1991 prelude no start - Honda Prelude Forum

catfishjoe · 06-16-2011, 05:54 PM

OK here's the deal

A friend of mine replaced the head gasket on his 1991 honda prelude, and now it doesn't start. Soooo he called me and I had him tow it to my shop.

Now I'm not very familiar with hondas, but here is what I've done so far. The car cranks good, but just won't start. I removed the valve cover and checked the timing, everything lines up. I also removed the dist cap and checked that the spark timing was right, it is. It is getting spark to every boot, and it is also getting good fuel pressure at the rail.

There are no codes. I then decided to check the compression. I got around 85-95psi on every cylinder. I could smell gas so I was thinking maybe the cylinders got flooded, so I removed the fuel pump relay. I poured some oil down each cylinder and did it again. I got around 110-120psi this time around. My question is, is that enough pressure for hondas to start? I'm totally lost as everything seems to be in order, but it just won't start.

I also noticed that he broke the coolant temp sensor, as the cork part of it was broking. Would that have anything to do with it not starting? It didn't have any codes so I didn't think it would.

If anyone has any ideas please lmk, I just can't figure out why it won't start.

Colfax · 06-17-2011, 08:53 AM

Hey Joe, welcome to the forum.

To start off, these are pretty easy to work on once you learn your way around them. Please don't take offense at any of my questions, but I don't know your skill levels so I have to ask. If it was running before the head gasket was replaced, then he did something wrong. You mentioned that the mechanical timing is correct. Tell me how you checked the cam to crankshaft timing.

You sound like you know your way around an engine, so I'm sure you also know that an engine needs three things to run; air/fuel mixture, spark, and compression. You said that it has good fuel pressure, but did you check that the injectors are working? Did your friend plug everything back in after the hg job?

As far as compression goes, 3rd gen engines had about 175 - 180 psi on each cylinder when new if I remember correctly. I had 125 or so on my old engine, and it still ran fine. It just lacked a little power. An internal combustion engine will fire with as little as 30 psi (although not well), so I don't think compression is your problem. But what you are reading is pretty low.

What I would do is:
1. Make damn sure every connector and vacuum line is plugged in. Also make sure all of the grounds are connected on the engine block. Especially the one on the coolant neck.

2. Double check the cam to crank timing. If that is off even one tooth it will throw off your compression numbers.

3. If everything above checks out, make sure the injectors are firing.

One other question, how good is your friend with cars? How sure are you that he did the hg right? Ask him what his torque procedure was and what the final torque number was.