The car runs great overall and cruises at 70 just fine. It rides on a set of Michelins and feels quite smooth. The issues are pinging on even light acceleration and a rough idle. The code 32 confirms it as EGR related so that makes sense. I ordered a repair manual so that should help. In the mean time, is the EGR valve controlled by the computer and a solenoid, or just by vacuum? I'll removing and cleaning out the carbon but sure how actually works
EGR code 32 on my 1991 Grand Am 2.5L
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Should have a vacuum hose. Pull it off and put another on and suck on it to see if the diaphragm is bad
I believe those were ran off "Ported Vacuum" The ECM checks EGR operation by using "Block Learn" values (Now called fuel trims).....If the engine is only running lean when the EGR should be flowing, The PCM will set a EGR DTC.
At least some TBI/4Tech Iron Duke's didn't have Knock Sensors, My memory is a bit fuzzy with some of this ancient stuff, Don't remember the last time I worked on a 4Tech?
Apply vacuum to the valve while the engine is idling, the engine should die or come close to it.. That should tell you if the valve is working and the passages are clear without taking it apart and to start looking upstream from the valve for problems..
My 1990 Century w/Iron Duke will on occasion throw that code. I've cleaned my EGR and even replaced with OEM, still does it.
That's where I would start.
If you have easy access to the valve, you can also start cold and immediately squeeze the diaphragm with your fingers.
I had code 32 on a 1994 Saturn. I took the valve off to clean it and found the pintle basically jiggling around inside. The code came back with a new valve, and the "activate at idle" test caused no change in idle quality. I finally figured out that the intake passage was sealed shut with hard carbon after years of burning a quart of oil every 400-500 miles.
I'm not sure this applies to your Pontiac, but the Saturn also had a solenoid that controlled vacuum to the EGR. I found some brittle vacuum lines while troubleshooting it.
I had that issue on my 90 G/A 2.5, was a bad EGR valve diaphragm.
When you introduce hot egr gas back into the engine, the fuel/air charge is less volatile, so when the valve stays closed, you don't get that displaced charge and it burns hotter...then pings.
Test the hose first.
When you introduce hot egr gas back into the engine, the fuel/air charge is less volatile, so when the valve stays closed, you don't get that displaced charge and it burns hotter...then pings.
Test the hose first.
I took the valve off and tested with a Mityvac. It won't hold ANY vacuum. There is NO movement. Diaphragm must be busted. Says Rochester Products on it so probably the original.
And so many counterfeits on Ebay and Amazon. No way a genuine Delphi is $15 or $18 when the normally go for $75.
Not showing the actual box is a big clue it's fake. Decided on this Standard one for $33 that's also cheaper but looks like the seller bought and never used. Also has much better feedback and isn't selling thousands of parts.
Delphi EGR Valve EG10019 for Buick Oldsmobile Pontiac Chevrolet Skylark 89-92 | eBay
This item is designed to be an exact replacement that meets or exceeds original specifications. Please ensure correct part fitment before purchasing this product. Contact the seller directly for additional product information and availability.
www.ebay.com
Delphi EGR Valve EG10019 For Buick Chevrolet Oldsmobile Pontiac 1989-1992 | eBay
Delphi EG10019 OEM General Motors 17090078. EGR Valves. New in Delphi Box. BUICK CENTURY 1991-1992 L4-2.5L Egr Valve. BUICK SKYLARK 1989-1991 L4-2.5L Egr Valve. PONTIAC 6000 1991 L4-2.5L Egr Valve. PONTIAC GRAND AM 1989-1991 L4-2.5L Egr Valve.
www.ebay.com
Not showing the actual box is a big clue it's fake. Decided on this Standard one for $33 that's also cheaper but looks like the seller bought and never used. Also has much better feedback and isn't selling thousands of parts.
Standard Motor Products EGR Valve EGV381 for sale online | eBay
Find many great new & used options and get the best deals for Standard Motor Products EGR Valve EGV381 at the best online prices at eBay! Free shipping for many products!
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Not if it is a positive back pressure EGR valve. GM began using positive and negative back pressure EGR valves back when still using carburetors to control EGR flow. Does it have an N or P at the beginning or end of the part number on the top side of the valve?
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Negative backpressure, ruptured diaphragm as you already diagnosed. I believe some of the aftermarket replacements are serviced by non-backpressure units.
The one I ordered above, has the N.
Now since it's mounted on the intake manifold, and the exhaust manifold is on the other side of the engine, is there a passage inside the head between the two? If so, how to clean without taking the exhaust manifold off?
Now since it's mounted on the intake manifold, and the exhaust manifold is on the other side of the engine, is there a passage inside the head between the two? If so, how to clean without taking the exhaust manifold off?
Exhaust passage through the head, apparently. I've never had a Duke/Tech VI. A coat hanger and a vacuum if the ports are blocked. I've only seen them clog on the intake side myself.
Get a bike brake cable, they're like four bucks if you don't have a junk bike. Fray the end, put the other end in the drill. Don't laugh, it works wonderfully.
Stuff it in there, run the drill. With the valve removed, run the car. If you did what you meant to do, the exhaust will be loud and the idle will be high, or it will otherwise show signs of a vacuum leak. Any chunks of carbon you break loose won't hurt the motor, but if you're worried, stuff some tubing in the end of a shop vac, plug the rest of the hole with a rag and duct tape, and vacuum the stuff out.
NOOOOO. The engine wanted to run away like a diesel. It's a direct path for air into the intake. That's like have no throttle blade and flooring the accelerator. I shut it down quick.
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