No spark help =(

[PDX-944]

So, I was sitting in grid at autocross, first run of the season after going widebody this winter, with much bigger tires, ready to shake the car down and test it out.
revved her up to move forward in line. at the top of the rev, it cut out completely and died.

now I have no spark. I do have fuel.

now, a few things:

I don't have a speed or ref sensor.
its running the wolf3d v400, sadly, as no one has any idea what a wolf3d is in the tuning world.

now, the ecu has an input trigger light on the side for the cam hall sensor, and it flashes when I crank. so the sensor seems to be good.
theres no spark from the coil.
the coil is good, I even swapped with a known good coil, which tested the same as the old one.

unfortunately the wolf3d software has no useful information in it about spark or triggers or anything.
im guessing its a wire issue between ecu and coil, however, the ecu plug nor ecu have any pins labeled, so that's going to be a PITA.

any ideas?

thanks!

[944 Ecology]

Can you convert it back to stock?

[v2rocket_aka944]

spark is usually based off a crank signal not cam, do you have a separate crank pickup?

[RRRacing1970]

We had a magnetic (pick up) for the crank sensor go bad (lost the mag. Field elec.) / and or lost the signal due to it being not gaped properly or it shifted?)... but if you rev'ed it up high RPM... the sensor might have moved and chewed up the mag sensor?
Ron...

[PDX-944]

Originally Posted by 944 Ecology

Can you convert it back to stock?

lol, no definitely not

Originally Posted by v2rocket_aka944

spark is usually based off a crank signal not cam, do you have a separate crank pickup?

the speed/ref sensors are gone, there is nothing in place of them. one of the plugs is empty, and the other runs to the cam sensor. this is the way the plug and play wolf3d kit is made. theres no alternate crank sensor

Originally Posted by RRRacing1970

We had a magnetic (pick up) for the crank sensor go bad (lost the mag. Field elec.) / and or lost the signal due to it being not gaped properly or it shifted?)... but if you rev'ed it up high RPM... the sensor might have moved and chewed up the mag sensor?
Ron...

I pulled distributor and inspected the cam sensor almost first thing, its still in place and isn't touching the plate that is mounted to the cam and spins between the cam sensor, which is a U shape and straddles the plate.
and the ecu is getting trigger from it, as I can watch it flash while cranking. I was hoping it was that easy too... ha

what im trying to figure out is how to test for trigger at the coil.
not testing the coil itself, but testing whether its getting any trigger, that way I can start fidgeting wires and see if it comes back. the wiring is almost all factory and you know how that gets...

[v2rocket_aka944]

See if you can get ahold of Pelican user "alxdgr8"
Pelican Parts Technical BBS - View Profile: alxdgr8

He is in Federal Way, WA, not really close, but he knows a thing or two about the Wolf system.

[PDX-944]

Originally Posted by v2rocket_aka944

See if you can get ahold of Pelican user "alxdgr8"
Pelican Parts Technical BBS - View Profile: alxdgr8

He is in Federal Way, WA, not really close, but he knows a thing or two about the Wolf system.

sent him a message. thanks!

[PDX-944]

Okay so I've verified that the cam sensor is using the speed sensor harness, while the reference sensor harness is empty.
The cam sensor is functioning correctly and giving 400ma to the ecu on trigger.
I have found the pin/wire on the 944 harness/plug at the ecu that triggers the ignition coil.

I can test for continuity between that pin and the negative terminal on the coil to verify the wires are good. Haven't done that yet.

I'm thinking because that trigger pin will always have positive voltage (coming from the coil), but not always a ground connection, I should test for voltage between the positive battery post, with negative probe on that pin, while cranking. Does that sound correct? Should bounce if I understand.

[smokintr6]

If it's using the speed sensor harness, and the speed sensor position on the bell housing, then it's a crank sensor, not a cam sensor. It's counting ring gear teeth, no way to modify that without losing the starter! The other sensor inside the distributor is the cam sensor.

You should be very suspicious of the original speed sensor wiring harness that is part of the car. I would consider replacing it with one from lindsey racing.

[v2rocket_aka944]

Hi,
The coil positive wire is black and runs from ignition switch->CE panel->direct to coil +.

The ECU controls the coil's negative (green wire) by pulsing the ground to fire the spark.

Sensor amperage doesn't matter - you need to verify the voltage output of that cam sensor.

[PDX-944]

Originally Posted by smokintr6

If it's using the speed sensor harness, and the speed sensor position on the bell housing, then it's a crank sensor, not a cam sensor. It's counting ring gear teeth, no way to modify that without losing the starter! The other sensor inside the distributor is the cam sensor.

You should be very suspicious of the original speed sensor wiring harness that is part of the car. I would consider replacing it with one from lindsey racing.

I was not clear, sorry - It uses the speed sensor harness, but it is a cam sensor (hall) mounted on the front of the cam cover. Documentation on the wolf 3d verified that this is the only pickup used for the 944

Originally Posted by v2rocket_aka944

Hi,
The coil positive wire is black and runs from ignition switch->CE panel->direct to coil +.

The ECU controls the coil's negative (green wire) by pulsing the ground to fire the spark.

Sensor amperage doesn't matter - you need to verify the voltage output of that cam sensor.

I ran a ton of tests today.
Great continuity between green wire at coil and green wire (pin 1) at ecu. Testing with test light, green wire is getting ground trigger at coil. Correct voltage going into black side of coil.
All signs point to "it should spark", but it's not. Numbers between running and non running cars are the same.

I AGAIN swapped coils between the running 944 and this car, tested both in the process, both coils are equal. Both coils run on other 944.

Power, trigger, everything is there, it's just not sparking on the wolf car.

Trusted friend believes the driver in the wolf computer no longer can pull spark from this coil.
Upon third swap of coils, I got it to kick twice on crank, but then no spark again.
Checking the tune currently, it's set to pulse as long as possible already, to charge the coil as much as possible, indicating it already struggled with the uf37 Bosch ignition coil probably. Perhaps I need a different more suitable coil, but that's where I know little and am stuck.

[PDX-944]

Pulled apart the ecu. Have a VB921ZVFI coil driver. Could this be getting weak? I don't know how to test. No oscilloscope...

I even tried upping the dwell from 2.99 to 3.49 and 3.75, nothing.

Both cars read 12v on pos coil, and 10.5ish on negative side while cranking. But one car sparks, other does not. This is making me crazy.

[PDX-944]

Alright so I replaced the vb921 with a bip373 and am up and running again! I don't know how I should adjust dwell or if I really need to...

[PDX-944]

runs great with the new transistor. had a blast this last weekend shaking it down.
having to get used to having so much front traction now. needing some more suspension work im finding now that I can actually steer
needing to go stiffer all around.


woooops


woooops again... lol look at that cone go!



that's better


shes a big girl

[TrailRider]

congrats on getting it running again!