E28 M5 swap restoration

[savannah996]

I may have misunderstood realoem on part #13. My mystery brass coolant sender wires maybe, 1. gauge, 2. warning light?
"13 TEMPERATURE SENDING UNIT/WARNING CONTACT 120CEL 1 62161360870 $101.09 "

[tn535i]

Yes exactly. I said that wrong temperature AND warning switch for the gauge but I'm not sure my gauge has the warning light similar to the low fuel light. I know later cars used this combo device and had the dash warning light as well. I need to check this sometime. I do NOT have #9 the TTS for a cold start injecotr on mine, not even a thrid bump in the casting for a third device is present.

[savannah996]

The one in the back is what most call the CTS Coolant Temp Sensor for the fuel injection input.

The one up front should have a part ending in 137 if it is like mine. According to BMWfans it is a coolant temp warning switch and will close above 120C. Maybe we have a high temp dash light?

[im looking into that right now]

IDK, it's not in the etm I have. My car also has a coolant temp switch on the radiator that will disable the A/C if the radiator gets too hot that I have not seen in the etm.

One more thing while we are at it. There was some discussion about the uselessness of a barometric pressure sensor. I can't find one on my S38.

[it should be part of the purge valve harness, and real close to the abs pump]

Either that or it is extremely well hidden. I know it's NOT tied into any part of the AFM wire harness I can see like it is shown in the ETM.

[/b]

[tn535i]

Yep I have a barometer.. but on the purge valve harness next to the windshield washer pump opposite side of the car from the AFM and ABS. Mine's a 6er.

[savannah996]

Well im giving up for tonight. The ect sensor seems to be working. The bigger brass sensor has a wire for my gauge and another unknown wire. Which has no continuity and no power, key on/off. Well the terminal it fits onto has like a few millivolts. We tried grounding it to see if a idiot light came on, nothing. I will pull my cluster tomorrow and see if such a thing exists.

I still need to know of the AC system has an electrical connection to the DME or if the motronic just senses a drop in rpm and adjusts via icv. Tune in next time for more hilarious adventures.

[tn535i]

In an M30 e24 schematic it shows a lead to the evap temp regulator for monitoring the clutch that also goes to Motronic pin 40. It is just after the high press cut out switch and just before the high temp cut out which then goes to the A/C clutch. Page 6411-0 of the ETM. On page 6411-1 for my M6 there is NO such input to the Motronic.

I'm assuming an M5 is the same. Since the base idle is spec'd higher in an S38 they probably decided it was unnecessary.

[bobby in Derby City]

You know what else. I can't find that temp switch on the ETM schematics, the big brass one you ask about. But the one behind it in blue is the CTS.

And I think you already said you did it, but I'd leave the ICV unplugged until you figure this out.

Still is part mystery though. It has 2 wires, one (br/wt) is for dash temp gauge (verified). The other one is br/vi and idk, While unplugged it does not goto ground...

I hope one of the S38 guru's clears this up. I've have had problems for along time finding information (never wanted to ask )on these coolant pipe sensors. I know the realoem diagram is actually showing the coolant pipe for the M88, which has three bung holes (LOL). Glad I now know at least the one towards the rear is the CTS.

[savannah996]

In an M30 e24 schematic it shows a lead to the evap temp regulator for monitoring the clutch that also goes to Motronic pin 40. It is just after the high press cut out switch and just before the high temp cut out which then goes to the A/C clutch. Page 6411-0 of the ETM. On page 6411-1 for my M6 there is NO such input to the Motronic.

I'm assuming an M5 is the same. Since the base idle is spec'd higher in an S38 they probably decided it was unnecessary.

Thanks for all the help tennessee, Ill be looking into that wire and the dme after lunch.

[tn535i]

Happy to help and I'm learning a few things along the way. Apparently the M88 used a cold start injector but it's hard to imagine it had the newer style temp gauge/warning switch combo.

When I get a chance I'm going to explore the barometric sensor thing. On the S38 it gets it's voltage from the AFM signal output to the Motronic. So it would be relaitive to the air flow in the first place with more correction as air flow increases. I can see where a bad sensor could throw the AFM signal way outta whack.
On an eta it gets 12v directly and the signal goes to the computer with no relationship to air flow at all. That must be corrected within in the computer. But I also recal the eta uses a corrected non-linear AFM output while the AFM response in later cars (like the S38) may have a linear output.

They did all this and changed things just to make us all crazy.

[savannah996]

the baro sensor gets power from afm circuit. that's all.
do you have a pic or can tell me how the little 90° connectors go? I deleted the pic off from my phone. 2 blue and one white. I know there is a fuel gauge and Speedo, last thing I need its to short something again.

[savannah996]

there is no coolant warning light on the cluster.
I checked for continuity on that one wire next to the coolant gauge sender. checked it between every pin on DME and gauge cluster and obc. fail

[savannah996]

it doesn't seem to go anywhere.


I opened up the DME too, tried to follow pins 33/34. didn't see much. funny they seemed to have different resistors and capacitors???. I took some pics I will post later

[savannah996]

Replaced the oem sender for my vdo set up,

[wkohler]

Have you thought about replacing that CTS? They're pretty cheap. Good baseline and they can affect the idle strangely enough.

[savannah996]

[Rich Euro M5]

OK to check that and both 33 and 34 have 12v but I'm not sure that will help diagnose anything. There should always be voltage at either location since the computer completes the circuit and pulls it down to ground internally to actuate the ICV.

I was thinking about it the other way around earlier but now I hope I have it straight. 12v always goes to the ICV and then the computer pulls either retract or extend (no jokes please) to ground to energize one or the other constantly on a time based cycle. More open means more time with 34 to ground and more closed means more 33. It is always either opening or closing but it happens fast enough the solenoid just sorta hovers in between based on the time based difference.

You can check voltage but I'm going to guess it will be 12v on each. I think you will need to check current on the close side to see if there is any at any point including key on. If not it cannot close. On the other hand you should get open current if even briefly at key on.

I think you ought to seek the S38 troublshooting kit to see if a known good motronic makes it do right.

Not eactly correct.

The ICV is driven by two transistors as you describe, however +12 VDC is applied to the center tap of the ICV motor winding. Pin 33 and 34 of the ECU provide the path to ground through the driver transistors, T560 and T561.As one transistor is biased on, the other is heading towards cutoff.
The ICV does not rapidly open and close continuously, it simply opens and closes based on the drive current from the transistors. When both driver transistors are driving the ICV equally, the ICV should be half open.

See the schematic of a similar Porsche 911Motronic ECU driver pcb.

[Rich Euro M5]

To answer your question about rigging the icv, you must have missed my earlier post. It currently has the ivc unplugged. Then I applied power to pin 2 and grounded pin 3 which retracted the valve all the way. Its idling nice. I just want to fix the real problem before I install my Dinan chip.

This is the base idle.

After engine warmup, and when there is no load on the engine, ie; A/C on, or other high electrical loads, the ICV should be nearly closed.

[tn535i]

I'm glad Rich knows it a little better, his explaination makes sense. Your DME is similar but different of course. There is a brownish round capacitor and a different bank of transistors. And I find you have to remove the board from the mounting plate (metal box) to see if the inputs at 33 and 34 swap sides on the board and connect through the little bridges. I can't say if those are fuse links but was hoping one would be obviously burned out. Was worth a look I thought.

I think if you know a good EE or similar they would figure it out with a DMM in about 2 minutes. Especially with the information provided above. If you were close we could swap DME and tried to figure it out. I'm still betting the part itself is < $4.

It is similar to an older car I had with three drivers for a triple coil on a V6. One shorted but it brought all thre coils to ground and when I figured that out I cut the one driver and it ran on 4 cylinders. I would have fixed it myself but the whole DME was sealed in goop of some kind and it would have made it a worthless core if I washed this out.

[savannah996]

Yeah if I could find someone local to swap out a DME that would be cool. Ill look up some local electronics repair places to have the transistors checked out. Its running pretty good otherwise, however it should be better when I get my 3" exhaust made.

[savannah996]

Its going in next week for header back exhaust with magnaflow muffler, cat delete, and 3" pipe. WIN!

Today I got the aftermarket vdo temp gauge working. Now tomorrow all the lights get hooked up and I can post a pic.

[savannah996]

I cracked the windshield trying to get it out and will cost $110 for a new one (ch-ching). Was my donor car leaking water inside? I think so.

[savannah996]

The midship magna flow was too low so plan b is to install a 3" in/out magnaflow cat where the cat normally goes and a magnaflow muffler/resonator in the back between the tank and spare tire. Sorry no pics of plan "A" today. I will get one for referance tomorrow before muffler shop tears it off.
Oh does she sound great over 4K! Has loud drone 2-3K though, thats why im putting a cat back in.
This was plan "A"'s muffler=

[pleasefixitup]

The midship magna flow was too low so plan b is to install a 3" in/out magnaflow cat where the cat normally goes and a magnaflow muffler/resonator in the back between the tank and spare tire. Sorry no pics of plan "A" today. I will get one for referance tomorrow before muffler shop tears it off.
Oh does she sound great over 4K! Has loud drone 2-3K though, thats why im putting a cat back in.
This was plan "A"'s muffler=

Whats the height of that muffler?

I want to put a magnaflow or any brand really in the tunnel on my next exhaust build--but I want something thin--like 3 inches.

[savannah996]

Recent pic. Still a work in progress=

[1st 5er]

I'm still here.



You plan to make Vintage in this beast?

[savannah996]

I'm still here.



You plan to make Vintage in this beast?

Cool, thanks for tuning in!
Ill have to research what and where that is. Im on baby duty today so my time is limited.
BTW everyone im parting out the donor M5, its mostly just basic E28 parts, all the "M" stuff im using. There is a thread in the "FS" section.

[savannah996]

Been a while since a update. Ive been trying to get work done but the wife was sick for like 5 days.
I blew out the sunroof drain lines with air a week ago. Just some preventative work.
I got my new windshield seal in and then cracked my windshield trying to get it out. 'nother $105 spent.
Got the windshield in though, rtv'ed the edge that the pinch weld goes into and by that time I was so frustrated I didn't even think to rtv the gap where the glass goes into. The lower metal locking trim was hard to get in. It took a couple days trying and finally dumb luck, I figured out how to do it.
Sooo it rained hard for an hour the other day and when I checked the car in the am there was a small puddle on the PS. Could it be the windshield seal? IDK. Im thinking I blew off a sunroof drain line. (I hope)
On another note I started putting insulation back in the car, luckily I have oem stuff. I worked in the rear seat first. I put this peel n seal in some places. I know its not dynamat but I didnt need to start from scratch just wanted to add a little extra dampening to the metal panels.
Round two with the exhaust is done. Now it has a 3" cat with 3" in/out muffler. When the guy opened the box I didnt see a name on it and I thought "oh no". So I only have 20-25 miles on it and I got some drone 1500-2000. I looked in the muffler today and noticed it was a glass pack, dang it I wanted a stainless steel packed muffler. Im a little frustrated, I dont like the rattle of a glass pack. Part of me is just glad to have a exhaust on there. But the good news is they have it set up for a oval 3" in/out can so I should be able to buy a flowmaster and have it fit right in.

[savannah996]

[pleasefixitup]

Been a while since a update. Ive been trying to get work done but the wife was sick for like 5 days.
I blew out the sunroof drain lines with air a week ago. Just some preventative work.
I got my new windshield seal in and then cracked my windshield trying to get it out. 'nother $105 spent.
Got the windshield in though, rtv'ed the edge that the pinch weld goes into and by that time I was so frustrated I didn't even think to rtv the gap where the glass goes into. The lower metal locking trim was hard to get in. It took a couple days trying and finally dumb luck, I figured out how to do it.
Sooo it rained hard for an hour the other day and when I checked the car in the am there was a small puddle on the PS. Could it be the windshield seal? IDK. Im thinking I blew off a sunroof drain line. (I hope)
On another note I started putting insulation back in the car, luckily I have oem stuff. I worked in the rear seat first. I put this peel n seal in some places. I know its not dynamat but I didnt need to start from scratch just wanted to add a little extra dampening to the metal panels.
Round two with the exhaust is done. Now it has a 3" cat with 3" in/out muffler. When the guy opened the box I didnt see a name on it and I thought "oh no". So I only have 20-25 miles on it and I got some drone 1500-2000. I looked in the muffler today and noticed it was a glass pack, dang it I wanted a stainless steel packed muffler. Im a little frustrated, I dont like the rattle of a glass pack. Part of me is just glad to have a exhaust on there. But the good news is they have it set up for a oval 3" in/out can so I should be able to buy a flowmaster and have it fit right in.

My 2.5 glasspack 4 inch body is freaking loud. at first it was awesome and fun considering how quiet and tame my other exhaust was. Now I'm wishing I had a stainless steel packed muffler.... 2 more months of this glasspack and then I can get the exhaust I want.

I have drone from 1500-2000 as well, except if you're just crusing in 3rd oro 4th at about 1800 it's very quiet and when you let off the throttle after stepping on it, POP POP POP

[savannah996]