start up idle

[LarryK 87]

have had this going on now for about a month. when the engine is first started, rpm goes to 1800,and holds there for about 3 seconds, then drops back to around 900. does this hot or cold.

any ideas what could be causing this?

 

[vigman]

Got a VAC leak

Somewhere.. time to strat lookin @ vac hoses!



Vig!

 

[1DOWN6TOGO]

does this for my '77 as well when i put her in park
may be completely unrelated, but thought i would ask
thought at first idle was too high, but it idles beautiful when runnin' in drive

any ideas?

 

[vigman]

Completely different

Your 77 is a CARB.. the premise might be similar.. but the control devices are different.


Vig!

 

[1DOWN6TOGO]

i should have stated that all differently.
i mean, i know i have a carb! :J
what i meant, was i am wondering if y'all knew what causes my problem. i just posted it there because the symptoms were the same, and it was convenient
it's not a big deal to me. hasn't given me any trouble yet.
thanks Vig

sam

 

[vigman]

Sam

I knew YOU knew you had a carb...the statement was intended for others ...not as savvy!


So a VAC leak will raise the idle by some amount...I would start checking lines in yours too!...and I know it's a train wreck under the hood of Later C-3's...

I hose at a time!


Vig!

 

[LarryK 87]

should have posted this with the original post, just missed it, all hoses ( Vac ) have been replaced ( underhood ) with new stock, car is also missing the Vacuum tank ( this line i capped off ). on a few occasions ( after having the ECM in Diag mode ), and IAC, TPS re-adjusted, engine starts perfectly RPM at start up is ~1000. as would be expected, it almost appears as the IAC is slowly moving its self to progressivly higher settings for start up, I did how ever try putting it into diag mode ( did not disconnect the IAC as you would when adjusting minimum idle ), key off, Remove diag plug, start engine, same effect, high initial idle, then settles down, ( i defeat this most of the time by starting the engine as if it is in flodded mode ) causes the engine to stumble at first, but it also allows the oil pressure to climb before revs climb to 1500+

Side note, i have not replaced the hard plastic Vac lines, as they all appear to be in good shape, ( or is that a bad assumption on my part)

 

[vigman]

Assumption

= make a ass outa U & ME!


Vig!