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1

Engine + Driveline / Another post for warm start/driving issues

« on: January 13, 2011, 07:57:51 PM »

I should also add that my spark plugs look fine and my brake booster vacuum is fine.... I'll keep adding things I forget as I remember.

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Engine + Driveline / Another post for warm start/driving issues

« on: January 13, 2011, 07:52:39 PM »

Okay, I know there are a few threads out there about this issue and a solution remains elusive. Here are my symptoms on my 1991 318i with 230k:

1) hard cold start, sometimes have to give it gas for 20-30 seconds before it will idle

2) inconsistent power delivery when cold. if I give it too much gas, the thing loses power, jerks, surges, loses power again, etc. if I let up off the gas, it evens out. This happens for the first few minutes of driving unless I let it warm up before hand

3) after driving up to temp, it sometimes (usually) is difficult to start after being shut off. if it does start, it is quite rough and sometimes requires some more juice from the gas pedal. it lugs and barely idles for a few secs and then surges way up because I'm pressing on the gas to keep it running. Sometimes a belt squeals when this happens - that one's a complete mystery to me for now.

4) even after it's warmed up it can lose power under load (i.e. making it difficult to accelerate to freeway speeds). I'll start accelerating just fine and then the power just cuts and sometimes jerks, but not as badly as it does during a cold start. Occasionally my CEL comes on when I'm on the freeway (the power loss happens at cruising speed if I, say, start going up a gentle freeway incline).

That should cover the symptoms, now for what I've done to trouble shoot.

1) the first thing I did was clean "the mess under the intake" thinking it was a vacuum issue. I replaced the O2 sensor at the same time. No change.

2) double checked my ICV. It's clean and it works.

3) checked my mass airflow meter. it tested bad, but didn't throw a CEL code. apparently the car has a default fuel map that it reverts to if the mass sensor fails so it will still drive okay. I tested 3 different junkyard meters before I found one that tested "good." the car ran WORSE - it also triggered a CEL code for my mass meter. I put the old one back on and the car became drivable again, albeit with the same symptoms. No CEL code anymore.

4) drained the tank, checked for crud on the fuel pump. changed fuel filter. currently on my 3rd bottle of fuel system cleaner. It SEEMED to improve with the fuel system cleaner at first, but the symptoms returned.

5) encouraged by the results from the fuel system cleaner, I took my injectors out and cleaned them, as well as put new seals on them (I thought perhaps one of my seals was busted and intermittently let pressure out the top, thus losing compression in one cylinder). The first two times I drove it was almost flawless. it started right up when cold and there was no driving stutter... my symptoms returned today and I almost got stranded at the parts store getting another bottle of Seafoam.

TPS is good, Temp sensor... I don't know, but it doesn't throw a code. I think my pressure regulator is fine, but I haven't checked my fuel pressure. it doesn't make sense for it to be temperature related and my vacuum lines are all replaced. Furthermore, lots of these things have already been suggested in some of the other threads that describe similar issues with no tangible result. Another suggestion was a plug on the wiring harness having to do with the catalytic converter and that checks out, too. There have been brief mentions of the cam sensor (maybe that would have to do with my sqealing belt on a warm start?) and also a clogged evap canister. I checked my engine ground and, while the insulation is screwed and it's dirty, everything's intact and nothing is frayed. my entire intake looks pretty clean. Other people in other threads have replaced the ECU with no change, as well.

My final note is that before I cleaned my injectors (which looked good, anyway) my CEL threw a "running lean" code. This has since ceased. Even though my CEL comes on while driving, the stomp test doesn't give an error. This makes me lean away from some people saying that injectors are dumping too much fuel in on start. the only difference in performance that I've been able to measure has to do with the cleanliness of the fuel system, but everything seems just fine! Okay, I believe that's my definitive analysis of my issue. someone. please. for the love of god. solve it?

3

Engine + Driveline / Warm start stall

« on: September 17, 2010, 06:30:42 PM »

My car has been doing funny things ALMOST like this. It started just like the OP described and got worse from there. By the time I started getting massive power loss as I accelerated and the inability to re-start the motor after shopping on the hottest day of the year, I decided to take care of "the mess under the intake." no change. In fact, I think it's even worse. I also replaced the O2 sensor, so I'm thinking fuel pressure (or AFM... or temp sensor... but the stomp test gives the all-clear)

4

Electrical / thermo-time switch and oil pressure switch

« on: August 29, 2010, 02:23:47 AM »

I'm in the process of replacing "the mess under the intake" and managed to (stupidly) not label the three connectors that come out of the black wiring box that go to 1) the 'remote thermometer sending unit,' 2) the temperature sensor, and 3) the oil pressure switch. I figured out that the temperature sensor is the one plug with two wires leading to it and which sensor is, in fact, the temperature sensor, but I am at a total, complete, hair pulling, cursing, punching, kicking, screaming, loss for which of the two remaining plugs go to which of the two remaining sensors. NOWHERE can I find a wiring diagram that even HAS the oil pressure switch or thermo-time switch on them - at all. no mention of them. anywhere. ANYWHERE. Does anyone know which ones are which!? ANYONE!? I just need to know which color wire goes to which sensor.

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Engine + Driveline / M42 weird starting issue

« on: February 02, 2010, 11:20:54 PM »

update on my similar issue - my battery was crap. it was good enough to work 98% of the time, but it wasn't cranking it quite fast enough for the fuel pump to kick on. I could hear the relay clicking erratically whilst cranking. new battery and it starts just fine.

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Engine + Driveline / M42 weird starting issue

« on: December 02, 2009, 10:09:31 PM »

From what I read somewhere on the M42, the fuel pump is only actuated once the starter turns the motor at 125 RPM or something like that. My fuel pump doesn't make a peep with the key in position 2 (in an E30, maybe it changed with the later models)

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Engine + Driveline / cold start valve?

« on: November 10, 2009, 02:44:08 PM »

My E30 does this as well, but there have been one or two occasions where it didn't start in the moderately cool weather. I cranked it for quite a while and the motor almost caught every few seconds - it would burble like it's about to start and then go back to cranking. 9/10 times it has trouble starting (cold only), it cranks, burbles, and then fires up. I was told I should check my fuel pressure at various places along the lines, but not only am I lazy but I also lack a pressure gauge (and my last experiment with fuel lines ended with gasoline shot down my ear canal... OH the pain). I looked in the Bentley and with the fuel pump working and the ICV mechanically functional (the jury's still out on whether or not it's getting a signal), I decided that the cold start valve might be shot. Granted, the Bentley I have covers my body but no the M42, so I haven't investigated yet.

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Engine + Driveline / it's a pain

« on: July 06, 2009, 03:18:23 AM »

I just checked mine for the first time - it just pulls out. The hard part is overcoming the spring and threading the cap back on! I wore out the muscles in my hands and forearms trying to figure out how to get it to thread once I pushed it in far enough until I just unsecured the washer fluid reservoir and moved it aside, after which I got a ratchet and socket on the cap which was on the end of the tensioner. Then I used an open end wrench as a lever against that metal ridge right there to apply pressure to the back of the ratchet to over come the spring tension; I was just able to ratchet it back on.

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Engine + Driveline / Is my oil too thick, resulting in a noisy chain?

« on: July 05, 2009, 05:52:51 PM »

I changed the oil out for 10w-30 and the noise is gone - I suppose I'll get a new tensioner, regardless. Thanks all!

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Engine + Driveline / checked tensioner, changed oil

« on: July 02, 2009, 06:16:21 PM »

I pulled my tensioner out and it seemed okay, but I wasn't sure what to look for. The spring was plenty tight - I actually had to use an open end to create leverage to overcome the spring and thread the cap at the same time. Anyway, I drained the 20W-50 and put in 10W-30 and it seems to have fixed the problem. I called a BMW repair shop to get some advice and was told that 20-50's way too thick and it could be that the oil just isn't going through some of the small passageways until it heats up and thins out.

11

Engine + Driveline / Is my oil too thick, resulting in a noisy chain?

« on: July 01, 2009, 04:09:58 PM »

I've been told to check the tensioner, which I just haven't gotten around to yet. I was suspicious of the suggestion for 20-50 (it's conventional oil, by the way). I'll check my tensioner today; I read that if I DON'T hear a bearing rattle then it's shot, is that correct?

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Engine + Driveline / Is my oil too thick, resulting in a noisy chain?

« on: June 30, 2009, 10:07:32 PM »

I've been reading up on the timing chain issues but don't want to believe that it's time for my timing chain to go. I just bought a '91 318i and I could have sworn the previous owners told me that they recently did a timing chain job. I bought it, everything was awesome, but when I changed the oil I used 20w-50 as per the owners manual recommended. Since then, I've noticed that for a minute or two after starting from rest, I hear noise from my timing chain - it's not too loud, but sounds kind of like a little diesel motor. From my research on these forums, I've seen that that sound means I need to replace the chain/sprocket/the works. However, the noise isn't that loud and it goes away once the oil heats up a bit AND it's really thick oil (I can't really believe it's recommended, but whatever). I didn't notice the noise before I changed out the 5W-30 that was in there, either, so that also makes me think it's just a matter of using oil that's too thick. I was hoping someone might give me some insight before I go buy a bunch of lighter weight oil or buy a valve cover gasket set so I can take it off to check the timing chain sprockets.