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Stalls out right after cold startup...starts right back up...

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Old 01-02-13 | 01:34 PM
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strang3majik's Avatar
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From: Hanover, PA
Stalls out right after cold startup...starts right back up...

I just picked up this 89 FC vert, and it runs great, but has a few issues.


First off, when I first start it when cold (in gear, in neutral, doesn't matter), the cold start function doesn't work correctly.

It'll start, idle kinda rough at around 1k rpm, then will stall out if I don't give it gas. If I blip the throttle quick, the high idle function will hold it at 1500rpm until it warms up and it idles smooth.

If I don't blip the throttle and it stalls out, it starts right back up and will idle rough for a couple minutes (sounds like a dirtbike) until it gets some heat in it and smells strong like fuel. Doesn't like to be revved at all either, so kinda has to clear up on its own.



But, I had my last vert and it would rev up to about 3k and work its way down to normal idle at operating temperature. This one doesn't do that.




Also, when at partial throttle cruise it has the occasional miss. Half to full throttle it runs and pulls very smooth, and runs very well. I can definitely feel the difference between this s5 and my old s4...its just at cold idle or partial throttle situations.


Also no smoke. I tried holding it at 5k for like 30 seconds then just letting off the throttle (I read to do that to check for smoke before), and no smoke.

And I plan on picking up plugs and a fuel filter this weekend. Just wondering if this seems more like an adjustment type of thing.
Old 01-02-13 | 01:58 PM
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From: tulsa,ok.
The 3,000 rpm high rev upon a cold start only occurs if the coolant temp is above a certain threshold. If the coolant is too cool the thermo switch sensor reads this and precludes the high rev procedure from occurring.
Old 01-02-13 | 02:20 PM
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Originally Posted by satch
The 3,000 rpm high rev upon a cold start only occurs if the coolant temp is above a certain threshold. If the coolant is too cool the thermo switch sensor reads this and precludes the high rev procedure from occurring.
What temperature is that at?

Its been in the 30s here, dipping into the 20s occasionally.
Old 01-02-13 | 03:01 PM
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From: tulsa,ok.
Actually, the sensor I spoke of is found at the radiator on S4's and I now see that you have an S5. Your system works a bit differently than the S4.
Old 01-03-13 | 04:15 AM
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Oh ok. Its quite annoying that it does it.

Basically a run down of a cold start...


hit the key, revs up to 3k then to 1k almost instantly, stumbles a little, then if let go will stall out.

If I blip the throttle it'll go back to like 1.5k and stay there til its warm.


But if I don't catch it in time and it stalls out, it'll start right back up, but idles rough as hell at 750rpm and smokes (white) but smells like raw gas.

Almost acts like a carbureted car in the cold without a choke.



And today I manually moved all the vacuum diaphram operated levers on the engine (no idea what they are...lol) and the slight miss seems to have gone away. Might have just been something sticking. No vacuum leaks to be found. I followed every hose and all are still rubbery.


And the car runs very very well at WOT. Going uphill in first and hitting second it spins quite a bit...haha. My perfect running s4 wouldn't even do that.
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