questions (noob alert)

[e30work]

just bought a 91 318is with bad wiring in the engine bay and bad wiring from an alarm removal.

do i use wiring diagram from e30 manual? or form the the e36?

edit: also he took the interior apart to get to the fuel pump so whats the best manual to decipher all the nuts, bolts, screws, clips? thanks

[bmwm42]

E36 manual

[Ryann]

You need the 1991 318i/s Electrical Troubleshooting Manual. I have the .pdf, shoot me a PM and I'll try to email it to you. It's like 16MB (hopefully small enough to email, idk).

also he took the interior apart to get to the fuel filter so whats the best manual for to decipher all the nuts and bolts?

^I find this confusing. Anyway, for this the e30 Bentley manual will work.

[e30work]

Went to check the battery in the trunk and the positive cable is connected to chassis (the short cable)... The long cable running into the interior is connected to ground. Is this the problem?

esit: For some reason "he" was able to rolled up the window with this configuration. Anyways I disconnected everything so that I could confirm. Thanks

[bmwm42]

The long cable is positive the short one is the ground if you have them backwards your going to burn shit up

[Adrian_Visser]

Smells like burning! Prepare for shit to be fucked up bro. Your alternator is probably fucked for one, the DME is proly fucked as well. Good luck.

[e30work]

ohh man what a long day, woke up at 6am, ate a sandwich and went at it. no reply from the forum so i went to google. keep in mind that i bought two e30 for $1000, a 93 325ic and a 91 318is. also this is the first time ive worked on a bmw. with a lot of reading i got the 325 to run perfect with no check engine light, however i still cant figure out how to get the speedo to work. as for the 318, heres what ive done.

*new battery
*rebuilt harness (cable to the alt melted) everything get correct voltage now
*check main relay, fuel relay, and os relay. (all good swapped out with 325 to test and also did the test with jumpers)
*fuse-link (fusable link) has correct voltage in the engine bay/hood so it should still be good.
*checked crank position sensor (510 ohms).. on order

- car cranks and turns
- need to find out what the main relay is for
- need to check dme

no activity from the fuel pump with a good relay should confirm its a bad cps since this is the last step before the fuel pumps gets power?? should the car start if i jump the fuel pump from the relay? or does the bad cps kill the dme too?

any other suggest appreciated. let me know if im headed in the right direction or if im missing something. thanks\

Edit: how do i know which cable goes to the crank sensor and which goes to the cam sensor? they both look the same, are in the same location, and have the same color wires. thanks

[bmwm42]

well for one the crank sensor is at the crank and the cam sensor is at the cam so that should give you an idea where they go. the speedo problem could be a few things speed sensor could be a dead cluster, dead speedometer, dead si board just to name a few. and yes if the cps isnt working the dme isnt going to switch power to the pump safety feature.

[e30work]

what i mean was how do i tell which cable from the harness goes to which sensor. the connectors are the same (3 pin) and are in the same location. they also seem to have the same wires.

so what can i diagnose to get my check engine light back on? thanks

[e30work]

are e30 and e36 crank sensor the same?

[rjcaptsean]

This might be a long shot, but based on my pictures, I would lean toward the upper connector being the cam sensor. If you can zoom in on this to see the harness, you will see that the cam sensor wire in on the top as it goes into the plastic frame and looking at the "set" that the wires have taken, it would go into the upper connector on the wiring harness box.


I know, totally a S.W.A.G based solely upon the 'set' of the wires.

Good Luck

[e30work]

thats the problem, i had to take the harness out for repair so now the connectors are mixed up. being that the crank and cam senor share the same connector, how do i know which connector from the harness goes to each sensor? it can easily get mixed up.

[rjcaptsean]

Dang, I was hoping somebody knowledgeable would jump in here. I totally suck at electronics. Here is a trouble shooting manual for the e30 and e36. Hopefully you can find a way to get what you need.

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

[Ryann]

thats the problem, i had to take the harness out for repair so now the connectors are mixed up. being that the crank and cam senor share the same connector, how do i know which connector from the harness goes to each sensor? it can easily get mixed up.

You could ID sensor connectors by pulling one out, let's say the cam sensor, so it's not "sensing". Then while a helper turns the engine over you could check for AC volts at the pins of each connector with a multimeter. The one with voltage showing is the crank sensor.

[Simon S]

Sweet Jimminy !
The pictured m42 is drool-tastically clean
Wow - someone spent a LOT of time on that.