It seems that this is a story as old as time but I will tell it again as none of the solutions I have found on this forum or others have brought my idle back down.

I replaced the head gasket and timing belt on my 1993 Accord, put it all back together, fired it up and the idle shot up to 3000 rpm and bounced to 3500 rpm. After reading some interwebs I replaced the TPS and the idle stabilized at 3000 rpm. I also replaced the all the other valves on the intake with used parts from a local junkyard with no change in idle. The last thing I tried was to tighten down that screw everyone mentions and it also had no effect.

After digging around forever I am stuck and pulled the timing cover, the distributor, and the little rubber stopper on the bellhousing of the tranny to double check my timing and found it to be quite close but not perfect from what I can see. When I have the crank pulley and cam pulley lined up at TDC the timing mark on the flywheel is not quite lined up. It sits about an inch down (toward the front of the car) from the little sights in the inspection hole.

I was given a suggestion to replace the thermostat to help and haven't had a chance to try it yet but I don't know if it will help because I have let the car idle(if you want to call it that) until it warms up and it does dip to around 2400-ish rpm and holds steady there.

So if there is anything I can try or try again that you think might get this thing back on the road I would appreciate it.

 

Something left unplugged? TPS connector switched with something else? Vacuum leak? Throttle cable as tight as you could make it?
You really need to be positive the timing is set correctly. It's kind of hard to recheck the work online, for instance did you completely remove the intake from the car?

 

Did you have the head shaved so it is perfectly flat and makes a good seal with the new head gasket?

Your description about lining up the cam and crankshaft is confusing me.

If you lined up just the cam marks with the cylinder head at TDC, then the TDC mark in the bell housing could be off. That would mean that you have the timing belt installed wrong. You would need to recheck that the timing marks line up at TDC.

I don't think there is a way to line up the crankshaft other than that mark in the bell housing.

Check out this thread showing how everything lines up on a 92 engine.

https://www.hondaaccordforum.com/for...ead.php?t=3977

 

I don't know what I could switch the TPS plug with and I checked for vacuum leaks by swapping in new lines one by one. I did not see a change with any of the vacuum lines.

I did not have the head planed. Also, those pictures are great and I wish I had seem them before tearing into this rather than looking at line drawings or the pix in the Haynes manual.

I did notice that the front balance shaft doesn't seem to be lined up (it looks like it's off by a couple teeth), and I will be correcting that tomorrow.

Here are some pictures of the timing marks. They look correct but it's hard to see if the cam pulley marks line up perfectly as I can't get lined up with it in the engine bay to verify it perfectly.

Crank pulley

Cam pulley

Inspection port

lined up better on the Inspection port

 

Most people suggest to get the head shaved, because the head may not seal properly when you tighten it down. Then you would have to go through all of this again.

I think that first pic is the crank sprocket for the balance belt. I can't see the mark on the engine block either, so I am not sure if it is lined up.

It is probably easier to line up the crank using that window in the bell housing. Then you should see if the two marks on the cam sprocket are lined up. If not, you will have to slip the belt off of the cam and adjust the cam, so it lines up properly. I attached a pic below of cam sprocket alignment.

Definitely make sure all of the marks lineup before you put everything back together. I think I checked mine 5 times before I was confident I got it correct.

 

I will pull it and use the flywheel mark. I have done headgaskets on about a dozen cars but this is my first attempt on a Honda and have never run into an issue like this before so it's driving me crazy.

 

If the timing pics were all taken at same time, the timing is good.

Suggest trying to modulate the idle speed by putting your hand over the air intake. If this has no effect (likely), then large amount of air is entering somewhere else; intake manifold gasket error, PCV, vacuum brake booster, etc.

good luck

 

They were, so thank you for the vote of confidence. I will try the intake test and see where it takes me.

 

TexasHonda - are you sure about that? There are two pics showing the inspection port. One lined up and then not lined up.

Roadki1 - On that first picture of the crank sprocket, I can't tell if you have the key inserted. That needs to be in there so the crank sprocket is properly lined up with the crankshaft.

 

The key is in there and both pictures of the inspection port are from the same time, one is just a better angle which allows you to see both sights lined up which was why i felt it might be slightly off since the timing mark doesn't quite line up with them.