Erratic acceleration - 99 Accord i4
12-08-2014, 09:21 AM
#1
Honda-Tech Member
Thread Starter
Join Date: Sep 2002
Posts: 76
Likes: 0
Received 0 Likes
on
0 Posts
Erratic acceleration - 99 Accord i4
1999 Accord, 2.3L, LX., manual, 170k miles.
Problem:
The car has erratic acceleration. It would hiccup (lose and regain power). Behavior is the same with car at rest and revving up the engine. No Check Engine Light CEL.
History:
Car lost power on the freeway and was towed to the dealership. The distributor igniter, distributor cap, spark plug, and plug wires were replaced. A week later the car was returned for said “hiccup”. Although the car does not die, the power is erratic. Dealer suspected the fuel pump so it was replaced. After paying the stealer ship $1200 for all said repairs, the car is no better off.
A MAP sensor CEL code later appeared so the MAP sensor was replaced. And since the O2 sensors were old, they too were replaced.
This is where I am now:
Since the idle is erratic, I suspect it could be the Idle Control Valve so I decided to get a new ICV. My research indicates that after replacement of the ICV, the idle has to be reset. I checked for vacuum leak and turned off all accessories. Sprayed carburetor cleaner on throttle body and intake manifold area, and no leaks were found. Ran the engine to operating temperature and disconnected the ICV valve. Adjust the brass screw above the throttle body so the engine rev to 550 rpm. Once the ICV is disconnected, the idle is supposed to go down to the point is would stall. However the opposite happened, rpm went up not down; rpm fluctuates 1100 to 1300. Turning the screw either direction did not affect the rpm.
Could the throttle body be bad? Do I have a vacuum leak somewhere? Could it be the EGR valve?
Any input is much appreciated.
Problem:
The car has erratic acceleration. It would hiccup (lose and regain power). Behavior is the same with car at rest and revving up the engine. No Check Engine Light CEL.
History:
Car lost power on the freeway and was towed to the dealership. The distributor igniter, distributor cap, spark plug, and plug wires were replaced. A week later the car was returned for said “hiccup”. Although the car does not die, the power is erratic. Dealer suspected the fuel pump so it was replaced. After paying the stealer ship $1200 for all said repairs, the car is no better off.
A MAP sensor CEL code later appeared so the MAP sensor was replaced. And since the O2 sensors were old, they too were replaced.
This is where I am now:
Since the idle is erratic, I suspect it could be the Idle Control Valve so I decided to get a new ICV. My research indicates that after replacement of the ICV, the idle has to be reset. I checked for vacuum leak and turned off all accessories. Sprayed carburetor cleaner on throttle body and intake manifold area, and no leaks were found. Ran the engine to operating temperature and disconnected the ICV valve. Adjust the brass screw above the throttle body so the engine rev to 550 rpm. Once the ICV is disconnected, the idle is supposed to go down to the point is would stall. However the opposite happened, rpm went up not down; rpm fluctuates 1100 to 1300. Turning the screw either direction did not affect the rpm.
Could the throttle body be bad? Do I have a vacuum leak somewhere? Could it be the EGR valve?
Any input is much appreciated.
12-10-2014, 10:51 PM
#2
MM Gruppe B
Re: Erratic acceleration - 99 Accord i4
Does the throttle smoothly open, or is it erratic or sticks? If the shaft is worn the blade will not fully close and **** open. Verify the throttle rotates smoothly. Verify throttle cable does not stick.
Possibly, spray over all joints/mating surfaces of the intake. Look for any false air leaks, including in the exhaust before the O2 sensor.
Unlikely.
If the EGR valve was stuck open the idle would lower, stumble and/or stall. Not surge.
Check your thermo sensors, if they are no longer working they may give a false signal and the rpms may be higher if the PCM believes the engine to be cold.
It could be a bad ground as well.
Make sure all ground cables are clean and tight, along with battery connections.
Possibly, spray over all joints/mating surfaces of the intake. Look for any false air leaks, including in the exhaust before the O2 sensor.
Unlikely.
If the EGR valve was stuck open the idle would lower, stumble and/or stall. Not surge.
Check your thermo sensors, if they are no longer working they may give a false signal and the rpms may be higher if the PCM believes the engine to be cold.
It could be a bad ground as well.
Make sure all ground cables are clean and tight, along with battery connections.
Thread
Thread Starter
Forum
Replies
Last Post
Silva Bullit DC4
Honda Accord (1990 - 2002)
10
03-07-2017 05:50 PM
Crazy3rdgen
Honda Accord (1990 - 2002)
7
04-04-2011 01:36 PM