Mechanics

ENGINE SURGES AT IDLE AND AT

2000 Honda Accord

Engine Performance problem
2000 Honda Accord 6 cyl Front Wheel Drive Automatic 55000 miles

I have a 2000 accord lx v6 that will not run smotth. It starts fine but immediatly the engine starts to surge up and down. I f Itake up to 3000 rpm it surges up and down. Like there is not a staedy fuel flow. When I bring it back down to idle it surges up and down and will die out on the down surge. I have replaced the iac vavle and the egr valve and coolant temp sensot and the throttle body with another tps and the map sensor. After clearing the codes the only code I get is for the map sensor. After checking the sensor there is a problem with the wiring somewhere between the pcm and the sendor. I have checked the wiring as far back to the wiring harnes as I can and did not find a short. But my question is can the map sensor fault be enough to cause this much of a major problem? The vehicle is not driveable at all. I guess I need to have some advise on how to eleiminaste anything that it might be from someone with knowledge on how these hondas work. I am from the old scholl where it it either fuel or electrical that caused the problem. Number 1- Is the map sensor fault enough to cause this kind of problem? Number 2- What else could it be and how do I diagnose what it might be if there are no other fault codes in the pcm/
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Pinebear
November 21, 2008.



Hi pinebear,

Thank you for the donation.

The MAP is one of the main component sensor for the idling circuit and the stalling when it surges down is most probably caused by it.

The surging up should be due to excessive air going into the intake manifold and possible causes are
1. Dislodged vacumn hoses.
2. Faulty PCV valves.
3. Faulty IAC valve.
4. Insufficient coolant or clogged coolant hoses to IAC.
5. Leaking manifold gaskets.
6. Throttle body plate/valve not closing fully.

KHLow2008
Nov 21, 2008.
It might be that the problem really is it will not hold a staedy rpm because of one reason or another. It might not be surging up and down. I believe now it it only going down from where I hold the accelerator pedal. Like it is starving for fuel or something else is causing the loss of rpm. Any answer would be appreciated.
Pinebear

Tiny
Pinebear
Nov 21, 2008.
Hi pinebear,

Is there anything that you do not understand about my explanation in my previous post?

The PCM would always try to maintain a constant rpm and when when something is out of spec, it would compensate and reduce resulting in the surging or erractic idling speed.

I would suggest cleaning the throttle body and IAC and recheck the idling speed.

KHLow2008
Nov 22, 2008.