MyE28.com

why no o2 sensor?

Jeremy wrote:The symptoms indicate vacuum leak. What have you done to look for one? I know the problem started with plugging the USB thingie into the Miller system, but that could simply be coincidence. The lack of idle change when pulling the dipstick and pulling the valve cover breather screams vacuum leak to me.

Jeremy

My thoughts exactly. I checked all the usual places, all the 4mm vacuum lines are on, dipstick seal is good, valve cover seal is new, inlet manifold gaskets are only 4k km old and were all torqued to spec, injector o-rings are all brand new, the larger vacuum lines (valve cover breather/ICV) and all the intake bellows are new and show no signs of failure. Brake cleaner testing all the vacuum lines result in no change to engine speed. I've not performed a smoke test. The one thing worth mentioning is the oil leak from the duck gasket at the back of the head. If oil is getting out, could it be possible air is getting in? It's been leaking for months and the car's been running fine, so I can't imagine that to be the cause, although it's still worth mentioning.There's got to be something up with the air metering though, fuel and spark are fine. I've got my buddy coming around again this afternoon with the old Miller software which was way less buggy than the updated stuff, so we're going to upload the tune with that and see if it makes any difference/rule out the software. I'll also try uploading from a different laptop to rule that out as a possible cause. I'm kinda lost for ideas now, and just hope I haven't overlooked anything obvious. I'll go through the engine harness with a fine toothed comb again today, and wire trace and test each of the ECU pinouts and there associated sensors/plugs to be satisfied it's not a wiring issue.

Could you maybe have pulled the USB plug prematurely when accessing the chip? Sometimes that can lead to data loss.

So I got advanced today and took some videos of what's going on, and put them on youtube for your viewing pleasure.

http://www.youtube.com/watch?v=W_6ZerGL ... ature=plcp

This is cold start. It runs and idles fine for a few moments before dropping down to 500rpm and will stall if no throttle input is given. The rattling is due to the low idle and lightened single mass, not engine knocking (thank god). The smell out the tailpipes is strong, and made my eyes water quicker than chopping onions.

http://www.youtube.com/watch?v=_HR48EOP ... ature=plcp

This next one is pretty self explanatory, shows what the indicated RPM is without, and with throttle inputs. Held at RPM there is a noticeable miss, although after cleaning the plugs which were quite fouled, this has subsided somewhat since the video was taken. You can see how the low rpm and miss shakes the car quite violently.

http://www.youtube.com/watch?v=16Yqhi2Q ... e=youtu.be

This one shows what happens when the ICV plug is disconnected and reconnected when the engine is up to temp. It has an effect on occasion, and sometimes does not. When dis/re-connected the first two times, there's no difference, however after I blip the throttle then remove it, you can audibly notice the change in the idle intake noise when it's disconnected, and when revved with it disconnected the engine stalls and there is a noticeable sucking noise coming from around the MAF area. I brake cleaner-ed the injectors, and manifold gaskets/vacuum lines, and there was no change as mentioned in my previous post. I am yet to remove and re-seal the valve cover, so that may have potential to be the cause based on the vicinity of the sucking sound as the motor dies. We performed the same test on Deans high comp M30, and the stock e23 735, and neither made the same sucking noise. Thoughts?

LandCruzer94 wrote:Could you maybe have pulled the USB plug prematurely when accessing the chip? Sometimes that can lead to data loss.

Even if that had of happened, the fact we've swapped ECU's, WAR chips, and tunes multiple times since to no avail would suggest that's not important.. I wish it were that easy

What you are posting sounds sooo much like the issue I had with an e24 that was in my shop.

http://forums.bimmerforums.com/forum/sh ... +nightmare

Rule out the o2 circuit.I cant believe the B.S. caused on this car because it! Whether or not the car was working without it before.

P.S. not sure about the workings of the WAR chip so im not sure what effect the o2 circuit may or may not have.

GI jonas wrote:What you are posting sounds sooo much like the issue I had with an e24 that was in my shop.

http://forums.bimmerforums.com/forum/sh ... +nightmare

Rule out the o2 circuit.I cant believe the B.S. caused on this car because it! Whether or not the car was working without it before.

P.S. not sure about the workings of the WAR chip so im not sure what effect the o2 circuit may or may not have.

O2 sensor is switched off in the WAR chip, and has been running and tuned to stoic without it so it can't be the issue..

Don't claim to know a thing about the Miller but the video where you unplug the ICV made me think maybe the TPS signal is bad? What happens if you unplug TPS or CTS or some of the basic things. If there is no change it usually leads me to believe it's gone bad.

I know it sounds too simple but it's worth a quick try.

I got really pumped about the Miller MAF and War chip earlier on this year (shortly after xmas) and told my fiance that I knew what I wanted next year....the $700 package deal fo the maf conversion/war chip. This thread is making me think twice about that.

I hope this gets resolved. Sounds like a royal pain. Sorry I do not have any input. Just a: Good Luck!

I've also been excited about the Miller MAF conversion although I was only going to grab the 'standard' chip and not the WAR version. Really thinking about skipping the whole thing now.

This thread has gotten pretty far and has a ton of views for Miller to not have posted. I thought they had a representative active on the forum at one point; am I misremembering?

I'm a new owner of a 1988 535i and noob on the M30. As of a week now, i've got the same symptoms as you. Engine is stock.
I started looking into the cold start system and at first the coolant temp sensor for ECU was not to spec when testing ohms. I also found cracked insulation on the 2 leads to that sensor. It also runs rich when cold starting in the morning.
This is my first intervention on this board but I know your frustation when working on a car of motorcycle and things don't want to go as we wish and faced with problems when all we want to do is enjoy the car.
Hang in there

Durden wrote:I thought they had a representative active on the forum at one point; am I misremembering?

They only post here when they want to make us aware of something they're selling. I don't think I've seen them answer any after-sale questions on this forum.

I still havent had any issues with my miller Maf, so I'll still make a recommendation for the product, but just be aware that your results may vary.

The last couple of times I've called them though they never seem to pick up the line, but when I press "1" for sales I get someone on the first ring. Hmmmmmmm.

Ok.

To elaborate a little on the issue, and although I'm not the only one who has experienced the negative side of the products and company, I have also like many many others, seen proof that what they sell IS worth the money, and CAN work to full customer expectations. I've had periods over the last few months where the car has run beautifully, better than it ever has, and have been satisfied with my ~$750 investment, recc. them to other members of the community.
Unfortunately, it's the periods in between that have tainted my hope for them. It's like walking on eggshells. I'm not the only one who is afraid to plug in the computer, or take a bit of fuel out at that load point, or (god forbid) lower the idle setting because you never know what is going to happen. That is completely contradictory to the entire premise of the product! It's designed to be fiddled with, it's designed for fine tuning, and ease of use. If I want to lower my idle speed at cold start, I expect to be able to without opening a pandoras box of fail: that's the whole reason why I invested in the product in the first place.

No one will agree that their tech support is decent, and that's a true shame, as that is a huge part of the automotive industry, especially when it's involving an electronically controlled piece of equipment that is designed to allow the user the ability to plug and play, without the prerequisite of a degree in programming or electrical engineering. That is the sort of skill we assume the developers to have, and be ready to offer up should an issue arise. This is clearly not the case.

Nevertheless, my basic conclusion is that if you have a stock engine, and want a little bit extra oomph, the MAF conversion with the supplied chip is an excellent option for an unmodified M30, and is worth the extra money over an ebay, or alternative aftermarket chip, however the programmable WAR chip is simply too underdeveloped and buggy. The software and tune coding Brody uses is a faux and an inconvenience at best, and although the potential is definitely there, the current execution is deplorable and the lack of interest, technical support and development are killing it. There are numerous standalone aftermarket systems for the same money, which are less complicated to install, and offer way greater possibilities and support to the n00b, or seasoned tuner alike, and if Miller intend to compete with such, they really need to pick up their act.

So got the car running yesterday. Idle issue was still there, but got it to settle down a little bit after swapping another coil into it, and took it for a drive once it warmed up enough to idle on its own (around 500rpm). Once warmed up, it performs perfectly. Lumpy consistent idle at ~850rpm like it used to, pulls well to redline, no missing or coughing under load. Was rather chuffed.

Cold start this morning however, is consistent with the underlying issue. Basically the issue has manifested itself into what I suspect is a lean running condition at cold start. Turn the key, idles at 800rpm for a moment, then idles at 300rpm before stalling. Holding the revs until it'll idle means it can be driven, and once warm, is perfectly fine and performance is %100. Idle quality once warm and having been driven, as mentioned, is normal for this motor/cam setup. I'm thinking the issue may have something to do with the ambient temp at the moment. It was running great through summer, cold start being ~15 degrees C, probably 20 inside the motor, but now the temps over night drop to 3 or 4 degrees C, i'm wondering if that has something to do with it. Any ideas? I can post a copy of the idle fuel map if needs be? I'm planning to hookup the datalogger to track the AFR's at idle to be sure of my diagnosis, and ideally would like to simply throw a bit more fuel in the map but i'm paranoid about playing with the tune now that the car at least drives once it's warmed up..

I am taking my high compression (10.25:1) B35 with about 1000 miles on it to the dyno today to get a proper tune. Right now I am running the 179 G3 cam 10 to 1 Miller base tune. The car always fires right up and initially idles at about 850 with a slightly lumpy idle due to the cam. Once warm the car idles at a steady speed but at anywhere from 1000 to about 1250 RPM. The car also has an issue when accelerating hard and it hits about 4000 RPM where it just bucks hard momentarily (almost cuts out) but will then continue to rev past that up to redline. My TPS is brand new as is my CTS. Fuel pressure is about 48 psi and I'm running 24 lb. injectors. All ignition components are new. Will report my results.

Disclaimer, I do not know anything about tuning the Miller MAF and chip but... what you describe sounds just like the car trying to idle on its default or 'off idle' ICV setting without idle speed control. Slow and probably lean cold because there is not enough cold compensation and then OK hot but still not controlling to computer prescribed idle. I know you said the programming change you made was to reduce the idle but are you sure at this point you still get a good TPS 'idle on' signal to the computer.

I've seen TPS switches with bad solder joints that also worked and then not worked with temp changes. Simple and easy to have a check with VOM.

tn535i wrote:Disclaimer, I do not know anything about tuning the Miller MAF and chip but... what you describe sounds just like the car trying to idle on its default or 'off idle' ICV setting without idle speed control. Slow and probably lean cold because there is not enough cold compensation and then OK hot but still not controlling to computer prescribed idle. I know you said the programming change you made was to reduce the idle but are you sure at this point you still get a good TPS 'idle on' signal to the computer.

I've seen TPS switches with bad solder joints that also worked and then not worked with temp changes. Simple and easy to have a check with VOM.

My thoughts axactly. Because it's the round e34 EHauto style TPS, it wasn't as straightforward to test. It's certainly set right, and the adjustment of the throttle body plate is set right, but there's a definite issue with either cold start enrichment, or idle signal coming from the TPS. I'd like to get a brand new TPS, but not for that price..

Just came back from dyno tuning on a dyno dynamics machine at Dent Sport Garage. Matt said their machine typically produces lower numbers than some other dynos and estimated about a 20% driveline loss for rwd cars. The car runs well and wasn't too far off with the Miller base tune. He had to pull about 2 degress of timing and added a bit more fuel at full throttle. It still idles at around 1000-1100 rpm when hot (will have to inspect ICV and throttle plate) and I have an intermittent misfire around peak torque at 4100 rpm so I have to go through my ignition system again to see whats causing the issue. Overall I gained 11 hp from tuning and about 10 ft/lbs. The motor curently produces 240 ft/lbs at 4100 and 205.4 hp at about 5200 rpm. The exhaust still needs work as I am still using B35 manifolds and there is a bit of a pipe restriction down stream of the manifolds just before the Y pipe as well. Not too shabby for an "agricultural motor".

This describes what happens with my car as well. On a morning start the car will idle fine until the oil pressure light goes out and then out of the blue it will stumble and sound like its about to die, although I don't need to stabilize it with extra throttle. That will only happens for a few seconds and then it will catch itself and jump up to about 1300 rpm or so and finally settle down to normal. Once it happens it wont repeat until the very next day, although all throughout my road trip last week it didn't do it at all. I know for a fact my TPS is adjusted properly, and I replaced my transfer pump thinking it was the issue but that wasn't it. I think it does seem to be temp related too.

Once I get moved in to my new house I'll explore it a little more, but I'll continue to post my findings.

Das_Prachtstraße wrote:So got the car running yesterday. Idle issue was still there, but got it to settle down a little bit after swapping another coil into it, and took it for a drive once it warmed up enough to idle on its own (around 500rpm). Once warmed up, it performs perfectly. Lumpy consistent idle at ~850rpm like it used to, pulls well to redline, no missing or coughing under load. Was rather chuffed.

Cold start this morning however, is consistent with the underlying issue. Basically the issue has manifested itself into what I suspect is a lean running condition at cold start. Turn the key, idles at 800rpm for a moment, then idles at 300rpm before stalling. Holding the revs until it'll idle means it can be driven, and once warm, is perfectly fine and performance is %100. Idle quality once warm and having been driven, as mentioned, is normal for this motor/cam setup. I'm thinking the issue may have something to do with the ambient temp at the moment. It was running great through summer, cold start being ~15 degrees C, probably 20 inside the motor, but now the temps over night drop to 3 or 4 degrees C, i'm wondering if that has something to do with it. Any ideas? I can post a copy of the idle fuel map if needs be? I'm planning to hookup the datalogger to track the AFR's at idle to be sure of my diagnosis, and ideally would like to simply throw a bit more fuel in the map but i'm paranoid about playing with the tune now that the car at least drives once it's warmed up..

Just came back from dyno tuning on a dyno dynamics machine at Dent Sport Garage. Matt said their machine typically produces lower numbers than some other dynos and estimated about a 20% driveline loss for rwd cars. The car runs well and wasn't too far off with the Miller base tune. He had to pull about 2 degress of timing and added a bit more fuel at full throttle. It still idles at around 1000-1100 rpm when hot (will have to inspect ICV and throttle plate) and I have an intermittent misfire around peak torque at 4100 rpm so I have to go through my ignition system again to see whats causing the issue. Overall I gained 11 hp from tuning and about 10 ft/lbs. The motor curently produces 240 ft/lbs at 4100 and 205.4 hp at about 5200 rpm. The exhaust still needs work as I am still using B35 manifolds and there is a bit of a pipe restriction down stream of the manifolds just before the Y pipe as well. Not too shabby for an "agricultural motor".

Kinda got two threads going on here. Matt's a good egg and knows what he's doing. Good numbers, another torquer, but your exhaust might be holding you back a bit.

I am still fighting an oscillating idle issue also but other than that, it runs great with the Miller MAF and chip.

Matt told me their Dyno has closer to 24% driveline loss.

^ Tod you are right there is more than one topic in this thread. I was originally posting because of concerns regarding unstable idle and/or incorrect rpm. I am still working through this as well but thought I would add the collateral info regarding my motor to give my input some extra context. My experience with the WAR setup is mostly positive but will hopefully will be even better after I resolve my running issues. Only then I can say with more certainty whether my issues are with Miller software or not.

Update for those interested.

I left the car with Dean (dean535i on the board) and he managed to get it idling reasonably well. He added 14 points of fuel to the idle map and blended the part throttle, cementing my diagnosis of lean condition at cold start. It now idles well, although as the miller goes through it's cycles, has a lean stumble at about 30 seconds after cold start, which evens out shortly after. Absolutely no explanation for why the software won't recognize the dyno tune as it used to, but at least it is drivable at cold start again, and performance hasn't changed thereafter. Still havnt had the opportunity to hook up the datalogger for exact AFR plotting, but we hope to do this soon just to get an idea of the cycles the Miller software runs through at cold start. I'll keep you all posted on our findings.

Das_Prachtstraße wrote: My thoughts axactly. Because it's the round e34 EHauto style TPS, it wasn't as straightforward to test. It's certainly set right, and the adjustment of the throttle body plate is set right, but there's a definite issue with either cold start enrichment, or idle signal coming from the TPS. I'd like to get a brand new TPS, but not for that price..

I know this is off topic from the millermaf, but I was wondering how you tested the round e34 EHauto style TPS? I've been looking for awhile now, but all I can find is info for the rectangular plug tps. Thanks

All I can say is that this is what happens when a company doesn't have cubic dollars to invest into a product like a large auto manufacturer can. Remember...cheap, reliable, or fast, but not all three.

Kyle in NO wrote:All I can say is that this is what happens when a company doesn't have cubic dollars to invest into a product like a large auto manufacturer can. Remember...cheap, reliable, or fast, but not all three.

Very true. While it doesn't really apply to the e28, there is a reason Dinan software and parts cost more than most of their competitors.

Did this ever get fully resolved?

Hi guys,
it's an old topic, but I'll share my experience with a similar situation after upgraded to Motronic 1.3 179 DME from 061

Idle goes up to 900-1200 RPM.
After checking both maps I sow it was a difference between ignitions and fuel maps.
Due to CR differences (mine M30b34 has 10:1, and I upgraded to 179 DME from an M30b35 with 9:10) ignition was a little bit advanced for new CR.

Retarded it for about 5 degrees into Low load map, and idles dropped to 650-700.

Definitely still have to change more for fuel and ignition.