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Volkswagen Jetta Engine Questions

304 messages,  Last post on Jun 11, 2013 at 2:53 PM

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Messages Page 26 of 32

#242 of 304 2001 VW Jetta Engine problem - one Cylinder is mis fire!! by ohbaobei

May 20, 2009 (7:51 am)

folks, i have a 2001 jetta and the engine light is on!!
 
Checked and was told 5th cylinder is mis-fired. meaning normal cylinders should have 190lbs pressure, but mine 5th only has 70 lbs pressure. was told as a huge problem and it will cost a lot to fix it!!
 
what should i do then?! the light was on actually one month a ago and it can drive Ok even long travel~~~
 
Anyone has any idea?

#243 of 304 Re: 2001 VW Jetta Engine problem - one Cylinder is mis fire!! [ohbaobei] by bpeebles

May 21, 2009 (7:07 pm)

Replying to: ohbaobei (May 20, 2009 7:51 am)
I am assuming you have the VR6 engine (The only 2001 engine with a cylinder #5) I also assume you are saying that a "compression test" was done and cylinder #5 measured lower than the other cylinders. It is also correct that this usually means you have SERIOUS engine damage.
 
My suggestion is that you get a "second opionion". Ask somone else to perform both a "compression test" and a "leakdown test".
 
If the same results come back... I would personally consider NOT fixing the engine.... continue to change the oil and drive it.
 
BTW: I am not convinced that low compression in one cylinder would make the CEL (Check Engine Light) come on. That may be another issue altogether.

#244 of 304 Re: 2001 VW Jetta Engine problem - one Cylinder is mis fire!! [bpeebles] by ohbaobei

May 21, 2009 (8:22 pm)

Replying to: bpeebles (May 21, 2009 7:07 pm)
bpeebles, thanks for the reply! our jetta is VR6, you are right!
 
the check result is : cylinder #5 has only 90 lbs. but the normal cylinders have 170 lbs. I think there is a big difference! So you think if I go to another shop and have the engine checked and get the same test results, we can still drive this car for a while? meaning the car is still drivable?will not damage the whole engine eventually?
 
what kind of results that might be got from a leak down test?

#245 of 304 Re: 2001 VW Jetta Engine problem - one Cylinder is mis fire!! [ohbaobei] by bpeebles

May 22, 2009 (4:45 pm)

Replying to: ohbaobei (May 21, 2009 8:22 pm)
A good engine mechanic should be able to "read" the results of a "compression test" and "leakdown test" to determine what has failed in your engine. There may be other tests they can do to help isolate the failure.
 
Based on that diagnosis, continued driving may, or may not cause further damage.
 
Low compression could be caused by several factors including
*) blown head gasket
*) carbon deposits built up on valves
*) Broken valves
*) broken piston ring
*) heavilly scored cylinder wall
*)..others
 
Virtually all of the "fixes" for these things requires tearing engine apart which is labor-intensive and often costly.
 
To answer your question about a "leakdown test". A "leakdown test" is essentually using a hand-pump to pressureize the cooling-system to normal operating pressure (using a pressure-meter)... then time how long the pressure bleeds off by itself. If the pressure bleeds off too quickly, this often means that the head-gasket is leaking coolant INTERNALLY into one or more of the cylinders. This is somtimes caused by a warped head.
 
If head gasket is internally leaking coolant extensivly.... engine may be difficult to start when cold and blow steam out exhaust when 1st started.
 
BTW: A warped head is often the result of OVERHEATING the engine at some point.... but there are other reasons this may happen too.

#246 of 304 Re: 2001 VW Jetta Engine problem - one Cylinder is mis fire!! [bpeebles] by ohbaobei

May 31, 2009 (9:53 am)

Replying to: bpeebles (May 22, 2009 4:45 pm)
one weird thing!!!! I did not do anything on my engine yet!!! Guess what, yesterday, the engine light is off.... (not reset by myself)
 
the only thing i did is before i drop my car to the shop and have it checked, i changed all the spark plug and add fuel injector cleaner. but the light was still on. so i went to check and was told that one of the cylinder the pressure is only 70lbs but should be 190 lbs. I was planning to have the car check again so i still drive it to work and yesterday the engine light is off.. I have no idea what happened.
 
is it sth good? or very weird?
 
thanks guys!

#247 of 304 Re: 2001 VW Jetta Engine problem - one Cylinder is mis fire!! [ohbaobei] by bpeebles

May 31, 2009 (2:59 pm)

Replying to: ohbaobei (May 31, 2009 9:53 am)
That is not "weird" at all... I told you several appends ago that I doubt that "low compression" by itself would cause a CEL (Check Engine Light)
 
The new sparkplugs and injector-cleaner may likely have have resolved the problem. (or made it go away for awhile)
 
A CEL will go out by itself if the detected fault is not sensed within 'x' number of "trips"
 
"x" is oftnen defined as "50"... but may vary based on the type of failure detected.
 
A "trip" is defined as starting engine cold and driving until it has warmed up.
 
Perhaps you hit the magic "50 trips" and the CEL went out.
 
(Official documentation for all of this is available if you want details)

#248 of 304 Re: 2001 VW Jetta Engine problem - one Cylinder is mis fire!! [bpeebles] by ohbaobei

Jun 01, 2009 (7:03 pm)

Replying to: bpeebles (May 31, 2009 2:59 pm)
I have been totally driven crazy by this 01 Jetta. Today the engine light is on again. but the car run smooth~~~ I have no idea what is going on with this car!!

#249 of 304 Re: 2001 VW Jetta Engine problem - one Cylinder is mis fire!! [ohbaobei] by bpeebles

Jun 03, 2009 (6:08 pm)

Replying to: ohbaobei (Jun 01, 2009 7:03 pm)
Read the codes.
 
Many autoparts stores (Autozone...etc) will "read the codes" for free.
 
Once you know wich "code" threw the CEL.... let us know what it is.

#250 of 304 Re: 2001 VW Jetta Engine problem - one Cylinder is mis fire!! [bpeebles] by ohbaobei

Jun 04, 2009 (10:25 am)

Replying to: bpeebles (Jun 03, 2009 6:08 pm)
the light was off yesterday and remains off today. Well, i am speechless now.. want to get rid of it so badly!

#251 of 304 2000 VW jetta exhaust problem by stems

Jun 06, 2009 (6:33 pm)

well i just recently bought this jetta from this dealership. within 2 days of getting the car the check engine lite came on and the car started throwing white smoke out of the exhuast. any ideas what it might be i took it to the dealer and they told me it was a sensor gone bad and for the smoke that started happening after they changed out the water pump.

Messages Page 26 of 32

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