CAM Sync with or without pullup

V3 SOFTWARE
1

I am having trouble with engine start and cam sync. Attached are my files. I have a 35-1 crank sensor with VR and a 1 tooth CAM sensor with hall. This is, I think, worked great for a couple of years until recently when I started having starting issues. About half the time, the car will start and immediately die. The times it starts, it runs great, no issues, etc. The times it dies, it just dies.

I finally ran a scope on it yesterday and the behavior is weird. When I use a pulldown resistor, it will start, but has the behavior above (this is what I have been running for some time). It also doesn’t seem to have a CAM signal. When I switch to a pullup resistor, it has a cam signal but will not start.

I can start the car with a pulldown resistor and let it idle. When I switch from pulldown to pullup, it immediately dies. Soooo confused.

The scope below reflects have a pullup resistor used. CAM signal, but no start.

Sample051326.emublog3 (58.6 KB)

EMU Black Porsche V3.050 060325.emub3 (60.9 KB)

scope_2026512_1816.emubscp3 (659 Bytes)

2

First of all your cam signal is weird. You get a lot triggers during engine cycle. So it is possible the cam sensor is broken as it worked several years.

3

I replaced the sensor itself a few weeks ago and nothing changed. It’s possible that it could be wiring issue - maybe the connector or something. I’ll take a look.

4

Any update on this? were you able to figure it out?

5

I did some digging and discovered that my cam sensor power fuse had blown. It wasn’t even working right.

Afterward, I did some testing. I was able to get cam signal/sync using any pullup resistor setting and any pulldown resistor setting. Weird.

I have only spent a few minutes on it, but I can’t figure out how to tell if the engine is running in sequential or wasted spark. I tested a bit and changed the setting from sequential, to wasted spark, to wasted spark on startup and after each change the engine would hiccup, but it would idle/run just fine. Here are a few scopes that I ran after changing the setting.

seq.emubscp3 (617 Bytes)

ws.emubscp3 (611 Bytes)

seq2.emubscp3 (617 Bytes)