V8 acceleration surges/pulses
03-23-2009, 07:28 AM
#1
Audiworld Junior Member
Thread Starter
Join Date: Oct 2006
Posts: 27
Likes: 0
Received 0 Likes
on
0 Posts
V8 acceleration surges/pulses
I noticed when I accelerate the revs don't go up smoothly. I replace a torn and old breather/vacuum hoses. That didn't help much. I replaced both fuel and air filters. The spark plugs look okay. Could it be the fuel pump? WOT seems fine.
graph of the revs that I am talking about. Don't pay attention to the 0s. The _ and / symbolize the revs
constant medium throttle input
4000rpm |000000 0 0 0 0 0 _/
3800rpm |00000 0 0 0 0 _/
3600rpm |0000 0 0 0 _/
3400rpm |000 0 0 _/
3200rpm |00 0 _/
3000rpm |0 _/
^^ It should be straight line ^^
help please
graph of the revs that I am talking about. Don't pay attention to the 0s. The _ and / symbolize the revs
constant medium throttle input
4000rpm |000000 0 0 0 0 0 _/
3800rpm |00000 0 0 0 0 _/
3600rpm |0000 0 0 0 _/
3400rpm |000 0 0 _/
3200rpm |00 0 _/
3000rpm |0 _/
^^ It should be straight line ^^
help please
04-16-2009, 07:38 AM
#2
I noticed when I accelerate the revs don't go up smoothly. I replace a torn and old breather/vacuum hoses. That didn't help much. I replaced both fuel and air filters. The spark plugs look okay. Could it be the fuel pump? WOT seems fine.
graph of the revs that I am talking about. Don't pay attention to the 0s. The _ and / symbolize the revs
constant medium throttle input
4000rpm |000000 0 0 0 0 0 _/
3800rpm |00000 0 0 0 0 _/
3600rpm |0000 0 0 0 _/
3400rpm |000 0 0 _/
3200rpm |00 0 _/
3000rpm |0 _/
^^ It should be straight line ^^
help please
graph of the revs that I am talking about. Don't pay attention to the 0s. The _ and / symbolize the revs
constant medium throttle input
4000rpm |000000 0 0 0 0 0 _/
3800rpm |00000 0 0 0 0 _/
3600rpm |0000 0 0 0 _/
3400rpm |000 0 0 _/
3200rpm |00 0 _/
3000rpm |0 _/
^^ It should be straight line ^^
help please
04-16-2009, 08:00 AM
#3
04-16-2009, 08:44 AM
#4
AudiWorld Senior Member
Join Date: Sep 2006
Posts: 1,140
Likes: 0
Received 0 Likes
on
0 Posts
First things first.
Make sure that the car has min 1/2 tank of fuel, AND you have disconneted the battery for a mininum of 10 min. This will reset all codes and adaptions stored in the ECU back to empty. Go for a ride - say 15 min, get the car up to operating temperature then start that 15 min clock.
Now check to see that there are no codes stored in the ECU (VAG-COM or blinked out). If codes are present what are they.
No codes? & Problem still exists.. You have ruled out most of the electronics from the VAG-COM tests. Look for vacuum leaks in the upper/lower sections of the intake, or intake to head gaskets. Look for (now that they are hot) bad spark plug wires (degrade with heat) measure with a OHm Meter. Has the airflow sensor been removed, maybe leaks under it?
Problem still exists, dump a gallon (roughly speaking) of Tolunine (spelling) into the tank, maybe water at the tank.
Make sure that the car has min 1/2 tank of fuel, AND you have disconneted the battery for a mininum of 10 min. This will reset all codes and adaptions stored in the ECU back to empty. Go for a ride - say 15 min, get the car up to operating temperature then start that 15 min clock.
Now check to see that there are no codes stored in the ECU (VAG-COM or blinked out). If codes are present what are they.
No codes? & Problem still exists.. You have ruled out most of the electronics from the VAG-COM tests. Look for vacuum leaks in the upper/lower sections of the intake, or intake to head gaskets. Look for (now that they are hot) bad spark plug wires (degrade with heat) measure with a OHm Meter. Has the airflow sensor been removed, maybe leaks under it?
Problem still exists, dump a gallon (roughly speaking) of Tolunine (spelling) into the tank, maybe water at the tank.
04-19-2009, 06:07 PM
#5
First things first.
Make sure that the car has min 1/2 tank of fuel, AND you have disconneted the battery for a mininum of 10 min. This will reset all codes and adaptions stored in the ECU back to empty. Go for a ride - say 15 min, get the car up to operating temperature then start that 15 min clock.
Now check to see that there are no codes stored in the ECU (VAG-COM or blinked out). If codes are present what are they.
No codes? & Problem still exists.. You have ruled out most of the electronics from the VAG-COM tests. Look for vacuum leaks in the upper/lower sections of the intake, or intake to head gaskets. Look for (now that they are hot) bad spark plug wires (degrade with heat) measure with a OHm Meter. Has the airflow sensor been removed, maybe leaks under it?
Problem still exists, dump a gallon (roughly speaking) of Tolunine (spelling) into the tank, maybe water at the tank.
Make sure that the car has min 1/2 tank of fuel, AND you have disconneted the battery for a mininum of 10 min. This will reset all codes and adaptions stored in the ECU back to empty. Go for a ride - say 15 min, get the car up to operating temperature then start that 15 min clock.
Now check to see that there are no codes stored in the ECU (VAG-COM or blinked out). If codes are present what are they.
No codes? & Problem still exists.. You have ruled out most of the electronics from the VAG-COM tests. Look for vacuum leaks in the upper/lower sections of the intake, or intake to head gaskets. Look for (now that they are hot) bad spark plug wires (degrade with heat) measure with a OHm Meter. Has the airflow sensor been removed, maybe leaks under it?
Problem still exists, dump a gallon (roughly speaking) of Tolunine (spelling) into the tank, maybe water at the tank.
Trending Topics
Thread
Thread Starter
Forum
Replies
Last Post
713Audi
A4 (B6 Platform) Discussion
4
11-09-2006 08:59 PM
Nvncibl
Audi 90 / 80 / Coupe quattro / Cabriolet
4
06-07-2005 02:15 PM
henrylford
Audi 90 / 80 / Coupe quattro / Cabriolet
5
01-02-2004 11:51 AM
