its weird when the car is warmed up and ill be driving ill let the rpm's drop to 1k then it surges to about 1.5k or 2 then falls down and may do that a few times unless i start going slow or i give it more gas. it allmost acts like the engine cycling if thers air in the cooling system, but that system is all new , new hoses, water pump, thermo, and radiator, and my father bled the air out. i jsut dont understand why the rpm's would surge , could it be a possable vacume leak ?
1989 Accord Lx-i hatchback (current DD project)
1986 Olds Cutlass 442 clone (never ending project)
3Geez resident body man
Owner of Wreck-less auto body
Originally Posted by gp02a0083
my car also has the same problem, same with my friends 95 prelude. im not completely sure whats wrong with it, but it doesnt seem normal
i dont know whast wrong with it , it does it after 1 or 2 min of startup and will do it alsl wehn i let off the gas and it hits 1k rpm then pops back up to 2k i dont know why i was thinking posably that thers a air pocket in the cooling system (we replaced the radiator,waterpump and most of the hoses) but i think it might have to do with a vacume line or something
1989 Accord Lx-i hatchback (current DD project)
1986 Olds Cutlass 442 clone (never ending project)
3Geez resident body man
Owner of Wreck-less auto body
i highly doubt that air in the cooling system would cause it to jump while idling. im guessing its a vacuum line, but im not completely sure
well at idle when hot , if the cooling system is gumemd up and the intake cant get fluid it does surge (happened with mine , the old man who had it before used only water so solve overheating probs, which gummed up the system) but i dont think it is the coolant system , im gonna have to spray soapy water on it or something and see if theres a vac leak
1989 Accord Lx-i hatchback (current DD project)
1986 Olds Cutlass 442 clone (never ending project)
3Geez resident body man
Owner of Wreck-less auto body
weird... my friends 95 prelude had that problem when he bought it 10 years ago...
well, first i would check the vacuum lines. when you get a vacuum leak on EFI cars, the engine will raise the RPM to keep it running. At least that is what my car does.
if all the lines checks out OK, move on to fast idle valve. over a period of time the valve spring will wear out and you will have to adjust it just a little. it is very simple.
On 3G and more 4 cylinder Honda engines the valve is located on the throttle body next to fire wall. it will have 2 coolant lines connected to it. if you are not sure what unit looks like, please download shop manual. it will explain the location of the valve.
It is very easy to adjust the valve. On 3G it will have two screws on the top. Remove the screws. you will see big plug. take wide screw driver (easy to do with wide one) and screw it down while the engine is running. this is what will happen: before your engine RPM will go up and down (somewhere in the area of 1.5-2K). If you screw the plug just enough to stop the engine from jumping up and down, you will have normal idle and normal fast idle.
If you screw in that plug too much you may change the fast idle speed. if that happens, you have no choice but replace the valve.
I have been told that you can take the valve apart and clean it and put it back together, but it never worked for me.
I hope that helps guys. if you still have the problem, send me a private message and we can try to fix the problem.
Alex.
yeah i had the same problem in 2 of my previous b20a accords and a civic. the pipe that goes through the throttlebody was blocked and water could not flow. we bypased it, and now it runs sweet.
Just curious, but in the chevies we bypass the coolant to the throttle body to give a cooler air charge, supposedly making a tad more power. Does the Accord EFI not like to have the coolant to the TB bypassed? I can't understand how this would be different, since the coolant is there to warm up the air for emissions and cold weather running. to prevent icing in the intake.
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