Bitz EFI no start/single injection flash

[motorstereo]

'81 911SC/ Bitz EFI conversion with Bosch CDI. Cross-posted to the Bitz EFI forum.

Car was running great, but occasionally a plug wire would unseat itself. The Beru wires were quite old so I upgraded to Clewetts. Engine did not run right with them when warmed up, I suspect the coil wire was not making good contact with the coil.

I installed a set of used, old Berus I just got after posting a WTB ad. When I went to start car to see if my warm running problems were solved or not, the engine will try to fire , for about a 1/2 second, then it just cranks and cranks. CDI box whines. Coil wire is sparking. I triple checked that plug wires are in the correct order.

All 6 plug wires test ok, I attached a spare plug to each connector, grounded the electrode, and had my daughter crank it over. All 6 made spark.

FPR reads normal.

Cannot hear injectors making any noise. I will buy a set of Noids tomorrow.

I decided to look at the Megasquirt box and I also unplugged and re-plugged the connectors on the front and back.

According to page 100 of the Installation guide , there are 3 indicator lights on the Megasquirt ECU box. The left LED is the Injection light, which flashes when fuel is squirted.

This Injection LED flashes once, and only once. The center light, Warmup, stays lit, Accel does not light.

Any ideas what might be causing this condition?

[motorstereo]

here's a short video of what the Megasquirt is doing

LED on the left indicates Injection

LED in center indicates Warm Up period

LED on the right indicates Accel

https://youtu.be/VTPacE4csMk

[Marwil]

Does the fuel pump run for two seconds when the ignition key is turned to the start position? Does it fire at all? Wondering if if could be the fuel pump driver?

[jpnovak]

Sounds like you no longer have a tach signal. The Bitz kit uses a zener diode to step down the CDI coil trigger voltage to about 18V to make it compatible with the MS ECU. This is connected on a "blue" wire. Check the input connections and see if you have disconnected this wire coming off the coil.

I would suggest to connect a laptop and see if you are reading an RPM input while cranking. Typical cranking rpm on a 911 is ~240rpm.

[OSC911]

Originally Posted by jpnovak

Sounds like you no longer have a tach signal. The Bitz kit uses a zener diode to step down the CDI coil trigger voltage to about 18V to make it compatible with the MS ECU. This is connected on a "blue" wire. Check the input connections and see if you have disconnected this wire coming off the coil.

I would suggest to connect a laptop and see if you are reading an RPM input while cranking. Typical cranking rpm on a 911 is ~240rpm.

Sounds exactly like my Rasant kit i recently installed - one flash and then nothing. The crank reference sensor was dead on arrival. Laptop showed a nice cam reference signal and a flat line on the crank. Unfortunately i had to by a new crank sensor and it fired right up.

[motorstereo]

Jamie--I have the Blue wire connected to the coil, on the positive side. I was just reading the installation manual and on p 83 I found this:

"Care must me taken not to bend this adaptor, thus breaking the internal components...The tach adaptor needs to be tie-wrapped down so it doesn't flop around as it will eventually break"

I have the adaptor secured, but I wonder if I have mangled it when I was routing and re-routing my plug wires. I will ask Tony if I can test it or if he can send me another one.

I tried to log the no-start conditions and it looks like Tuner Studio recorded a 12 kb file, but I am not sure how to interpret the file in MegaLog. I will attach a jpg of the file, I'm not sure I am able to attach the .mlg file itself.

Marwil--yes, the fuel pump works for 5 sec then shuts off, indicating the ECU is doing something.
------------

"I would suggest to connect a laptop and see if you are reading an RPM input while cranking. Typical cranking rpm on a 911 is ~240rpm."

[motorstereo]

Tony at Bitz Racing suggested I bypass the Tach Adapter and wire in a 5k Ohm resistor . the 5k Ohm resistor finally arrived in the mail yesterday. I soldered it into a length of stranded wire and crimped a ring terminal to one end.

I took the tach adaptor off the coil, and put my 5k Ohm wire in its place. I made a Western Union splice with my wire and the blue wire.

My resistor / wire reads 4.95 k Ohms, so I know there is continuity between the blue wire and the resistor which is now on the + side of the coil.

When I fire the engine, I see one brief flash of the Injector light on the ECU. The engine turns over but does not fire.

Tomorrow, when I have a helper, I will disconnect the resistor wire from the coil and feed 12 V to it intermittently while cranking to see if the injectors fire.



[QUOTE=jpnovak;11858363]Sounds like you no longer have a tach signal. The Bitz kit uses a zener diode to step down the CDI coil trigger voltage to about 18V to make it compatible with the MS ECU. This is connected on a "blue" wire. Check the input connections and see if you have disconnected this wire coming off the coil.

[motorstereo]

I sent the ECU back to Tony and he reflashed the firmware. Problem solved.

[jpnovak]

Glad you have it working again.