Hi,
I changed the timing belt on my 98 4-cylinder Honda Accord and the car was working perfectly. Then I decided to adjust the valves and when I was done I turned on my car and the engine shook a lot and the revolutions were very low. Sometimes when the car is idling the revolutions go down to 0 and the car shuts off. I was thinking it's a air/fuel ratio problem, but I don't see any broken hoses.

Then yesterday when I was driving and the Engine light came on, the code was P0172 (too rich). Today I adjusted the valves again and it didn't improve. However, I noticed the timing belt was loose and when I turn the crank pulley the tension of the belt goes from one side to the other.

This is my first car and I'm learning how to do maintance in my car.

I believe when I was adjusting the valves for the fist time I loosened the timing belt.

 

How long did it run after the timing belt install prior to adjust the valves?

Have you checked the timing marks on the crank pulley and cam gear? I would check them and adjust belt tension.

 

Ehh, sounds like it could be a clearance issue.

Like asked above, how long did you run the motor after the TB?
Did you adjust the valves immediately after running it, or did you let the engine cool completely first?

What clearances did you adjust the valves to?
I am not certain of your lash specs but they should be close to the F22's 0.010" intake and 0.012" exhaust.

And could you elaborate on what you mean by this...

 

After changing the timing belt it ran fine, I thought working on cars was easy and decided to adjust the valves one day later and this happened

I haven't had time to do that but I'll do it as soon as I can.

 

I drove the car for a day after TB. When I first adjusted the valves I let the engine cool down for about 1 hour. The second time I adjusted the valves, I let cool down overnight.

For intake I used 0.25 mm and for exhaust 0.30 mm. These specs are under the hood

 

You might have adjusted the valves too tight, and the valves have to be adjusted after the car sits overnight or is completely cooled down.

I adjusted mine too tight and had some rough idling issues

 

One thing I forgot to mention is that since I bought the car (used). The air would come out of the vents even thought the AC/Heater were off. Air still comes out of the vents. And I was getting about 17-19 MPG.

 

I adjusted the valve and then the following day I tensioned the timing belt. The situation improved, however, I now got a misfire on cylinder 1. But I think it's the vacuum leak that is causing it because when I first changed the timing belt I bolt 2 bolts on the valve cover.
Do you think there is a relation between the vacuum leak and my new permanent misfire on cylinder one? The misfire wasn't there before I tensioned the belt.

I got new spark plugs and check the spark plug wires which are working. The car stalls every now and then now when idling

 

I would double check both the valve clearance and timing mark as it doesn't hurt to do so. I agree with you though that a vacuum leak can cause a mis-fire in that cylinder. Though, if your valve lashes are too tight, your engine will kill instantly at cold start.

Happens to mine when I thought I did it right the first couple of times. Keeps killing on me whenever I go to start it at cold.

 

I would double check both the valve clearance and timing mark as it doesn't hurt to do so. I agree with you though that a vacuum leak can cause a mis-fire in that cylinder. Though, if your valve lashes are too tight, your engine will kill instantly at cold start.

Happens to mine when I thought I did it right the first couple of times. Keeps killing on me whenever I go to start it at cold.

 

I am having a similar problem with my 97 Acura CL. I changed the TB and a couple of days later the CEL came on indicating a misfire on cylinder no.1. I did some diagnostic testing with the ignition/fuel components, but everything was fine. Finally found that the valves were a little tight and needed to be loosend. I cleared the p0301 code and drove around to see what would happen, but unfortunately the misfire returned. I have been reading up on the TB replacement threads and noticed that all suggest that cylinder no.1 should be at TDC. I know I made sure the camshaft sprocket was aligned to the top, but unsure of which cylinder it was on. Could this cause my misfire?

 

Timming can cause a mis fire, if you feel you have a vac leak spray brake clean on any gaskets around the intake manifold, it will try to die if there is a leak. you can also use carb clean or starting fluid but idle should raise.. When you do the timming belt you actually go 2 or 3 teeth past TDC on the crank, slip the belt on the turn it those 2 or 3 teeth back to top dead center and tighten the tensioner.

With the valve lash adjustment there should be alittle drag between the cam and the the "pad", but you should use the tool made for valve lash and you can get it from snapon and such for pretty cheap. If using a wrench with a screw driver you have to be very very carful when locking down the 10mm bolt as it can move the adjuster alittle when snugging up.

 

I checked the timing mark and they were right. To do that, I just took the upper side cover off and checked marks on the camshaft and the white mark on the crankshaft. I also adjuted the valves again making sure the next thinker blade wouldn't fit.
And I did a compression test on the cylinders:

Here's the data, the units are psi:

Cylinder 1: 0, 20 (After oil)
Cylinder 2: 165, 160, 215 (oil was added, 10 strokes), 210 (8 strokes), 195 (5 strokes), 185 (5 strokes)
Cylinder 3: 170, 172, 165, 170 (Before oil, 7 strokes),210 (After oil, 7 strokes)
Cylinder 4: 162, 165, 160 (before oil,8 strokes), 180 (After oil, 8 strokes)

I didn't have any compression on cylinder 1 and didn't hear any strokes. Do you think a vacuum leak can cause 0 compression on cylinder 1?
I still have random misfire and constant misfire on cylinder 1.

Also when I was drilling out one of the bolts on the cylinder head, I dropped on accident 100 mm long bolt into on the holes next to the exhaust valve on cylinder one please see the picture below:


(This is not my actual cylinder head)

where does this hole go to? I couldn't get the bolt with a magnet. I turn on the engine and it makes noise, but it doesn't seem to interfere with the engine.

 

Wowzers.
Ok, a vacuum leak won't cause a cylinder to have zero compression.
However, since you did add oil to #1 and saw very little improvement, that suggests either a bent or burnt valve, possibly head gasket but not likely.
You will have to pull the head and do more repairs.

That hole is an oil drain.
Since your head is going to have to come off anyway, just get the bolt out when you take it off.

 

Why did you run the engine KNOWING you dropped that bolt down there?! No telling the damage you have done to it. Pull your head.

 

I think that hole leads to the oil pan... time to pull the oil pan

 

I took the car to the mechanic, it had 2 bent valves on cylinder 1. And he also said the (some) valves on cylinder 2 weren't sealing properly, so the machine shop had to do fix that. He also pulled the oil pan and got the bolt out. The car is working fine now.

However, I was in a parking lot today the revolutions went down and it shut off? And if I turn the steering wheel when idling the car revs. It stalled just once in like 4 days that I've been driving it

When I've on the highway I've gotten a check engine light which I haven't been able to check because the car has a short circuit n I have to disconnect the battery, so that clears yhee CEL every time

Do you think the car has a vacuum leak?