A 1990s Automobile Without An EGR Valve?

[TallPaul]

My wife's '92 Aerostar 3.0 has no EGR valve. The mechanic saw a metal plate blocking the opening where the EGR typically would mount. They did not see any hoses for it to be mounted off the engine either. They called the dealership parts department and were told there is no EGR listing for this van. This puzzles me as I thought and EGR valve was an essential piece of anti-pollution equipment, like catalytic converters and lead free fuel. What gives?

 

[55Test]

My 1990 Cutlass Ciera wagon doesn't have an EGR valve either.

 

[eljefino]

You can also cut NOX with valve overlap or a 3-way catalyst.

As a truck, the aerostar gets more lenient regs too.

Sometimes you'll find an automatic tranny without EGR and a stick shift with one... since one could in theory lug the stick shift car to a point where an automatic would have downshifted. Lugging= NOX.

 

[Drew99GT]

My 94 Corolla doesn't have one.

 

[brianl703]

The 91-93 49-state Ford Escort/Mercury Tracer doesn't either but it still has the connectors for the EGR solenoid and the sensor, leading me to wonder if someone had stripped all of the EGR components off of it. At least until I thought about it and realized that the computer would be giving a code and a light because of the missing components..

 

[Kestas]

My 91 Mercury Tracer 1.9L had an egr valve. It gave me problems which I diagnosed and I ended up blocking the passage.

 

[punisher]

Late 80s to early 90s Ford 3.0s did not have an EGR valve, except for California emissions.

Your underhood sticker will tell you what is what as far as emissions info is concerned.

 

[TomH]

I used to own a 92 Suzuki Swift GT (1.3L DOHC 4cyl). No EGR valve on that one either.

 

[T-Keith]

GM 3800s in the mid 90s did not have an EGR valve.

-T

 

[Chris142]

I don't think the 4.0 Jeep has one. My 02 does not.

 

[Ryan00TJ]

My Jeep 2.5L does not have one nor my 2002 LS1 V8. Like was stated before in 2001 Chevrolet changed the cam in the LS1 and the valve timing did not require an EGR valve. Earlier 97-00 models had an EGR valve.

 

[Sparkman]

quote:

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Originally posted by eljefino:
Sometimes you'll find an automatic tranny without EGR and a stick shift with one... since one could in theory lug the stick shift car to a point where an automatic would have downshifted. Lugging= NOX.

---

I do have some specific knowledge in this area. The '95 Subaru Legacy 2.2l engine from a manual tranny vehicle doesn't have EGR, the auto tranny car does have EGR. I know this because a friend and I recently hunted high and low for a 2.2 to swap into his wife's '99 Outback, the engine needed EGR to prevent trouble codes.

 

[Gary Allan]

Yep, like Ryan ..both my jeeps just use cam overlap and ignition timeing to leave enough spent combustion material around to cool the next combustion cycle. It's the same with my 3.0 Mitsu.

 

[TallPaul]

Well now I know.

Strange how we make assumptions based on little fact (or a small and very biased dataset) and internalize them to the point that we believe them and are stunned when they are shown to be wrong.

 

[MNgopher]

1991 and later Jeep 4.0L inline sizes have no EGR valve.

1987-90 4.0l engines in the Cherokee / Comanche do have an EGR valve though.

 

[OdinsRage]

01-02 f-bodies, no EGR

My 96 vette with LT4 engine, no EGR (only LT4 got NO egr, the Lt1's had it)

 

[NJC]

quote:

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Originally posted by TallPaul:
This puzzles me as I thought and EGR valve was an essential piece of anti-pollution equipment, like catalytic converters and lead free fuel. What gives?

---

My '84 Accord has no cat or EGR - but tests with ~2500ppm NOx

No EGR on the '89 Volvo either but last emissions test a few months back rendered
It seems to me if the automotive engineers can manage low enough combustion temps without having to pump inert exhaust gas back in, this would raise the efficiency. Not sure though.

 

[Jimbo]

True. The NOx problem only surfaced after engineers in the 1960's tried to lower CO and unburned hydrocarbon emissions by raising combustion temps running as close to perfect air:fuel ratio possible with a carburator. Unfortunately, you get lean misfire on some cylinders with a carb due to uneven fuel distribution and poor atomization, so they were jetted just slightly rich of peak, the highest temperature point.

EGR and/or retarded spark timing were the early solutions. Modern multiport EFI systems combined with high energy igintions can run lean-of-peak, lowering combustion temperatures without misfire. Reduction cats clean up the small amount of NOx that is still there.

 

[NJC]

Really? Wouldn't slightly rich be preferable?

This would lower NOx plus be a lot easier on the engine. I think I've seen a dyno graph with associated stoich but I can't recall where it was to 14.7:1 - I think it was rich as the power curve went along.

 

[The Critic]

IIRC, the 4-cyl Ecotecs on the GMs don't have one either.

Mike