10 replies to this topic

[Wink]

Hello, the car is a 1985 Civic 4WD Wagon-bone stock. I all of a sudden am getting less than 10 mpg and stalling amounts of oily water building up inside the air cleaner. If the car sits for several minutes, it will restart and drive normally until it just runs out of power and dies again. This goop smells like blow-by, and there is no evidence(sight, smell, or taste)that it contains antifreeze. No overheating or other oddities. Any ideas??

[zakats]

hard to say
you could start by replacing your intake manifold gasket, carburetor base (big chunk 'o rubber), and do a leak down test to see if you have a bad head gasket

[Wink]

I know the coolant is going somewhere-the car is about 1/2 gal. low every month. However, coolant has never shown up in, on, or underneath the car, nor does the exhaust smoke other than at cold start-up. I have performed compression and coolant system/cap pressure tests but to no avail, all seems normal. The car does have 220k on it, and probably more wear than normal considering it is the heaviest form of Civic.

My theory is: Coolant is being burned and a percentage is ending up as blow-by. The cold temps(4F) are condensing the vapors from the crankcase upon entering the air cleaner and causing my problem.

I will disconnect the crankcase evacuation hose from the valve cover to the air cleaner, and see if this eliminates my problem.

Edited by Wink, 16 December 2008 - 05:00 PM.

[Christ]

I 2nd the leakdown/compression test. It's a good way to diagnose a large array of problems and potential discourse within an engine.

[Wink]

Ok; my theory was at least partially correct. I took off the valve cover to air cleaner hose and then ran a long hose from the valve cover to exhaust out the bottom of the engine compartment. Car runs perfectly fine now, other than the tapioca colored goo coming out of said hose onto the ground. I don't get it-especially since there is no coolant in the oil or crankcase...wtf?

[Bubba]

The valve cover to air cleaner hose should be an air inlet to the crankcase. If you have goo coming out- that means you have so much blowby that the pcv vacuum hose (between #2 and #3 intake runners) can't handle it all. I bet you have a head gasket that is only leaking under high coolant pressure (when the car is hot) and like you said- the coolant is being burned/boiled. You might take off the pcv vaccum hose and be sure its not gunked up shut.

Is the rad always full? i.e. Is the system sealed well enough to develop enough of a vacuum to suck coolant from the overflow bottle as it cools down? That was my first clue before my head gasket went bad/the overheating tendency started.

I agree that it's odd- usually in your situation, the oil filler cap or dipstick will have a little bit of froth on it.

[Wink]

Bubba: I did not remember that it was the inlet-but now that you mention it that is weird. It's running ok now so I'm not going to try to fix anything further till spring. Not that I'm super lazy but it is 4 degrees outside here.

BTW: What kind of mileage are you getting? Just curious because I just picked up an 84 CRX DX 1.3 5-sp from the junkyard-just because it is a dx 1.3 5-sp. I've heard 70mpg rumors out of the 1.3 with the right gearing.

[Bubba]

BTW: What kind of mileage are you getting? Just curious because I just picked up an 84 CRX DX 1.3 5-sp from the junkyard-just because it is a dx 1.3 5-sp. I've heard 70mpg rumors out of the 1.3 with the right gearing.

I just have about 400 "break in" miles on the engine after the rebuild. The first tank was only 28 and the last tank was 33- but it's been cold and 90% has been city driving. I plan on doing a 6 hour highway trip in the next few weeks- that's where the HF trans shines- in fact, the tall gearing is a real pain around town and when pulling a trailer.

I'm an FE guy- you can see my mileage records here.

When the car was stock (1.5 liter and DX transmission), was getting mid to upper 30's on the highway. I found an 84 CRX 1.3 HF trans for $75 at a junkyard and that bumped me up to 42-44mpg on long interstate trips (plus it made the engine run much slower/quieter). Even though the 1.5 was still running good, I found this 1.3 at a pull a part and rebuilt it. I'm hoping it will get me over 50 mpg on the interstate, but I might need to wait for warmer weather until it gets that good. My 1.3 came out of an 87 Civic standard hatchback- so it doesn't have the roller rocker arms that I heard the 84 CRX 1.3 had and of course its not as aerodynamic as the CRX. I just bought an adjustable cam gear but haven't installed it yet.

Edited by Bubba, 19 December 2008 - 11:06 AM.

[Christ]

Bubba: I did not remember that it was the inlet-but now that you mention it that is weird. It's running ok now so I'm not going to try to fix anything further till spring. Not that I'm super lazy but it is 4 degrees outside here.

BTW: What kind of mileage are you getting? Just curious because I just picked up an 84 CRX DX 1.3 5-sp from the junkyard-just because it is a dx 1.3 5-sp. I've heard 70mpg rumors out of the 1.3 with the right gearing.

There's a guy on my other forum - Ecomodder.com - Pulling 70 avg from a EG Civic CX hatch.. but it's aero-modded and looks like a wingless plane, and he's using driving technique as a catalyst for his mileage gains. The coefficient of drag on his car is .17, where the stock cD of the CX is higher than .30.

If HE can get 70mpg with mostly driving technique in a much heavier, more powerful car, maybe YOU could get better than that with a lighter, less powerful car? Worth a thought, ain't it?

[Bubba]

There's a guy on my other forum - Ecomodder.com - Pulling 70 avg from a EG Civic CX hatch.. but it's aero-modded and looks like a wingless plane, and he's using driving technique as a catalyst for his mileage gains. The coefficient of drag on his car is .17, where the stock cD of the CX is higher than .30.

If HE can get 70mpg with mostly driving technique in a much heavier, more powerful car, maybe YOU could get better than that with a lighter, less powerful car? Worth a thought, ain't it?

I bet your talking about this guy right (below)?

Yeah- the lean burn CVCC engine in a lighter car should be superior for fuel economy. But I can see how injectors would have better atomization. A lot of guys on the FE forum drive 92-95 Civic VX's and get into the 50's- but then they have to pay big bucks for the 5 wire oxygen sensor when it needs to be replaced...

Edited by Bubba, 19 December 2008 - 11:41 PM.

[Christ]

I bet your talking about this guy right (below)?

Yeah- the lean burn CVCC engine in a lighter car should be superior for fuel economy. But I can see how injectors would have better atomization. A lot of guys on the FE forum drive 92-95 Civic VX's and get into the 50's- but then they have to pay big bucks for the 5 wire oxygen sensor when it needs to be replaced...

Yep, that's basjoos' car.

Guys on ecomodder are all about using the D15Z1 (VX engine) in other hondas to get better FE, b/c of the lean-burn mode it's ECU has.

BTW, that car was featured off Ecomodder in the "doing it wrong" thread at the VW forum LOL.