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Mpower
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Discussion Starter #1
Hello All E30 fans,
I have a 91 325ic automatic, I love this little car,but i think it hates me, the gas milage is killing me, Its about 14 or 15 mpg in the city, is this normal?my 1997 M3 gives me about 20 mpg in the city.
I've replaced whatever was there to be replaced,Oxy sensor, themostat, temp sensor, sparkplugs, filters,intake manifold gaskets,
The car has 181kmiles on it and the engine pulls streong and the transmission is shifting smoothly, all I can get out of a tank of gas in the city is about 200miles,
I suspect the AFM , I played with it and there was no difference in the Mpg, the car passed the california smog test perfectly, it doesnt burn oil at all, no leaks anywhere,(pretty unusual for a BMW this old).
Well I'm stuck, If anybody can give me some idea of what might be wrong with the car ,I'd really apreciate.
Please If its possible direct your inputs to my email address
[email protected]
Thanks
Henry(Losangeles)
1991 325ica,cosmosblack on modenainterior, and working powertop :) and a hardtop.
BBS RZ 15x7
1996 M3 cosmosblack on Modena
 

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My wifes 92 325ica with 16's on it gets 23 mpg average overall out of a tank and we live in the DC area. Same style traffic, mixed.

Is the transmission shifting properly? ie are you getting to fourth gear? Is it low on fluid? brakes dragging? Have you done a compression test? The engine could be getting tired but doesn't seem likely but I don't know the maintance history on it either.
 

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Mpower
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Discussion Starter #3
Sent: Tuesday, June 14, 2005 8:08 AM
Subject: Re: "E30 325ica gas milage" update


Hi:
Thanks for the input, as far as the transmission shifting correctly, it does shift correctly and with a very little jerk at the time of shifting. The eigne compression might be OK since it runs, idles and pulls very good, plus it passed the smog test with better than average readings.
Some tell me its my driving style, might be true too, I have to admit that I have a heavy foot, and being used to the M3 power, maybe I'm expecting too much from this little car.
But I have also tryed to take it easy while driving this car and I couldn't get more than 16 mpg on average.
There is one last part that I think I have to replace and its the air flow meter.
Any opinions on that?
Thanks for your help
Henry
 

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did you try the 02 senser? If it isnt working properly it could be making your air/fuel mixture run rich which could cause your car to not properly burn all the fuel and waste it.
 

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Mpower
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Discussion Starter #5
Re: Gasmilage

Yes I have replaced the following parts but no changes what so ever has hapeened to the gasmilage
1- New Bosh Injectors
2-New O2 sensor
3-New intakemanifold gaskets
4-ECU temp sensor
5-sparkplugs
6-all new filters
7-new thermostat
8-mobil 1 10w30 oil
have tryed all avaliable gasolin grades 87, 89, 91 oct in california
and still I'm getting 14 15 mpg
all i can think of is the airflow meter or the feul presure regulator
the car passed the californioa smog with flying colors
doesnot burn one drop of oil the car pulls strong for its age and milage (currently 181k miles.
A full tank of gas (14 gal) gives me 200-220 miles in the city
is it normal?
The gasmilage on the freeway is excellent,
Thanks for all your inputs
Henry
 

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I'm no expert here by any means, but I have a 1988 325iC and I get from 26 to 32 mpg. If I drive hard (probably how you do) a little over 20. Just a thought. Do you have a leak in your gas tank? 14 seems extremely low.
 

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Mpower
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Discussion Starter #7
There are no leaks anywhere.
I also was wondering if my driving distances could be the problem, I drive short distances in the city , like max 3 or 4 miles everytime I start the car
Henry
 

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Mpower1 said:
There are no leaks anywhere.
I also was wondering if my driving distances could be the problem, I drive short distances in the city , like max 3 or 4 miles everytime I start the car
Henry
Yeah, that's not going to help. I had a stick shift version, and probably got around 18-20 in mostly city driving (IIRC). I don't think I ever got up to 32, except maybe for long downhill stretches, on the highway. 14 seems low, but with an automatic, a/c on, and only short distances, you might get mileage that low without having something wrong.
 

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Mpower
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Discussion Starter #9
Re: gasmilage

there are only 2 more things left to be replaced, the airflow meter and the feul pressure regulator, I might change the regulator and see what hapenes, I disconnected the vaccum hose that conects the intake manifold to the regulator and plugged the hose on the manifold side, and didn't see any changes.
Thanks again for all your inputs
Henry
 

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My question to you ? are you mainly driving up hill? because it does make a difference I found out that if I plan all my trips travelling down hill I actually can go 100 mpg verse up hill when I can only get 23 mpg. Give it some thought, Just put in Neutral and coast down hill. I'll guarantee you'll see improvement. Problem solved
 

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My car in mixed traffic gives me around 280 miles/tank with a mix of heavy traffic and open freeway.
Go test your car on a Sunday morning, fill the tank and drive 200 miles on the freeway at 65-70, then top it off and compute your mpg.
If it's 23-25, you're doing fine I think.
 

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Bavarian Autosport
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Those short distances probably aren't allowing the car to completely warm up. They run quite rich when they are cold. If that's what you're basing your mileage on probably nothing is wrong with it. When new the car was rated at 20 city and 23 highway according to the Bentley 3 series enthusiast's companion book. That was on non-ethanol gas too and typically you lose a bit of mileage over the old ratings with the wonderful 10% ethanol gas we all have to deal with now. I average 25 with my hardtop but it's a 5 speed and it's almost all highway.
 

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Your really not going to get much better than what your getting ,it's a 23yr old car after all give it a brake .There could be a few things that affect mileage you haven't thought of though, like have you checked to see that your tire pressure is right and the same at all 4 corners ,also what size and brand as well as type of tire are you using performance tires are not great for mileage and less expensive tires tend to create more rolling resistance .Smaller tires also can contribute to mileage loss for the same reason ,this is one reason most MGF don't use anything less than a 16" tire anymore.You could have other issues but it sounds as though you've done a good job addressing all the common problems and your car really would not run very well in you had a faulty AFM or fuel pressure regulator .
 
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