another no start !! whith a twist !!

[joecrotch]

Any Ideas on this would really help?

ok about 3 months ago i went to breakfast turned car (87 eta) off and when I came out it would just crank and crank there was 35 psi on the fuel pressure gauge thats what I have it set at. but there was no spark. so I have been wanting to put on my new turbo ( old on was leaking) and change to the stage 3 clutch. so i decided just pull the engine and tranny and rebuid from ground up. well I have her all back together and same thing. while it was out I did find the tdc tab had broken off so i swapped flywheels. it is still on there but no spark. so next I thought ah obc code relay so pulled the box and while cranking I manually would trip the relay. here is where it gets wierd. ok with the relay switch circuit completed there is power to the fuel pump and it runs constantly with the ignition in run. if while imcranking with the relay on the rpm gauge doesnt work there is no spark but fuel is fine. if I trip the relay and crank, the rpm gauge starts working and the car starts until the fuel is depleted so I hot wired the fuel pumps to run tried tripping the switch and starting ran for a second then spark just cut off. aaaaaaaahhhhhhhhhh wtf is this shit.

also there is a single shielded wire that runs along the front of the valve cover it has 12v to it any ideas what that is?
and there is 2 spade connectors coming off the wire harness just outside the fire wall they are shielded I think they were for the washer fluid but cant remeber.

[SmokeE30]

single shielded wire is the knock sensor down on the block next to the passenger side engine mount. the two spade connectors go to a 2 prong sensor on the firewall right above and twards the driver side of where the harness comes threw the firewall, its just 2 metal prongs coming out of the firewall so its easy to miss.

[joecrotch]

single shielded wire is the knock sensor down on the block next to the passenger side engine mount. the two spade connectors go to a 2 prong sensor on the firewall right above and twards the driver side of where the harness comes threw the firewall, its just 2 metal prongs coming out of the firewall so its easy to miss.

dude thanks! I had found the knock sensor a while ago. but those 2 spade ones were driving me crazy! thanks!

[joecrotch]

Ok still having this prob I am losing my mind have read every no start post on every e30 forum and tried everything that fixed the other peoples cars. nothing I just bought my third dme last night gonna try that I am sure the chances of 2 ecu's going bad is very rare but it might happen. does anyone have schematic for the motronic 027 ecu or a way to trouble shoot or test it to see if its good. any help please!! I am seriously thinking of scrapping the e30 for scrap. I love this car soooo much but i already have over 15 grand in it and I dont want to get rid of it! I'm desperate here I'm a mechanic by trade and I cant even figure this out!!!! lolol here is a list of things I know are good and how I checked them.

-battery is brand new and is kept on charger while working on car
-injectors click on and meter reads battery voltage
-tab on flywheel was broken off I replaced it back on with jb weld still holding hasnt moved and is intact
-tranny sensors both read .1006 ohms +- 10
-fuel is at a half tank
-spark plugs are new
-spark plug wires are new
-coil is a new accel super stock
-cap and rotor are brand new
-fuel pump is putting out 40 psi steady ( thats what I have it set at)
-checked fusible link good
-added 2 0 gauge ground wires from block to frame
-power to main relay
-no spark unless I trip the obc relay to shut off fuel pump then car runs till fuel is gone
-my psychiatrist says i better fix this soon it may be fatal lol

[joecrotch]

So I am gonna keep updating this so that anyone having the same issues can learn from my journey.

So I now re wired the car back to all stock(I had a hard wire powering the fuel pumps) Except that I removed the 13 button OBC and OBC relay. To remove the relay you must jump the green and green/red wires together on the plug that goes to the OBC relay box because that powers the main relay.
So as It stands I have Power to the fuel Pump when the key is in the on position, constant. I have Injectors working and pulse while cranking. The only problem is that there is NO rpm signal. When the 2 green wires for the obc are jumped the tach signal stops. When I disconnect the jumper wire the tach signal comes back but the fuel pump wont come on.

I know the fuel pump staying on with the key in the on position is a bad thing but the way I see it its at least getting fuel so. next I gotta work on the tach signal!

[jlevie]

You need to trace back through the system to find out why the fuel pump is on all the time. It should only run when the DME grounds the fuel pump relay coil when the DME sees timing data from a rotating engine. There's a decent chance that what ever is causing that is related to the no start condition.

The fuel pump relay coil is provided with switched power from the ignition switch. The contacts are also provided with switched power via a fuse. The DME grounds the coil to turn on the pumps.

The coil is supplied with switched power and the DME grounds the coil for each spark.

[joecrotch]

I'm thinking the DME is bad So I am trying to locate and buy a good 027 DME so hopefully that will be it. everything else I have either replaced or determined good via bentley tests. thanks !

Also is there a way to check the dme pins for resistance to actually see if its good or not?