression test next, I guess. I'll also go to Woebst tomorrow. It's close by.

 

Thanks.

[2B_orNot2B 8,451]

After your trip to FFM take a paper wipe of the exhaust tailpipe to see if there's any sign of oil passing through the system. If so (that's also another symptom of blow-by) then a fouled lambda sonde may be giving a false reading to the ECU which in turn could be affecting the idle speed. If the oiling is serious it can cause plugging of the catalytic convertor too. Removing and cleaning the lambda sonde is unlikely to be easy as they tend to be virtually heat welded fast. You should have a mechanic do it as they are both equipped for and accustomed to the job. It's better for you if they break it in the attempt than if you do it yourself.

 

Start keeping a very accurate record of your oil consumption by kilometer and do the same wrt your fuel usage. Don't go by the fuel gauge as that is not a reliable method. Fill the tank as near to the brim as is safe and, after a round trip or two, refill it to the same level taking note of the exact kilometers driven. Whether you do all the work yourself or involve a mechanic such accurate data is very useful both as a diagnostic aid and to verify, or otherwise, any improvements achieved later.

 

2B

[kaffeemitmilch 1,294]

I keep record of the mileage exactly like that. BUT, here's a surprise. The car was BRILLIANT today after the fuel system cleaner. NOT A HICCUP! And, at high RPMs on the autobahn, it sounded beautiful. It started immediately, and the idle didn't budge from a calm 750-ish. What do you think about that? Could this just be a temporary reprieve from the hell that lies ahead? Or, did I solve it by de-sludging something?

[2B_orNot2B 8,451]

:D <- that's what I think about that!

 

If your fuel injection system was gummed up then the injector cleaner might have improved matters. Dirty injectors could have the equivalent effect as a weak, or unreliably operating, fuel pump. You may indeed have been fortunate and cleared some intermittent effect.

 

OTOH, as a mechanic, I have often known marvelous improvements in performance to occur when, after months of neglecting a daily driver (the cobbler's shoes syndrome), I'd finally succumbed to temptation and taken the car through the car wash!

 

I'll keep my fingers crossed for you, but would still suggest you do a little more on the diagnostic front before cancelling any resurrection of the maintenance schedule.

 

2B

[kaffeemitmilch 1,294]

I had no idea the cleaner was really that good, and that it did that much cleaning. I thought, for the most part, it was a scam, but that it cleaned a little bit at least. This is just miraculous. I will definitely keep an eye on the car, though. I'm hoping sticky valves were forcing stuff past the piston rings, and that's why I was seeing smoke coming out of the engine breather tube. Still not sure about the oil, though apparently the oil was changed about 3 months ago, and they might have overfilled it? Do you recommend any other additives, be it for the gas tank, the engine oil, or anything else that I can get from Woebst?

[kaffeemitmilch 1,294]

Well, car ran great for a couple of weeks, and then a few days ago started the same stuff again. Today, I cleaned the throttle body and the entrance of the intake manifold, and it ran great. SO, I feel this is an issue of the oil separator and breather being clogged, causing oil to be thrown into the air box and the throttle, intake, etc, and then onto the valves. The fuel injector cleaner must've cleared that all for a bit, but now it needs it again. Is this a fair chain of events?

 

It would be, if not for the fact that when the engine is started after sitting for a while (cold), there never were problems. Some suggest the problem could be the coolant temperature sensor being faulty instead. It might be telling the ECU that the engine is cold all the time, and when it's actually warm, too much fuel is being added, and the rich mixture is causing problems (hence the high revs at warm startup). However, the coolant temperature gauge seems to be running fine. Are the two not connected?

 

The oil being shoved up could also be because of the sputtering once in a while, could it not? In this case, the temperature sensor might something I should change just to eliminate it as a problem.

 

BTW, how do I keep track of oil usage?

 

Also, if this is indeed all caused by worn piston rings and a shit engine, can the dealer be liable? It hasn't been a year since we bought the thing.

[Allershausen 6,414]

 

BTW, how do I keep track of oil usage?

 

You use the dip stick to check the oil level and when it gets low you pour some oil in. Then you check it again on a regular basis and see if the level goes down, and if it does you put some more oil in. This can't be what you mean, because if you don't know how to do this you should be taking your car to a garage to have it looked at and not trying to fix it yourself.

[sosarx 1,661]

Too much oil could also lead to this, and as Allershausen said, if you don't know how to check this truly very basic thing- better see a mechanic

 

Another thing to check : the oxigen sensor (Lambdasonde) could give wrong information and by this lead to various problems.

[kaffeemitmilch 1,294]

Haha. I know how to check the level that way, but that doesn't seem very precise. I thought there was a more accurate way. you were referring to.

 

Yah, the O2 sensor is also on my list. When I get time to give the car the once over, and then take it to the garage for the stuff I can't do.

 

Will ask my partner if all this started after the last oil change she did in November or something. If so, then that could be the culprit.

[bal00 1,917]

There's a number of potential issues with this engine:

-Dirty throttle body. After cleaning it, the ecu should be reset/recalibrated.

-EGR valve defective

-crank sensor defective

-ignition coil defective

-defective intake air or coolant temp sensor

-cracked intake manifold

 

A cracked manifold would be most noticeable in high vacuum situations, so that wouldn't be my first guess. The throttle body has been cleaned already, so that's probably not it either. Some oil residue is normal, the throttle body just isn't supposed to have a layer of grime on it. Since the engine doesn't have a MAF, oil in the intake shouldn't cause any major problems fo the engine either. That leaves the crank sensor, EGR valve, ignition coil and temp sensors.

 

The temp sensors you can test with the code reader once you have it, the ignition coil would most likely produce misfire fault codes, the crank sensor you can't really test and it probably wouldn't throw any codes, but that can be quite troublesome to replace, so I'd test the EGR valve first. Pull the vacuum hose going to EGR valve and plug it with a screw or something similar, then check if it runs any better.

 

The fact that it happens when it's warm outside may point to the crank sensor though, because it's a Hall effect sensor and one that is borderline would most likely cut out when it's warm.

[bal00 1,917]

By the way, I wouldn't read too much into the blowby/smoke from the crankcase ventilation. Some blowby is normal. If you want, you can twist open the oil cap (with the engine warm and at idle) so it just sits on the opening. If it does a little dance, that's alright. If it ends up getting blown into the air, that would be excessive.

[kaffeemitmilch 1,294]

Blowby is fine. Recently replaced the coolant temperature sensor. So far, the car hasn't been acting up, so hurray? Do need to take care of some maintenance, though. Acceleration at low speeds and gears is patchy.

[AKJeeper 30]

When's the last time the car had a fresh set of spark plugs in it? I just tuned up a 1999 VW Jetta 2.0L, it ran like crap under load. A new set of spark plugs, spark plug wires, distributor cap & rotor, and some new vacuum hoses (to replace the perished ones) made the car feel like new again. :)

[kaffeemitmilch 1,294]

Spark plugs are exactly what I'm going to replace. Maybe wires too, but can't afford those for now. No rotor; just a coil. Not changing that unless the spark plugs don't help.

[Blue Cow 255]

whats it run like if you take the air filter off?