I have a 2000 AP1 that a friend and I just finished putting back together... or so we thought. A little over a year ago, I was driving to work and the car overheated. In the process of trying to determine what was causing it to overheat (I think I have it narrowed down to a bad fan switch, but that's the least of my worries right now), it got to the point where it was getting compression into the radiator and wouldn't start. We tore the engine down and found a very small spot in the head gasket where it looked like coolant was getting through, but not enough to get that much pressure back into the radiator. I sent the head to be checked for cracks and see if it was in spec, and though there weren't any cracks, it was .018" out of spec, so they shaved it back into spec. I got the head back, got new gaskets, and we got the engine put back together last night. It will turn over, but there's no spark to the coils. Also, the compression is reading only about 65-70 PSI on cylinder 1, and about 90 PSI to cylinder 2. The timing is set properly, and I checked all the fuses and all of them are good. I don't get a CEL (which is odd because there's a bad O2 sensor that started throwing a CEL not long before the car quit running) and if I plug a scanner into the OBD2 port it doesn't pick up a code. Is it possible that the ECU got fried somehow, or is my problem more than likely something else?

 

did you use the original honda oem gasket? or 3m or other aftermarket?

 

They're aftermarket gaskets. I can't remember the brand name off the top of my head.

 

what is compression on cyls 3 and 4?

If they are good, you will be tearing the motor back apart. Unless the valve clearance is tighter than zero then that would yield those numbers in cyls one and two.

 

Double post, sorry.

 

I'll have to get back to you on that. We ran out of time last night and didn't get a chance to check them. I might be able to test them when I get off work.

I should mention that at this point I'm more worried about not having spark than I am about not having compression, so I want to start with at least getting spark to the coils. Once I can at least get the engine to run, then I'll start worrying about compression.

 

id honestly be more worried about the low compression...in the future you should really use OE gaskets for shit like a head gasket...just my .02 cents...good luck

 

Thanks, I need all the luck I can get right now. I guess what I meant to say before is, I'm concerned about the compression, but it seems like it's easier to narrow down the cause of that than it is to figure out why I'm not getting any spark, so that's the problem I want to solve first. Is it possible that a cam or crank position sensor is bad and is causing both of those issues? I know that if they're not working it's supposed to send a signal to stop it from firing, and I wonder if it could also have something to do with a lack of compression. I also find it very strange that the ECU was showing a code for a bad O2 sensor when the car was running, but now doesn't even give me a CEL for anything. I'd think that the ECU would detect that something's more than just a bit off if it has no spark or compression, unless the issue is somewhere between the ECU and the coils. I guess there's also a possibility that, since the car sat so long with a bad battery, the ECU got reset and can't pick up anything to throw a CEL for if the engine isn't running. All I can say is, I'm stumped, and so far everybody else seems to be too. I live in Bumf@#k Egypt, so the nearest Honda dealership is 2 hours away, and unless it's absolutely unavoidable I'd prefer not spending my life savings letting them even look at the car for more than 5 minutes, let alone work on it.

 

Step number 1, post compression for 4 cylinders, not two. If they are ALL low, the fix may be simple. If two are low, then the valve clearance needs to be checked.

If those pan out, then she needs to come apart.

 

Update: I finally got back to work on the S2000. Compression is low on all four cylinders. The highest reading was 120 on one cylinder, the lowest was around 70. It's all coming through the valves. The spec I found on valve clearance was .008" for the intake and .010" for exhaust, and they are in spec with that.