91 iX no start, but not throwing any codes

[zcenterb]

Hey r3v,
So i just bought a 91 iX the other day and have been trying to trouble shoot that fact that it won't start. It will turn over great, but i seem to not be getting any spark. Also, i seem to have a pretty legit battery drain somewhere that i cannot find... as far as the parasitic drain goes, i have unplugged/removed everything i thought could be the culprit like Airbag system (was tampered with prior to my purchase anyway), stock alarm system, air-conditioning system, radio... the only thing i have yet to unplug is the OBC but I'm not sure if that will even help.

The car is getting full power to all relays and all the relays work, all fuses are good, etc, main/fuel relay is grounding and working as it should, but the engine is not getting spark. I checked the power line coming into the Coil (the one with the +) and it is getting a steady 12v in, and seemed to have been getting power out of it as well, but it was inconsistent, obviously beaus it was charging and discharging as it should i think. I replaced the coil pack, distributor rotor and cap, and the line from the cap to the coil, all proven working, with no luck. PO replaced all spark lines and sparks and as far as i can tell they are all good.

So, im stumped.... Anything that you guys know of the could be causing something like this? Bad DME/Harness? I also replaced the Crank pos sensor with a proven working one but nothing. Ill figure it out eventually I'm sure, but any help would be appreciated.

Thanks in advance

[fresh_TD]

Check your ground cable from the block to car

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[EyExR]

I would check main relay and DME. Then maybe fusible link...

Also. I would pull the distributor cap and make sure everything looks good. I've had the center pin of my cap lose it's spring and this caused a no start...

[spdracrm3]

how are you testing for spark and where ? need to check if anything is coming out of coil buy using a spark tester or holding the disconnected distributor cap end of the coil wire close to the valve cover or something metalic on the engine (be sure to hold the plug wire with insulated pliers or you could get shocked yourself) and have someone help crank it over while you look for spark jumping the gap of about 1/8- 1/4 inch. if no spark out the coil wire to ground test the ECU control of coil by using a test light on the coil - terminal and again have someone crank engine and see if test light lights up with key in run ,and then flashes with engine cranking . if test light doesnt flash the ECU is not sending signal to coil to fire , at that point you either have a wiring issue an ECU issue or ECU is not receiving RPM /cyl id signal it needs to operate.

download you correct ETM here and study the engine electronics pages for where to test at ECU pins if further testing is needed

http://www.wedophones.com/BMWManualsLead.htm

[zcenterb]

Ground from block to chassis is good, i tested sparks by your second method spdracrm3 (take out a spark and hold it close to clean metallic VC) and got no spark thus assuming i had no spark, and i replaced my distributer cap, distributer rotor, plug wire from cap to coil, and the coil itself with known working ones from one of my other cars and got nothing. Ill try your light test today and see if i get anything. The odd thing is though, its not thawing ANY codes... even when i disconnect an obviously code throwing plug like the HFM plug... is this a DME problem?

[zcenterb]

Just out of curiosity, what injected poundage/color do these cars run stock? Because i just noticed i had some odd yellow/tanish looking ones... and i know my other e30s all run the blue top 17s or whatever those are.

[spdracrm3]

Ground from block to chassis is good, i tested sparks by your second method spdracrm3 (take out a spark and hold it close to clean metallic VC) and got no spark thus assuming i had no spark, and i replaced my distributer cap, distributer rotor, plug wire from cap to coil, and the coil itself with known working ones from one of my other cars and got nothing. Ill try your light test today and see if i get anything. The odd thing is though, its not thawing ANY codes... even when i disconnect an obviously code throwing plug like the HFM plug... is this a DME problem?

if you are using a sparkplug to test for spark you need to ground it fully against valve cover and look for spark in gap. if you use a plugwire alone you need to hold it slightly away from metal and watch for spark to jump gap. and test the coil spark output alone to see if it is working and its not a problem inside distributor

these are very early and basic motronic ECU's and do not set codes as easily as today ECU's do , so dont be surprised if it take a long time for a code to show if at all

[zcenterb]

I know, i did both, no spark with either... picked up a brand new distributer and rotor and replaced them and still just turns over with no spark. Still need to test the output on the coil.

[Liquidity]

New cars don't throw codes for a no-start either. If the ECU doesn't know the engine is spinning, it assumes it's not, and it can't throw a code.

[zcenterb]

Already tried the Crank sensor, replaced it with one from a running car. Nothing.

[spdracrm3]

New cars don't throw codes for a no-start either. If the ECU doesn't know the engine is spinning, it assumes it's not, and it can't throw a code.

not true,l the newer ECU's have a starter engaged signal input and will set a codes for no crank/cam/maf/map sensor input knowing the starter is engaged after 10-15 sec.especially with the push start systems so it will turn off starter after long crank no start which is actually controlled by the ECU now too....

[zcenterb]

bump, checked my engine-chassis ground and thats good.

[zcenterb]

confirmed no power on that top plug wire going from the coil to the distributor cap. So I'm not getting any power out of my coil to ignite my plugs. I am getting 12v on both of the wires going to the coil though.... and spark seems to be the only thing I'm missing... any thoughts?

[johnt325ix]

Timing? Check if distributer is in wrong position.

[johnt325ix]

Also, are you sure your getting fuel? 2 fuel pumps in that car.