 engine sputtering?, 4k rpm why? |
|
|
|
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG.
This site is not affiliated with Porsche in any way. Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners. |
|
|
  |
| GreatPumpkin |
 May 30 2010, 11:54 AM
Post
#1
|
|
Member  Group: Members Posts: 122 Joined: 28-October 07 From: Centerville OHIO Member No.: 8,272 Region Association: None  |
ok so starting from a stopped position when in first gear, i start to go and i reach about 4000 rpm and the engine sputters and doesnt pull anymore. shortly after about a second the engine starts to pull again.? why is this ? distributer? coil? i dont know. spark plugs were replaced along with the wires not to long ago,maybe a month ago. answers please...... (IMG:style_emoticons/default/headbang.gif)
|
   |
 
|
| GreatPumpkin |
May 30 2010, 11:56 AM
Post
#2
|
|
Member Group: Members Posts: 122 Joined: 28-October 07 From: Centerville OHIO Member No.: 8,272 Region Association: None |
also it doesnt matter if its at full throttle or not even at about half when it reache 4k it sputters for a breif period of time.
|
|
|
|
| type2man |
May 30 2010, 12:36 PM
Post
#3
|
|
Member Group: Members Posts: 355 Joined: 3-March 09 From: Miami, Fl Member No.: 10,127 Region Association: South East States |
QUOTE(GreatPumpkin @ May 30 2010, 01:56 PM)  also it doesnt matter if its at full throttle or not even at about half when it reache 4k it sputters for a breif period of time. Is it carbureted or fuel injected? |
|
|
|
| ericread |
May 30 2010, 12:41 PM
Post
#4
|
|
The Viper Blue 914 Group: Members Posts: 2,177 Joined: 7-December 07 From: Irvine, CA (The OC) Member No.: 8,432 Region Association: Southern California |
There's a lot to think about here. First, we have to determine where the issue is; Fuel, spark or mechanical? Since you have not said anything about an unusual sound, let's eliminate the mechanical issue.
Fuel; At 4K RPM, you're starting to use some fuel. Could it be fuel starvation? If you are accellerating to 4k RPM pretty quickly, the fuel pressure could go low for a bit, then catch up in the few seconds after initially hitting 4k. You're probably not accellerating above 4k the same way you were getting to 4k. So check your feul pressure system. Another issue could be spark. I have experienced a dist cap that was cracked, but not enough that you could visibly see. However, at speed, the cap deformed a bit and caused a significant misfire. The bad cap gave me problems at specific rpm. Preliminarily, still think this may be a fuel starvation issue. Fuel pump, fuel filter, pinched fuel line, clogged mesh filter in tank, or something like this. If you get to 3500 rpm and slowly, very slowly raise the engine speed to 4000rpm, do you still experience this problem? Just a thought or two... Eric Read |
|
|
|
| Maltese Falcon |
May 30 2010, 02:18 PM
Post
#5
|
|
914 Guru Group: Members Posts: 5,049 Joined: 14-September 04 From: Mulholland SoCal Member No.: 2,755 Region Association: None  |
If it's a d-jet efi, check the condition of your throttle- position unit on the throttle body. You can snap off the plastic dust cover and clean out most of the dust in there. Use a M-A-F sensor aerosol spray on the rest of it and let dry. The problem can be the wear/tear on the rheostat portion of the T-P ; it basically wears out in the most driven area (3K to 4K rpm). My 2.0 had a sputter at 3,600, and I changed it out for a spare...problem solved. I think that I saw someone on World selling repro printed circuits that will allow you to rebuild yours. Might solve your problemo.
Marty |
|
|
|
| GreatPumpkin |
May 30 2010, 09:36 PM
Post
#6
|
|
Member Group: Members Posts: 122 Joined: 28-October 07 From: Centerville OHIO Member No.: 8,272 Region Association: None |
its fuel injected. no matter how slow you accelerate when you get to about 4000 rpm the engine is unresponsive for about a second then keeps accelerating
|
|
|
|
| GreatPumpkin |
May 30 2010, 09:36 PM
Post
#7
|
|
Member Group: Members Posts: 122 Joined: 28-October 07 From: Centerville OHIO Member No.: 8,272 Region Association: None |
its fuel injected. no matter how slow you accelerate when you get to about 4000 rpm the engine is unresponsive for about a second then keeps accelerating
|
|
|
|
| detoxcowboy |
May 30 2010, 10:03 PM
Post
#8
|
|
Senior Member Group: Members Posts: 1,294 Joined: 30-January 08 Member No.: 8,642 Region Association: Africa |
TPS, Fuel Pressure, but I had simular power vacumn at 3500-4000 experience with a mal-adjusted MPS... ECU gone haywire??
Does it sputer at 4000rpm underload only or will it do the same sitting in the driveway in nuetral..?? That would be a tell.. The TPS does not care about vaccum.. Mps issue: part load.. Failed aneroid cell: Causes the car to run rich at idle, with poor part-load response. Maladjustment: Many owners and mechanics have tried to adjust the sensor by removing the epoxy-covered "plug" and turning the adjustment screw inside - this often results in unpredictable behavior |
|
|
|
| underthetire |
May 30 2010, 10:51 PM
Post
#9
|
|
914 Guru Group: Members Posts: 5,062 Joined: 7-October 08 From: Brentwood Member No.: 9,623 Region Association: Northern California |
Advance sticking in the dizzy. Put some light machine oil in the felt under the rotor.
|
|
|
|
|
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:
|
Lo-Fi Version | Time is now: 9th May 2025 - 04:31 AM |
Invision Power Board
v9.1.4 © 2025 IPS, Inc.