635csi Injector ECU Problem ??????????

[davidsorensen]

Hello,

Car: 1986 635csi (150k miles):

I have been experiencing an intermittent (and very frustrating) problem of poor acceleration (sputtering) or after a short drive time (1/2 mile) the car dies at a stop sign and won't re-start. When this happens the ignition turns over for about 4 seconds then briefly pauses for 1 second. The most recent episode included a couple small backfires. After 1/2 hour the car re-started. Another time it was towed and then started at the repair shop but was running poorly (sputtering -receiving excess fuel).

The repair shop did basic troubleshooting, finding only a cracked air intake boot (replaced). The injectors were replaced about 5k miles ago but I'm now told the problem could be some intermittent failure within the injector elec. control unit (ECU). However, the car will never fail while at the shop (murphy's law) which makes troubleshooting impossible....Main fuel pump and relays were replaced 2 yrs ago (pumps are not noisy at this time anyway).

Can anyone share a similair experience or recommend how to troubleshoot the injector ECU and/or individual sensors, switches within the ECU? Should I replace the ECU unit ($500. part) and hope this solves the problem? Or replace thermo-time switch and oxygen sensor, cold start valve?

Any guidance/feedback is appreciated :-)

Thanks & Cheers,

David