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sounds good. I will jump x 30s then start. I will note if it's warm or cold, and time from last shutdown.
I will have to read this later, just got back from the eye doc. I can't make out what I am even typing. LMAO
I did make out what I quoted I think. Don't do it warm. I explained that. The opposite will happen, it will start harder if you have a leaking injector. Just do it on the dead cold starts. That will give us a baseline later you can do warm tests. Lets just get one fact established and go from that one thing. If it always starts perfect cold then we can move on to the hot starts and see if the longer the pump runs have a negative effect on the start. I can't read that but don't see red so I guess I will post it.
 

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now, 90 is "CLAMP 15" or "terminal 15". is that the ignition switcth at position 2?
I have been searching through what I have on this computer, not much. I am still looking 15 is either the main relay or unloader relay, something in that area under the hood, not the ignition switch, without a wiring diagram it is possible that the path to 15 runs trough the ignition switch.
 

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Fuel level resistance. I found this while searching so I might as well post this now you might need it later.
951728

OK found one 15 is the unloader relay, look at the top.
951729

Just another for confirmation this is the ground diagram.
951730

I have nothing on the signal wire,(power that throws the switch) The top one is power out, and I think the power in runs from the main relay or possibly it has constant power you could test that with a volt meter. It is one or the other. The signal wire should come from the DME, but I can't say I remember for sure, but I have gone through all the diagrams on this computer. Replacing the unloader relay is not a big deal and not expensive, and the only real way to rule it out is by ruling everything else out or simply replacing it.
 

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Discussion Starter · #24 ·
Thanks for the info on unloader relay.

Questions (I don't know how to read these electrical diagrams!)

1. since terminal 15 signal goes from ignition switch to the unloader relay, can the switch be the problem? if there is one problem that cause all my electrical issues, e.g. fuel gauge, tire pressure control, start, etc. would it be the unloader or the switch?

2. Happy to throw a new relay in, but... WHERE is the unloader? I cannot find anything on M5Board. google found some picture showing the unloader relay in the trunk where the fuel pump relay is. However, that picture was not one from an M5, but another E39, and the fuel pump relay is not a tall black thing like I have in the M5, but a light green relay. RealOEM shows there are 3 of these relays, all with the same part no. 2 of them in the trunk on the right, one called relief relay, the other load-shedding relay. I take it they are one and the same. There is a third one called compressor pump relay in the middle of the trunk somewhere? I suppose I don't need to worry abou that guy. Yet another diagram shows it is under the hood, below the cabin air filter on the right. Where is it in a Canadian car? and how can I be sure I am changing the right relay? Is it always pine green in colour?

3. I read there can be MULTIPLE unloader?

Picture attached is from my car. The pine green all the way to the right has the correct part number of the relief relay K6326, 61358350566. Question is if this is the right guy or not? and if there are multiple, where are the others hiding?
 

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Not sure what is going on, but your post was here and now it is gone. I don't know that the unloader signal wire comes from the ignition switch, I would suspect it comes from the DME. Even if that is the same part as the unloader relay, that is not the unloader relay. The unloader relay should be either in the DME box or one of the boxes just outside it, best guess. I don't have access to WDS here so I can't tell you for sure but the WDS will say exactly where it is. Check some of the Aussie threads for hard start or no starts pretty sure Rosie has posted the location several times.
When your post shows back up I will read it again and get back to you on your other questions.
 

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Not sure what is going on, but your post was here and now it is gone. I don't know that the unloader signal wire comes from the ignition switch, I would suspect it comes from the DME. Even if that is the same part as the unloader relay, that is not the unloader relay. The unloader relay should be either in the DME box or one of the boxes just outside it, best guess. I don't have access to WDS here so I can't tell you for sure but the WDS will say exactly where it is. Check some of the Aussie threads for hard start or no starts pretty sure Rosie has posted the location several times.
When your post shows back up I will read it again and get back to you on your other questions.
Aussie cars are quite different to US cars, in that they’re RHD Euro spec, so things are very switched around in the engine bay.
My recommendation is to just replace all those relays (except maybe the wiper relay) in the E-Box next to the DME - they all have a function and they’re all now at an age where they’ve done a lot of work and more than likely have burnt contacts and high resistance. And they’re cheap and easy to replace.
 

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Guess it is worth checking old posts, I saved the pics and will repost them. I posted this before. There were two so I will give you both. One is the DME and the other is the unloader and since they are side by each it would not be hard to replace together.
951745

951746

Those are both in this sucker just in case.
951747

The screws for the cover can get stuck frequently and the captured nut just spins. If you run into that look down where the nut is hidden and squeeze the plastic with pliers and that should be enough, not too hard though.

You might have several small issues that on there own would not cause a problem or hard start, but combined are giving you this issue. If the unloader relay is not right you should get no fire from the coils, your vids all seem to have fire but seem weak on the fuel air ratio, could be a few things but most often fuel.
 

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Discussion Starter · #28 · (Edited)
Thanks for the info regarding relay.

Let me report some findings:

First, cold starts.

By cold start, I include ONLY starts with engine at room temperature, between 20-23C. And I consider cold ONLY when the last shutdown was cold.

So with that definition of cold start, I performed 4 cold starts after jumping the fuel pump relay for approximately 30s, then I start the car. ALL 4 starts were quick, almost immediate start, what I considered normal, and what I remember from before.

There was one cold start that I did not jump the relay, but instead, leave the key in position 2 until fuel pump stops in 2 seconds, then crank. It cranks for 1 second or less, and then car starts.

I drove the car, and sure enough, some 15-20 minutes after shutdown, I get a hard start.

I decided to examine the injectors for leak. Here is how I did it:
1. starting oil and coolant temp 90C
2. test 1 oil and coolant temp approximately 75C, test 2 oil and coolant temp approximately 70C
3. plenum off
4. intake funnels x 8 off
5. key to position 2, making sure the fuel pump went on
6. WOT
7. examination with scope


At least 3-4 injectors looked like this. I think I have an answer?!

The injectors were cleaned and filters replaced. How did they manage to damaged them? Or did the cleaning process simply unmasked the leaky injectors?

So I need new ones now?

I will recheck with cooled off engine at room temp
 

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Or did the cleaning process simply unmasked the leaky injectors?
Pretty sure that is what we were going to find, when you said you had the injectors cleaned. I have never cleaned a set that did not leak.
I am alone in my contempt for pro cleaned or ultra sonic cleaning, but I have had zero success. I have great success just using bottles of cleaners though. Since I am alone in my contempt I don't talk about it or things turn into oil thread like, Lol.
This is why I think it happens. The crud that we are most concerned with in the fuel system is very hard when it gets deposited, just like any mineral, It is harder than the metal it sits on. The pintle pounds into some of those deposits many times a cycle. The metal the pintle is suppose to seal on gets damaged.
Ultra sonic cleaning removes it all so now the pintle does not seal. If you just use a bottle of cleaner that breaks the crud down by softening it but it does not remove it all. The now softer crud still gets pounded into the little imperfections and seals the pintle.
I rebuild diesel injectors because we replace the pintle and seal, but car injectors I either bottle clean or replace.
You need new ones but you have some choices, I replaced mine with originals but there are others out there that will do the job without re-tuning the car. I don't know what they are though.
I think that @smithr found a replacement and wrote a thread, maybe that tag will get him to chime in.
You could also talk to the place that did your cleaning, they might help you out a bit, but this was not really their fault other than they must have experienced the same results I was getting, also they should have done a better job testing and found the leaks.
At least you have learned this lesson. In Can "guaranteed to pass" does a great job cleaning injectors and leaving just enough that they don't leak, but don't use more than the recommended times,IIRC once every 8000KM or they might leak also.
 
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