1987 Buick Regal Idle / accelleration issues

WE4TURBO

MEMBER
1987 BUICK REGAL
6 CYL
2WD
AUTOMATIC
135,000 MILES

'87 Turbo-T. The car bogs badly at launch but will ramp up if brought up slowly. Also will backfire back up through the intake ( pre-ignite? ). Does not want to idle at start-up and will float up & down as though searching and will stall unless you feather the peddle. Once warm, will maintain idle. I seem to detect a miss, it's not smooth. It's the same with the stock chip or mini-mag performance chip. Prior to this and for some time, at start-up, the exhaust smelled super rich, with blackish not grey, smoke until warm. Replaced the fuel filter. Fuel pressure is good at 28#. Got 93 octane in it with a can of 108 octane boost. Ck. Eng. Lt. Will flutter at times, then stay out. Unplugged mass air and noticed a slight change, probably ok. KN intake filter clean. Suspect a flat or dead injector or plug? ECM good. Jacobs wires. ICM issue? How do you test an injector? Getting one out looks rough.

1 Reply

ERNEST CLARK

MECHANIC
1,730 POSTS

Because of the black smoke (running rich), I'd suspect a leaking fuel pressure regulator. Just because the fuel pressure checks out, doesn't mean the little diaphram inside of the regulator isn't leaking.

What this will do is allow extra fuel into the intake manifold through the vacuum line. But your fuel pressure will remain in spec.

Pull the vacuum line and smell/look for fuel. If there's ANY, then the regulator is bad.

Then I'd perform a cylinder drop test by pulling the plug to one cylinder at a time. If you notice a drop in idle, then that cylinder was firing correctly. If not, then that cylinder was dead. (Ignition/bad injector)

To check an injector, you'll need a set of noid lights or a balance tester. (And getting to the injectors will be ROUGH!)