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Rough idle on cold starts

Help, Advice, Owners' Discussion and DIY Tutorials on all Volvo's "mid era" rear wheel drive Volvos.

1975 - 1993 240
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Coffin88245
Posts: 2
Joined: Mon Dec 02, 2019 10:54 am
Year and Model: 1988 245
Location: Florida

Rough idle on cold starts

Post by Coffin88245 »

Just installed the Bosch 3 injectors on my 88 245 n/a.. idle and throttle response has improved tremendously. Unfortunately it now seems to have a pretty rough idle on cold starts.. after u give it a little gas and warm it for a short period of time it smoothes out and runs like a champ.. any ideas as to why this would be happening..?
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93Regina
Posts: 2813
Joined: Sat Jan 18, 2014 7:11 pm
Year and Model: 93:240/940
Location: Sunflower State
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Re: Rough idle on cold starts

Post by 93Regina »

Coffin88245 wrote: Mon Dec 02, 2019 11:09 am....any ideas as to why this would be happening..?
Mismatch of injectors installed to LH's default fuel program....so, once started, increase RPM for say twenty seconds, then back off throttle.

Once heated O2 sensor is active, LH "sees" the richness, and decreases fuel pulse duration for decreasing fuel input.
Coffin88245
Posts: 2
Joined: Mon Dec 02, 2019 10:54 am
Year and Model: 1988 245
Location: Florida

Re: Rough idle on cold starts

Post by Coffin88245 »

Any way to fix the issue with a tune..? They are not performance injectors just stock upgraded as far as efficiency.
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