Hi. I need help in figuring out what is wrong with my car. I just replaced my cylinder head and valves with a used head and valves. I kept the old camshaft and roker arm assembly. I installed with a new head gasket, intake and exhaust gaskets.

However, now the car idles fast and is very hard to start when hot. When cold, it starts quickly, but seems to immediately bog down at ~200 rpm for 2-4s, then rise to 1500-2000. It idles fairly steady, with no surging, however I do see some erratic variation sometimes. After it warms up, if I shut it off, then try to start, it is very hard, and will usually only crank when I play with the pedal some.

Ive checked every vacuum hose, cleaned the injectors, checked all the connectors, cleaned the IACV (cleaned the filter, have not sprayed it down with carb cleaner, as I read to do afterwards), adjusted the FIV, checked the MAP sensor, etc....

I also did a compression check (in order):90 110 130 90. I know I have worn rings, but could that cause such low compression, and could this low compression be causing my problems? Also, when I put the timing belt back on the cam, I put it back on the same teeth it came off. However, I could not get the TDC mark to line up, it was off maybe 2-3mm.

The only mods are I/H/E. I also have an adjustable fuel regulator with a gauge, so I can check my fuel pressure. No error codes are given.

Any help would be greatly appreciated. I have been working on this car for probably over 100hrs now with nothing to show for it.

 

Forgot to add that the reason for the head/valve swap was because I had a burnt valve. The head/valve set I put on was the original set that was on the engine. I replaced that set with the newer set (The set I just took off) because the cam sprocket came loose and sheared the key that locks it in place. I then broke a lobe off the cam by either : trying to start it in this condition, or sometime while removing the cam (not sure when it happened). I just went ahead and replaced the cylinder head with a rebuilt cylinder head (again, the one I just took off)

Also, the valve blew while on a 3hr drive to my parents and "the hard to start while hot" problem occurred after around an hour drive back (I stopped at a rest area, when I parked it stalled out, and would not start again until I scraped down the plugs with a wire brush)

One more thing, while on the way to my parents, before the valve blew (a piece around 3mm in diameter was missing) I stopped and got gas at an old shell station, then went across the road to get food. After eating, the car started, then immediately stalled out. I started it right back up and (I believe) it idled bad but did not stall.

Just trying to give as much info as possible.

 

You need to start with correctly setting the valve timing. If the valves open at the wrong times, they can be open during part of the compression stroke, decreasing pressure. The notches on the cam sprocket should form a line that is parallel to the top of the cylinder head with the "UP" mark in a generally upward direction. The up mark doesn't have to be straight up, just not pointed down. With the gear in this position, the crankshaft timing gear should line up with the notch on the oil pump housing when the belt is tight.

 

Thanks for the reply. We adjusted the valve lash twice already, and I have done it several times previously, so I believe thats not the problem, but the cam not being in the right position might be. The TDC mark that Im lining the cam up with is the TDC mark on the cover behind the sprocket that is on the bottom left. From my Haynes manual, and online research, that is the proper reference mark for a d16z6.

When I line the crank up to TDC (with the white mark perfectly lined up with the pointers on the belt cover), the TDC mark on the cam sprocket is like 3mm to the left of the pointer on the back cover. This weekend Im going to take the belt off and move it a tooth, but I believe it will move it too far. I will take pics when I do so.

Also, I was able to lower the idle down to around 1000rpm by screwing the idle control screw in all the way, but it is missing pretty bad. I believe it was missing before as well, but didnt notice it.

 

I don't want to sound rude, but I never mentioned the valve lash. Just want to be sure we're on the same page. You shouldn't be reusing the old timing belt, assuming you are. If you can replace it, compare the size of the two belts to see if the old one was stretched. It sure sounds like you have the correct mark for the cam gear. You might try installing the belt with the crankshaft pulley removed and lining up the notch on the bottom gear with the pointer on the oil pump housing. Is your crankshaft pulley the type that has rubber on it?

 

Sorry, but misread your original post. Thought you said "valve lash", not "valve timing". Im am using the old belt cause its not that old. I replaced it a couple of years ago. Also, the marks lined up perfectly before I took the belt off (80% sure of this). I also didnt have any of these problems before. My pulley doesn't have rubber on it from what I remember.

When I switched the head, I loosened the tensioner bolt, and slid the belt off the cam sprocket. Then slid it back on after the swap, ensuring that it went on the same teeth, turned the crank a little, and then tightened the tensioner bolt. How often should you replace the timing belt?

Thanks for your time so far.

 

Timing belt schedule is 90k mi/72 mo and it's often recommended that you replace it when performing work requiring that you remove the belt. Also, enough force to break a cam lobe could easily stretch the belt. The timing belt doesn't necessarily need to be noticeably stretched in order to cause problems. All it takes is a little. If money's too tight atm to just replace it, you could take the old belt to a parts store and compare it to a new one. Even if it's just a little out of spec, you should be able to tell when it's pulled tight next to a brand new one.

 

Here are some pics of the cam sprocket, crank pulley, and the timing belt. As you can see, the TDC mark is barely off, this is the closest that I can get it to line up. Is it a stretched belt for sure? Also the timing belt rides very close to the edge of the sprocket, and i believe is rubbing against the cover (you can see a lip on the edge of the belt). Is this normal? where should the belt be riding? Ive checked to make sure it is tight, and it is. Deflects ~1/4".

One other thing. I tested the resistance of the plug wires, and they are all ~1K ohms or lower, except the number 1 wire, which is 4K. Is this OK? Haynes says if it is less than 25K ohms, its good, but I dont really trust Haynes.

Will test the ig. coil tomorrow. Thanks for any help!

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I installed a new ign. coil and wires. didnt help, but really didnt think it would. Ive been driving it around, and it seems to drive ok, except for being very sluggish and lacking power. However it idles very rough, enough to shake the car, and the engine is a lot louder then before, sounds like the valve train is louder.

Im thinking that it might be a bad valve or two, but I have not noticed any backfiring.

Ive pretty much gave up on it. now im looking for new engine.

 

Forgot to add, It will not start while hot. I have to wait for it to cool down. Not sure if this is because of the bad compression or not.

 

I had that exact same problem and it was from the HG leaking and coolant getting on the plugs. If i used coolant it would be worse, if I used water it wasn't a big deal.