Hi Everyone, OK, I've taken off the EGR, as finally 'fingered' by code 39. It's 'carboned up', which I'm hoping is why it did so badly in the smog test. Please tell me how it should be cleaned. Thank you....Roger.

 

Roger,
Sorry, no. I've never done it. I'd prepare myself, however, for the possibility that a clean EGR might not eliminate the code. I hope and am optimistic it will - and it's a good idea in any event. But, several things can trip that one as I recall. I think I got rid of mine last year by replacing the solenoid!
Cheers,
Scott

 

Carb cleaner spray will do the job. Wear gloves, the stuff is nasty.

 

Thanks a lot, Scott and Mike.. Scott, which solenoid did you replace, by that I meant where is it ?.....Roger.

 

Roger:
The EGR vacuum solenoid toward the LH side rear of the engine. See page 6-11 of the Haynes manual if you've got it.

Cheers!
Scott

 

Thanks Scott, Yup, I have the Haynes I'll go take a look.. Thanks again.....Roger.

 

Hi Scott, I shoulda looked under the bonnet before bothering you with, what I now see was a stupid question. It was staring me in the face ! Thanks again......Roger.

 

Roger,
...didn't somebody say there is no such thing as a stupid question?! Anyway, the 'easier' ones are the only questions I have any shot of being able to answer.

Cheers,
Scott

 

Scott, I started her, pulled off the vac line to the EGR valve, there was no discernible difference in engine speed or note. Where should I go from here ? Help please......Roger.

 

Roger,
Did cleaning the EGR not clear the code?

When my solenoid was bad, the car ran almost perfectly. It chugged a couple of times and stalled out on me once. But otherwise, it was running pretty normally - normally enough that my mechanic didn't think it was bad. But we couldn't get that code to clear. I figured I'd replace it anyway just to be sure. (Expensive gamble, though, because those things are like 90 bucks!) Anyway, it worked.

There is a twin solenoid as part of another system on the engine - toward the front - but I cannot remember its function off hand. It may be possible to swap it out to 'test' whether it clears the code or not.

Scott

 

EGR Code 39 means the ECU did not see the temperature sensor signal rise when it tried to open the EGR valve. That could be for several reasons. Most likely the EGR passage at the bottom of the intake manifold is coked up [carboned up]. There is a temp sensor in the passage that gets warmed when the exhaust is allowed to flow. Quickest test is to put gloves on or use a couple of rags for protection, then cup both hands around the EGR valve and with your fingers push up on the EGR diaphragm while the engine is running. If the passage is open, opening the valve will almost stall the engine. If nothing happens, the passage is plugged up and will have to be taken apart and cleaned. If it passes that test then there is either a failed EGR Valve, failed solenoid or no vacuum supply to the solenoid.

BTW, the EGR Valve can't be tested except while on the running engine. Using a vacumm pump to test will not open the valve because it has to have the exhaust backpressure to close an internal check valve and allow vacuum to open it.

Good luck!

 

Thanks Scott and Steve, I 'tested' the EGR valve, when I had it off for cleaning, by sucking on a line I'd attached to it and watching it rise. Does not this mean that this part is working correctly ?.........Roger.

 

The way I test the EGR valve is to have someone touch the valve diaphragm from underneath and have another person rev the engine with the car in DRIVE with the brakes ON REALLY HARD!!!!!!!!!!!!!

The ECM will only activate the EGR with the trans in gear.
The EGR should react and move the diaphragm with the engine revs above IDLE.

Another way is to attach a gauge to the vacuum hose and do the same thing to see an indication of the change in pressure.

A rise in VACUUM (oxymoron) will indicate that the solenoid is operating properly.

The EGR TEMP SENSOR is in the intake manifold and has to SEE a rise in TEMP from the HOT gasses striking the sensor.

If the sensor does NOT see the temp increase,then it flags a fault.

You can remove the IACV to access the passage to the EGR TEMP SENSOR from the top (straight DOWN) to GENTLY remove the carbon from the EGR passage with a drill bit. Sometimes this works if you can clean enough CRAP from the passage to get the gas flow to contact the temp sensor!!!!!!!!!!!!!!!!!!!

The best way to clean it is to remove the oil filter and pull the plate that holds the temp sensor along with the hex nut connecting the EGR pipe to the exhaust manifold.
Clean everything and reinstall.

bob gauff

 

Thanks Bob, I'll see what I can do, per your instructions, next week. One thing though, when I start her up and she's idling, disconnecting the vacuum line to the EGR makes no difference to engine speed or tone. Is it because the engine is cold, should I let it warm up first ?......Roger.

 

The EGR DOES NOT operate at idle.

bob gauff

 

Actually, a properly functioning EGR valve will not open with vacuum applied unless it is on a running engine. They are "negative backpressure" valves, with an internal vent valve that is closed by the pressure of the exhaust, allowing the vacuum to pull the valve open.

Cheers,

 

Thanks Bob and Steve, I'll give your suggestions a try, when I can get another pair of hands on it. The wife's broken her ankle, so things are a trifle tricky at present......Roger.

 

I've heard some people have eliminated the EGR. is this possible?

 

I have been driving around the past two and a half years with no EGR. First my valve was bad, then the solenoid. My inlet under the intake was so carboned up it was very clean cut and hard at the top with a 1/8th inch hole. Looked so good and the EGR valve still made the engine sputter a bit so I thought that was how it was supposed to look. So I replaced the temp sensor too.

Today I just got done expanding that 1/8th inch hole to something more like 3/8th - 1/2" after the hole plugged completely; EGR works much better now.

Getting to the jist...

From what I have seen the default ECU action for EGR system fault is "Disabled EGR." AFAIK there is no way to fool the ECU not to throw the fault like you can with the air pump. With that said my car does seem to run better when it is not throwing the code (could be placebo). EGR makes the engine run cooler and have less emissions during cruise. Why would you want it disabled?

 

I figured the smog/EGR robbed power. Is this not true? I should say this also. The car I have has a smog pump, but not belted, so not working. Cant find a belt listed for it anyway. How can I seal off the smog hoses and is there any vacum problems with this?