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Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 3 Series / 4 Series > E30 (1982 - 1993)

E30 (1982 - 1993)
God's Chariot. The E30 was produced primarily from 1982 through 1991. The cabriolet was the one exception which was produced through 1993.

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  #1  
Old 09-20-2008, 10:41 AM
nich.j.anderson nich.j.anderson is offline
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Location: Westminster, CO
 
Join Date: Sep 2008
Posts: 19
Mein Auto: MKIII Jetta VR6, E30 318i
Cool M10 Timing and Fuel injection

Yo everybody,

My name's Nick and I'm in the process of saving (I look at it that way) a 84 318i from my high school shop class. My teacher is for sure ADD and old school, so you can expect just about anything to be wrong with this car. The last time I saw the car run properly was 4 years ago in Beginners Auto. But then to teach some kids how to fix timing he ripped out the distributor coil and wires and cranked her for a while, and said here you go. I'm glad I wasn't in that group because they spent the whole semester trying to get the timing back, no joke. Well now it's four years later and I've become obsessed with cars. VWs have mainly been my thing, but I took on a '72 Datsun truck, I've worked at a VW Salvage Yard in Edmonton, I've been auto-crossing and love it. And for what it's worth I pretty much rule at Forza 2. I now drive a 97 MK III Jetta VR6, which is a bad assed model but consumes gas, and every time I autocross that rear trailing arm gets more and more out of whack. I just checked the camber (with a square) and the rear wheels are at 3 and 5 negative camber and I have no idea what the toe is but it can't be good. I've been dying to tune it and try out all the different ideas I've simulated in Forza. But I, unlike most teenagers I know, don't believe in raping a good car. My Jetta's in good shape, it's a rare model as far as 90s VW are concerned, and the only mods that I would consider morally sound are expensive, and I can't afford expensive. So that's where this old beat up 318i comes in. The interiors pretty beat but not horrible. The dash is effed, same with the timing and probably the fuel injection. The body is straight with the valence missing, and some un-finish repaired body damage. I don't think there's any emblems, but on the bright side I found four more matching original rims and tires in the trunk and an extra radiator some other misc stuff. Pretty much it boils down to is a cheap project car for me to play around with my never ceasing ideas. I plan on spending next to no money and paying for what I do spend money on with money from parts out of it. I want to be able to take it auto crossing and if I blow the alignment out of whack it wont matter in terms of driving to school the next day. I want to play around with alignment, and different parts of the engine, but for the most part the amount of power in unimportant. I want to strip the car out and make it as light as possible... Anyway none of that will happen unless I buy it and the one thing I want to do is see it run properly (or close) before I commit to it. My teacher's selling her to me for $318, the old fart thought he was pretty clever. He really is though, but you'd have to label it as street smart, except that he could never get the BMW running properly again.

Anyways to the reason I'm posting.

Problem: It's hard to start as in it will turn over and suddenly stop, but it will start. Once it does start you have to keep it revving then it'll idle on it's own. But it idles at 2000-3000 rpm and it skips sometimes, making it sound like a rev limiter. If you tap the gas hardly it will crap out but sometimes it starts will fire up once it drops down to like 500 rpm then will rev back up to 3000rpm. If you hold the gas it will rev beyond 3 just fine.

The hard starting and it's background indicates to me advanced timing, but I wouldn't think the crazy idling would be related to timing, unless the fuel inj. system has a way of compensating for the timing.

Anyways I'm sure it's a combination of problems. I haven't eliminated enough variables to be able to start troubleshooting anything. I'll be buying a Haynes this week as well.

What I would like from knowledgeable Bimmer guys is a background on the ignition and fuel injection system. Just go over the concepts it all operates off of if anyone could. I only get to work on it when I am at school so I'm asking for the sake of allowing me to develop theories while I'm at home day dreaming. Things I need to do before I can truly trouble shoot would be change gas and oil, go at all the connections with electrical cleaner, and probably change every vacuum line, since they are almost none existent.

In the mean time if someone could enlighten me on how the fuel injection system and ignition system works in a M10 powered 318i.

Thanks,

Nick

P.S. I've always been horrible getting information out of forums, probably because of my novels I write at the beginning. So please get past that and post a response. Don't make me put some controversial thread title to get traffic ha ha. I'll state the superiority of Ford Mustang, or Bush's amazing reign in office.
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  #2  
Old 09-20-2008, 11:09 AM
nich.j.anderson nich.j.anderson is offline
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Location: Westminster, CO
 
Join Date: Sep 2008
Posts: 19
Mein Auto: MKIII Jetta VR6, E30 318i
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  #3  
Old 09-20-2008, 10:55 PM
Rekcedbob Rekcedbob is offline
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Location: Southern California
 
Join Date: Jun 2008
Posts: 65
Mein Auto: 1985 Bmw 318i
I know the ECU controls the injectors based on inputs from various sensors. The Bentley manual does a good job of showing how to test individual components, like the temp sensors, throttle control valve, idle control, etc. This process of elimination works for me. I had problem not unlike yours, and after verifying the operation of many different components, I replaced the Idle control valve and idle computer, no more problems. i was shocked at the prices for these parts so I went to Ebay and got both parts for $30.00. The Bentley manual is better than Haynes, in my personal opinion. The illustrations are better and the proceedures for repair are outlined with precision and detail. I got mine on Half.com for a much lower price than new.
Good luck.
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  #4  
Old 09-21-2008, 01:07 AM
nich.j.anderson nich.j.anderson is offline
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Location: Westminster, CO
 
Join Date: Sep 2008
Posts: 19
Mein Auto: MKIII Jetta VR6, E30 318i
Thanks alot, I'm going to go looking for a Bently.

Another thing I just remembered that stood out to me was when I had the key in the ignition and in the on position but not started, the fuel pump continuously ran. I would think that the fuel pump would pump the gas to a certain PSI then turn off, but it kept running. Also I went under the hood with it in the on position and with my amazing stethoscope (large flat head screwdriver), I pin pointed loud noises to see if they could give me any hints. And there was a ton of swirling sounds in the vacuum diaphragm at the end of the fuel rail (towards the front), also the last fuel injector was noisy (technically the first I guess, closest to the front). What I would like to know: is there any return system for excess fuel in the injection system? I am very confident that there is fluid movement in the system. Vacuum diaphragm noise makes me wonder if there is any 'false' vacuum mechanism?

My mind gets wrapped around things, especially when I can't interact with it since she's locked up in a automobile death yard.

Does the Bentley manual include a lot of good diagrams for the operation of components with each other and with-in them selves? Does anyone have any good resources that they could share of diagrams? I would much rather understand the system than blindly test components, although that is extremely important as well.

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  #5  
Old 09-21-2008, 01:16 AM
nich.j.anderson nich.j.anderson is offline
Bum Shop Rat
Location: Westminster, CO
 
Join Date: Sep 2008
Posts: 19
Mein Auto: MKIII Jetta VR6, E30 318i
Diagrams like this are a good place to start to understand the interaction of components (in a basic sense). I like arrows and usually like a short paragraph that corresponds to numbered components (as in information already written with the diagram, I'm not asking anyone to write anything but reply's).

So once again, any diagrams for the M10's ignition system, and related, or good sources to these diagrams would be awesome.

Thanks,

Nick
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  #6  
Old 09-21-2008, 02:29 AM
nich.j.anderson nich.j.anderson is offline
Bum Shop Rat
Location: Westminster, CO
 
Join Date: Sep 2008
Posts: 19
Mein Auto: MKIII Jetta VR6, E30 318i
Lightbulb Update

Did some research, the last diaphragm on the fuel rail is the fuel pressure regulator and it returns fuel that exceeds a certain PSI, not the pump turning on and off. So the noise is just fuel passing through back to the tank, which is never something to complain about these days. There's also a dampener in the mix there somewhere, but that's irrelevant.

Doing the research and if anything is faulty it's most likely Idle Control Valve, Throttle Position Sensor, and maybe cold start valve. But before I go crazy I should at the very very least put some new gas in there and replace all the vacuum lines. Actually now that I think about it I think that and timing should significantly improve the problems. But I have a limited amount of time to work on it at school, and I hate standing around scratching my head when what I thought would help did nothing. So I'm just trying to compile a list of things to try when I don't see improvement.


(not an M10 ICV, not even BMW I don't think)

On a side note the thing is exhaust-less, and I've been talking to my Physics teacher (AP Physics which I don't feel guilty bragging about since I am at the same time taking 11th grade english in my 12th year), and I've decided to build my own muffler. I want to combine pieces from an old Cherry Bomb my friend is done with from his old F-100 (thank god, it was loud) and concepts from 'reflection' type mufflers. I'll be using the baffling a little bit, but I want the cherry bombs mostly for it's outer shell which is 3 inches in diameter, and I want to use them to cancel compression waves by reflecting the waves back on them selves. Haven't looked at the specific science behind it yet, so any ideas will be BA. I'll also post a separate thread about it.
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  #7  
Old 09-21-2008, 11:04 PM
Rekcedbob Rekcedbob is offline
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Location: Southern California
 
Join Date: Jun 2008
Posts: 65
Mein Auto: 1985 Bmw 318i
I work in education, we only have one AP-Physics class in our school. I know you'll like the Bentley manual for this car, I have an 85 318i and it works for me. The book does a good job covering the entire car, an impressive publication compared to today's text books. A good website to look up part numbers is realoem.com, use the VIN field to verify the actual date of your car's manufacture and parts.

Read about the brazen bull. I think if you construct the muffler with the right pipes you can get it to sound like a bull, which would be cool ... I think? Just don't cook anything or anyone in it. I have a VW horn with an inline resistor to knock the voltage down a bit, sounds like a sick duck, makes people laugh when they hear it. I'm mildy retarded I think.

This forum is an excellent resource of information, as is the manual. Don't forget to search for specific articles and blogs about problems and solutions for your car on the web. I've seen some write-ups on repairs from DIY's that are unmatched by any other resource. Nevertheless, I believe most times you will have to break out the manual and ohm meter to figure out whats wrong with engine driveability issues--other issues are more easily recognized and solved visually and or with a good ear.
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  #8  
Old 09-23-2008, 08:47 AM
markseven markseven is offline
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Location: John 3:17
 
Join Date: Apr 2004
Posts: 7,395
Mein Auto: BMW M Power
nich,

I am at work and don't have time to read through this thread, but I did want to add that the E21 guys will be able to help as well:

http://www.bimmerfest.com/forums/forumdisplay.php?f=133

Mark
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  #9  
Old 09-24-2008, 08:47 PM
nich.j.anderson nich.j.anderson is offline
Bum Shop Rat
Location: Westminster, CO
 
Join Date: Sep 2008
Posts: 19
Mein Auto: MKIII Jetta VR6, E30 318i
Thumbs up

The E21 guys can help me because of the M10? Anyways for the most part I have the idle and the timing figured out. I've figured out what's working but not why, and have been able to get around the problem so it works and runs till I can figure exactly where the problem is.

So it's been idling at 3000 rpm. I take the Idle Control Valve off and hook it up to a battery, and what do you know it closes perfectly. Hook up a multimeter to the connector of the ICV and there's no signal, even after the engine is warm. So I come up with a cheap easy, kind of clever, fix. I go to home depot, go to the plumbing, and find a valve for water that allows a similar diameter amount of volume through. I clamp it to the hoses in place of the ICV valve. Turn the car on with it open, then slowly close it till the idle begins to drop till it's about 1500 rpm. At this point it's really shaky from the timing being advanced, so I loosen the distributor and slowly turn that and retard it. As the engine become more stable and the rpms drop I then closed the homemade idle valve more, then would retard the timing. I went back and forth till now it idles perfectly at 800 rpm, or as perfect as I can get by adjusting it by ear.

Didn't take my phone today so no pictures, but I'll post them as soon as I get them.

For the original ICV. It is a solenoid which is controlled by the Idle Control Unit, located under the dash above the glove box. I took a look at it and it looks clean and untampered with, and I don't think that would be something to go out, typically. But on the wiring diagram it seems to me that it takes on-off type inputs from temperature related things, so when the engine is still cold it can fast idle to warm up. Plus it takes input from the AC so the valve can compensate for the extra load. Also it detects engine RPM. So I figure the best place to start would be to go through and check all the input components and make sure they have good connections and etc. If they all seem to work fine I'll have to look for the leads to the sensors/switches, then I'd check the control unit.

The homemade valve may suit my needs just fine, as it's not a daily driver, but I'd like to know why it is not working because that same sensor could be effecting something else.

Anyways I'll keep updating till it's figured out. Maybe the water valve idea may work for someone else.
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  #10  
Old 09-25-2008, 07:20 AM
markseven markseven is offline
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Location: John 3:17
 
Join Date: Apr 2004
Posts: 7,395
Mein Auto: BMW M Power
Quote:
Originally Posted by nich.j.anderson View Post
The E21 guys can help me because of the M10?
Yup.
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