Ok more or less title says it.. I'm putting a stock ecu with rtek 2.1, harness and the 13bt into an 84 BMW 318.. Its out of a 1988 10th anniversary.. The motor was blown rebuilt and installing for grassroots.. Other plans for the AE.. All is wired minus emissions circuits, egr blah with block off plates.. Leading and trailing coils all have good power... Spark is great but when the motor is turning spark is lost.. That's while the starter is engadged.. If I were to pull out the CAS and turn it with an electric gun at low or high rpm spark is constant and great and so are the injectors, but installed, it's lost under the starter load, the injectors are not, Unless there is a signal that needs to be input into the ecu. But then why would I have good spark and fuel when we spin the CAS manually.. Ive tried 2 other ecus to eliminate the ecu and a second CAS .If anyone needs pics, I have pics of all the ecu pins.. All grounds and key and constant power inputs and correct, fused, and relayed.. And verified that the fuses and relays are working properly. Sorry didn't label them 1,2,or 3 I forget which is which and tired and frustrated.. Ask any questions.. I'm just unsure if an input is necessary.. Note, I did get it to attempt to start on carb cleaner so I know its runnable and I tried bigger batteries to eliminate tcranking speeds..ECU is an N333. Thanks in advance!

Large plug top

Large plug bottom


Medium top

Medium bottom


Small top

Small bottom


The black with red wire in this last pic was moved to test for an input signal I know this is missplaced please ignore it lol

 

Are you using a Map on the Rtek or are you just going under the stock setting in the Rtek?

 

On a stock RX-7 there are IG1 fuses and IG2 fuses. IG1 fuses are powered w/key to on and start, but IG2 fuses are powered w/key to on, but not start. So if you had the IG1 fuses,which are necessary to run the engine (IG2 fuses are not) powered by an ignition wire such that they only have power w/key to on but not w/key to start then you would lose power to certain relevant items when the key is put to start.

 

The ignitions are both controlled by one switch controlling 2 fused relays.the key in the BMW basically only unlocks the steering wheel and controls few power options like window, wipers etc. the engine ecu and harness are separate from the chassis completely.

On the rtek, I'm using load vs rpm.. I've misplaced the palm pilot so I can't get into the ecu which makes me mad so I have to source one and see what the ecu sees..

 

On an RX7 only the necessary things to run the engine are powered by the IG1 fuses as everything not germane to running the engine are not powered by these fuses. This is done to focus the battery voltage on those things relevant in running the engine. Power windows and wipers are not examples of relevant items. If there is too much voltage draw, the ECU will not work as intended.

Pin 3I of the ECU powers the ECU so it requires the necessary voltage w/key to start for it to work properly.

 

I know without a doubt 3J has power while starting but I didn't check 3I I know that 3I has power prior to turning the motor..I'll double check when I get home..and I'll make a schematic of my wiring

 

Pin 3J isn't responsible for powering the ECU even though it is the battery signal, but the ECU would work fine even if 3J was disconnected. And pin 3I would come from the Main Relay in the standard wiring setup.

 

Ok, sorry to keep you waiting.. i didnt make the schematic because i know its all good and i even jumped relays and potential issues.. 3I has good power before and during starting and to even go a next step i made sure at the coils they both had good power drops to 10.7 then right up to and steady at 11.5v. And i took it another step further and added a second battery to eliminate too much draw. I did this by hooking up the starter wire to the second battery and the ground connected to the engine ground i connected, 6 gauge wire.. i turned the motor, it turned faster which i expected but still lost spark.

Im still looking into it on all the free time I have.. I have my daughters first birthday this weekend so thats why I havnt had much time to reply lots of setting up.. any more ideas im open to and trying just about anything lol

 

You might want to look over the CAS connection and w/that wiring there might be a grounded shield associated w/the wiring. Also, have you tried just getting spark on the leading coil while leaving the trailing coil disconnected. And the coils need a good ground from the contact it makes w/the body to work appropriately.

 

I learned they needed to be grounded on my last car, ever since all my coils have had there own added grounding wires, and i have done that on here.. so thats a good check lol thats whats wierd about the spark.. its just all there when the CAS is out and spinning it by hand or with an tool.. but after its installed its not there.. and believe me, i know all the gears are in tack ive looked down inside and watch everything turn.. im stuck in a voltage draw but i doubt it after i set up a whole second battery.

 

Another thing to do is unplug the AFM and try once again to get spark w/key to start as the AFM can interfere w/this aspect of the engine's operation.

 

Ok, sorry to sorta leave this empty but I've still been working on this.. Not everyday like I wanted too but still going.. Too sum up what I've done, replaced ecu, replaced CAS, sent out injectors to be sure the weren't clogged, replaced stock BMW fuel system with rx7 walboro fuel pump and repaired broken wires in made harness.. Everything has lead me too a final issue that I cannot beat.. And it seems to have been the issue all along.. With other **** jut found and checked along the way..

I do not get spark at low starting rpms but when it is raised I begin to get spark with no issue.. Why would I not get spark a starting rpms..