On the 944 Turbo, the ignition signal originates in the DME, but then makes a round trip through the KLR. This allows the KLR to retard ignition timing when needed. If the KLR malfunctions, the ignition signal can effectively die inside the KLR and never return to the DME. The result: no ignition, no start.
For testing purposes, you can bypass the KLR by removing its main 25-pin connector and installing a jumper wire between pins 9 and 16. This loops the ignition signal directly back to the DME.
With the KLR connector removed and pins 9 and 16 jumpered, the engine should start and run. This is for troubleshooting only—don't drive the car this way, and definitely don't drive the car hard this way. In addition to losing knock protection, the KLR normally supplies the full load signal to the DME, so if you drive the car hard with the KLR bypassed, the DME will try to run off the part throttle maps even at wide open throttle -- which isn't good.
If the engine starts with the KLR bypassed but not when the KLR is connected, the KLR is likely faulty. Fortunately, many failed KLR units can be revived by replacing the EPROM and/or reflowing cracked solder joints, so it’s worth trying those fixes before sending the unit out for repair or replacing it. For reasons unknown, I've seen several KLR units come back to life simply by replacing the EPROM. If you need a new KLR EPROM, you can burn your own using our images and chip-burning guide.
- 951-KLR-Bypass.png (1.14 MiB) Viewed 527 times
- jumper-wire.png (347.73 KiB) Viewed 527 times
.