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2.8 Runs Rough When At Operating Tempature


HondaEater

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My 2.8 started running rough only when warm yesterday after I swapped the rear (went from 3.45s to 3.73s, changed a valve cover gasket (driver side) and slightly adjusted the rocker arms on that side cause I had a bunch of slack and valvetrain noise. It runs fine when cold but once it warms up it sounds like its cammed and idles very low any ideas I kinda need this fixed today this is my daily driver right now
 
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HondaEater

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I also replaced the throttle body spacer looking thing (big plastic price with gasket material on it) that sits between the carb and intake manifold because my previous one had no gasket material on it and it was believed to be causing my high idle
 

adsm08

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Did you reset the computer memory and adjust the carb after fixing the suspected air leak?
 

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Nope. I guess pull the negative cable from the battery (how long?) I don't really have an emissions analyzer to reset the carb plus like stated before this is only happening when warm
 

kimcrwbr1

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Go back and adjust the valve lash per spec on a cold engine.
http://www.therangerstation.com/tech_library/2_8L_Performance.html
disconnect the battery for 1/2 an hour and make sure everything is plugged in before you start it up. To adjust the valves when it is cold pull the covers and spark plugs. stick your finger in a hole turn the crank clockwise with a socket until you feel compression and adjust those two rockers to spec. You can adjust the carb without an analizer with a tach or a vacuum guage. But first adjust the valve lash and put a new PCV and breather filter. Have you checked the timing and how far does it advance when you plug the spout back in.
 

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Im on my way to my buddies house to check the timing now. When I adjusted the valves on drivers side I just tightened them up until they had a tiny bit of play in them. Which way do I turn the screws to lean the mixture? And are those screw settings just for idle or no?
 

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When the engine is cold adjust the intake at .014 and the exhaust at .016. With the solid lifters you need to account for expansion when the engine is hot if they are too tite the valves will not close all the way when it gets up to temp. The idle air needles are on the front base of the carb. Turn them both out 3 1/2 turns from the lightly seated position and start the engine up make sure all the sensors are plugged in and the computer is reset. That includes the IAT in the air filter housing. Once up to temp unplug the idle motor on the front of the carb and adjust the idle air screws for the highest rpm or vacuum pressure then plug the idle motor back in it should idle down to around 700 rpm if the anti diesel screw on the drivers side of the carb is touching the throttle lever turn it out until the idle motor controls the idle. I just put the air filter housing off to the side to keep it plugged in to both the sensor and vacuum line for the preheater door. Hopefully you wont need to do anything after you adjust the valve lash to spec
 

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im still getting some lifter noise should i run a heavier oil like 15w-40? ive been running 5w-20 motorcraft oil
 

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5-20 is way to thin for that engine.

10-30 minimum. With that amount of age 15-40 wouldn't be a bad idea, especially in summer.
 

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Thanks adsm08, it ended up being the dizzy set at zero and not 10* set it back and it runs okay again besides the fact my pinon seal is leaking ( i dont know how i just replaced it yesterday when i put the new rear in) and i have a bad valve train tap after i tightened up the rockers
 

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Will the 15w-40 quiet up the top end alot? Also, does anyone have any ideas as to how my pinon seal is leaking and its a day old lol it was installed correctly and flush but I did have to take the original plate for the driveshaft to bolt into and put it on the new 3.73 rear could that be my problem
 

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Running different oil will do nothing if the valve lash is not correct besides you can throw a pushrod also. My motor has over 200,000 and runs the best with a 5w30 blend and a motorcraft filter but if your engine is leaky dont use synthetic it will leak faster. On the axle how was the pinion seal surface if there was a groove worn in the surface of the pinion where the seal is you can maybe press it in a little further so it is not riding in the groove or when you put it on dont press it all the way in so it has a good surface to seal to.
 

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Even after I had adjusted my valves I still have one that makes noise on my driverside, but it has just become something I have come to love and have bloked out of hearing.

As for oil, I run a thicker oil then what it says from the factory, 10w-30 IIRC high mileage penzoil and fram filter (dont start nagging on the filter i use). Winter time I run thinner oil due to the engine doesnt really get to full temperature due to my work is about a mile away and I dont travel far either in the winter.

If the pinion seal needed changing, the axle seals may be comming soon too.
 

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How do you tell the difference between a valve tap and a bent push rod(s) when it comes to noise..
 

adsm08

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Also, does anyone have any ideas as to how my pinon seal is leaking and its a day old
The seal isn't your problem. The pinion is. Was there a nice groove worn in it right about where the seal would ride?
 

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