1997 Honda Accord V6 2.7l C27A4 Non-Vtec 24 Valve
Check compression with engine at normal operating temperature and throttle in wide open position. Prior to performing test, disable ignition and fuel
injection to prevent fuel from being sprayed into cylinders while cranking engine. Ensure is fully charged and that cranking speed is 250 RPM. Standard
reading should be 135-178 psi. The maximum variation between cylinders is 28 psi.


Ok, well, mine won't start.

Any idea what cold psi should be?

After this engine is pulled, can I just hook a bump starter to it and spin it over and check compression that way?

I'm having a REAL difficult time in finding a "good" engine replacement for this one. I believe the head gasket is blown and the engine has 290k miles on it. So if I can't find a replacement, I'm thinking about just redoing the heads (I still have the brand new timing belt I haven't put on yet, I guess now is a good time LOL )

Also, are these heads iron or aluminum? For some reason, I'm thinking these C series had iron heads on them? Maybe?

 

For the Honda C Engine, both the block and the heads are die-case aluminum alloy (the block has cast iron cylinder liners).

 

In whatever vehicle, I've always measured compression cold but I removed all the spark plugs first (so disabled ignition this way) which means the crank speed is good (no compression) and the battery drain is therefore a whole lot less. Never worried about fuel injection disabling.

 

Disabling the injectors prevents fuel from washing down the cylinders & diluting the oil at the rings.

 

Since I've never looked at the Honda EFI programming I don't know the answer to the following question:

• When in start mode, do the fuel injectors spray a default amount of fuel from the built in maps, or does it measure the weight of the intake charge and meter fuel out accordingly?

I ask because if it is the latter and the spark plugs are removed, then given there will be virtually no air movement past the throttle body, there should be no fuel sprayed by the fuel injectors.

 

It just occurred to me there's an easier way. And you might be doing this anyway when you measure compression.

Many cars have an interesting little programmed feature. With the throttle wide-open during starting, they don't inject any fuel. That's to help you clear a flooded engine, in a similar manner like you would back in the day of carburators.

 

Oh yeah, as a possible answer to your question.

Seems to me the spark plug hole isn't big enough to prevent ALL movement of air. There's probably enough resistance to draw something past the MAF. And older Hondas didn't have an MAF, they used (RPM) x (displacement) x (manifold pressure)

So if you're NOT holding the throttle wide-open, it would have to use it's normal method of calculating fuel-rate otherwise the air/fuel mix would probably not be within the combustible limits.

Disclaimer... I don't work in the automotive industry so I don't REALLY know the answer.