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Discussion Starter · #1 ·
Hi guys,

Did a full tune-up on my 87 900 8V about 4 months ago... and just wanted to know if my gas range is typical.

Replaced:
Fuel filter
Air Filter
Plugs
Wires
Dist. Cap
Dist. Rotor
Cleaned all ground points.
Oil change/filter
Tranny flush/new oil (15W-30, had a bit of noise beforehand, gone now, shifts GREAT)
Might have been a few other things, but that's basicly it.


Last time I filled it up, I got I think right around 260 before the light was on for an extended period of time (mine will flicker for a day or two) Right when it was on the E Line, I fill up. I've run out of gas many times in this car, seeing as how it seems to go staight from "1/4 tank" to Empty.

This does include some spirited driving. I beat the hell out of my saab. WOT most days. Car has 230K miles on it, and still trucking just fine. Has a small small amount of lifter noise, but seems the more I drive the car, the better its getting.

Only thing I have done to it that is "non-factory" is gutted the catalytic converter to help get a bit more top-end out of the motor.



Also... does anyone know of a good write up for removing the speedo unit? I think the gears could use some loobing. The speedo never worked since I've had the car, but the odometer works just fine. I've read this is a common problem on saabs, and a simply lubing of the gears should fix it.

Thank you for your help,
Classic900
 

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Hey there -
For the speedo, take the speaker cover off and look to see if the cable has just come loose from the back. Mine does it all of the time believe it or not.
I have an 86/87 c900, and like you I recently did all of the major tune up stuff, tranny, oil and so forth. Mine is an 8v non-turbo 5-speed. I manage to get no less than approx. 400+ miles out of a tank of gas, in the city.
Now, my odometer does not work, but I know that I drive 37 miles a day in it, 5 days a week to and from work, not on the freeway.
I also drive the crap out of it, all over Atlanta on the weekends. So, 37X10 days = 370 miles
Add another 25 or so for the weekends, running around here and there. I fill up on the thursdays that I get paid, and still have plenty of gas 2 thursdays later!
 

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Hu Flung Dung said:
Hey there -
For the speedo, take the speaker cover off and look to see if the cable has just come loose from the back. Mine does it all of the time believe it or not.
I have an 86/87 c900, and like you I recently did all of the major tune up stuff, tranny, oil and so forth. Mine is an 8v non-turbo 5-speed. I manage to get no less than approx. 400+ miles out of a tank of gas, in the city.
Now, my odometer does not work, but I know that I drive 37 miles a day in it, 5 days a week to and from work, not on the freeway.
I also drive the crap out of it, all over Atlanta on the weekends. So, 37X10 days = 370 miles
Add another 25 or so for the weekends, running around here and there. I fill up on the thursdays that I get paid, and still have plenty of gas 2 thursdays later!
Interesting car you have there. A 400 mile range -- assuming you're fueling when the gas light comes on (and your system is correctly calibrated -- meaning you have just under 2 gallons left when the light comes on) means that you're getting between 26-27MPG in the city. That's an excellent number. It's more than the car is rated for. A 5 speed should do about 28MPG on the highway. You're almost doing that in the city. Great car.

Classic900: Your car seems like it's doing well -- what it's suppossed to -- given how you drive it. In the city, especially for a fast driver, anywhere from 19 to 22MPG is normal. You're just under that, but you're driving hard. Ease up on the gas and you should come in within a normal range.

I responsed based on my experience with an 87 5speed and my current 89 automatic; as well as reseraching EPA fuel economy figures.

Siggy
 

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More tips on improving the mileage.

1. Check/correct the timing. It's probably off. Made a big difference in the acceleration of my 8v.

2. Make sure your idle is steady and around 750 or so. 900-1,000 is too high. Check the Bentley for the exact number.

3. Replace the Oxygen sensor. It's $35 for the 8v NA, not bad compared with $100 for a turbo. The replacement interval is 70,000 miles I think.

4. Search the forums about gutting the cat. I thought it improved the turbo, due to better airflow/spool-up for the turbo, but I thought it hurt the NA. I know that my 8v ran awful (No power) when my header pipe sheared off before the cat.

5. 87 vs. 89 octane will make a difference too.

I'd say you should be able to get 300 miles/tank if you take it a little easier. Before my odometer broke, I was getting about 25-28 mpg from my NA, mainly highway. My Dad claimed to have gotten over 30 mpg when the car only had 70,000 miles, but I doubt it.
 

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Discussion Starter · #5 ·
Thanks for the replies guys!

I know its not a cable issue, as the speedo kinda does the crazy dance... cruising about 45... it'll go from 35 to 100 really wildly. Gotta be a gear issue inside the panel. Odometer works fine. Accurate.

I do need to do a timing adjust... I'm sure its off more than a few degrees.

I have a question though. I honestly have no idea how mechanical fuel injection works.... but since there is no ECM controlling fuel (As far as I know) what exactly does the 02 sensor do??

I really need to get a factory service manual for this puppy. Anybody know of a PDF version online?

As far as the octane issue: I have always been told that a non-forced induction engine, with moderate compresion ratios (not a newer high compression engine) will ALWAYS run better with 87 octane. N/A cars shouldnt need 89 plus, as all you're doing is raising the flash point of the fuel, therefor reducing horsepower, making you press on the gas harder (in theory, that is)

Any kind of forced induction, I know to use 90+. Always been a mis-conception with the ricer honda kids, who think that 110 octane racing fuel is making their car "mAd FasT y0!!!" when all its REALLY doing is reducing horsepower.

Also... if I take a corner a bit sharp (what can I say... I BEAT UP THIS CAR!!) then I get a VERY strong gas smell. Like its leaking or something. I lifted the cargo area under the trunk, to see if that hose connection for the fuel door has come off. No leaks what so ever, and cant really re-create the smell when the car is standing still. Only when making sharp turns. Its definately raw fuel, not the smell of running without a cat. I know some cars run bad with no cat... as the exaust doesnt have much backpressure... however I havent noticed any bad side effects from taking it off. No difference in economy, but I did pick up a fractional amount (according to the EXTREMELY ACCURATE butt dyno ;) ) on the top end.

Is there any kind of easy to do performance adders to squeeze just a few more horses before she blows? I kind of did a ghetto CAI to the air filter canister, using the front driver air inlet. Took out that nasty aluminum header wrap thingy.... sucking in hot air straight from the exaust manifold isnt very good for performance ;)

So my reading continues!!!
Trying to locate a decent 16V turbo to do a swap some day... wouldnt mind rebuilding it and possibly building the motor up a tad to take some boost :)
 

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Sounds like you are really getting into the car . . . then you must get the Bentley manual. Make sure you get the 8v. You can also order them from chain auto parts stores like Kragen, Autozone, Checkers, etc. It's about $45, but so worth it.

Or, buy it here
http://www.saabcentral.com/bookshop.htm

As for the octane. I noticed improved climbing ability with the 89 octane.

Try using the search tool for issues like the gas smell. Believe me, you'll find something.

Eventually some one WILL tell you to get the 16v turbo if you want to go faster. But I kept mine, because it's much simpler to work on.
 

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Classic900 said:
I know its not a cable issue, as the speedo kinda does the crazy dance... cruising about 45... it'll go from 35 to 100 really wildly. Gotta be a gear issue inside the panel. Odometer works fine. Accurate.
The speedo needle bit is really simple. There's a magnet spinning on the end of the cable and another on the axis of the needle. There is also a watch-spring attached to the needle trying to turn it back to zero. It's probably dirt in the needle axis making it stick.
 

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Calibration? I'm definetely not sure about that. My fuel light sometimes will come on when it looks like the guage has plenty of gas, and sometimes it will come on when it looks likt the needle is below the lower red mark. Sometimes it flickers, sometimes it doesn't. Sometimes I drive it for a day with the light on, sometimes I get gas immediately. I know how far it is to-and-from work, and I know how many days I commute in it at that distance before I have to get gas. There's no doubt in my mind that it's getting well over 400 per tank :) ^ )
I need to take the car on a freeway trip and see how far I can actually go..it hasn't been on the freeway for a while, other than driving across town and such.
Road trip!:D I might fix the odometer too one day HAH

The guy I bought it from, who is a long time Saab mechanic and purchased it new, told me at the sale that he always got well well over 400 miles to a tank when he put this 8V NA in it (it use to be a 16V turbo). I didn't believe him at the time, thought it was a sales pitch, but turns out I'm hardly ever putting fuel into it. Good thing!
Hope it stays that way!
 

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I get about 22-23 City with my 8V N/A 900 4-door with a 5-speed. I tend to get about 25 on the highway if I keep my windows up. I also have a roof-rack with snowboard and bike attachments adding drag. Most of the time I drive it relatively economically, but I do drive it hard on occasion (220K and she's still purring!)
 

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Classic900: Please, please, please find out where that fuel smell is coming from. That is not normal and gasoline is nothing you want to be breathing or be smelling inside a car.

I would not waste my money with higher octane. From a simple economics persperctive -- even if it did raise you fuel economy a few percent (which it won't) you're paying 10% or mor for the higher octane. It's like purchasing an expensive widget to raise fuel efficiency -- but the widget is so expensive it's unlikely that the total amount of money saved through fuel efficiency improvement will never equal the price of the widget over the expected life of the car. Higher octane allows you to run at a higher compression ratio without detonation. Higher compression ratios result in higher thermal efficiency through more efficient combustion. To change compression ratio you have to machine parts of the engine or change pistons. You are not going to do that, that is expensive and not necessary. A low compression engine running higher than needed octane will actually experience unchanged, if not very very small decreases in efficiency. If your timing is too far advanced, or if you have hot spots (for example carbon deposits in the combustion space), or plugs of too high a heat range -- all bad things -- higher octane will lessen detonation, but the best strategy is to correct the problems rather than to cover it up with more octane.

I do think that you are within a driving-style-change's distance of having fairly normal gas milage. At the same time, it appears that you have conflicting interests. Maximizing fuel economy and increasing power are diametrically oppossed objectives. I think that you probably should sell the 8V and go get a turbo with a 5 speed. Reading your interesting post leads me to that prediction of what you really want. Cars, especially Saabs, are such objects of emotion and emotions are the hardest to correctly identify. :cheesy:

Turbo. Drive safely and enjoy!

Hu Flung:

That's some car! It reminds me of the fact that the only time I seem to hear about people's activities in the stock market is when they get rich and buy a big house. Most people actually lose money or make very modest gains. :D

I'm not sure how a car can get gas milage so much better than normal -- are you driving with a tailwind?

I never rely on the gas gauge to get my gas milage. Each and every time I get gas, I top off and reset the odometer. When I refuel I divide the odo reading while at the fuel pump by the exact amount of gas the pump displays that went into the car. I do this every time because changes tend to flag an impending problem. I just bought a 89 auto and on my first refueling, it did 19MPG, and I spend a lot of time idling in California traffic and I idled the car for 15 minutes after an engine steam clean. I'll probably do 20 MPG next time (I found a few vacuum leaks and the charcoal cannister was connected to nothing).

That engine of yours should go into a museum after it's run out!

Siggy
 

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Siggy said:
) I'm not sure how a car can get gas milage so much better than normal -- are you driving with a tailwind?
Siggy
Would having the old Turbo exhaust piping, muffler and such have anything to do with it?

When the 16v turbo was taken out, only the engine was swapped to 8v NA. The exhaust system, muffler and tailpipe are all leftover from the 16v turbo. It's a *little* loud, but I don't hardly notice it anymore. I've always wondered if that affects the engine in any way shape or form. I was worried at emission time, but it passed better than any of my other cars, ever. Toyota, Honda, Volvo...none have ever passed to well. I was floored the first time I took it in for testing.
Don't know. Mabe I got lucky with this engine? My wife use to drive the car, just around town here and there, not a dialy commute, and we NEVER gassed it up. It would go forever and we sit in Atlanta traffic much like Cali traffic (I've lived both places so I'm familiar!) quite honestly I liked Cal traffic much more than Atlanta traffic HAH
 

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Hu Flung Dung said:
Would having the old Turbo exhaust piping, muffler and such have anything to do with it?

When the 16v turbo was taken out, only the engine was swapped to 8v NA. The exhaust system, muffler and tailpipe are all leftover from the 16v turbo. It's a *little* loud, but I don't hardly notice it anymore. I've always wondered if that affects the engine in any way shape or form. I was worried at emission time, but it passed better than any of my other cars, ever. Toyota, Honda, Volvo...none have ever passed to well. I was floored the first time I took it in for testing.
Don't know. Mabe I got lucky with this engine? My wife use to drive the car, just around town here and there, not a dialy commute, and we NEVER gassed it up. It would go forever and we sit in Atlanta traffic much like Cali traffic (I've lived both places so I'm familiar!) quite honestly I liked Cal traffic much more than Atlanta traffic HAH
California traffic is the worst on the planet, and until astronomers find optical images of other planets, or vehicular traffic on stars, I'll assume California has the worst traffic in the universe. I see people using compueters, eating, cell-phoning, shaving, reading, applying makeup and now -- watching TV in traffic. And they're safe. What can they hit while going zero MPH?

A lower restriction exhaust would help increase power at higher RPM. If that results in you using less right foot, then it could help fuel efficiency. Less exhaust back pressure (caused by restriction, bends, etc.) reduces the ability of the piston to evacuate burned combustion gases and accordingly reduces the partial pressure of oxygen in the cylinder for the next cobustion event. If your cam has some overlap, it also reduces the amount of scavaging that occurs (the tendency for an outgoing exhaust pulse to create a partial vaccum drawing in an increased amount of intake charge). You might also have an excellent exhaust tuning arrangement where pulses BETWEEN cylinders are lining up very well and creating a good header scavaging affect. All of this increases the ability of the engine to breathe which goes to more power gains. But again, increasing the intake charge density means more fuel! The offset to this is that it takes less throttle to get the car to a desired speed and your less into the throttle to maintain a given speed.

Anyway, while power improvements on the order of magnitude of your fuel efficiency improvements are claimed by exhaust component manufacturers (some that strecth the truth, I'm sure). I don't think your gas milage is explainable by exhaust differences.

Siggy
 

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Discussion Starter · #13 ·
Well, I'm not really all that concerned WITH the gas mileage, it was more to see if something wasn't quite right with the car... and I was running pig rich.

It has a very very hard time running for the first 10 minutes. It will idle fine, but when I start to press on the gas, it gets BOGGED down and basicly its like the spark just cuts off. My prediciton was it was running WAY too rich. Hence the gas mileage question.

This car still gets FAR FAR better mileage then my last car (89 1.3L Rx7 Rotary.... we all know how those puppies STARVE for fuel).

As far as the performance aspect.... I'm not looking for something "fast" or expecting anything really... until I do go turbo. But it won't be this car. I got this car for free, and honestly i hate the 4 door. I'd much rather have a 2 door SPG with spoiler option. Those I like. Jet black, with charcoal 8 spoke wheels, and possibly some of that beautiful Erebuni body panels on it. :cool:

Anyone know someone on this forum that has the aero pieces from Erebuni? They make alot of quality products for the RX-7, so I emailed them for some pictures if they made something for the 900.. and surprisingly they DO!

This is all they sent me, which they say can be found on their site.




I think the *** end of that car is dead sexy, and I do have a small amount of experience with glass... so i may modify the front end, to smooth it out a bit. That's my goal however... pick me up a nice 2 door SPG turbo, and if possible do the above aesthetics.

Thanks again for the help guys!
 

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It has a very very hard time running for the first 10 minutes. It will idle fine, but when I start to press on the gas, it gets BOGGED down and basicly its like the spark just cuts off. My prediciton was it was running WAY too rich. Hence the gas mileage question.
My '85 8v has this same problem. I assumed it was operator malfunction. I just got this car a couple weeks ago and it's my first 5-speed in almost 8 years, so I'm a little out of practice on the clutch ;oops:

If it is running too rich, what's the most effective solution? The guy who owned the car before me says he was getting at most 300 miles to a tank, which is only 18mpg! It's only got 190,000+ miles on it, so surely it should be getting better mileage than a gas guzzling Ford. The fuel gauge is inaccurate according to the previous owner, but I'm not so sure of that. I've thought of tossing a 5 gallon can in the trunk and just driving her til she dies to get true reading on the trip meter and see if the gauge still works. It's no big deal to replace a sender, but I'd rather not spend the $$ if it's not necessary.
 

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NCSaabStory said:
So with the light on I should still have somewhere between 60-100 miles left on the tank?
I'd get pretty worried around 25 miles after the light. The warning lights have a pretty bad rep for being unpredictable/inaccurate.

The 22-23 mpg was based on my experience in my SPG. The light usually comes on around 12.5 gallons (Used gallons that is). The most I've ever run is 13.5 gallons in my SPG and my 8v. My 8v hit the warning line (Not light) at 10.5 gallons, whereas my SPG hits the line at 12.
 
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