Correct Idle Speed for 5.7L 350 V8

Thread view:

Enable EMail Alerts

Start New Thread

Thread rating:

austin - 30 Aug 2006 04:13 GMT

I have an '86 GMC 1/2 ton pick-up that now has a 5.7L 350 V8 in it.
The emissions control label on the front of the engine compartment is
for the original engine (a 4.3L V6) and says I should set the fast idle
speed to 2200 RPM and the idle speed to 500 RPM. Does anyone have an
idea if these numbers are good to use for setting the idle speed on my
V8 as well?

The truck has A/C, automatic transmission, I've got the spark plugs
gapped to .045, and the ignition timing is set to 8. Rochester
Quadrajet M4ME Carburetor (17085210).

Anyone know the proper idle speed specifications for this type of
engine?

Thanks,
austin

Reply to this Message

austin - 30 Aug 2006 04:27 GMT

Don't know if this really matters, but a minor correction needs to be
made: the timing is set to 6 BTDC, not 8.

> I have an '86 GMC 1/2 ton pick-up that now has a 5.7L 350 V8 in it.
> The emissions control label on the front of the engine compartment is
[quoted text clipped - 12 lines]
> Thanks,
> austin

Reply to this Message

Whitelightning - 30 Aug 2006 04:39 GMT

> I have an '86 GMC 1/2 ton pick-up that now has a 5.7L 350 V8 in it.
> The emissions control label on the front of the engine compartment is
[quoted text clipped - 12 lines]
> Thanks,
> austin

Gap sounds right, idle speed hot in gear 600 rpm, 800-900 rpm cold in gear.
What year engine, and is it all original ie correct distributor for the year
of the engine?

Whitelightning

Reply to this Message

austin - 30 Aug 2006 05:35 GMT

Thanks for the post, Whitelightning. It's an older engine (I would say
roughtly the same year as the truck--mid-80s) that had a couple misses
in it when I bought it. I had it rebuilt a year ago. The distributor
matches and they work well together. Sorry I can't be more specific
about the year. I've looked all over the engine for the VIN number
(down by oil filter and along the engine case pad especially) and can't
find it.

Austin

> > I have an '86 GMC 1/2 ton pick-up that now has a 5.7L 350 V8 in it.
> > The emissions control label on the front of the engine compartment is
[quoted text clipped - 18 lines]
>
> Whitelightning

Reply to this Message

austin - 30 Aug 2006 05:57 GMT

Yeah, I should have mentioned about the original numbers: the emission
control label says the fast idle 2200 RPM number should be set in Park
or Neutral, and the 500 RPM idle speed set in Drive. The truck is due
for a TX emissions inspection soon, so I might retard the timing some
before I take it in. I think specifications say it should be set at 8
BTDC (4 on the timing indicator), right?

austin

> Thanks for the post, Whitelightning. It's an older engine (I would say
> roughtly the same year as the truck--mid-80s) that had a couple misses
[quoted text clipped - 28 lines]
> >
> > Whitelightning

Reply to this Message