‘93 750il M70 cranks but won’t start

[Kroeger750]

Hi everyone,

I’d appreciate some guidance with my 1993 bmw 750il that cranks over but will not start.

The eml light is on, along with the check engine, and traction control light. After reading through the forums my first impression is that the throttle bodies may need to be rebuilt but I figured I’d ask you all before I go through the time and effort of rebuilding them only to be left sitting... again.

Something I noticed is that when I turn the key to position 2 with the car off (obviously), if I push the pedal it will only move the throttle body on the left side of the car, aka right bank. One time though I cycled the key and tried it again and only the right side throttle body, aka left bank, would move.

The other thing that I noticed is that there is a ton of what I believe is engine oil on the ground, it has been sitting there for about 3 days now.

The temperature outside for the past few days has been floating around zero degrees and I think this may be part of the issue also because last weekend when it was around zero degrees outside,It started quite rough and had to be manually shifted through the gears in limp mode all the way to work, I also noticed that there was an unusually excessive amount of oil on the ground from where I had parked the night before, oddly when I checked the oil later it was only a little bit low. After work it started right up smoothly and ran great until a few days ago.

Hopefully you can give me some guidance with the information I shared. Otherwise I will plan on rebuilding the throttle bodies this weekend.

Thanks for the help.

[theBMWbeast]

The throttle rebuild isn’t that bad. More of a cleaning than anything. I would start there, although I think the car would start... Check voltage, low battery will do weird things. Start by verifying what you are getting, check for spark and fuel. Could be a multitude of things wrong, but maybe only 1 thing preventing the car from starting.

[shogun]

Must be more problems, do a stomp test https://www.bimmerforums.com/forum/s...e-pedal-faults
items to check https://www.bimmerforums.com/forum/s...power+ultimate
When the throttle bodies are out of sync for more than 2%, the engine will still start, but run in limp mode.
To start at least in limpmode it needs fuel, sparks from spark plugs and signal from the crankshaft position sensors.
Crank and Cylinder Index Sensors M70 https://www.bimmerforums.com/forum/s...&highlight=cps

[Kroeger750]

I have performed quite a few stomp tests on this car and I have gotten a lot of random codes that don't make sense in the past like probably four months ago I got one for a camshaft or crankshaft position sensor even though the car was running fine and when I did another stomp test the same day it didn't show any codes. When I did the stomp test this time I got 1235 and 2235 which I believe are unknown codes.

Also we put in two new Bosch fuel pumps this past summer, and a new autozone battery within the last few months.

My new problem is that the new battery is dead from trying to start this car so many times. I tried to jump start it with my truck but it couldn't keep up with cranking the car over. It would crank over once at the right speed and then would just become so slow that I quit.

When I tried jump starting it around 11am today I noticed that both throttle bodies were now turning when I depressed the gas pedal, possibly because it was getting warmer outside(almost 30 degrees farenheit).

[theBMWbeast]

Get a battery charger from harbor freight for $30. Low voltage is not your friend. Elsewise disconnect the plug from the coil and verify spark from the coil. Then do the same from the distributor to verify spark to the plugs,

[Kroeger750]

The car is parked outside at my apartment complex so I can't really put a battery charger on it. I need to be able to jump it and then drive for a while to recharge it.

Ok, I was starting to look into testing the fuel and spark systems, I'm thinking I may test these before rebuilding the throttle bodies if they seem to be easy to check.

There is a good chance that it may need new fuel filters and spark plugs because this car was sitting for a few years before we got it back on the road in August, but if it ran alright a few days ago I couldn't imagine that either of those would just go bad overnight.

[shogun]

You can test the fuel pumps easy, ignition off, remove the fuse box cover in engine bay left side near the heater valves, on your 1993 750 the fuses for fuel are 23 and 24, see here http://shark.armchair.mb.ca/~dave/BMW/e32/e32_93.pdf
squeeze the 2 fuel hoses coming up there and test if they are pressurized. Then use a jumper wire from B+ post and hold the other end briefly on top of fuse 23 and then on 24, then you should hear the fuel pumps and then test the fuel hoses again.
If it sat for a few years, then there could be the problem with bad fuel at the bottom of the tank or moisture. Or also the fuel injectors could be gummed up.

[Kroeger750]

Would it show me what is wrong if I got a cheap code reader off of amazon or would that be a waste of time and money. Can a cheap code reader read the eml?

Was looking at a CREATOR c110 a couple of weeks ago but never pulled the trigger... maybe now is the time lol

[theBMWbeast]

You need a code reader that plugs into the round diagnostic port under the hood. Peake used to make one, you might be able to find it used.

[Kroeger750]

This CREATOR C110 is sold on amazon along with a bmw 20 pin adaptor and if you go to the adapter description it says that it works for e31, e32, e34, and e36.

Creator C110 link:
https://www.amazon.com/CREATOR-V5-9-...06ZZG39RP?th=1

Creator Bmw 20 pin adaptor:
https://www.amazon.com/CREATOR-V5-9-.../dp/B06ZZG39RP

[shogun]

I have my doubts that these will work on our E32, the Creator C110 as per ad works for BMW between 2000 - 2014 and for cars before 2000 with the 20pin connector. But our E32 are even not OBD I or OBD II, they are pre _OBD1.
So unlesss someone has tested it on your 1993 DME M1.7, I have my doubts it will work.

[Kroeger750]

I went out connected jumper cables with the other car running and turned the key position to 2 and I put my ear right next to the fuel pump location and I didn’t hear anything so I went and got some fuel line and disconnected the pumps and connected them to my spare fuel line which I ran outside the trunk and I didn’t get any fuel when turning the key position to 2 but I got fuel to come out when I tried cranking over the engine.

Also when I was turning it over to test the fuel pumps, the last time it ran out of battery until it just clicked which was bizarre because I had the jumper cables hooked up to a running car battery and to the correct jumping locations under the hood so I pulled my jumper cables off and touched them together, and it didn’t spark at all. These are brand new jumper cables and when I inspected the terminals and wire it seemed to check out ok. Odd but that is what I’m going to investigate next.

[shogun]

Maybe you did not hear the fuel pumps, they run just 1 second in such case, here explained

for the Motronic 1.1 and 1.3 but we should assume it is the same on the M70 engine 1.2 and 1.7:
When the ignition is switched on. the ECU briefly earths fuel pump relay contact 85 at ECU terminal 3. This energises the relay winding, which closes the relay contact and connects voltage from terminal 30 to terminal 87, thereby providing voltage to the fuel pump circuit. After approximately one second, the ECU opens the circuit and the pump stops. This brief running of the fuel pump allows pressure to build within the fuel pressure lines, and provides for an easier start.
The fuel pump relay circuit will then remain open until the engine is cranked or run. Once the ECU receives a speed signal from the CAS, the relay winding will again be energised by the ECU, and the fuel pump will run until 3 seconds after the engine is stopped. The 3 seconds delay in switching off the pump relay allows the fuel pump to maintain pressure on engine shut-off to avoid engine run-on.
http://www.bimmerboard.com/forums/posts/869745/
also check fuel pressure.

Check the battery with a load tester, maybe it is dead. Also check the 2 fusible links under rear seat passenger side https://www.bimmerforums.com/forum/s...=fusible+links

[Kroeger750]

Update:
I got jumper cables that worked and connected them to the bmw, then I proceeded to remove the distributors and stick a screwdriver in the coil wire to see if it had spark when I turned over the motor, both distributors checked out good, also I watched both rotors turn and did not see any cracks in the distributor caps.

Now I am going to try to find a battery tender and remove the battery from the car and bring it inside overnight with a tender on it to charge it up and ensure that we have a good battery. Tomorrow I will try to test fuel pressure and then all that should be left to be malfunctioning would be spark plugs, spark plug wires, and the crankshaft position sensors which I can diagnose when the time comes.

Am I right about all this or should I be doing anything differently?

I will also check the two fusible links under the seat when I remove the battery. Will they be easy to see or should look it up in the forums first?

[shogun]

That sounds like a good plan, fusible links : click my link above there are the detailed infos, 1 can been seen immy in a black plastix box behind the battery, that one powers all fuses and relays under driver side rear seat fuse box, the other one is hiden in shrink wrap, inline fuse, that is the important for you!, goes from the battery towards the funnel under rear door to the engine bay to the B plus pole and powers all DME modules, one more post for that line is inside the fuse box, if the power does not come there, then the engine will not start. You can also check this fusible link at pin 14 diagnosis port. X6400 is the power post inside the E box. It feeds only DME loads. ETM Page 1361-01 for M30 and 1367-00 for M70 + M30. Fusible Link A is 50 Amps. That one is inline in the red wire and covered with plastic shrink and goes from the battery towards right side under the doors.Just follow the thinner red wire from the battery. E32FAN commented:
If your Fusible Link A is intermittent, then the voltage at post X1540 will be low and fluctuating. This is easy to measure, at D100 Diagnostic Connector, pin 14. Pin numbers are shown on page 8500.0.20 X1532. And the numbers are molded into the connector.
This is shown on page 1360-01 in the ETM. http://shark.armchair.mb.ca/~dave/BMW/e32/e32_89.pdf
Pin 14 is battery power, see here the pinout https://pinoutguide.com/CarElectroni...g_pinout.shtml
Page 0670-10 Fusible B is 80 Amps. It feeds all the Rear Power Box loads. That one is usually behind the battery inside a black plastic box.

Also test the 2 crankshaft position sensors http://www.bimmerboard.com/forums/posts/1072189/
you can see all fuses and relays also at the end of the ETM, there are pictures of all relays anf fuses, connections etc and explanations http://shark.armchair.mb.ca/~dave/BMW/e32/

[Kroeger750]

Ok, thanks for all the pictures and advise, it really speeds up this whole process.

I think the crankshaft position sensor seems to be a bit difficult/confusing to test so I think I’ll save that for after I test for spark and fuel pressure.

Update:
I went out to the car and checked both fusible links under the rear seat and both showed no resistance on my ohm meter so they should be good to go, I didn’t check what you mentioned about pin14 in the diagnostic plug but from what I understood that isn’t necessary to test, if the fusible links are ok. Am I right about that?

Also I pulled the battery out... almost locked myself out, whew anyways I continued on and brought the battery inside and connected it to my new battery maintainer and when I connected it, it showed that the battery was at 65% which seems odd because the battery couldn’t even turn the engine over once by itself.

Anyways I am a lot further than I was yesterday and am starting to have hope that I may actually figure this out and get it running by the end of the week. But we’ll see what tomorrow brings. Thanks for all the help, I couldn’t keep it on the road without you guys.

[shogun]

I guess the fusible links should be o.k. , no need to test at pin 14 at the diagnosis port. But you could check if you have 12V at the engine bay in the relay box where the DME relays are, see 7100 component location chart page 7100-11 X6400 B+ junction point http://www.e32-schrauber.de/bmw/s-kw-sensor.htm
Here some more info how to test the CPS, the plug pins http://www.e32-schrauber.de/bmw/s-kw-sensor.htm

[Kroeger750]

Good news, I charged the battery overnight and installed it back into the car today about after about twenty seconds of turning it over it fired up. 👍

It ran a bit rough upon the first start up but I let it run for a minute or so to let it figure it self out a bit, then I turned the car off and started it up again and it was quite smoother but still had a eml so I check to see whether or not both throttle bodies were moving and only the passenger side throttle body was moving, left bank, so I turned it off one more time and then it was firing on all twelve cylinders so that’s good news, now I’m gonna get the battery tested, along with the alternator, and then probably rebuild the throttle bodies and replace the fuel filters to hopefully make it run smoother and eliminate the difficult and rough starts in the cold.

Also the code reader should show up today so I will update you and tell you if it works and how well it works.

Thanks everyone for the help, we’re so glad it’s back from the dead.

[shogun]

Good news,
that it did not start up first on all 12 cylinder, could be that either spark plug 6 or 12 was not firing first, that are the ones where the cylinder identification sensors are located around the ignition wire from distributor to spark plug. Check those spark plugs.
Your M1.7 DME system may have the catalysator protection system, read here http://www.bimmerboard.com/forums/posts/1221671/ Catalytic converter protection function-Ignition circuit monitoring
The ignition circuit is monitored by the cylinder detection sender (pin 16) on ignition line 6 (or 12). If it detects no ignition signal on ignition line 6 (or 12) , the fuel supply to to the relevant cylinder bank is cut out by shortening the injection signal. The sender monitors the entire primary side of ignition, and cylinder 6 or 12 on the secondary side.

when you change the fuel filters, also change the short fuel hoses before and after the fuel filters, they are usually very brittle and could leak fuel, item 19, 26, 27, 30 http://bmwfans.info/parts-catalog/E3...double_filter/
if you cannot find it, buy good quality fuel hose 8X13MM Gates Barricade , you can bend the hoses with Unicoil hose bender http://www.gatesunitta.com/en/unicoi...bending-system

[Kroeger750]

Thanks, thatÂ’s some useful information. I think I may just replace all the spark plugs because they have to be at least twenty years old and arenÂ’t very expensive.

I was assuming I would replace the fuel lines surrounding the filters, I also have thought about replacing the vacuum lines around the engine as I have heard they are prone to cracking and will cause problems when the do crack.

Also I tested out the Creator c110 scanner with the e31, e32, e34, and e36 adaptor. You were right itÂ’s junky. All it did was give me error codes and told me to turn the key off and back on. Also theyÂ’re weÂ’re tons of grammatical errors in the manual. I decided that I should double check and be sure that maybe it wasnÂ’t working because I wasnÂ’t running the right software but when I went to the link to download the latest software my antivirus protection on my computer shut it down and told me the url I requested has been blacklisted so yeah, I will be returning that for a full refund this weekend.

[Kroeger750]

One more quick question,
Can I drive the car without those plastic distributor covers on? I took them off to check the distributor and never put them back on because it was a hassle and I feel like I’ve seen those two distinct orange distributor caps poking out of the engine bay on quite a few e32’s

[shogun]

no problem to drive without, that is just a kind of water splash protection. As you did disconnect the battery, idle might be at the beginning a bit rough, but the more you drive, the DK will sync, or make a DK sync https://www.bimmerforums.com/forum/s...of-M70-engines