Fuel economy problem.

[mael]

Hello. I'm new to auto forums. Please be patient with me.

It's a Honda. A wagon. The engine is 547cc. The transmission is 5-speed manual.

I think it is hovering around 18 - 20 years old.

It's done around 110,000kms.

* I got it at about 95,000 and until that point I think it had been properly (if sparsely) maintained by a garage.

Since I got my hands on it I've done little maintenance-wise, but have had a few things fixed.

I'll explain the problem as I see it for starters:-

The fuel economy is terrible at the moment. I think it gets about ten kms to the litre on a good day.

My wife normally has the car most of the time and I just get to drive it occasionally, so I'll have to take her word for it that the economy suddenly went bad. Personally I don't see it as being an instant change, but over a period of a couple of weeks.

The car has never got more than around 12 to the litre, but that was tolerable as neither of us drive with economy in mind most of the time. - But the little Honda was a little rocket when it went reasonably - plus we've got three kids and I like humping stuff from one place to another - so it's a potentially very handy little motor. But with this fuel economy I wouldn't be surprised if it died soon through poisoning the whole top-end with whatever remains of improperly combusted petrol.

I have checked the air-filter. It ain't that.

I have changed and properly set - the plugs.

* They carbon-foul within a day or so. Formerly the carbon fouling was fluffy, and recently it seems to be thinner and more powdery - (I believe this is an improvement).

I've set the timing with a xenon light. - It's all right.

I have checked the valve-rocker clearance and they are all within >reasonable< expectation and not 'out' enough to warrant meddling with them at this stage - I think.

I've checked the vacuum hoses (there's a map on the engine hatch).

* I eventually omitted much of the vacuum system as I became more desperate to locate where the problem might be. - It's mostly still connected, but I've bypassed the EGR and I've disconnected two of the vacuum motors from the Keihin carburettor - the ones on the auto-choke side. It's spotlessly clean.

I've had the carb off at least four times. I can assemble it with my eyes closed I reckon! I've had the practise.

I just cannot get it to run any leaner than it is, but it's sooting the plugs. I'm beginning to wonder if the problem is something I wouldn't want to attempt to fix myself, - like perhaps a compression problem or maybe the exhaust is blocked?

I have set the idling circuit on the lean side, and also reduced the tickover to about 500RPM in a (vain) attempt to make a dent in the appalling fuel economy.

I have disassembled the main barrel of the carb, but apart from cleaning the jets and polishing the needle and cleaning around the vacuum chamber, I've just left it as it was as there didn't seem to be any obvious adjustments on it anyway.

I had the coil off and tested the resistance. It seemed all right, and I've had my wife turn the key while I hold a live sparkplug with a screwdriver and zap the car body. It's sparking, but I wouldn't know if it was a particularly good spark or not.

I've taken the distrubutor off and had it on the bench and it seems all right. It is now very clean and as far as I can tell, it should be serviceable.

I've even had the EGR off to check it was opening and closing properly and I can't find anything wrong.

* There's probably a few more things I tried - or 'nearly' tried, like I was looking for the 'main relay' for an hour and a half before I realized it didn't have one!

* So chaps! . . . What's wrong?

I ought to mention that when I'm trailing behind my wife when she's driving, her car smells different from other cars. The smell would be described as being acrid, and at high concentrations it would sting the eyes I would imagine.

Also, we've had the car for over a year, but about a month after we got it, the igniter apparently blew. It just stopped dead and the garage had to winch it on board a recovery truck. - I'm a points man that is to say I haven't touched cars for a long time! I knew there was no spark but I can't work on an igniter!

Then a month or so after that the fuel pump expired. Both the above problems were sorted out by the garage we bought it from. (Not actually free of charge, but it was done inexpensively).

The car has been poorly for about a month now. We don't have the money to drive anywhere until we get it fixed. - It seems to be beyond me, so I'm asking you people as my only other hope is to take it to a garage and pay to get it done (hopefully) properly.

*** There's always little bits that enter my mind which might be of use to people familiar with the symptoms of engine problems. There was something lurking in my noggin when I was half-way through the last paragraph. Anyway, ask and I shall respond if more info is required.

It has been suggested that I ought to do a compression test. That sounds terminal. I suppose the valves must be pretty black so maybe that would reduce the compression?

* A Honda service mechanic has stated the economy will become as normal when I replace the 'packing' on the rocker-cover. We're due to receive this 'packing' in a day or so. I'll also put in a new air filter at the same time.

I'm frustrated and confused, but not quite beat yet. I'd appreciate your assistance.

[DanD]

Well that’s quite a story and I’m not really sure what to suggest next; other than disabling the EGR is defeating your purpose of improving economy; what is “the 'packing' on the rocker-cover”?
“It would sting the eyes I would imagine.” That’s telling us that yes it’s burning way too much fuel, why, can be very difficult to answer.
I believe these are the transition years from a carburetor to injection, some of the function of these carbs were managed by a very basic controller (computer); using sensor inputs and output devises to control fuel mixture.
So the problem may not even be the actual carb but a sensor; such as engine coolant sensor (always reading cold), engine vacuum sensor or the O2 sensor (if it has one).
There are also a number of computer controlled output devises like solenoids that apply or remove vacuum signals to the power valve and mixture control valves in the carb.
These thing were a nightmare with all of the different systems on them to control emissions, that even when they were relatively new, they were a bugger to repair economy and drive ability issues.
Again with you removing vacuum lines, you may have aggravated the problem. Good luck I think your in for the long haul on this. The dealerships here won’t even touch a carburated engine anymore. The techs don’t know them and the parts are all but impossible to find.
Dan

[aafilho]

check if they have catalytic converter and if is not blockec(clogged) and restrining the exhaust system. just my 2 cents.

Good Luck

Alden

[Tech]

also check to see if one more more brakes are stuck, but jacking up the car, have wife to pump the brakes up and hold then for a few seconds then release them they u see if you can turn the wheel ok or if its stuck.. if stuck in the front and have disk brakes, then calipers are stuck... the one that is on the side where the wheel want turn.. or flange line coming down to caliber is worn and fluid isnt escaping...... if back brakes and drum brakes.. and one or more is sticking, then brakes binding.... adjusted to tight, or possible clip broke causing brake or brakes to bind against drum