2.8 Roadster possible intake leak, symptoms?

[JKuhn]

So the next step (meaning now) should be to check the timing, as suggested by the BMW mechanic?

And what do you mean by INPA?

[rf900rkw]

From the evidence gleaned from a continent away, timing is the next place I would check. Of course, if I was there actually listening to the car and watching a scanner, I may go a totally different direction.



https://www.bimmerforums.com/forum/s...xperimentation

[JKuhn]

I do have a couple videos I just took (engine start, 1st gear pull, engine revving), I can combine and upload them if it's of use. But keep in mind the car's behaviour is very inconsistent.

I'll also go through that thread.

[rf900rkw]

Everything you need in the INPA thread is in the first post. Abel did an excellent job of keeping the relevant latest info up top.

[JKuhn]

So basically I should buy one of those PC-based systems?

And should I combine and upload those videos? If I do it's going to take a while (with our pathetic internet connection). Shouldn't take too long though, since it'll be short.

Oh, and by timing, I assume you mean the physical alignment of the chain, as the BMW mechanic said?

[rf900rkw]

Yes, cam timing via the chain/sprocket installation.

I've never been able to tell anything from videos or audio clips.


If you have an old laptop laying around, there's little to buy, only a $10 cable. The software is all there in that post.

[JKuhn]

Then I just need to find the right seller (both of those don't ship to ZA), and wait a full month (or longer) for it to arrive. EDIT: Unless I can get it locally. Since it's meant for VW cars (and they do BMW as well), I might succeed at Goldwagen.

I'll speak to the more trusted mechanic again, hear what he says, and find out what it will cost there. I do know if I get the sensor cleaned he can do it Monday.

[JKuhn]

I went to see the mechanic and discussed the car in more detail, his opinion is that the VANOS is acting up. The car will go in next week to have the VANOS fixed.

Hopefully this will be the end of the problems. I do know I've suspected the VANOS since just after I bought the car, after I found out how it should pull on the bottom-end.

[MartyBtoo]

His OPINION is that the VANOS is acting up? My mechanic has a software test routine that raises the engine speed then exercises the various VANOS mechanisms and reports back. That's how we found that one of the VANOS solenoids was sticking on my car.

Marty

[rf900rkw]

Vanos "acting up" won't cause this. To set a 340 requires the intake can timing to be at a point not reachable by the vanos.

[JKuhn]

I'll discuss it with him then.

EDIT: I didn't have the codes with me, but I did tell him what the diagnostic printout said. He said that incorrect cam/chain timing should immediately throw a CEL. Also, will the car run so inconsistently if that is the problem (and with it sometimes running great)? Seems to me that sometimes it's right (all the way from idle to redline), sometimes it's a bit off, and sometimes it's WAY off. I don't see how a static problem like that could cause such wild variations.

[deni2s]

He said that incorrect cam/chain timing should immediately throw a CEL.

I had incorrectly timed cams after upgrading my m52b28 to s52 cams and there were no error codes at all. The power delivery was constant but not as high as expected. Fuel consumption raised by at least 20%. Not sure how much it was off, but mechanic who fixed it said he can see looking at opened at the engine that they are off, but it will not be visible on photos. Did the vanos "while we are here", just in case, but it was ok anyway.

I had once dead cam position sensor. Car lost like 50% of power, and there was sensor error code. Changed the sensor, that fixed it.

Just sharing my experience, in case it helps to lead to good decisions. I would start with replacing cam position sensor (as it's cheaper), and then doing the vanos and checking the cams timing if needed. Make sure you use reputable OEM brand for sensors.

[JKuhn]

Off-topic question. I noticed on the diagnostic printout that it says it's a MS43 and M54B22, while the car should (according to a VIN checkup and the registration data) have a M52TUB28. I do know the engine was replaced at 16k km(!), but don't know why yet. I first have to find out WHERE it was replaced, before I can get access to the records. What should I make of that? Also, I can't say how reliable this is, but comparing it to my father's 3.2 Captiva, admittedly ancient carb-converted (edit - it's a Weber 38DGES) 280SE and some other "normal" cars I've driven and considering how the car is running right now, I don't really get the impression that it's a 2.2.

EDIT: Oh, and deni2s: As I said, mine is very far from constant. I do get the impression that the top-end is at the very least close to normal though.

[deni2s]

EDIT: Oh, and deni2s: As I said, mine is very far from constant.

That's one more reason why I would start with replacing camshaft position sensor before checking cams timing. Your symptoms don't sound very similar to my misaligned cam symptoms, but maybe your misalignment is very aggressive...

M54 is totally different engine, misleading title might draw away M54B22 owners with their experience away from this thread...

Decat without disabling postcat lambdas also doesn't makes a very good impression about the guy who did that.

[deni2s]

Off-topic question. I noticed on the diagnostic printout that it says it's a MS43 and M54B22, while the car should (according to a VIN checkup and the registration data) have a M52TUB28. I do know the engine was replaced at 16k km(!), but don't know why yet. I first have to find out WHERE it was replaced, before I can get access to the records. What should I make of that?

No need to find out why it was swapped with less powered one - definitely not because it was running too good. Maybe it was overheated or defective or whatever.

[JKuhn]

The question is, would that info be trustworthy? As I said, I don't get the impression that this is a 2.2.

EDIT: I do know that it still has a throttle cable, but from what I've read it's common to keep that when people do a M54 swap. Oh, and the owner before me (I think it was the one before me, the one before that had the car stock) ripped the factory exhaust out and put a larger diameter mild steel system in. So that must be when it was decatted.

[MIKYZZ4]

Oversized diameter exhaust system on a NA engine is know to cause loss of low end power.
Research "reasons oversized exhaust cause loss of low end power"
This is what I've been told:https://www.clown-shoe.com/single-po...the-right-size

[rf900rkw]

At this point I really don't know what to say. We now find out it has a mystery motor with an M52TU throttle and a totally incompatible M54 DME. I guess a priority would be to sort out what in the hell you have exactly.

[JKuhn]

Oversized diameter exhaust system on a NA engine is know to cause loss of low end power.
Research "reasons oversized exhaust cause loss of low end power"
This is what I've been told:https://www.clown-shoe.com/single-po...the-right-size

I haven't read that yet, but it's not massively oversized (I'm actually not even 100% sure what the stock size is, but I do think it's a bit larger than normal). And in my personal experience a slightly larger exhaust can give better performance, with worst case unnoticeable losses on the bottom end (my Mazda has more top-end and more torque from hand-advanced spark timing and a 46 ID exhaust).

rf900rkw: I'm getting more and more proof that the car has been ghetto-fixed by at least one previous owner. From what I've read the M54 can be recognised from the injectors and valve cover(?), so I'll try to find out what it has. I'm not unfamiliar with unexpected suprises (I tend not to look at the best examples available, except with the VW where I bought the ONLY example available), so I'm not giving up yet. It is rather frustrating though, knowing that I might have a weaker (and wrong series) engine in there, when it's meant as a long-term show car project (like I said, it doesn't feel like a 2.2 though, so maybe the DME went out and this is what the previous owner found?)

[deni2s]

Is it really so hard to post a picture of your engine bay here? I'm pretty sure most folks here will id the engine instantly...

[JKuhn]

Doing it now. I didn't before, because as I understand the M52TU and M54 look the same unless you remove stuff.



Regarding what I've done myself: I spoke to the BMW mechanic again. He said that he knows the M52TU as the "old" M54, and that I should look for the engine code to see exactly what it is. Unfortunately I can't do that right now, as the car will have to be raised from the ground. I also spoke to someone I met at a local show. She said that when they had the car they were under the impression that it was a normal 2.8, and they never replaced the engine or computer. So no leads there, except that the car aparrently pulled well (also they sold the car because it started to get some issues and they got afraid of potential costs).

[BimmerBreaker]

Look at throttle body while someone in car moves gas pedal. M52tu will have a cable you will hear/see moving. M54 is drive by wire and doesnt have a throttle cable

[JKuhn]

I can see the cable. As I said, it does have a cable. But the DME (MS43) says it's a M54B22.

[deni2s]

I can see the cable. As I said, it does have a cable. But the DME (MS43) says it's a M54B22.

Did I got it right that the only source why you think it's an m54b22 is some diagnostic printout? I wouldn't trust those... Even your code numbers where in hex system, not sure what software they were using.

[deni2s]

I can see the cable. As I said, it does have a cable. But the DME (MS43) says it's a M54B22.

IMHO M54 conversion to cable throttle requires adapter plate between throttle body and intake manifold. You can look if you have it.