Hello,

Several months ago, My truck was throwing a '43' fault code which is for the EGR system. A few weeks ago, I got around to putting in a new EGR Valve and cleared the code. Today ,after being fine for about three weeks, the dreaded check engine light came on and stored the '43' code again <img src="/forums/images/graemlins/angry.gif" alt="" />. What do I replace now? <img src="/forums/images/graemlins/confused.gif" alt="" />

Thanks in advance,

-Aaron
1995 SR V6 DOHC with all the factory toys!

I'm not familiar with the 95 EGR but on my 88 it's the passage way that gets clogged with soot.

This vehicle uses an EGR temperature sensor to report EGR flow to the ECU. First open the EGR at idle. (push up on diagphram with finger or use hand vacuum pump) If the passages are open, the engine will stall. Next go to EGR temperature sensor, (Just below EGR) Disconnect two wire connector. With the key on test the red and yellow wire for 5 volts and the black wire for a good ground. If ok, reconnect wires to sensor. warm up engine. While monitoring voltage at the red and yellow wire, rev up engine. The Egr should open and you should see a drop in voltage. Get back with the results and we can isolate the problem further if needed.
Conner

Conner,,
O.K. , I Didn't make it to step two of the test...Pushed the diaphram closed on the EGR valve and the engine had no response (it didn't stall) I can see the valve working when I rev the engine so I assume that everything else (temp sensor,etc) is working. I guess my 'passages are not open'. What Now ?? <img src="/forums/images/graemlins/confused.gif" alt="" /> Do I have to remove the upper intake plenum to clean these passages?

-thanks for the help.

Aaron
1995 SR V6 DOHC

That would be the most efficient way.
Conner

Yea- efficient, but is there any easier way to get to these passages (where are they and how do I get to them?) Can't I just spray throttle body cleaner onto the big hole that the EGR bolts to or will I catch my truck on fire!? I am just looking for any BTDT's for cleaning these passages on the 3.5L DOHC engine as I am not confident in removing the upper plenum. <img src="/forums/images/graemlins/scared.gif" alt="" />

-thanks
aaron

I dont think throttle body cleaner will cut the carbon. There are carbon buster chemicals out there but they may take time depending on the amount of blockage. I had success using an old speedometer cable in a drill to unblock a passage in a honda. But that sytem was blocked in one small area. If it was me i would do it right and make sure the carbon is all removed.
Good luck Conner

AFAIK (and based on the 3.0L), the only way to really clean it thoroughly is to remove the plenum, take off all associated hardware (including plugs) and use a strong solvent like Berryman B-12. After the inside is completely clean, flush it with plain water and let it dry before reassembly.

I don't know if you have an air valve in the plenum, but if you do the solvent may eat any plastic or rubber shaft bushings - so if there's anything assembled within the plenum it should probably be removed before using any solvent.

There may be better solvents, but from experience I know that Berryman B-12 will do the job - but it does take several cans (maybe 6) and you need to do the job in an open space - preferably outdoors - as the fumes are powerful and harmful to your health.

B-12

Good luck,
Frank

I need help. <img src="/forums/images/graemlins/scared.gif" alt="" /> I don't need to clean the passages throughly for now as my engine needs $5000 worth of work in the near future. At that time, the upper plenum can be throughly cleaned when my lower plenum gets replaced, my valve seals get replaced and my head gaskets get replaced. <img src="/forums/images/graemlins/barf.gif" alt="" /> For now, I just want the satanic EGR passage open!!!!! <img src="/forums/images/graemlins/evil.gif" alt="" /> I used 12 ga. wire, aircraft cable, coat hangers, and finally- a piece of speedometer cable attached to a drill at 3/4 speed and all of these go in 5-6 inches into the EGR passage and then stop cold. Certainly this carbon buildup can be "broken through" with a piece of cable traveling several hundred revs per sec.?!!!!!! <img src="/forums/images/graemlins/angry.gif" alt="" /> how big is this passage opening where it enters the hollowness of the upper plenum 'chamber'? Does the passage start out large at the EGR and get smaller as it goes toward the opposite opening? I need to know --Without removing the upper plenum- how to get thru the carbon buildup so that my EGR functions properly and my "43" fault code leaves me the heck alone!!

THANKS IN ADVANCE FOR ANY HELP/INFO THAT CAN BE OFFERED TO ME (other than removing the upper plenum)<img src="/forums/images/graemlins/patriot.gif" alt="" />

-aaron

p.s. I am very frustrated with this truck right now.Would compressed air blown into the passage clear it out??

I don't have a spare plenum to use to find out where the EGR ports run, but from memory I think it makes a loop inside the plenum and back around to the EGR valve with an internal passage. If my memory is correct you'll have a tough time trying to rod it out. Maybe someone else has a spare plenum and can check it for you.

If your engine needs $5000 worth of work, you need to send it to me for an overhaul. <img src="/forums/images/graemlins/lol.gif" alt="" /> That sounds quite high.

Frank