1986 BMW 325 - New Member

BoneStock · 10:03 AM

Purchased 1986 BMW 325. Drove car home and loss of power. Called mechanic who told me to strike or hit the fuel pump under the car a few times - starts and runs ok. Drove for 3 days and then same. Electrical connections to pump are fine.
I plan to replace pump and filter - any advice would be appreciated. This is the first BMW that I have owned. Parts site suggests that inline pump should not be replaced unless pump in gas tank is also replaced? I have no history of the car and it could have been sitting for a while.

BoneStock

markdas · 09-18-2012, 07:02 PM

You may want to do some fuel pressure tests before you change the pump (s). That system is quite cumbersome really and by the sound of things, you do need to start renewing some stuff.

Firstly, check that both pumps are running when the car is on, this is easier if you remove the rear seat and with a cheap mechanics stethascope listen for a low whirring noise. If that pump doesn't lift fuel out of the tank and give the high pressure pump a good feed pressure, then the high pressure pump will struggle.

Check that the high pressure pump is runing too, jack up the drivers side and support it, the feel/listen for that one running too!

Its a good idea to buy a fuel pressure test kit, its just a gauge, some hoses and fittings that allow you to measure the pressure the pump is delivering at the fuel rail. You should have a pump capable of giving you 4-5 barg (and more) and the fuel pressure regulator then controls the pressure in the rail by spilling fuel back to the tank as needed. If you get a good constant pressure, try pinching off the return line momentarily and see the pressure climb rapidly, it if moves up to 10-12 barg all is well with the pump.

We run an endurance race car and had lots of fuel issues. To simpliy things, we took the small pulse dampener out all together, its in the line after the filter. I suggest taking that out, it doesn't do much and can fail. Change the filter too and check the metal fuel lines under the car are not dented or pinched, especially the return line and breathers.

With these cars getting older, 2 new pumps and a filter isn't a bad idea.

Good luck

BoneStock · 09-27-2012, 04:13 PM

Thank you, markdas!

BoneStock · 09-28-2012, 04:06 PM

I left something out...car ran fine for three days after bringing it home. I had to strike the fuel pump a few times first day. I took the car to a shop to put on rack for inspection and had all the belts replaced at this time. The next day I turned on the a/c while driving and some screaching noise... then a block or so later the power problem again. I got out and struck the fuel pump again and got it restarted. I was able to get the car home but had to place it in neutral at red lights and keep my foot on the gas to maintain idle. The a/c will only work on the high position and I see that this is the blower motor resistor. Could the a/c trigger this problem with fuel pump?

Frajo · 09-29-2012, 07:42 PM

Somehow I doubt there is a relation between FP and AC

BoneStock · 09-30-2012, 06:14 PM

Pulled out a spark plug and oil foiled. I'm thinking rings, valve seals or head gasket?
The car runs and I am able to move it around but very rough idle and then cuts off. Any advice about how to proceed would be appreciated.

markdas · 10-03-2012, 11:54 PM

Idle problems could be a lot of things.......even though you are hiting your fuel pump each time you have a problem it may be something else. If you think the fuel pump is sticking, try and confirm that. If it is, then it won't get any better on its own......start thinking about a new one once you are sure the wiring and fuel pump relay are both good. (check under the hood there are 3 relays that are well worth checking, and renewing and carry 3 spares in your glovebox) then put a tie wrap around each one as they can work lose)!

Idle can be affected by the smallest vac leak, so work your way through the engine bay and check each hose carefully. Some will need positive pressure leading to the throttle body.......so give the large elbow boot a good squeeze, remove it, clean it, inspect each rib and flexi section, clean up the throttle body too with some cleaner.

Check all the small bore vac hoses and replace them as they are cheap anyway.

The idle control vavle and the MAF need to be in good condition and cleaned with some carb cleaner

Do a compression test if you still think your plugs are fouled (when did you change them - or was that the previous owner......change and gap them and use the cheap copper core ones, rather than expensive irridium stuff that are 3 x the price as an E30 seems to like the bog standard copper things! If you ahve decent and balanced compression across all cylinders (about 140-170 psi) then go with it for now. If you are thinking of an engine rebuild, its a big job to do correctly and new rings and bearings are only the start of it unless you want to do it all again later (oil pump, gaskets, head bolts, main seal, rear main seal, timing belt, water pump, tensioner etc etc)

Having said that, if you intend to keep this E30 going, then find out if you can when the timing belt was last done.......they can snap and then you are in for a big repair.....change the oil and filter too!

BoneStock · 10-04-2012, 05:10 PM

Than you again, markdas. I pulled all the plugs and it is only the first cylinder (front of the car) that has some oil. The others are carbon black. I cleaned with some carb cleaner, checked gaps and put back in. They are the expensive kind. I just purchased car and have no history on it.
I also removed and cleaned the idle control valve but it was moving on its own easily. All hoses are good and the distributer cap looks brand new from peaking at it under the cover.
I pulled out the air filter and other components tonight. The air filter needs to be replaced and I will get to the throttle body this weekend. If you have any more information about the vital relays then please post a link? I did change oil already and did not notice anything unusual...antifreeze. The first cylinder concerns me. I also read in another chat room that an idle compensation mechanism is connected to a/c, power steering, ect - computer?

markdas · 10-05-2012, 01:04 AM

I don't think I have any pics on my phone right now of the 3 relays......if you lift the hood and stand at the drivers side wing by the wheel, there should be a black cover over 3 standard looking relays......usually there are 2 orange and one white. The right hand relay is for the O2 sensor, the middle one is the fuel pump relay and the left hand (white) one is the main relay.

Just make sure all of them have good clean terminals and are well seated.

If the main relay goes then your car wont start, same with the fuel pump relay.

Not sure if cylinder 1 is typical of engine wear, it could getting oil from the breather systems, or more likely, its the one that usually gets oil dribbled into the hole when re-filling with engine oil, so that when you remove the plug, you may think that the oil came from inside, when really its just the plug hole full of oil?

Id still change those plugs for some nice cheap copper core type, the M20 engine responds better to those I find. Also, invest in a compression tester and put your mind at rest about the engine condition?

If I find some pics, I will post them up!

BoneStock · 10-15-2012, 12:00 PM

Thank you, markdas...I pulled throttle body off and everything in front of it. Air filter was a little dirty and replaced it. I also pulled and cleaned ICV but it made an easy click already. The breather tube from throttle body to valve cover gasket was full of a vaseline like oil so I cleaned it out and ran a coat hanger around in the valve cover port.
I started the car and it runs and idles fine. When it was first started I heard a "screaching" sound from the front? It went away temporarily but came back. I experienced this before when the car died but it runs fine now. I thought this could be the ac or heater fan but the ac switch was not engaged. All the fan belts were replaced by a professional a few weeks ago when I brought the car home.

BoneStock · 10-15-2012, 01:14 PM

valve cover...

BoneStock · 10-15-2012, 05:56 PM

I am now thinking that this could be a power steering noise...

markdas · 10-15-2012, 06:27 PM

Good work on fixing the idle. All those things you have done are essential for these engines to run smoothly!

As for the noise, it does sound like a belt sliping perhaps, it could also be the PAS pump bearing, the Alternator bearing or water pump? Try and eliminate each one by taking off the belts one at a time and seeing the result.

Other option is to CAREFULLY use a mechanics stethascope on all the rotating equipment at the front of the engine. If you hit something that is spinning, it will hurt yours ears so be carefull!

You should hear a nice constant whine from the PAS pump, no squeeling or bubbles, nice constant whine from the alternator. For the water pump probe the hoses in and out and also a couple of places on the block from the passenger side.

While you are there, also check the front crank pulley area and make sure the toothed pully is running true and not wobbling!

BoneStock · 10-15-2012, 08:46 PM

The car is very hard to steer. I thought it had a power steering issue at first until driving it on some mountain roads. Is this normal for this car?

I did notice that the alternator is not perfectly aligned? The shop that replaced the belt said nothing about this...I will follow your suggestions tomorrow.

I will also need to address the rich mixture issue. I read at another site that the "blue plug" or coolant temperature sensor can cause this problem but I do not know how to identify it. The thermostat housing has several sensors and the Pelican article on replacing this is also not specific.
Do you know if the Bentley manual has a list of all sensors with locations and testing procedures? Is it possible to troubleshoot with the data port on this model with laptop interface or other affordable device?

markdas · 10-16-2012, 05:32 PM

Steering on a well set up, good tyre pressures etc is quite light actually. Check the level in your PAS reservoir and with the front raised, make sure the rack moves smoothly from side to side.

It could be this system thats causing your squeeling if the belt is slipping, or the pump bearings are failing?

Alternator has a simple pivot bolt and adjuster set up, so it should be easy to align or check the bracket is torqued up,

The coolant plugs I think are interchangeable......which means you could have the ECU signal for coolant and the temp guage signal plugs mixed up. Try marking them up and swapping them over I think the temp sensor on the engine side of the thermostat is the ECU signal, and the other one is to your guage.....I need to look at our car and confirm (Im away from Houston right now).

BoneStock · 10-17-2012, 04:01 AM

Thank you again, markdas...I'll inspect steering tonight.

I have four sensors on thermostat housing. Photo 1 is from driver side and shows brown sensor and another with two connectors? Photo 2 is from passenger side and shows two sensors - one is yellow or dirty white (lower) and the other is brown (upper)?

Are you able to identify these? Could this be the problem? Any difference with the blue sensor?

BoneStock · 10-17-2012, 03:53 PM

Markdas, What kind of plugs do you like? The car has WR9LS which is specified in the owner's manual.

I may have triggered the screeching by turning the fan switch on high. It only works on high and cleaning the resistor did not help.

markdas · 10-17-2012, 07:45 PM

Well, our car is a 24 hour endurance race car, so we have hacked the wiring a little, but those temp sensors should be the same on our car (1989 engine I think) 325is.

I am working in Indonesia, so not able to look at the car and cant remember from memory what our temp sensors look like....I do think we have a blue and brown though!

In terms of plugs, use the nice cheap copper core $2 a plug things from Pelican or similar. We change the plugs every other race as a precaution (we do about 800-1000 miles in a race). We have tried the more expensive Bosch irridium things and there was no differance, in fact we even felt it was missing a little nearer the red line, so we changed back.

BoneStock · 10-21-2012, 03:49 PM

I have the alternator with four bushings and they need replacement. I'm sure this will take care of the screeching as the belt had worked loose again. I also ordered two new temp sensors.
I inspected the power steering pump and rack and do not see any leaks. I have reason to believe the car may have struck a curb in the past. The tie rod had to be replaced and the front apron was also cracked. I plan to pull the power steering pump and rebuild it? Is this a logical first step? The car drives and handles well but just hard to steer at lower speeds. Could the pump be failing and not leaking? All hoses are good and it is holding fluid. Is the pump rebuild procedure as easy as it appears?

markdas · 10-22-2012, 06:32 PM

I don't think I would go to the trouble of a re-build, rather just replace the PAS pump with a new or recon unit and know that it will outlast the rest of the car.

We actually deleted our PAS based on the fact its always on a track.

Inspect your engine mounts too, while you are under the car, they can go very soft and shear off, allowing the engine to move enough for the PAS pump impeller to eat into the radiator lower hose!