Comments on: "91 Chevy pickup, with replacement engine will only stay running with pressure to the accelerator.Any Ideas?

By: W M

W M — Fri, 14 Nov 2008 10:58:59 +0000

Check for a bad/broken/disconnected/hiding vacuum hose. From what you have said it probably won't be a little one.

Did you forget to hook up the brake booster?

Ideas:

PCV
Idle air motor
Intake manifold gasket (did you use the "end pieces"? They squeeze out and leak!)
I would check the timing too, should be about 10 degrees advanced.
Firing order 1-8-4-3-6-5-7-2 Clockwise
Insufficient Fuel pressure (pump/filter/regulator)

EGR leak/disconnected?

Bring it on over to my house, we can fix it!
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Mechanic/ASE Parts Specialist

By: Trisha

Trisha — Fri, 14 Nov 2008 10:18:59 +0000

does sound like a vaccum leak but may also be the pick up coil in the distributor, try unplugging the link connector for the timing to the distributor if it runs better replace pickup coil. The link connector is located on the passenger side firewall behind the relay cover
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By: George K

George K — Fri, 14 Nov 2008 10:02:59 +0000

you have your vacuum hoses crossed.
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By: stallion1948_lloyd

stallion1948_lloyd — Fri, 14 Nov 2008 09:56:59 +0000

if it lopes then its probably a vacume leak somewhere.try checking vacume hoses.
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By: Sparky

Sparky — Fri, 14 Nov 2008 09:18:59 +0000

Sounds like a vacuum leek or bad gasket.
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By: deltech

deltech — Fri, 14 Nov 2008 08:28:59 +0000

Be sure timing was set correctly If that cks out good i would look at fuel pressure. should be 14 psi to run right .specs call for 9 to 14 but thats misleading .Most TBI engines need 14 lbs
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By: done wrenching

done wrenching — Fri, 14 Nov 2008 08:16:59 +0000

Check the distrib timing.set it at 0 BTDC (you have to disconnect the tan w/black wire at pass side firewall). Also you could have egr sticking open or vacuum leak.
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By: Mad Jack

Mad Jack — Fri, 14 Nov 2008 07:51:59 +0000

The engine is fuel injected.

The idle speed is controlled by the engine management computer and can not be adjusted.

Check that the idle air control valve. It is located on the throttle body. Make sure that it is connected and working. Check that the wiring was not damaged during the engine swap.

If all that was correct, possible the camshaft was installed incorrectly when the engine was rebuilt. Place #1 piston at top dead center. Remove the water pump, harmonic balancer, and timing cover. Check that the timing marks on the timing chain sprockets are correctly aligned.
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By: hardly_d

hardly_d — Fri, 14 Nov 2008 07:39:59 +0000

Hmm the answer above this one about the idle speed is a good one..also check the timing on this puppy..sometimes things are over looked in doing total replacements
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By: Michael S

Michael S — Fri, 14 Nov 2008 07:14:59 +0000

Vacume hose off the Timeing advance silinoid .
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