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Discussion Starter #1
I’ve been observing this problem with my 88 Milano Gold 2.5 for the last several months — basically since the temperatures cooled off this fall:

It struggles to start and idle when it’s cold outside. The symptoms can range from an occasionally miss while driving to just running like complete crap (and not idling) after cold starts to violent backfiring after a cold start on a cold morning. The car usually runs well after being FULLY warmed up.

Today was a perfect example of its behavior. I went out to start it around 9:30 am when it was 40 degrees (F) and it took a moment to crank and then ran like garbage for about a minute at which point I removed my foot which was lightly placed on the gas pedal and it died.

Came back this afternoon at 3 during our unseasonably warm 70 degree Colorado day and it started right up, idled perfectly and ran great to and from my quick trip to the grocery store.

I can’t find any vacuum leaks, which doesn’t mean they’re not there.

I’m thinking it could also be the extra cold start injector or the coolant temp sensor.

Anyone else solved this problem after experiencing similar symptoms?

Thanks,
John
 

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The hard starting sounds like either the Cold Start Injector not firing, or the Thermo Time Switch not telling it to fire. These should really only effect approximately the first 7-10 seconds of running.

The general poor running when cold sound like something else. Perhaps the Aux Air Valve is not working properly?
 

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Discussion Starter #3
Thanks JoeCab! I’ll take a look at the auxiliary air valve. If mine ends up being kaput does Centerline have a replacement?
 

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I’ve been observing this problem with my 88 Milano Gold 2.5 for the last several months — basically since the temperatures cooled off this fall:

It struggles to start and idle when it’s cold outside. The symptoms can range from an occasionally miss while driving to just running like complete crap (and not idling) after cold starts to violent backfiring after a cold start on a cold morning. The car usually runs well after being FULLY warmed up.

Today was a perfect example of its behavior. I went out to start it around 9:30 am when it was 40 degrees (F) and it took a moment to crank and then ran like garbage for about a minute at which point I removed my foot which was lightly placed on the gas pedal and it died.

Came back this afternoon at 3 during our unseasonably warm 70 degree Colorado day and it started right up, idled perfectly and ran great to and from my quick trip to the grocery store.

I can’t find any vacuum leaks, which doesn’t mean they’re not there.

I’m thinking it could also be the extra cold start injector or the coolant temp sensor.

Anyone else solved this problem after experiencing similar symptoms?

Thanks,
John
I have the same exact problem with my 88 verde.
 

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The hard starting sounds like either the Cold Start Injector not firing, or the Thermo Time Switch not telling it to fire. These should really only effect approximately the first 7-10 seconds of running.

The general poor running when cold sound like something else. Perhaps the Aux Air Valve is not working properly?
Do you know where the aux air valve is located
 

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AAV is a good place to start, but also check that your hot idle is properly set. If the hot idle is too low it'll aggravate any cold running issues.

Don't trust the dash tach, check with an external tach. Spec is 950 +/- 50 but target the higher end. Idle is set via the adjustment screw on the idle bypass hose: 17mm screw with a 19mm locknut IIRC.
 

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This isn't the original part. The original part is very expensive. Even Volvo 240DL uses the same Bosch AAV. Here is a possible alternative. Not even sure this can work, but in principle it should do the same thing

 

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AAV is a good place to start, but also check that your hot idle is properly set. If the hot idle is too low it'll aggravate any cold running issues.

Don't trust the dash tach, check with an external tach. Spec is 950 +/- 50 but target the higher end. Idle is set via the adjustment screw on the idle bypass hose: 17mm screw with a 19mm locknut IIRC.
How do I locate the hot idle, do you mean the throttle body? That cable that gets pulled on when I hit the accelerator?
 
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