E28 528i No start/Idle

[AlessiRocks]

Hello,

So I posted here a few months ago about my E28 not idling properly. Well it still doing the same thing and now it will not even start. I'm going to make a list of everything that has been done to it.

-New injectors.
-New inline fuel pump and intank fuel pump.
-New Fuel filter.
-Replaced cracked hoses.
-New cap and rotor.
-New ignition coil.
-New leads.
-New spark plugs.
-Tested Air flow sensor with one off another car.
-New FPR.

After all that work the car will still not start and if it does start it will not idle properly. All parts are OEM. Does anyone have any clue as to what it could be? I also made sure that the vacuum is all good but maybe someone can give me a tip as to where to look although I think all the lines are good.

Engine model is an M30B28 euro model. Car year is 1986.

Thanks in advance.

[bmwdirtracer]

In spite of all the parts you've replaced, you still need information to diagnose the car.

When the car is refusing to start, do you actually have spark? Do you have correct fuel pressure? I understand that you'd expect to have correct fuel pressure, when you've replaced all the "active" parts in the system, but there are other possibilities, so no matter how many parts you replace, you still need the test. {What if the lines are switched? What if the return line is crushed? What if there's rust in the tank?}

Same for spark: What if one of the crank sensors are bad?

And as for the air: Checking for torn hoses is a good thing, but you can easily miss a major leak, unless you do a smoke test of the intake system.

Compression test might be in order, too.....

And then there's the sensors: Coolant temp sensor is about ten bucks....this is one part that it's okay to just throw at it, because it's so cheap. (Not the one that goes to the gauge, the one for the DME)

Just as a very easy test: Try starting the car while holding the throttle pedal half way down. Do not pump, just hold it half way. This can "get around" a couple of possible items. If it works, we'll have more info.

[AlessiRocks]

Spark has been tested and is all in order, same goes for the fuel pressure. The compression test also showed the engine was ok.

My bet is that one or more sensors have gone bad so I guess I will give the coolant temp sensor a try. Could the auxiliary air valve also affect this issue? My car has no ICV.

As for the easy test you mentioned, it has already been tried but nothing happened. Weird how the car worked all perfect before this and now it's acting like this.

If it helps the car started giving some problems after replacing the FPR vacuum line, basic maintenance and resetting the service lights but the car still worked after all this. It was only a day after where it didn't want to start.

[dworthy]

I would suggest doing a pin-out from the glove box to ensure the wiring harness is complete as well as voltage drop tests. Along the same lines, check the grounds on the motor plus the ones going to the DME. If all is well and you find no faults, then I would crack open the DME to see if there is any burnt circuits.

[AlessiRocks]

I'm not sure how to do what you mentioned as i'm not experienced with electrics but I guess this is a good opportunity to learn. Also forgot to say that we tested an ECU from another car and still no results.

[parkerbot]

Replaced cap and rotor...new plugs and wires....not starting / idling right....have you rechecked and verified you didn't swap plug wires. I'd be lying if I said I'd never done this XD.

[dworthy]

Replaced cap and rotor...new plugs and wires....not starting / idling right....have you rechecked and verified you didn't swap plug wires. I'd be lying if I said I'd never done this XD.

Very good point, as the cap is not marked, but still possible to plug them in wrong if you are not looking 1-5-3-6-2-4 clockwise if I remember correctly from the square aligning piece.

[AlessiRocks]

Yeah thats a good point. I will check, although at the same time I hope it's that but I also hope it's not because if the car has been stopped for 3 months because of that i'm going to feel like an idiot haha. Will check the whole ignition but if it's all correct, I have no idea what it could be. The car stopped starting because the fuel pump broke and now it won't idle when the issue was fixed, like i'm so confused.

[AlessiRocks]

Well everything seems to be plugged in correctly. I'm trying to trace back what I did before this happened. So I changed the fuel pump and filter, I replaced the oil and reset the inspection and service lights by using a wire since I didn't have a tool. Could resetting the lights using the cheap method have broken something electrical? I could test the main relay. I'm soon going to order the coolant sensors and give them a try but i'm just trying to think what it could really be.

[dworthy]

Did you prime the fuel system after replacing the fuel filter? I like to just take a wire to the #1 fuse and give it power, this turns on the fuel pump and pushes the air out of the fuel rail and filter.

If you jumped the 13 pin diagnostic port correctly, then it shouldn't be an issue. I would have to pull the book out to see if there is a DME connections.

[AlessiRocks]

I didn't prime the fuel system. I was thinking it could be that because of the weird idle. What I did do was turn the key to the ignition position a few times before starting the engine to make the pump build up the pressure. I will still do what you said as I replaced the injectors recently.

I reset the service lights following the instructions I found on the forum. The car started up after resetting the lights and ran the whole day. But maybe I thought it could have damaged something else.

[dworthy]

I had to think back as you have the Bosch L-Jetronic system, which never come to the U.S. It is a very basic system, and the DME doesn't need much input to be able to run. I think the closest system would have been found on the E-21 320i built from 1979 to 1983.

Do you have the Haynes manual from England?

So this is what I would do in order:
Test Coil
Test Coil wires and plug wires
Test the Distributor internals plus air gap
Test the fuel pressure

Lastly what spark plugs did you install? Bosch Coppers (W8DC) are the best for that motor, and I have seen newer platinum plugs foul out on those motors.

[bmwdirtracer]

Yeah, I stopped replying when you started talking about the distributor cap not having numbers on it....meaning it wasn't Motronic. And then of course there was the "Auxiliary Air Valve", instead of an IAC valve. Funny, my old '83 533 had the distributor at the end of the camshaft; it's hard to imagine an '87 big-six with a much older system?

Here's a link that might prove helpful, though:
http://www.firstfives.org/faq/ljet/jetronic.pdf

Darin, I think the 320i was K-Jetronic (mechanical), wasn't it? (At least the '83 I worked on recently was....)
http://b2resource.com/PDFs/bosch_k-jetronic.pdf

Since the car started and ran for the day, after resetting the service lights, that's not the problem. I would say, however, that you need to recheck all the tests which were done

[dworthy]

Chris, I think you maybe correct on that, for even in Europe, they still ran the K-Jetronic in the E-21 323i until 1983. With the introduction of the E-30, came the L-Jetronic. I have to go in the basement and pull out the older books I have down there on those systems, and compared to today's, man are they basic!

[AlessiRocks]

@dworthy I do have the Haynes manual so I will take a look at what I can find to test what you mentioned. As for spark plugs I changed them with some Bosch ones, not sure which ones now, but I will order the W8DC plugs as you mentioned and try them out.

@bmwdirtracer Been reading through the links you gave me and I have already learnt a few things. Maybe I can put them to use when I take a look at the car because i'm going to double check everything that has been done and take some measurements to see if everything is within spec. Although I don't think my car has mechanical injection, I still found the link interesting to see how those systems used to work.

Currently I have a list of parts that i'm going to order since most of those were going to be changed anyways. As mentioned I will make sure everything is within spec and that everything is plugged in the correct order, although I have checked it already, maybe I missed something.

I'm also going to link this image as it may be useful, I took this image the same day I picked up the car and it was running which is why it still looks dirty, also no work was done to it in this picture yet. I will post back when I have checked everything and hopefully found what it could be.

HLBib2nh.jpg

[AlessiRocks]

Well I just checked everything was in spec and it seems to be. Even borrowed a tool to check the timing and it was all good. But what I did find is that the spark plugs I had put in where not doing a good spark, they were all over the place and not only that but there was just too much fuel going in.

From this I can guess that it's just not burning the fuel correctly or that too much fuel is going in which happened with all the injectors I tried. Now that it has it's original injectors it seems to run bit better but the idle is still really rough. It either has something to do with the new parts in the fuel system or the spark not getting delivered appropriately but I still can not explain why the spark plugs were faulty. Could the O2 sensor have gone bad which is why too much fuel is going in or is there too much fuel because it isn't getting ignited? At least I think I narrowed what it could be down a bit.

[dworthy]

Humm I don't think that motor ever had an oxygen sensor, as it was never designed for one like the M30 B33/B35 motors.

One reason to explain the fuel soaking is the plugs were not firing. When that happens, the fuel can wash the cylinder walls clean and you will lose compression, thus the car will not start.

How does the coil look? Did you test it yet? Is it getting power?

[AlessiRocks]

The coil is new and working as it should compared to the old one that was in the car. It definitely is getting power and the resistance is correct, at least according to the Haynes manual. Strange thing is that all the plugs were bad. This happened with the last set of plugs too. Also forgot to say that the car starts now but it won't idle.

[dworthy]

Then that would point more to a vacuum leak, does it also seem a bit down on power as well?

What were the last set of plugs in the motor? You can clean them off to be able to read them, interested to see if they were the correct ones. Some part stores will give you the wrong ones as the database maybe wrong.

[AlessiRocks]

It is down on power as when I try to engage the clutch it just starts to stall.

The last plugs were some Bosch Super Plus Spark Plugs, the store said they would work on my car although I didn't really trust them but since plugs are cheap and the olds ones were done I gave them a try anyways. The W8DC you mentioned are still to be ordered since I want to order a few parts all together. Overall I checked the tubes and connections and everything seemed fine. Is there anywhere I must specially worry about? The boot is in good condition and so are all the the tubes going to it, there are some lines (one coming from the distributor and the other from the throttle body) that go to what i've been told is some kind of vacuum control which I removed and put back on so maybe there are the lines are the other way round and overall the rest of the lines including the ones going to the FPR are also good as they are new.

[dworthy]

There is about 3 or 4 vacuum lines, and the ones that goes to the distributor are important, for it works the timing advance. IIRC there is one that goes from the valve cover vent hose into the intake, that one like to crumble too.

Yeah, wait from the new plugs, and in the meantime, I would leave the old ones out to ensure all the fuel evaporates from the motor and then put a little bit of oil in each cylinder and turn over by hand. That way the rings are able to build compression with fresh oil.

[E39MGirl]

Just a quick note for future reference. It is always a good idea to include a new post on the original thread, or at least include a link to it so people can find it easily to see what you did back then. As Chris mentioned, a list of parts isn't enough.

Did you check the cold start injector to make sure it wasn't still operating when the engine was warm, or leaking after it was supposed to shut off?

Also, if the electrically heated auxiliary air valve on those early engines is dead the engine will not idle and will run rich - fouling the plugs. Have you tested the auxiliary air valve? They were a very common failure back in the day and, unlike the later units, do not respond to cleaning.

[AlessiRocks]

Alright I will keep that in mind for the future. Still somewhat new to posting on forums.

@E39MGirl The cold start injector is working as it should when I tested it months ago. The engine stalls before even getting warm but the cold start injector turned off after a few seconds and didn't seem stuck. What I have not tested is the Auxiliary Air Valve, it looks clean but looks can be decieving so I will take a look at that.

@dworthy When inspecting the hoses I cracked one of them when taking a look at it so that one probably wasn't in good condition, it was the valve cover hose actually, the one you said. I'm going to order a full set of hoses but first i'm gonna vacuum test everything since it's probably a better idea than just guessing. That's something i've learnt from this forum. I have let any fuel in the cylinders evaporate and I will put some oil in when I install the plugs.

[AlessiRocks]

Well little update. Car starts now but it idles at about 600rpm and when I rev it it's kind of rough, sounds like a slight misfire. There also is a lot of white smoke.

So what has been done now is replace the Auxiliary Air Slide Valve with a new one, checked all vacuum lines and replaced the ones that were broken so now it should be all sealed, changed the plugs with the correct ones and a friend found a brand new AFM which is now on the car. I also ordered the coolant temperature sensors but I think I got the wrong ones. There are 3 sensors and only one of them had a reference so I have to check that out so I order the correct ones.

As said, the car starts and it holds the idle at 600rpm but there is a lot of white smoke. Could this be some timing issue or something wrong with the distributor? Also looking around I couldn't find any speed or crank reference sensors, is this normal in my model?

- - - Updated - - -

I should also add that the ignition leads are indeed plugged in the correct order.

[dworthy]

If the AFM is brand spanking new, it will need to be adjusted. There is a hex head this is called the air bypass, while it has been years, you will need to get that set. It will also adjust your idle and you will need an exhaust gas analyser to be able to set it properly.