Buddies car wont start

[BustaRhymes325i]

The car is an 87 325e, and it will crank over but not start. Here is what we have concluded:

changed ecu
changed coil
crank sensors check out
fuel pump runs
smell gas at tailpipe
new distributor cap

I believe he replaced one of the relays in the smaller relay box, forward of the one closest to the firewall. We are stumped, and he is a lazy asshole. Im now stuck troubleshooting this.

[jlevie]

The first step in solving this is to find out if there is spark when cranking the engine. No spark would mean:

Lack of timing reference data to the DME (crank position sensor problem)
Lack of power or start signal to the DME (bad main relay, bad fusible line, ignition switch problem)
Bad coil

Spark at the coil, but not at the plugs could be:

Bad distributor or rotor
Broken timing belt
Bad ignition wires

If you have spark the next check is to see what the pressure in the fuel rail is. If the pressure is low the possibilities are:

Bad fuel pump relay or fuse
Bad fuel pump
Bad FPR

[SpecM]

and he is a lazy asshole. Im now stuck troubleshooting this.

tell your buddy to buy a bus pass

for reals tho... sounds like you're not getting spark. Make sure that the (+) coil lead has 12v when the key is on. Check the plugs, clean them. See if you have power at the plugs... report back...

EDIT: nevermind, just do what Jim says ^

[BustaRhymes325i]

Yes, he replaced the coil, and when we crank it, it does not give spark. (we are running a wire straight off of the coil to a spark plug, bypassing the distributor) I think at one point it was producing spark, but now is not. That has made this troubleshooting a bit more difficult.

He did not replace the crank sensors, but measured the resistance, and I think they were within the correct range. My inclination is to just replace these and see what happens...

[jlevie]

First check to see if there is power, a start signal, and ground to the DME. You can see the wiring diagrams for the car at http://wedophones.com/BMWManualsLead.htm. If the DME pins for those are seeing power and ground and the coil has 12v on the positive terminal and there is continuity from the coil negative lead to the DME and you don't have spark at the coil, the problem has to be either the DME or crank position sensors.