Car jerky when cruising at constant speed
02-07-2009, 08:43 PM
#11
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Join Date: Jan 2006
Posts: 65
I'm assuming all this has been said but its most likely either a lean surge or boggin. Check your o2 sensor, fuel pressure, voltage at fuel pump, and connections to fuel pump, fpr then worst case an intermittent ground on an injector line.
02-13-2009, 09:53 PM
#12
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Thread Starter
Join Date: Nov 2005
Posts: 36
The problem has got worse so that it jerks back and forth even when accelerating now. It used to just be when at a constant rpm. I changed the oxygen sensor but the problem is still there. I'll check the fuel pump voltage, fuel pump connections and then look for a grounding problem tomorrow.
Any other suggestions?
p.s. also it bogs down when accelerating hard in the higher rpm range. It goes hard, bogs, goes hard again, bogs etc. but is intermittent. Sometimes it's terrible, others there is no problem at all.
Any other suggestions?
p.s. also it bogs down when accelerating hard in the higher rpm range. It goes hard, bogs, goes hard again, bogs etc. but is intermittent. Sometimes it's terrible, others there is no problem at all.
03-04-2009, 02:43 PM
#13
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Join Date: Jan 2009
Location: Phoenix
Posts: 2
I'm having this problem with my gsl-se though not as severe as you describe. I'm not sure if this will help, but read it over and see if any of it makes sense to you. Not much of it does to me w/o looking at a manual.
https://www.nopistons.com/forums/gsl-se-idl...p;hl=gsl-se+won
https://www.nopistons.com/forums/gsl-se-idl...p;hl=gsl-se+won
03-06-2009, 10:44 PM
#14
Senior Member
Join Date: Nov 2002
Posts: 3,108
Originally Posted by Slipknot Rob' post='916642' date='Feb 13 2009, 10:53 PM
The problem has got worse so that it jerks back and forth even when accelerating now. It used to just be when at a constant rpm. I changed the oxygen sensor but the problem is still there. I'll check the fuel pump voltage, fuel pump connections and then look for a grounding problem tomorrow.
Any other suggestions?
p.s. also it bogs down when accelerating hard in the higher rpm range. It goes hard, bogs, goes hard again, bogs etc. but is intermittent. Sometimes it's terrible, others there is no problem at all.
Any other suggestions?
p.s. also it bogs down when accelerating hard in the higher rpm range. It goes hard, bogs, goes hard again, bogs etc. but is intermittent. Sometimes it's terrible, others there is no problem at all.
Before you go chasing random stuff and getting into a hopeless loop, Have you confirmed that the TPS is good? Have you confirmed you do not have any bad mounts (trans, diff, and or engine?). A out of spec TPS combined with broken mounts will cause the car to resonate as you experience.
03-10-2009, 06:42 PM
#15
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Thread Starter
Join Date: Nov 2005
Posts: 36
I had a fuel flow test done. It came back reading at about 1/6th of where it should be so had a Walbro pump, relay and new plugs put in. The problem is still there but now I know that it is not a fuel issue.
The cat had collapsed inside so I gutted that but that made no difference to the problem.
The shop I brought it to believes that is most likely a wiring problem causing ignition to be intermittent. I'll have a look at the TPS and try and pin point the problem down to one rotor/coil and one sparkplug.
Any other suggestions? Is there any point seeing if there is any problems the ECU has picked up?
The cat had collapsed inside so I gutted that but that made no difference to the problem.
The shop I brought it to believes that is most likely a wiring problem causing ignition to be intermittent. I'll have a look at the TPS and try and pin point the problem down to one rotor/coil and one sparkplug.
Any other suggestions? Is there any point seeing if there is any problems the ECU has picked up?
03-10-2009, 11:34 PM
#17
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Join Date: Nov 2002
Posts: 3,108
Unplug the O2 sensor and drive around and see what happens. The car will just stay in open loop using more gasoline, but there would be no feedback loop that might cause the ECU to go rich and lean on wild swings.
Personally I think your TPS is bum, or your CAS is in rough shape.
Personally I think your TPS is bum, or your CAS is in rough shape.
03-11-2009, 03:27 AM
#18
Junior Member
Join Date: Mar 2009
Posts: 8
Originally Posted by j9fd3s' post='909586' date='Oct 9 2008, 11:43 AM
i think its more likely to be a bad o2 sensor, or tps
yeah its his tps... I just an FC last week and I got the and paied for the car with a bad tps and i still been driving it since for a week now with a bad tps.... so yeah its the tps that is casuing his jerky problem and such.
03-11-2009, 03:28 AM
#19
Junior Member
Join Date: Mar 2009
Posts: 8
Originally Posted by Slipknot Rob' post='909573' date='Oct 9 2008, 06:00 AM
Ok , first of all I've got a JDM S5 TII with a rebuilt motor about 5000kms ago. Everything is stock except for a street/extend port and pod filter.
I've replaced then spark plugs and ignition leads recently so highly doubt they're the problem.
Occasionally when I'm driving along at a constant speed the car starts to jerk violently. The only way to stop it is to accelerate or take my foot off the throttle.
It feels like I'm stabbing my foot on and off the throttle.
It seems as if there's an intermittent ignition problem in one of the rotors so it will fire, then not, then fire, then not etc. all within a moment. It had slowly been happening more often.
I've checked to see if the connections of the leads to the spark plugs and coils were loose.
Any help please guys. I'd rather fix this myself than take it to a shop to get fixed.
I've replaced then spark plugs and ignition leads recently so highly doubt they're the problem.
Occasionally when I'm driving along at a constant speed the car starts to jerk violently. The only way to stop it is to accelerate or take my foot off the throttle.
It feels like I'm stabbing my foot on and off the throttle.
It seems as if there's an intermittent ignition problem in one of the rotors so it will fire, then not, then fire, then not etc. all within a moment. It had slowly been happening more often.
I've checked to see if the connections of the leads to the spark plugs and coils were loose.
Any help please guys. I'd rather fix this myself than take it to a shop to get fixed.
03-28-2009, 02:16 AM
#20
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Thread Starter
Join Date: Nov 2005
Posts: 36
I can't find the green 3-pin connector near the air filter. My car is a Japanese Import. Is it possible that it isn't on the JDM models? I ran a code check but no blinking of the check engine light. I actually don't think I have a check engine light in the center console of warning lights. Could this be a JDM difference as well?
FC MidNight Blue, I don't understand what you mean about shifting jerky. My car's manual as it is turbo so the car shifts how I shift it.
FC MidNight Blue, I don't understand what you mean about shifting jerky. My car's manual as it is turbo so the car shifts how I shift it.