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Old 07-06-2022, 12:50 PM   #1
3wagons
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Default 1978 245 kjet ground issue

My 78 245 Kjet M46 started running rough after sitting for a couple weeks. Assumed it was a fuel issue. Like pressure is 68 psi, cold control pressure is 30 psi, and with the CPR warmed up, pressure is 50 psi. All seem to be in spec.

The issue was when attempting to check the control pressure with the CPR warmed up. With the wire reconnected the pressure was not rising and remained at 30 psi. I installed a jumper plug and wired it to 12 volts plus a ground and the pressure raised to spec within 5 minutes. With the key on, I have 12 volts at the CPR plug, but no continuity to ground. Also checked the plug to the auxiliary air valve and it's the same issue. 12 volts, but no ground.

The intake is off the car right now as I'm replacing the gasket and replacing all the vacuum lines and resealing the injectors as well.

Where should the ground to the CPR be? Am I missing something here?
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Old 07-06-2022, 01:41 PM   #2
hiperfauto
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The ground wire(s) are on the intake manifold near the TPS bracket.

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Old 07-06-2022, 03:15 PM   #3
dl242gt
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There should be two black ground wires on the intake manifold and they both should be on the two separate bolts on the manifold. Do not connect the two grounds together as that will affect proper operation of the lambda system.
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1982 242 turbo. 338k miles. MVP coilovers and 3" exhaust. Flowed 405 with a V15. Cossie turbine housing with upgraded compressor housing. 90+, IPD remote oil filter. Some other goodness, too. Been lots of fun over 25 years. Restored in 2k. Now ready for a 2nd restoration.

1993 245 Classic, 440k miles, enem V15. IPD bars and chassis braces. Simons sport exhaust from Scandix. sbabbs ezk chip. Been a good road warrior. Genuine Volvo rebuilt leaky M47.
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Old 07-06-2022, 05:31 PM   #4
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Thanks!

I had forgot about the ground at the cold start injectors when I was testing it. It was not connected with the intake being off at the time.

All the grounds are hooked back up and the intake is back on. Still barely running. Going to have to dig deeper now.
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Old 07-07-2022, 12:39 PM   #5
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Believe I have it sorted finally. Noticed the frequency valve wasn't buzzing. Checked the relay and it was solid corrosion. Swapped in another relay, and no luck. Checked Dave's relay page and realized it was the same as a K relay. Dug one out of the parts box and installed it. Runs great once again.
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