starts very normal but dies (no stalling)

[rasmith9]

Update - Starts Normal Then Dies

I have researched on several sites with 1984/5 M10 information on a problem where the car starts and then dies but nobody has yet to provide the resolution. I hope to fix this once I can get to the solution.

Here's what occurs: the car starts up great (no engine miss, full throttle response, etc) but then only runs for about 5 seconds when the fuel from the Cold Start Valve/Thermo-time is used up. Then the engine dies from lack of fuel.

The checks I've done thus far are:
Fuel pressure at rail (via "T fitting"):it's in spec (43psi) so the pumps are working.
Coolant Temp Sensor: resistance cold and hot and both are in spec.
AFM/TPS: both working as should
Fuel Pump relay: pressure is good, so assuming this is ok


The de-bugging I've done thus far is:
Disconnected the AFM: won't run
Disconnected Thermo-time: won't run
Disconnected ICV: won't run
Disconnect Coolant Temp Sensor: Engine runs but does so poorly (also checked the CSV with this and it shoots spray for 4 seconds then closes, so the injectors are pulsing with the sensor unplugged - albeit not running well).

What would cause the injectors to not open and close releasing the pressurized fuel?
ECU? (BTW is the ECU and DME the same in this car?)
Fuel pump relay? (I've read that I should jump between pin 30 and 87 does anyone have a diagram, I'd like to jump but don't know which to connect) but the pump is pressurizing so that doesn't make sense to me.
O2 Sensor?
Ground Strap on Engine to frame (I've checked all others and all good)
Ignition Module: wiring looks great module is very clean

Any help would be appreciated.

[thebutterson]

Does the fuel pressure stay at 43psi? Or does it start there and die off? The fuel is initially primed, and from there I believe it requires an rpm signal. If the pressure dropped off once the engine started that would let you know that there is no signal to maintain fuel pump operation. I would try swapping DME's if jumpering the fuel relay doesn't work. I have a spare for an 85 I'll sell you if you want.


You can get a schematic here: http://wedophones.com/BMWManualsLead.htm

[rasmith9]

Conclusion - ECS

Sorry for the delay in responding. I am posting the resolution so other who have had the same problem might be able to resolve it a bit easier. The problem was the ECS, I purchased a used one and installed and it fully resolved the problem.

BTW, before the ECS was installed, the fuel pressure stayed at 43psi while the engine running (and the coolant temp sensor disconnected) and increased with RPM's.

What led me to think it was the ECS was the Bentley reference to the pins on the harness not getting power and additionally, there was a video on youtube of another M10 owner demonstrating a faulty ECS circuit board. Not quite sure what his issue was but every time the board was flexed the car ran...

Anyway, hope this helps others.

[hahaitzskippy]

Sorry for the delay in responding. I am posting the resolution so other who have had the same problem might be able to resolve it a bit easier. The problem was the ECS, I purchased a used one and installed and it fully resolved the problem.

BTW, before the ECS was installed, the fuel pressure stayed at 43psi while the engine running (and the coolant temp sensor disconnected) and increased with RPM's.

What led me to think it was the ECS was the Bentley reference to the pins on the harness not getting power and additionally, there was a video on youtube of another M10 owner demonstrating a faulty ECS circuit board. Not quite sure what his issue was but every time the board was flexed the car ran...

Anyway, hope this helps others.

sorry to be a noobie but what is the ECS>

[hahaitzskippy]

bump? what is the ECS?

[dk318i]

This is exactly what my 85 does. I just picked it up and it will start and run for 5 or so seconds and then just shuts off.

Bump, for what the ECS is.

[gettinscurvy]

I have yet to find a solution to my issue. What the hell is the ECS?

Sent from my SCH-I545 using Tapatalk

[packratbimmer]

The 310 ECU from the early cars will not run the later cars with the 328 ECU.

The fuel pump relay on those cars is more complex than say an M20 325i. Try swapping out "known good" relays and see what happens. Also. I think the relay contacts can be cleaned though I have never done it myself.

The third thing to keep in mind on the early 318i is that the car will not run with a bad coolant temperature sensor - there is no limp mode. I always carry a good spare in the road kit!

[gettinscurvy]

Hmm. I'll have to look into this. The car is an 85 with an 84 engine. I've swapped and 84 DME with the 85 DME frequently for testing purposes. Without being at home to physically check, how could I find out what number the DMEs are? is 84 a 310 and 85 a 328? Or is 328 for the late model 318i's with m40 or m42 engines? I have not replaced the coolant temp sensor I believe, so I think I will order one.

[gettinscurvy]

I have replaced number 6 on this list though. Is that the Temp Sensor in questions?

http://realoem.com/bmw/showparts.do?model=1374&mospid=47315&btnr=11_0683&hg=11&fg=35

[gettinscurvy]

Also, I have purchased a new fuel pump relay from Pelican and there was no change in operation. So my current assumption is that I have 2 working fuel pump relays.

[hahaitzskippy]

ok to update.

found that the ICV vacuum line returning to the intake boot was not secure. put it back and and VROOM!!! SHE LIVES!

strange too because i made sure all the lines were in place... adjusted timing by sound (not the greatest way).

so the car fires up and stays on... weird i have no idea what really happened.

imma get a timing light and try to work on it this weekend. mechanic friend helping me told me it was running rich too.

who do i fix that?

[packratbimmer]

I know you are in CA so not sure about emissions, but you can just advance until you hear pinging then back off a tad. In other words, you can advance the timing beyond specs for a little extra umpphhh!!!