Re: egr valve- - mine sticks open under load so i disabled it.what long-term effects???

I don't know about that engine, but some GMs have the ignition spark advance set assuming there will be EGR flow when warm. If there isn't, you may get problems with knocking (or if it has a knock sensor, it will just be making the ECM retard the spark timing all the time).

Reply to
Robert Hancock
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I think this is 100% to do with the hotter combustion chamber temps.

Reply to
Clem

A typical vacuum operated EGR valve is opened by directing ported intake manifold vacuum through a thermovacuum valve (to prevent operation until the engine is warmed up) to the EGR valve. This vacuum is identical to manifold vacuum, except it is 0 at idle. This vacuum signal is strongest at lighter loads and falls off to essentially 0 at WOT. So, it would be incorrect to think of it as opening under a heavy load. More modern versions of the above would use a solenoid controlled by the Powertrain Control module to modulate the vacuum to the valve and in that case direct manifold vacuum would normally be used and no thermovacuum valve is needed. Control of the EGR valve is almost always the same:

OFF when cold OFF at idle OFF at WOT Modulation inversely proportional to engine load

Reply to
saeengineer

I've been watching this thread because my "new" $100 car has been throwing the codes for a faulty EGR valve (don't recall them at the moment). The new $100 car is an 87 Grand Am with the 3.0 in it.

I've seen mention of a way to clean them. Is there a web site describing the process? Or can anyone here explain it for me? Thanks,

Chris

Reply to
scooter

Why even worry? For $100 if you only et to drive it for a month you will be ahead. ;)

mike hunt

scooter wrote:

Reply to
BenDover

LOL

The body on it is in such good shape that I've decided to keep it running for a while. It had a bad motor in it when I got it & I found a decent motor on ebay cheap. If it's still in decent shape by the time my 14yr old son gets his license, it may go to him. That and it's a heck of a lot easier on gas than my van.

Reply to
scooter

There is no code for an EGR valve fault.

describing

Buy a new valve gasket and high temp gasket sealer.

Remove the EGR valve

Some deposits can be cleaned/loosened with carb cleaner

Clean the passages with a drill bit, being very careful not to enlarge the passages.

Coat the gasket with sealer

Reinstall EGR valve and torque bolts to spec

Reply to
saeengineer

Where did you get that information?

The vehicle in question is an 87 Grand Am which outputs 2 digit trouble codes. The only GM vehicles of that era which used 3 digit codes were Cadillacs.

=46ive digit OBD II codes of that range are for Knock Sensor or CKP.

Reply to
saeengineer

No problem Andrew.

=46ord codes 326 - 337 indicate EGR (EPT or EVR) CIRCUIT problems. These do not necessarily indicate a fault with the EGR VALVE.

P1408's proper Title is, "EGR Flow out of Self-Test Range." Again this would point to a check of the DPF(E), EVR, or harness circuit.

The only code I am aware of that points directly to an EGR Valve fault is Ford P14077 - No EGR Flow - Valve Stuck Closed or Faulty. This code is only set during a Ford KOER test.

The remark I made was directed at the 87 Grand Am, and I still stand by it.

Reply to
saeengineer

I don't think there's anything special about cleaning the egr valve.

The gunk is a bit tougher and might actually need to be scraped, which is not possible in some areas on the valve assembly. I believe that's why it's usually not recommended to clean it.

Try not to get solvent on the flexible membranes (that pull the valve open when vacuum is applied). Test to be sure the membrane is not leaking air, and give 'er hell with the solvent of your choice.

My new favorite: $0.78 per can carb cleaner from Wal-mart.

It's fun to learn about how the thing works (simple really for the price they expect). It might help for a while. If not, you're out 78 cents and the cost of a gasket.

Reply to
Clem

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