Car Forums  

Go Back   Car Forums > Technical Discussions > Repairs & Maintenance
FAQ Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
Old 07-15-2003, 08:23 PM   #1
vwfreak
 
Posts: n/a
91 Jetta Rough start

Let me start by saying I am fairly novice at auto repair and I won't pretend to know more than I do.

With that out of the way here's my issue I have a 1991 VW Jetta, 1.8 L automatic with 125k miles. All the recommended maintenance is completed at the recommended intervals. For the past few days, when I start my car (after sitting for more than four hours), the engine revs itself four or five times usually from idle to 1500-2000 RPM then smooths out. If the car hasn't been sitting long, this doesn't happen.
Being a novice, I checked the rotor and distributor cap. I noticed some build-up so I changed them (my level of know-how ) ) even though they only have under 10k on them. No difference was made. I am wondering whether changing the plugs and the cables will do anything or I'm barking up the wrong tree.
Please advise other diagnostics I might run. Thanks!
  Reply With Quote
Old 07-16-2003, 03:54 AM   #2
vwhobo
CF's Anal Orifice
 
vwhobo's Avatar
 
Join Date: Feb 2003
Location: Redneck Hell
Posts: 8,630
Re: 91 Jetta Rough start

Quote:
Originally Posted by vwfreak
Let me start by saying I am fairly novice at auto repair and I won't pretend to know more than I do.

With that out of the way here's my issue: I have a 1991 VW Jetta, 1.8 L automatic with 125k miles. All the recommended maintenance is completed at the recommended intervals. For the past few days, when I start my car (after sitting for more than four hours), the engine revs itself four or five times usually from idle to 1500-2000 RPM then smooths out. If the car hasn't been sitting long, this doesn't happen.
Being a novice, I checked the rotor and distributor cap. I noticed some build-up so I changed them (my level of know-how ) even though they only have under 10k on them. No difference was made. I am wondering whether changing the plugs and the cables will do anything or I'm barking up the wrong tree.
Please advise other diagnostics I might run. Thanks!

Not likely an ignition problem. Sounds suspiciously like a vacuum leak that goes away. First try looking at the auxilary air regulator. It is essentially a device that gives you a controlled vacuum leak to raise idle speed during warm-up (very rough description). Also look at the intake duct between the airflow sensor and the throttle body. Check specifically for cracks on the underside. Any leak here can cause this to occur also.

If you don't have a manual get one now, it'll show you where the aux regulator is and how to test it. Robert Bentley is the best for VW's, they made the factory service manuals. At least pop for a Haynes manual. For your car you need #884, probably around $15 at your friendly local parts house.

Good luck and let me know what you find.
__________________
Thanks for the pic, jedimario.

"Everybody believes in something and everybody, by virtue of the fact that they believe in something, use that something to support their own existence."
Frank Vincent Zappa, 1940-1993

vwhobo is offline   Reply With Quote
Old 07-16-2003, 05:23 PM   #3
vwfreak
 
Posts: n/a
Thank you sir! I have the Haynes book - I'll check to see how it addresses your instructions. If it doesn't, I've heard great things about Bentley's. Maybe now's the time to upgrade. BTW, do you know if the Bentely's CD-ROM is preferred? It's all they have for my 2002 Eurovan. Take care.
  Reply With Quote
Old 07-16-2003, 08:15 PM   #4
vwhobo
CF's Anal Orifice
 
vwhobo's Avatar
 
Join Date: Feb 2003
Location: Redneck Hell
Posts: 8,630
Quote:
Originally Posted by vwfreak
Thank you sir! I have the Haynes book - I'll check to see how it addresses your instructions. If it doesn't, I've heard great things about Bentley's. Maybe now's the time to upgrade. BTW, do you know if the Bentely's CD-ROM is preferred? It's all they have for my 2002 Eurovan. Take care.

Paper, CD, the info is all the same. I personally prefer book in hand but this is the 21st century and have gotten used to going to the computer. I'd have to put up new buildings to hold the books I would need to take the place of my AllData. Progress marches on. 8)
__________________
Thanks for the pic, jedimario.

"Everybody believes in something and everybody, by virtue of the fact that they believe in something, use that something to support their own existence."
Frank Vincent Zappa, 1940-1993

vwhobo is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
1992 Mazda 929 engine won't start...not the battery myarbrough1 Repairs & Maintenance 8 02-11-2005 08:36 PM
94 VW Jetta idle rpm problem vwjetta Repairs & Maintenance 3 02-16-2004 06:15 AM



All times are GMT +1. The time now is 05:04 AM.

Powered by vBulletin Version 3.5.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright 2002 - 2011 Car Forums. All rights reserved.