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88 Renix CPS wiring harness plug end


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Howdy guys. I am having a situation where the 88 was running ok Friday and no start on Saturday. First time issue in all the years I have owned her

Went through the following new parts as a matter of...not having changed them in a while...

new Dist cap & rotor, new coil, and replaced all 3 relays, new fuel filter & fuel pump, CPS (and drilled out the holes in the mount ears to slide the contact point closer to the flywheel) ...still no start though it seems way closer as of the hole drilling.... Three weeks back did new air idle control motor as it was sticking and my idle rpm was wonky, changed her oil, air and oil filter new plugs.....

 

I am pretty certain I have found the culprit and the original CPS finally shot craps. It is evident that a previous owner had to re run the wires from the original as there were multiple splices in both wires that would normally go to a female plug end into the wiring harness from the CPS was the Siemens high altitude version...which is not what I can source. I have found cruisers mostly renix tips and will pick up another (second one) CPS from Napa... Following this the  CPS conversion to advance the timing (ie conversion to high altitude ...etc). I figure if it is NOT the problem I might as well confirm it and move on..

 

Here is the question part...

When the original CPS was left in and the wiring spliced, the wires were run direct into the harness, not plugged in as would have been original.

in other words the male plug was cut off the pigtail from the CPS...can someone please post a photo of a renix wiring harness where the CPS plugs in. I don't have a problem wiring the new on back in the same way ( hell she ran great all these years before and after the AX15 conversion from the original 5 speed pukegoat.)

I just want to be certain that I don't have a better option....

 

Many thanks for any and/ or all comments...

 

Buffalob.

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I don't have a picture, but there's not much to tell you. The wires for the CPS connector come out of the main loom that runs by the injectors/past the throttle body near the back of the head.  It's a 3 pin GM weatherpack connector, you can buy one from Pico with the pins/seals (so no splices) for $5~.  There is supposed to be a clip on the bellhousing and on the back of the head for the CPS wires, and without them there is potential for the wires to become pinched/torn.  If there is splices in the wire anywhere then it is suspect and I would pull the loom off and check things.

 

I think Cruiser has a picture out of the manual showing how the wire is routed and where the clips are supposed to be.  They're often gone as people replace the CPS and just throw the wire in there.

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Regarding the two wires that connect the CPS to the harness, it possible the wires have been reversed

when I was cleaning up the splices?.....or does the CPS just send a pulse?

What color are the two wires (in the loom) being tied in to the red / white leads on the CPS....or does it matter?

 

It was so wet and dark last night all I had time for was to mount the new napa CPS unit (modified now as "high altitude") and twist the wires together to try and fire her up. I have not yet checked AC volts... Still no start....

Will be back at it this evening......

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9 hours ago, buffalob said:

Regarding the two wires that connect the CPS to the harness, it possible the wires have been reversed

when I was cleaning up the splices?.....or does the CPS just send a pulse?

What color are the two wires (in the loom) being tied in to the red / white leads on the CPS....or does it matter?

 

The CPS polarity does matter. It will shift (retard or advance, I don't know which) the ignition and injector timing by no more than 5°. Could this cause a no start, once again I don't know. Flip the wires to find out. What I do know is that CPS connector pin A should go to ECU connector pin C1.

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12 hours ago, DirtyComanche said:

 

Why?  Seems rather inconvenient.

Because the resistance in the factory wiring harness was too high. Think C101 here....

 

So, the CPS bypass kit was invented. CPS wires directly to ECU. 

 

I think the bulletin was 18-58-88.........

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Glad to know...

I have now modified the new Napa CPS to advance the timing. I have checked AC volts to confirm adequate output.

Will re-check my wires for correct polarity and hard solder them in and shrink wrap......

 

Still at this point no start....

 

I will continue on refreshing connections and a full inspect on the harness to bring it up to snuff.

Is there a specific sequence to this process you would recommend?

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