CX 2.5 Starts but will not idle

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Hydraulique
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Joined: 16 Aug 2026, 12:24

CX 2.5 Starts but will not idle

Unread post by Hydraulique »

I have a 1985, Series one CX Prestige with injected 2.5 liter engine. It had been sitting for about 5 months and now starts up only if I tap the gas but runs rough, and will not idle even when run to temp. Most recently It backfired once. I have checked the intake path and all seems tight. Plugs all look ok and seem to be getting spark. Compression is great at 150. New gas in tank and I drained tank to be sure all was clear. I ran some techron in the gas to see if I could clear a bad injector- no luck. I did install a new battery before this round and I now see one yellow wire and spade connector that is not terminated on the left side near the battery. No obvious destination. Anyone encounter this situation before? Thanks!
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mickthemaverick
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Re: CX 2.5 Starts but will not idle

Unread post by mickthemaverick »

Not sure what you mean by 'tap the gas' ? :)
I used to be indecisive, now I'm not so sure!
I used to ride on two wheels, but now I need all four!
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myglaren
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Re: CX 2.5 Starts but will not idle

Unread post by myglaren »

mickthemaverick wrote: 19 Aug 2026, 15:31 Not sure what you mean by 'tap the gas' ? :)
Blip the throttle!
Hydraulique
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Joined: 16 Aug 2026, 12:24

Re: CX 2.5 Starts but will not idle

Unread post by Hydraulique »

Yes, Just so. Pardon my americanism. I found it would start if I blipped the throttle- but ran rough. Normally, that would flood the engine. Thanks
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xantia_v6
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Re: CX 2.5 Starts but will not idle

Unread post by xantia_v6 »

I am not sure exactly which injection system your car has, but typically the early Bosch systems fired the acceleration enrichment fairly directly from the TPS, regardless of the other sensors.

I would firstly be checking the coolant and air temperature sensors and the wiring to them.