P0205 - Injector Circuit Malf cylinder 5
P1590 - mfr controlled veh spd, idle control and aux inp
P0305B - Cyl 5 misfire detected

I'm thinking that P0205 tells me I can skip any wire and plug troubleshooting on #5 and should go straight to taking the IM back off to see if the injector is plugged in correctly. I was really hoping to have this thing back together and NOT have to take things apart again...any thoughts?

Also, I'm not sure what the P1590 is about. My cruise control has been broken a long time, would that be causing this code?

 

Did you take the injectors off of the manifold??

Yes, check the wire to injector #5.
Check the wire was also not pinched.

 

I only unplugged the multi-plugs off the injectors.

#5 wire looks to be fine.

 

Not sure where your code reader got the text info, but here are pages from the Bosch manual for the ECU to tell you how those codes are generated. It is the best translation of the original Klingon text.

1590 is not the cruise control, it deals with the rough road signal system from the SLABS ( a system that tells the engine computer to disable misfire monitoring, the vehicle is being driven on a rough road and we don't want to distract the driver who is having a helluva good time holding it between the ditches).

And 205 is most of the time a pinched, broken, crushed, skinned, or compromised wire. With no fuel squirt to cylinder 5, misfire would be expected.

The wiring for the injectors is a common hot battery from fuse 1 in under hood box, this goes to all injectors. So you should read +12 at them. The individual injectors have a switched ground provided for each via the ECU. Cylinder 5 uses a yellow/green wire that leaves the injector and goes to pin 2 on connector C0636 on the ECU. Perhaps a little voltmeter work would be a nice change from busted knuckles under the hood...

 

Use your finger to trace the #5 injector wire back from the plug
to where it goes to the harness loom.

There may be a part where the insulation is cracked or the wire is flat - the copper inside is parted and only the insulation is intact holding the wire
ends together.

Also - inspect the pins in the injector by using a flash light. make sure the two contacts are proud.

You can check continuity with a sewing needle at the loom end and
the VOM on ohms X10 at the plug end.

The sewing needle will put a small hole in the insulation though.

I used this method on the crappy Jaguar XJS I had.
All the wiring was hard baked by the intense engine compartment heat.