Cleaning and bench testing EGR MAIN    

Calif style EGR above 1995         and the back side, showing the carbon packing.       and view 3 the back side.
This part is the rear of the intake manifold on all 16v engines and on the right side of the 8v engines, in full casual view.  On 16v Kicks, use wifes hand mirror to view this part way in back of engine.
You are here because the stall test failed.  or code 51 (P0400 ) DTC Failures.

Typical EGR main valve. 1.6L (see end for 1.8L and newer cars)  The grunt work of EGR repair.
The below photo does not show the Thermoproble.  But is there on all CALIFORNIA  many a Sidekick or Trackers.  (some non USA cars don't even have EGR AT ALL, some  JDM cars don't)
(this is part of the 50k mile service in all Suzuki and Gm books under scheduled Service.
The main can fail in many ways:  (If you do not know how to inspect this device or test it, just buy a new one at Rockauto.com $110 (about)

  • Stuck open (or 1/2 way open ,etc) (motor stalls , as a result , all Suzuki's EGR love to do this just as the ECU, commands the valve closed as you slow to a stop at any stop sign. "a classic EGR failure"
  • Stuck closed   ECU reports DTC 51 or (400) total EGR failure and fails smog test for NOX.
  • Diaphragm cracked (fails the cleak down test,  8 inches HG, for 30seconds, must not leak (a standard test in all automotive repair  books ever  published)
  • Spring bad (rusted to nothing?)
  • Main shaft inside damaged, worn, galled, binding, etc.
  • Bad or damaged valve seat. (won't seal closed  with you blowing on it with lips, yes, it's leaking darn.
  • Cracked housing
  • Missing gasket at base or leaking air into the induction system.
  • Fails to return closed 1 out of 10 times, (a classic failure) sticky piston rod, most can be cured with lots of carefull cleaning of this shaft.

I get the DTC or Stalls at any stop signal driving.  I CLEAN IT, especially if the stalls are random and I do BOTH valves.

Click it to zoom. This the MAIN.  It must operate smoothly and not stick open or closed.
Stuck Closed will trip a DTC 51 (or 0400), open will cause, stalls. It must close with a sharp, Thunk sound.
It moves (see arrow Small spring , this moves)  about 1/4" or 7mm by hand flexing the center diaprham piece.
If your finger is too large, for the skeleton holes?, take off the valve and do all the checks and cleaning on a bench. (on car use hand miror to see the Ring device)
On the right photo below, is the view showing factory stock skeleton holes (rim, slots) see them? See the metal base ring, in the inboard side of the diaphram?  you flex that ring ! to do any stall test. and to check if the valve not jamming up.



VIDEOs  (I can not find a very good video, just on cleaning the valve or how to test it.)
This  video Joe DIY EGR cleaning,.
His Q-tips are silly IMO, don't use them they are too weak  and leave cotton contamination behind..

The next video shows excellent procedures.
One more Utube vid, a pro at work

You are first cleaning the EGR, because this test below failed.
See 8v Sidekick nearly stall using a had vacuum tool to pump the diaphragm back and nearly stalls motor (good test)
https://www.youtube.com/watch?v=UPO7B7yH43w


There are 3 or 4 off car tests and 2 on car, the below are bench tests only, hit Home above for other tests.

OFF OFF CAR testing. 
(two  6mm screws, it's off 10mm hex heads) do not force them, 7ft/lbs max CCW, use lots of Penetrating oil and jog the screw to get it loose.
Use Antiseize lube on both screw treades for life time of trouble free service.


The Diagphram leak down test.  #1 tests,  if this is a failure , all is lost.
Using a vacuum hand pump  "Mityvac or HF clone" make sure the diaphram don't leak down for 30-60seconds. wihttp://t3.gstatic.com/images?q=tbn:ANd9GcQ8siSH3yx9Pj093U3mQpIx4gGG0x6mHC4Ap-yQx4vr0AJoswBAth 8 inches of vacuum. applied.
If it leaks down , it is trash.  (cracked diaphragms are an end  of life issue)
Second , we do the "Oh my,  it's just crap test"  "careful physical examination takes time"
EGR main inspections and testing. off car.
  1.  Look at the EGR main, it has split open the casing? , cracked? , smashed ?, or is diaphram busted or torn,  yes?, then trash it.
  2. The leak down test is next, if bad trash it,  EGR main.
  3. Are  the ports fully packed with carbon? clean it out with a 16 penny nail or other sharp object.  "ice pick"? (very common and most can be cleaned)
  4. The MODulator  nipple, in  above photo ,can fill with carbon, clean it out. so it flows air to port 2 at all times.  (this is just a free path port to #4 exhaust header) I uses bailing wire to jab in, and clean it.
  5. Flex the Diaphram washer at its base  (ours is skeleton-iszed !) , push up , using above diagram as guide of up. If you  can't move it or it sticks and cleaning won't allow it to move, it's trash. (or clean it over and over till it does work right)
  6. At this point the EGR might be servicable. (after cleaning and the piston moves easy and snap back closed fully with a loud thunk each time)
  7. Use a vacuum tool and pull 8inches vacuum on the nipple, can you suck back the piston and valve and the release the vacuum and it returns closed all by its self?  do so 5 times.  if it does that , the EGR main is ready for service (hope)

I clean it until:
I can move the piston 1/4" of an inch ( about 6mm)  by pushing the diaphram by hand,  from its stop.  On CAR, the  16v cars are hard to reach, the EGR main. use hand miror to find the slots.
It ,the piston, MUST snap back with a snappy clunk. If not, the seat is jammed with carbon or the piston bushings are coked up (dirty)

Make sure the PUTT PUTT tube  (my slang) to MODULATOR  (a bent tube)  is clear, if not,  clean it out fully. (on car pull this rubber tube here, and hear the putt putt sound idling), if not?, its bad.
More tests:
Blow testing it:
Blocking the Moduator tube is the first step here. Duct tape anyone, or?  Just plug it somehow for this test.
Next, I blow in to the 2/3  ports on the dirty side. and make sure I can't blow in any direction the path  2 or 3 above.
If I can blow through it, , it's trash time.  ( leaks here, make  the engine, idle way too slow and horrid misfire and shaking of motor below 800 RPM ) The EGR is commanded closed at idle.
If I don't want to kiss my EGR (blow testing) , then trash it, or use rubber tubes (virgin hoses) for your lips to EGR interface. (you can buy hose and rubber hose cone adaptors to make up a lips free, blow test kit)
Apply vacuum to nipple 4 and the valve must flow air, as you blown on port 2 or 3.
if not? free flowing,  its clogged then clean it. or trash it. Clean repeat, test, until this flow test passes.

Once this far you can put it back on the car with a new gasket 99cents at Felpro,  and do the STALL test.  ROCKauto.com has EGR MAINS , for about $110.00
end : 1.6L, G16 engines.
DOHC cars.  ( I have more books now on
The 1.8L  J18 and J20 (and newer cars) My 04 v6 has this same type part except it has a 90 degree mount. ( and very hard to remove)
Can be disassembled and cleaned. It sure CAN and is easier to flex the spring , see it?
See it here. top removed?  clean it out  With CARB CLEANER,  Clean it like you want to eat off it.  After all you are kissing it , LOL !!!


Some Suzuki's, not all, one can turn the ignition key from off to IGNition ON and Some ECU's will reset or cycle the EGR during boot up.
My Suzuki  1800 Suppliment  J18 motor ,says page 6-97 says, EGR will cycle for 0.6 seconds, each key on.  (for the guy who told me that is not true, there is the proof)
This Trick  can be used to test the valve for cycling or post cleaning checks.  I use split popcicle sticks to help clean it. Or womens cuticle sticks !!!
The last and for sure test is the live test with rear wheels rolling.  EGR will operate moving and a HOT motor. Click  HOME above for details.

Drawing 2: click it, to see fully assembled form!
Below photo shows, the stepper motor removed. Doing so makes it easier to clean,  because you can flex it easy.



Old school Suzuki parts 90-98  1.6L




rev 1   ++++ 9-6-2010