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UPDATE on MAP Sensor Install...

1569 Views 8 Replies 2 Participants Last post by  1st Gen Legend
Ok... as I mentioned in my other post we found out we had a code 3 on our 88 Legend. According to the FAQ section the 3 equates to a faulty MAP sensor. So, today my son and I replaced the sensor. Also found the rubber air horn was torn at the throttle body clamp area and were able to remedy that problem with some electrical tape until we find a good used one. We cleared the code in the computer by removing the battery cables for about a 1/2 hour while we changed the oil and filter.

Test drove the car and it ran perfectly. When we came back to the garage, we let the engine idle and to our dismay it started showing the similar symptoms ae before.... BUT, not happening nearly as frequently.

I checked the computer for codes and it just gives one flash one time. No other flashes..

We looked all over for bad or damaged vacume lines or any other issues. The car is bone stock and a virgin void of any modifications.

To recap, the idle seems to hunt. It will idle perfectly then dive down in rpm, then return to normal. Where do I look next?
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Did your car have any tune-up done?
No tune up to this point. I didnt think it was urgent because of how the car fires up at one turn of the key. Also it does not lack for power at all... What do you susspect?
Hmm, could be numerous things. Spark plugs can be foul, also want to see how the cap and rotor are, also if you have some carb cleaner, try spraying at the vacuum lines to see if it changes idle. Also make sure the air filter is clean.
Were planning a full tune up. Fuel filter, plugs, wires, cap/rotor and air filter. I will try the ether method of trying to find a vacume leak in the mean time.
Thank you for the suggestions.

PS where is the PCV? I couldnt find it!!!
The PCV valve is located on the front valve cover. On the middle of the valve cover is a plate cover with 2 bolts. Under that is where you'll find the PCV valve.
My son was talking to a friend today who owned an integra at one time. He listened to my sons legend and said his integra used to do the exact same thing, He fixed the problem by installing a new EGR valve. Is this something I should be looking at? Dang EGR valves are expensive!!!!
Well why don't you try to remove it and clean it? But if it was the EGR, the ECU would've picked up and gave a code for it. You can also test the EGR by removing its vacuum hose and apply vacuum to the EGR. If done right, the car will shutter/shut off if it's working properly.

Ok... Pulled the PCV and it seemed sticky. Cleaned it up and it was nice and loose. Next, I adjusted the fast idle valve down to its seated position as per a You Tube help video. Next, we played around with the idle itself. The hunting problem went away when we held the idle around 800-900 rpm. So we adjusted the throttle cable to hold 800 rpm. The engine was warmed up and the problem seemed fixed.... Then a couple of hours later, with the engine cold, outside temp around 28 degrees.... we started it up and it seemed ok, but when we jigged the throttle a little, the rpms dove down to almost stalling one time. As it warmed fully, the problem went away. Now, this was at night. the headlights on and the heater/blower on high. The electrical load seemed to drop the idle rpm down some. I think I might try to adlust the idle speed with all the accesories on and engine cold next and maybe give it about 50 rpm more. I think were on the right track beacuse it really ran nice and didnt do the hunting once after the first time I adjusted the idle speed.
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