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Old 05-09-2013, 07:27 PM   #1 (permalink)
MPG is not linear police
 
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Talking Just got a 89 Civic HB

I just picked up a 89 Civic hatch, 4 speed manual. It is raining on and off here, so pics will have to come later. The body is in great shape. Driving a 4 speed is...different. I kept trying to throw it into 3rd at 20 MPH and it just wasn't having any part of that. Odd that it gets better mileage than the 5-speeds. Fueleconomy.gov has the 4-speeds at 29/35 and 5-speeds at 27/33. Taller gearing?

I was wondering where should I begin with the ecomodding? Since it is so old, there is no ODB, nor a tach, so I'll have to do fuel calculations by hand. Maybe invest in that MPGuino in the future? I don't know much about it other than it exists.

I do need to get the throttle looked at because it will stick slightly and I'll have to blip the throttle or put my foot under the pedal to clear it. That is going to literally waste gas until I fix it. I'm 99% sure I'm going to have to take it to a shop because I don't know where to begin to fix it. If anyone has any ideas, I'd appreciate the help.

This car will be doing all my short trips around town, compared to the 4.6L Mustang, I should save a fair bit of gas in the long run.

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Old 05-09-2013, 08:50 PM   #2 (permalink)
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That's a strong choice for wheels! As for the sticky throttle, there's a few things you can try. Get a can of WD40, climb under the dashboard, and spray the pivot point where the gas pedal mounts to the firewall. Then pop the hood, and have a look at the very top of the engine. You'll see the throttle cable going across the valve cover and to the throttle body. There is a bracket that holds the cable at the edge of the valve cover. Those tend to get bent when people remove the valve cover, and end up holding the cable on a weird angle so it can make it sticky. You want the cable to be nice and flat there pointing at the throttle body, not pointing down at it. The one in my '90 was bent, so I just smacked it with a hammer until the cable was sitting flatter and closer to the valve cover, and it actually made a difference. Maybe it will work for you too. Good luck!
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Old 05-09-2013, 09:58 PM   #3 (permalink)
MPG is not linear police
 
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Thanks, I'll give it a shot in the AM.

I think I'm describing my problem wrong. The pedal isn't stuck, but pulling up on it does help, but it will just rev for no reason, or idle real high until I blip it. I think you're right with the cable. My googling has revealed that this is a common problem with the 4G Civics.
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Old 05-09-2013, 10:18 PM   #4 (permalink)
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Cables are cheap, it could just be corroded and sticky. When it idles high, does it surge? As in does it rev up, then down, then back up again, or does it just stay high the whole time?
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Old 05-09-2013, 11:03 PM   #5 (permalink)
MPG is not linear police
 
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When I start it, it will rev up for a bit (3-4 seconds) then down. It is a little hard to start. It will crank for about a second. It just seems like a long time because I'm used to my Mustang just firing right up. It has only been occassionally driven over the last 2 years, according the the previous owner.

I will be getting tags tomorrow, so I've just taken it around my neighborhood tonight (my road is a side street, off a side street, of a side street and it isn't a cut through to anywhere. 0% chance of cops.) and sometimes when I let off the gas to shift, it is still revving like I didn't step off at all.The guy I bought it from drove it to my place, taking on the DC beltway just at the start of rush hour, on his tags.


I am 100% sure it is the TB or cable. This isn't a totally pressing matter because in Maryland I can register it as a Historic Vehicle (20+ years or older and not substantially modified. I also will pay less insurance and tag renewal fees as well. I think I will put on 3000 miles a year. Max. It has 155,xxx already) and there is no new-title inspection required. Just pay for the title transfer, tax, tags and go. It does limit how often I can drive it (like highway usage) but it is my around town car.

I plan on getting a full inspection in the future and hopefully being able to fix everything on my own if anything fails inspection. If it passes/I get it to pass, I would consider switching my tags to normal car tags, so I won't have driving restrictions. I knew what I was getting into buying a 24 year old car (my GF was 7 when it was built -- EEP!) and that I'll have to DIY for a bit. Having the bike and another car, I feel confident that if I fudge something up, I still have wheels to make it to the parts store.

The head/tail lights and rims are all new. It has some very used racing seats for the front and a racing style steering wheel. Tire treads look good. I'll over-inflate by about 10% over max sidewall. I'm going to do a full oil change and change out the battery, just so I know it is fresh. It had a new paint job in the last 2 years. It is a dark plum-y with metal flakes. Matches the flakes I have in my Mustang (Mineral Grey).

It is at about 1500 lbs lighter than the Mustang (1940 vs 3480) and it feels like it. It is what, 70 HP(?), but it moves pretty well considering. It reminds me of my first bike, late 90s 250 Ninja. Despite the low power, it had decent pep. Where I plan to drive this Civic, I will face 25-45 MPH limits, so the lack of power doesn't concern me. Who knows, maybe in 5 years (if I had the cash) I would just do an engine/tranny swap, for a VTEC, that all the kids are doing these days.

And if money were no object, I'd just rip out the engine and fill the hatch full of batteries and go full EV, but alas...
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Old 05-09-2013, 11:17 PM   #6 (permalink)
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Ya sounds like a cable issue. Or perhaps a temperature sensor for the hard starting? If the ECU is confused as to what temperature the engine is at, it might be trying to keep the high idle on to help the engine warm up, even though it's already warm, which would explain the revving. I asked about the surging because when older Hondas get low on coolant, they will surge idle as they aren't getting a proper temperature sensor reading and they get confused. When the temperature sensor cracked in my Saturn, it caused all sorts of weird problems that you'd spend a fortune trying to get fixed, and it was just an $11 part failure. So my best advice is use your google-fu to research, then narrow it down to the most likely. Then start with the cheapest of those ha ha. It's an '80s Honda - it's one of the few things that will be left moving besides cockroaches and old Mercedes diesels after the end of the world lol. Whatever is wrong with it more than likely isn't serious.
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Old 05-10-2013, 01:01 AM   #7 (permalink)
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A can of throttle body cleaner in and around the throttle body should help it run better as well.

Change the transmission oil, it takes regular motor oil in the transmission, synthetic works great, 0w30 makes it shift smoothly in the winter.

The 4 speeds were great, 4th gear is pretty high and is only out done by the CRX HF transmission but is most likely not worth the cost and work unless you need a new transmission anyway.

If you end up needing tires, 155/80 R13 are the best option.


You end up with one of my favorite cars.
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Old 05-10-2013, 03:32 PM   #8 (permalink)
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My CRX did something similar with the throttle; pulling up on the pedal would get the RPMs back down again. I pulled off the intake and hosed the inside of the throttle body with carb cleaner and wiped it out with a rag. Had to do that several times before the rag came out without a bunch of gunk on it. The throttle closed just fine after that!

With a four-speed, I think your car is probably the base or "DX" model, with DPFI (Dual-Point Fuel Injection, a throttle-body injection setup) instead of MPFI (Multi-Point Fuel Inejction, a standard port injection setup). Anecdotally, an MPFI swap gains a bit of power and fuel economy for the DPFI cars. But it is some work.

The MPGuino is an Arduino-based MPG meter. You solder the board together, plug it into your desktop or laptop computer, and load in the MPG program. Then you hook it into power, ground, the VSS (Vehicle Speed Sensor; inside the speedometer of that generation of Civic) and fuel injector wires.

-soD
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Old 05-21-2013, 02:42 PM   #9 (permalink)
MPG is not linear police
 
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Ciderbarrel's P*2 - '22 Polestar 2
90 day: 108.13 mpg (US)

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Quote:
Originally Posted by Ryland View Post
A can of throttle body cleaner in and around the throttle body should help it run better as well.
Ok, I have the cleaner but I feel so stupid that I can not figure out where the TB is.

NM. I found it. I'm used to dealing with my Mustang's huge intake that I didn't realize what I was looking at in the civic
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Old 05-21-2013, 02:59 PM   #10 (permalink)
MPG is not linear police
 
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Join Date: Jun 2011
Location: Charlotte, NC
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Ciderbarrel's P*2 - '22 Polestar 2
90 day: 108.13 mpg (US)

Ciderbarrel's Civic - '08 Honda Civic LX
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Thanks: 7
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Quote:
Originally Posted by War_Wagon View Post
Then pop the hood, and have a look at the very top of the engine. You'll see the throttle cable going across the valve cover and to the throttle body. There is a bracket that holds the cable at the edge of the valve cover. Those tend to get bent when people remove the valve cover, and end up holding the cable on a weird angle so it can make it sticky. You want the cable to be nice and flat there pointing at the throttle body, not pointing down at it. The one in my '90 was bent, so I just smacked it with a hammer until the cable was sitting flatter and closer to the valve cover, and it actually made a difference. Maybe it will work for you too. Good luck!
It doesn't look bent. It appears to be pointing directly at the TB. I'm about to take the intake off and spray it down with cleaner.

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