several tech questions(idiot buys bmw)

hoh

hoh

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hi all ..from a newbie
history:
first of all i let my licence expire 20yrs. ago ...so last year i started driving again useing a 93 VW when that was hit my neighbor sold me his verry nice 86 325..thinking that this almoast 20 yr. old car would be easy for an idiot like me to work on...i soon realize why bmw's are so sought after ...the technology used in the 86' was the same as the 93 ' Vw...now i have done whatrepares i can and tried to find info on mesg. boards but i think it's time to ask for help...
questions:
#1: I have a problem with fuel econ. , the gas peddle is verry touchy. i can get 38mpg in 4th but if i push a hair more or less it drops to 25mpg or deceleration occers( respectfully)..is this how an 866' 325 sould perform . I can't get over 25mpg in 1st 2nd & 3rd without decceleration occuring,,,this may be because i installed a performance chip, but i was told this would improve mpg's...now i have no referance to fuel economy w/out the performance chip because i installed it before replaceing a bad exauhst ...so before i put the old chip back in does any have any input for me?
#2: i also have a problem w/ idle fluxuating ..i have read some other posts about this, like O2 sensore(replaced )..but i did read one about a controle flap where the air fist comes in, something about it being bent due to backfires (can't find the post) any insight on this would be good . i'm thinking this because the car ddid backfire when i bought it..(previous owner to car to local shop and was told that this could not be fixed...me personaly have never heard of a machine that could not be fixed)
#3: car missfires periodicaly(ie: a slight hesitation, a dropping of of engine power for a moment)..i saw a poast about crossfireing w/ plug wires i will check for this in an hour when it's dark..any ideas
#4: my oil light(the one on the dash to the right i belive the pressure or pump not the servise indicator), comes on alot..is this normal
#5: the check engine light has been flashing since i got it (drives me nuts),
a friend told me that i need a special tool for this ..can't i just reset it myself(verry verry poor ) w/out buying an expensive tool??
#6 i have some vibrations above 55mph wich mellow out obove 80mph..i saw some poast that said the wheels may need balanced on the car..i have also bought a set of slightly used control arms, (that i'm scared to install)..they are much better than the ones that are on it(ie: the gromit towards the rear is not looking to good on the ones i have installed now)...coulld that be the cause.

anyway this is a nice ride i have already got my hands on another engine(complete for $300) and the koni shocks and strutts witch i don't know how to install yet...and i hope that my questions are not so stupid as to adjitate some of you... thanx HOH
 
hoh

hoh

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oopps...one other thing..i replaced the intank fuel transfer pump...but the main pump under the car is makeing a noticeibly loud whirring sound...is this normal(someone said it is)...or should it be quiet...i hope that it wasn't overloaded buy haveing to compisate for the intank pumps malfunction...thanx HOH
 
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epj3

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#3
1. Don't watch your MPG gauge when you're accelerating. It changes per speed and your rpm, so if you're going 10 mph at 3,000 rpm in first, obviously you won't go as far ona tank of gas like that if you were going 65mph at 3,000 rpm in 5th.
2. I think it would probably be the idle control valve, idle control computer, OR the cold start injector might be kept on. Get a bently manual from www.bavaut.com (my favorite place to get car parts)

4. Definitely not normal!! Check your oil level, that's the oil pressure light. That's quite crucial, and if you don't get that taken care of SOON, you could end up with a seized motor ($$$$$$$$$$)
5. There are a few methods to get it checked. Try turning the car to run and quickly pushing the gas down 5 times... it should blink a few times (the CE light), or just turn it to run and count how many times it blinks.


For everything else.. I'd definitely say get a bently manual. It's the bible to bmw repairs.
 
jrt67ss350

jrt67ss350

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#4
This car is an '86, so it is a 325e, not a 325i. Hence, it doesn't have a Check Engine light. Don't bother following Eric's advice for number 5, because it won't work on your car. The light that is flashing is the check control light located between the speedo and the tach. That flashing light is telling you to look at the Check Control panel up above the rearview mirror. What lights are lit up on that panel? Since your oil pressure light comes on periodically, I'd guess that the Engine oil light is lit up. If not, you can turn that flashing dash light off by pressing the Check button on that panel above the rearview mirror.

I agree with Eric's other answers. My '87 shows about 7 mpg when accelerating in first and second gear. You don't get the best mileage unless you are cruising at interstate speed in top gear. When you load the engine during acceleration, the mileage drops significantly.

The vibration at speed could very well be caused by worn ball joints in the control arms and worn control arm bushings (the grommet towards the rear). If your control arm bushings look bad, then they need to be replaced and are likely a cause of the vibration, especially if it is a side-to-side vibration from the front end. It'd also be a good idea to have the wheels balanced, as 3 series BMWs are very sensitive to wheel balance - if they are just a little out, then the front end will vibrate.

The miss firing could also be cap and rotor - what kind of condition are they in?
 
hoh

hoh

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hey thanx all....esspecaily for your politeness,
fuel economy in town is out the window i guess....i have the bently manual...and i've used it for some thing but ....(well my cognitive skills are low due to an accident which also affected my memory)...so it makes hard reading for me add in that i havn't worked on a car older than a 1980...but I'll get to a friend that may help...but as for the idle control valve, idle control computer, OR the cold start injector , I suppose that i can swap the ones off of the spare engine in a trial and error method..thanx for limitting the poibilities for me....as for the oil pressure light ,, i soppose that the pump is in the oil pan...I let the 2 manual(bently and onother) at my mothers near lancaster,Pa...(i,m in DE), or i'd check now...but i'll definately have someone look at it before i go and pick hem up...the light does not come on when the motor is cold and some times it goes off aas i heel-to-toe trough turns...i would assome that it is working but somehow then looseing pressure ..i guess it'll be for a mechanic to decide....as for the control arm bushings(see i'm learning), they look very worn, but they look easy tto replace ...so maybe tomorow i'll give i a go and put the better ones on ...though i was hopeing to put the shock upgrades on at the same time(but i think i need something called a sping compressor for that)..as for the wheel balance when i said balanced on the car i ment that they should be balancedwhile on the car...the guy that sold me the parts told me the same thing that they are very sensive tho balance but as usual i probably missunderstood him..also i didn't mention that i tried to have the car alligned and at the shop that i whent to they had my tire pressure at 25lbs..i drove to Pa like that(lucky i din't have a blow out)...
anyway i just whent out to check the indicatoer light the only lights that were on wre the brake (wich comes on sometimes but goes out when i tap the brakes) and the coolant light wich comes on when the coalant is slightly low this usualy goes out when i fill it a quarter inch more...but did not this time...but this time when i depressed the check button overhead the flashing check engine light whent out...go figure i guess i'll try to clean up the leads that conect to the sensor on the vessel that holds the coolant maybe this will rectify the problem...ha my wife just found the chiltons manual ...I'm looking at the oil pump it seems that thier is also some kind of tention that needs to be set on a drive chain
...boy i am worried that my engine may already be damaged...as for the check oil light it came on once , i stopped checked and added a little oil and it whent out....but it also looks like i could change the pump also w/ my spare ....anyway i feel like i'm getting tiered and not making to much sense...i'll let you know how it turns out...HOH
 
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ratphoto

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#8
The mpg gauge measures manifold vacuum, not the actual mpg. Since manifold vacuum changes depending on throttle position, engine load, etc., it provides a rough estimation of what the mpg should be under specific conditions.
 
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epj3

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ratphoto said:
The mpg gauge measures manifold vacuum, not the actual mpg. Since manifold vacuum changes depending on throttle position, engine load, etc., it provides a rough estimation of what the mpg should be under specific conditions.
Click to expand...
You're very wrong. If it read manifold vacuume, then HOW would it say 5 mpg at a steady 3,000 rpm in first gear (remember the engine speed being 3000 rpm is ALWAYS 3000 rpm regardless of how fast the car is going), but 30 mpg at 3,000 rpm in fifth gear???

There's nothing on the vacuume/intake system that goes to an econoguage or any kind of sensor anyways. It all has to do with the RPM's + Speed.
 
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