CRX HF fuel mileage?

I've been driving this car the last few months.
It's getting about 31 MPG in town, and the tailpipe is sooty, so I know it's got
a problem.

Two questions:

1 - What's the real-world expectation for fuel mileage? It's rated around 50,
but I'd expect 40 - 45. Is that about what others get with these things?
2 - Any idea what could cause the overrich condition? It doesn't want to idle
either, unless I keep the A/C switch on (A/C clutch disconnected) which kicks
the idle up to about 1200.

Thanks in advance
Rex in Fort Worth

 

You don't mention any year, but I would usually get 42-44 MPG out of
my 85. It probably could have used a tune-up and done better. As for
your problem, do you have any ECU codes? As just wild guesses as to
things that could lead to rich conditions...dirty air filter, plugged
catalytic convertor / exhaust system, improper fuel pressure, wrong
ignition timing, bad O2 sensor, faulty spark plugs, wires, distributor
cap/rotor.

31 MPG around town is not too bad, but I suspect it could be
better...unless you are letting the car warm up for 15-20 minutes
before driving it each time.

Corey

 

|You don't mention any year

Sorry. It's a 1990

| but I would usually get 42-44 MPG out of
|my 85. It probably could have used a tune-up and done better. As for
|your problem, do you have any ECU codes?

No codes. They'd show up in the small window in the ECM, right?

As just wild guesses as to
|things that could lead to rich conditions...dirty air filter

It's new

| plugged |catalytic convertor

Nope, looked at it when I changed the head

| exhaust system

Shrug. Looks fine, no rattles

| improper fuel pressure

Have not checked that.

| wrong ignition timing

Possible. I changed cam, timing belt, and installed a brand new distributor.
I timed it by the book (shorted the plug) but could not quite get the marks to
line up. So it's 'close'.

| bad O2 sensor, faulty spark plugs, wires, distributor
|cap/rotor.

All new except the wires, which appear fine. No arcing, no misfires under load
|
|31 MPG around town is not too bad, but I suspect it could be
|better...unless you are letting the car warm up for 15-20 minutes
|before driving it each time.

Nope, I drive off immediately.
|Corey

Thanks for the input. I think it's basic diagnosis of the EFI at this point. I
just haven't devoted the time to learn the system and check each componenet.
Hoping for a shortcut, or a known common problem.

| (Rex B) wrote in message
|> I've been driving this car the last few months.
|> It's getting about 31 MPG in town, and the tailpipe is sooty, so I know it's
got
|> a problem.
|>
|> Two questions:
|>
|> 1 - What's the real-world expectation for fuel mileage? It's rated around
50,
|> but I'd expect 40 - 45. Is that about what others get with these things?
|> 2 - Any idea what could cause the overrich condition? It doesn't want to
idle
|> either, unless I keep the A/C switch on (A/C clutch disconnected) which kicks
|> the idle up to about 1200.
|>
|> Thanks in advance
|> Rex in Fort Worth

Rex in Fort Worth