Lira (euro DS mtech II 318is reshelled, 24v swapped, also now BAR'd)

[kronus]

whoa! that is a serious e30 and a legitimate 320is!

[jrobie79]

i wish the underside of my e30 looked like that....friggin northeast winters

[kronus]

a pressure washer'll do that for ya ;)

also, something is wrong with my M50. This is copy pasted from my thread in the 24v subforum in the hopes that maybe someone will see it.


the symptoms

once car is hot, idling for less than a minute will lead to it violently stumbling once, throwing the 1221 O2 sensor code and having a rougher idle thereafter.

No code is thrown during driving.

Power feels normal until code is thrown, there is no misfire or hesitation.

The idle is normal until code is thrown.


things I've tried with no effect

replaced oxygen sensor with a new one

replaced MAF with a different used one

replaced ICV with a cleaned, working one

replaced injectors with known-good ones

replaced coils with known-good ones

replaced spark plugs with new ones

replaced fuel filter with a new one

replaced TPS with a known good one

checked manifold vacuum; -20inhg (in spec)

leakdown test; 0% 0% 3% 1% 0% 0%

smoke test; no leaks

reset ECU; no change

replaced ECU with stock-tune 413; no change


remaining diagnostics

meter out the TPS

meter out the MAF

monitor fuel line pressure

[kronus]

update: 3.2 bar / 46PSI in the rail with the car on.

[TrixE30]

Sounds like your issue is when it goes into closed loop. 3.2 bar is a little low for the M50tu. It should be closer to 3.5bar, doesn't sound like much but the slightest fuel pressure drop when in closed loop can cause a lean misfire. Are you still using the M42 fuel pump? Once the code is thrown and the idle becomes rough, how does it run under a load/higher RPM? could have something to do with EGR if you still have it, or CCV, PCV?

I may be wrong but its something to consider. just my .02 cents.


awesome build BTW . I wish I could get some headway on my E30 (11 years in the making project).

[wark]

In!

[pandaboo911]

I saw this on craigs and thought of your car somewhat. An Mtech2 with an M3 engine.

http://losangeles.craigslist.org/lac/cto/5285009012.html

Crack pipe

Sounds like your issue is when it goes into closed loop. 3.2 bar is a little low for the M50tu. It should be closer to 3.5bar, doesn't sound like much but the slightest fuel pressure drop when in closed loop can cause a lean misfire. Are you still using the M42 fuel pump? Once the code is thrown and the idle becomes rough, how does it run under a load/higher RPM? could have something to do with EGR if you still have it, or CCV, PCV?

I may be wrong but its something to consider. just my .02 cents.


awesome build BTW . I wish I could get some headway on my E30 (11 years in the making project).

3.2 bar is high for idle. it should be 43psi at idle IIRC. 3psi will make almost no difference though. The problem is eslewhere

51psi should be with the vacuum line of the FPR unplugged.

it's definitely triggered by something that runs in closed loop if the car runs well before operating temp

[kronus]

the weird thing is it's fine at operating temp as long as i'm driving it. it's the idling that pops the CEL.

[kronus]

also I guess I missed an update cause i've been busy with the darn CEL

the car is back from the exhaust shop and, well, good news and bad news on that front

the following things happened
- the front flanges and x pipe got cut off a stock e36 325is downpipe
- pipes were run from the flanges placing the x-pipe in a stockish location
- two Walker 80801 CA cats were welded in post-x-pipe
- a stock e36 M3 muffler had its nice pipes and flanges cut off and new pipe run directly to the cats

good news is that it was all run really high up and form-fitting to the body, so I have a ton of clearance



bad news is it's a bit of a hatchet job. the work is well done, but not really.. right.







the ehxaust tips will be extended, waiting for them to be delivered

eventually (when I do the suspension), I'm taking the exhaust down, grinding down the welds and welding in a flange post-cat so that I don't need to take the whole thing out in one giant-ass piece every time I want to fiddle with stuff behind it.

the plan was to BAR it and then do the suspension refresh and sideskirt repair, but my new appointment isn't for a while.

Sounds like your issue is when it goes into closed loop. 3.2 bar is a little low for the M50tu. It should be closer to 3.5bar, doesn't sound like much but the slightest fuel pressure drop when in closed loop can cause a lean misfire. Are you still using the M42 fuel pump? Once the code is thrown and the idle becomes rough, how does it run under a load/higher RPM? could have something to do with EGR if you still have it, or CCV, PCV?

I may be wrong but its something to consider. just my .02 cents.


awesome build BTW . I wish I could get some headway on my E30 (11 years in the making project).

thanks! and get to work!


I think it runs fine in closed-loop until it has to sit around and idle while hot. it'll run for a while when cold, as well, just eventually hits some amount of cold idle and trips over its own shoelaces

I'm still using the m42 pump, yup. I haven't volume tested it but car doesn't seem to have a miss at WOT at all.

I haven't run it with the CEL on, that test is scheduled for tomorrow.

the CCV/PCV is new and seems to be functioning normally. the purge valve is present and hooked up as well, but I haven't tested it for function yet.


also I've been giving it the beans while testing, and the M50 has a totally pleasant amount of power. I see why you people do this now :evil:

[kronus]

I've metered out the TPS, CPS, CTS, ATS, MAF and O2 sensor and everything is nominal. still chasing this stupid thing.

edit:

CPS: 528 ohms

TPS: 1450 ohms to 4790 ohms, full sweep is fine

ATS: 2340 ohms at ambient temp

CTS: 1990 ohms at ambient temp

MAF: .8V at idle, ground ok

O2: 2500 ohms heater resistance, continuity to DME ok

beating my head on it: yes

[kronus]

went to a shop with an autologic unit; either there's a O2 sensor wiring fault, or both MAFs I've been testing with are bad. Car wants to run lean.


also got the sides done. first, template



then drill (I started with a 3/8" bit and then used a step bit to enlarge to 5/8")



then mount



then get the pods on





then drive out into the daylight and admire



I also got the 80/88 fan switch in, but it's not engaging the low speed, so my fan resistor is likely trashed.

[pandaboo911]

I doubt it's the MAF, it worked when I pulled it and it was stored indoors. Also cleaned the piss out of the element.

They typically only go bad when there's oil deposits from a filter on the element.


Sent from my iPhone using Tapatalk

[kronus]

yeah, I tried three other MAFs with the exact same behavior.

yesterday I swapped the harness to an unmodified E36 M50 one. tomorrow I am putting together an X20-C101 adapter and will see if it's any different. if it works fine, I'll repack it in to the M42 housing.. I have some hope.

[Julien]

is your car loosing the 5v reference when it starts acting up?

[kronus]

dunno! where can I check that

also finished up swapping in harness that came from a known good car. same symptom.

swapping cam/crank sensors, and if that doesn't work I'm going to start sacrificing small animals.