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First time BMW owner. Just purchased a 1990 525i. Help?

18K views 79 replies 11 participants last post by  BMR_LVR 
#1 ·
So I just bought his car today. Kind of an impulse buy, but from everyone I talked to it was a good deal. It's in amazing condition for being a 90' and having 150,000 miles. I paid $1800 for it, it has no mechanical issue and runs well and like I said is in amazing condition. Did I get a decent deal? Regardless, the car is mine. So I have a few questions. What kind of problems should I look out for? What things will I come to love? What kind of aftermarket parts are available and should I even bother with them? I know very little about BMW's but assume they don't need anything aftermarket to drive amazing. Thanks for any help, I'm extremely excited to own this car and can't wait to start workin on it and driving it.
 
#37 ·
GREAT LIST!

The only thing I disagree with is your choice of spark plugs. I would always go with the good old copper ones since these older engines designed in the 70's respond better to copper than to the fancy new metals.
It is pretty much the same thing except that the new metals are meant to last longer. I think running the stock copper plugs are best though.
 
#38 · (Edited)
The engine may have been designed in the 70s but the ignition system and everything else has been updated over time. There is no apparent reason why it should respond better to copper ones, unless they generate a bigger spark etc for some reason. Can you advise me on why you believe it to be so?

In any case, the copper ones are ok. Get 2 or 4 claw copper ones. Then pull them out once every 12-18 months for an inspection, cleanup, and A light sand down of any accumulate crud on the tips, before reinstallation.
 
#39 ·
I don't know why, but the general consensus is that the new metal plugs cause the M20/30 engines to have decreased performance.

Maybe its a personal preference thing, but people have complained about the new plugs as of late, and people have not complained about copper plugs for the past 30 years.
My opinion is based on the experience of others and not empirical evidence. I would imagine it to be hard to test this kind of thing, so go figure.
 
#40 ·
I don't know why, but the general consensus is that the new metal plugs cause the M20/30 engines to have decreased performance.

Maybe its a personal preference thing, but people have complained about the new plugs as of late, and people have not complained about copper plugs for the past 30 years.
My opinion is based on the experience of others and not empirical evidence. I would imagine it to be hard to test this kind of thing, so go figure.
Well, anecdotal evidence has its value as well. Hmm.
 
#41 ·
Radian has posted an outstanding writeup on important to-dos when it comes to adjusting your valve clearances. He includes certain better-than-oem suggestions, that were not available when the engine was originally built all those moons ago. Please see :

http://www.bimmerfest.com/forums/showthread.php?t=487113
 
#43 ·
Wow thanks a ton for all the information. That will really help me getting my car where i want it to be. Yea this is the older OBD1 and Autozone only does OBD2 (my side job as at auto zone) but no worries. Cool sounds like i have a lot to work on over these next few months. What would you recommend i start on first? I have a 2 week old baby, 2 jobs and go to school full time so i dont have a lot of time to work on my car. But, i do make time for it so i will be starting on your list as soon as possible. So its perfectly safe to put a few gallons of diesel in my engine? Also, why do you suggest the diesel engine flush? Would you recommend this for any other brand vehicle, or is this particular to BMW engines? Thanks again for all the information, its a huge help.
 
#44 ·
I did not say a few gallons of diesel. Anything from 1-3 quarts, on an empty or nearly empty tank, with an immediate top up of regular gasoline. I.e. you are moving from one pump to the adjacent one and doing this. This cleans our your fuel system all the way to the injectors and is worth alot more than the couple of ounces that you get with commercial FI cleaners. higher volume of cleaner = better cleaning. Figures.

The diesel crankcase flush can be done on any vehicle as well. This is an engine flush. It should be obvious why an engine flush is a good thing. 1 quart of diesel is really cheap and since you're only using it every time you change your oil out at 12k-15k miles (if you are using fully synthetic fluid) it is a mild expense and inconvenience.

Your first priority is to kill all the no start issues. Source for an purchase all of the items on line. When you have them ready, get to them immediately. If you had intended to do your engine belts, WP and fan clutch, do those as well together with the CPS swop as you'll be removing the fan clutch and shroud and that makes replacing the CPS much easier. The CPS swop, fuel pump/pump o ring swop, electrical relays, fan clutch, water pump and (for good measure and because it is like only $20) the thermostat, should take a skilled diyer about 4 hours at a relaxed pace with adjournments to the BBQ set up nearby. Oh yes, get a new rad cap, bleed screw, flush out your radiator, and use cheap, birghtly coloured and strong smelling coolant from walmart. Like I said, will only take you around 4 hours to do all of the above so you can sort it out in one weekend.

This will pretty much eliminate all of the known and common no-start issues with your car, along with a partial refresh of your cooling system which is the next biggest annoyance with our baby.

Then, you can do all the other things down the line when you have time to inspect the car's undercarriage and have strategised everything you wish to do and when.

Please read through the sticky threads at the top of the forums for more useful information.

Read through Bentley's procedures on each repair before you do anything, and its a great idea to have a reliable torque wrench and extra hose clamps on hand to do things the right way first time.

Oh and btw get and keep a set of car fuses in a plastic bag, in the fuse box. Anything electrical that stops working, the fuse box is where you should check first and swopping out the busted fuse usually fixes the problem permanently. If the fuse keeps blowing, then you've got a component problem and you need to think about that.

rgds, Roberto

p.s. Change the upper and lower rad hoses if their internals are caked with rust or they feel too hard and brittle to the touch. The hoses will run you $20 each and last for 10 years so its no biggie.
 
#45 ·
Haha whoops, my mistake. The lack of sleep may be getting to me. Yes 1-3 quarts makes much more sense. Ill be needing to fill up in the next day or two, so i will do this then. For the time being, im going to see if i can get my hands on some relays and a fuel pump off eBay (unless you recommend another website). Also, a question to whoever might be able to answer it. My E34 has a keyless entry system, but i was wanting to update the clickers. Both of mine are old, square and pretty beat up. The circuit board inside is rather big and trying to fit it in to another type key/clicker would be hard if not impossible. Would anyone know how i would go about making replacement clickers work? I assume as long as i can get my new clickers to activate the relay that unlocks my car and disarms the alarm ill be fine, but i have no idea how to do that. I should be sleeping as i have work in a few hours, but since i finally have free time im going to read through the stickies and search for parts. Very glad i stumbled upon this forum.
 
#46 ·
Only buy from Ebay if its marked oem. For our fuel pumps, the OEM manufacturers were Bosch and Piersburg. The oem for electrical relays were Bosch. OEM for crank sensors was Valeo (not sure). Ebay may be suspect sometimes, if you're not too familiar with names as yet. Suggest you goto websites such as rockauto and pelican parts. It might be pricier (not always actually) but these are items that you change once in 10 years so its well worth paying more for it. And if you purchase everything at one spot, you'll get shipping combined. Furthermore, these guys also sell things like seals, belts, etc, and you may get volume discounts.

No clue about your keyless system I'm afraid. :) Good night.
 
#47 ·
Just ordered a fuel pump, OEM of course. Next up will be the crankshaft sensor, possibly TPS as well. I just need to find the TPS sensor in my engine so i know for sure which one to get. Also, installed some new lift supports for my hood so it now stays open on its own (so nice to not have to prop it open). It idles rough sometimes, and i want to clean out the ICV. However, i am not 100% sure where it is. I am however 99% sure it is right in front of me, at the top of my engine. I looked in the bentley manual and couldnt find anything.



This is not my engine,but a pic i found on google of the same engine. Its the piece with two hoses, one going to the intake and the other going to the air box. Correct? If so, how do i get it off? Just pry it off like the hulk?
 
#48 · (Edited)
Just ordered a fuel pump, OEM of course. Next up will be the crankshaft sensor, possibly TPS as well. I just need to find the TPS sensor in my engine so i know for sure which one to get. Also, installed some new lift supports for my hood so it now stays open on its own (so nice to not have to prop it open). It idles rough sometimes, and i want to clean out the ICV. However, i am not 100% sure where it is. I am however 99% sure it is right in front of me, at the top of my engine. I looked in the bentley manual and couldnt find anything.

This is not my engine,but a pic i found on google of the same engine. Its the piece with two hoses, one going to the intake and the other going to the air box. Correct? If so, how do i get it off? Just pry it off like the hulk?
First, your TPS is directly under the throttle body. It has a 3-pin connector coming out of it.

Your ICV is circled below:


If there are no clamps then the hoses just pop off their barbs. BTW the other end connects to the intake boot, not the airbox.
Clean it out with carb cleaner. Let it soak for a couple mins. Make sure the vane inside rotates freely. Also check the Bentley manual for resistance specifications, the exact numbers escape me atm.
 
#49 ·
When you pull off the main air hose (the bigger of the two that you mentioned) from the side on the engine, the first piece of round metal that you'll see will be the throttle body. There should be a hinge next to it that's connect with a metal cable which leads all the way back to the accelerator pedal, that you can just push down with your hands. That opens the butterfly valve and you'll be able to spray carb cleaner everywhere in order to clean it up.

Youtube surely has videos on stuff like this and probably for your specific engine. Youtube has videos on everything.

Why do you need to purchase a new tps ? Are you getting persistent error codes ? Usually, thus cleaning it and the connector with contact cleaner, applying dieletric grease to it and fixing it back would be all that you need to do. Do that, clear any error codes that might still be there, and then see if things make a difference.

The better thing to do would be to purchase a torque wrench, the requisite tools for resetting valve clearances, and to purchase intake manifold gaskets for when you remove your intake manifold to give it a good internal clearning.

Here are two threads that would persuade you better on the importance of this. Bear in mind that the dudes who posted this were going after other problems and only spotted the dirt in the intake manifold along the way :

http://www.bimmerfest.com/forums/showthread.php?t=528017

http://www.bimmerfest.com/forums/showthread.php?t=486999

The crud in there was not caused by the issues that they faced with their engines. It builds up naturally over time.
 
#50 · (Edited)
Hey, congrats on the car buy! I just purchased the same year and model and love it and are going through the same thing you are. Systematically changing everything when I can afford it. However, and people who know more then me please confirm. But hold on buying the new TPS for the stomp test issue.

The 1990 525i, doesn't have a stomp test feature. That didn't become available until the 1992 models. You can find the thread here, I read it from one of the sticky's "mechanical things you should know...". Its the first post under "stomp test procedure"

Again, BMW specialists that are on here, if I'm wrong post, that way I know, he knows, and its confirmed. Hope I help and thanks guys.
 
#51 · (Edited)
Hey, congrats on the car buy! I just purchased the same year and model and love it and are going through the same thing you are. Systematically changing everything when I can afford it. However, and people who know more then me please confirm. But hold on buying the new TPS for the stomp test issue.

The 1990 525i, doesn't have a stomp test feature. That didn't become available until the 1992 models. You can find the thread here, I read it from one of the sticky's "mechanical things you should know...". Its the first post under "stomp test procedure"

Again, BMW specialists that are on here, if I'm wrong post, that way I know, he knows, and its confirmed. Hope I help and thanks guys.
That information on the stomp test page is wrong. They got that from the bentley manual and the bentley is wrong in that regard.

All cars with Bosch Motronic version 1.3 and above have stomp test capabilities, that goes for ALL e34's.

Heck, even my 8/88 M20 has stomp test capabilities.
 
#52 ·
What you should be buying would be the crankshaft position sensor.

Great that you've got the pump. ;-) You'll need the fuel pump's fuel tank entry orifice's O ring as well. If you forgot that, please purchase it before installation.

Please don't forget an assorted set of car fuses kept as handy spares, and new relays for your fuel pump, dme, abs and o2 sensors. Especially a new relay for the fuel pump (but you might as well get them for everything else along the way). The old relays can be kept as spares.

You're nearly at the point where you'll be sitting back, reading posts, and wondering why people have no start problems with their E34s.
 
#53 ·
Dont have time to go through the last few replies and commen on them, just have to ask a quick question. Going to work this morning i got in my car and tried to switch to reverse and nothing happened. It seems i cant switch to any gears, it sort of just easily flows through all options. Whats my problem? Any help would be greatly appreciated as my car is out of commision at the moment.
 
#55 ·
Ill give that a shot when i get back from work. Some of the possible problems ive been reading include my transmission being shot. However i dont think thats the case as it shifted just fine when drivig. It just feels like its not catching when trying to put the car in reverse, drive , etc. Thanks for the info Robert
 
#56 ·
Just so you'll know, my previous E34 lost reverse at 256K miles. It wasn't worth it to me at the time to have the transmission rebuilt. One option if yours is going out is to do a 5 speed swap.

Good luck.
 
#58 ·
I need some more time to fully test your idea, each time i do my kid starts crying or something happens. So right now i havent gotten it to normal operating temperature. However, i cant really put it in neutral. I can adjust the shifter so it reads "N" on my dash but it doesnt actually switch in to neutral. I checked my fluid and it is indeed low, so i am going to put some more in there. However, i am a bit confused as how to do that. Ive read through the bentley manual and understand i need to find the fill plug on the pan, remove it and fill from there. But locating that seems to be harder then i though. I bought a jack and jacked it up to look under there, but i only see the oil drip pan. From what i read, there is a drain plug on this pan just as there is a drain plug on the oil pan. But i only see one pan with a drain plug underneath. I know im probably missing something obvious, so feel free to slam some common knowledge in my face. To make matters worse, the birds seemed to be having a ****ting contest on my car and i cant even move it to avoid their droppings. Poor car.
 
#63 · (Edited)
How did you check the fluid ? Was it through the dipstick ? That must be the case, since you don't know how to locate and remove the fill plug and so couldn't have checked any other way.

This means that your transmission has a dipstick. This means that you can top up tranny fluid through the dipstick, using a small funnel which can be purchased at hardware stores. So you don't need to go through the drain plug etc.

Don't know why I missed this point earlier. Stressed out I guess. :)

I wouldn't be surprised if your radiator guy did not do a good job with your water pump, thermostat and fan clutch. Many of those squeaky noises in your video are belt/pulley related. I just changed my water pump yesterday and was told by my new mechanic that the water pump's pulley did not look right. He asked me if I had had an accident before ! That's the only way that dent got there. I hadn't, and surmise now that the mechanic who did my water pumps last year and years past much have negligently handled the pulley, and/or must not have bothered to take the 30 seconds that it takes a seasoned person to quickly inspect it before reinstalling it.

So, if I were you, I would go back to whoever did this for you and get him to fix it. Insist the noises showed up shortly after you got your car back. Usually they do start out with softer squeals before getting loud enough for you to hear with the hood closed. You might not have heard the initial issues.

Is your engine a single overhead cam or a twin cam ? If its a single cam, you have something called valve lifters (google and youtube), and they need to be adjusted to maintain correct clearances, ideal performance, and avoid that 'tick tick' sound I seem to hear in your car. The valve cover gasket is also changed during this operation. Depending on who is doing it, this could be take nearly 2 - 3 hours to do correctly.
 
#60 ·
Fixable problems. Probably some pulleys, tensioners, and loose belts too. Fixable problems. If they are related to the pulleys etc they should have been done during your radiator job. The mechanic who did it should have checked all of this (takes 3 minutes) along the way, its being professional.

Don't worry about the terrible sounding engine. All the issues are fixable. Do the fuel filters and run diesel through your fuel tank to clean the injectors. Clean out the ICV (idle control valve). Check and clean or replace all the spark plugs. Clean the throttle body. I'm sure your engine will run really great. It just sounds clogged.

You mentioned the throttle position sensor earlier. In my experience, that usually does not go bust, but it helps to clean it and its connector with contact cleaner before you reconnect them. Ideally, after cleaning, coat both the connector and TPS with dielectric grease before you reconnect them back.
 
#61 ·
Awesome, thats some good news. Yea when i get time i want to clean and check my sensors. Along with cleaning my throttle body, and intake. I just cleaned my ICV today, I just need to get my transmission working so i can actually drive it. Thanks a ton for all the information, you are very knowledgeable and it really is helping me out.
 
#62 ·
Sorry I never got back about the door lower trams. No clips no glue they are retained by their own shape. Flush out dirt (salt?) dry and refit after you clean up the bottoms of the doors. About a once in 2yr job.
 
#64 · (Edited)
I think you should get your car to Joachim and have him look at it quickly. Let him take 15 minutes with it and at least tell you what's wrong. Especially tell him to inspect everything that the other mechanics did recently. You can come back another day to do the actual repairs, if he is not free. It might be a very good idea to just get a heads up in case something major is about to happen.
 
#78 ·
I just re-read through the entire thread to see who came closest to diagnosing the problem and it seems like PP94 came the closest :thumbup:

This problem and resulting solution remind me to always use the KISS (keep is simple stupid) principle.

Glad you got it sorted out Byork7. And Kudos to you for all of the other stuff you have done. You are amassing a great amount of experience to pass on to other members, especially those with the M20.
 
#66 ·
So update time. My kid has been in the hospital for the past week, which is why i haven't posted on here or worked on my car at all. However, i finally got some time today to work on it. Here is (which i doubt). I have yet to try your suggestion paper plane, i will do that before i go to a junkyard though just in case it is that simple of a fix. When i was taking apart the shift lever and such, i noticed a small piece just hanging out freely, any idea where it goes? I didn't see anything like it on the gently manual.



 
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