E.G.R.  Exhaust Gas Recirculation problems ? in the USA and Canada :          

A complex topic only, due to 11 years of evolution from crude vacuum magic, to simple single electric motor valve.
Getting Diagnostic Trouble Codes associated with this EGR system?
The only magic is in the modulator, and most respond well to cleaning!
Is the ECU throwing , DTC's  51? or P0400 ?  

If you drive a "SLICK KICK" , any JDM car , with  no EGR at all? :  hit the back button. :
Fails smog ?  Stalls at stop signs?  or engine won't start? Barfs DTC's for EGR?

This page is a generic overview of issues, the next link cover all exact systems used.
Go to my EGR year index,  far below now !

The GOAL?, is this EGR gas flow graphic. (NOX reduction and cooler exhaust valves)

Why EGR systems vary by year, and country, some countries, don't even have the EGR.

You can spend all week end ,cleaning it  , or do the 3 tests. "Stall : Bark : Live"!
Warning ! Do not use more that 5 foot/pounds  of reverse  force on the  2 EGR  main 6mm screws, or they will SNAP off. GO EASY HERE !
The Stall test means you made  it stall  or near stalls ,  With a  hot 800 RPM normal idle speed.  The strong engine can do 400 RPM and shake during test. (normal)
The Bark test is starting a engine with the EGR tube or valve removed, to see if the ports there bark, if not, they are plugged up. Path blockages.
The bark check needs to be done 2 ways, on at the top EGR main large hose, (off) and with the EGR removed.
None of the tests are 100% definitive, some say, sure  but, gee, if both tests fail , that is in fact  a hard failure.
Mostly, the 2 tests passing does not prove the 4 quad ports are clear, in the inake manifold. 
The early MPI engines ,the 4 quad port intake manifold, has test, but if the ' test passes and the EGR main if working, (opens) then the stall test fail ,proves
that 4 ports are clogged, 1 to all 4.  (no matter if the stall test fails, here, the intake needs to come off to clean those pesky, EGR tiny ports. x4.)
The tests are: (A fast review):  (there are many tests, not just this short list)
  • STALL TEST (use a hand vacuum tool to do easy and safely)
  • BARK TEST 1 (Hose of bark at hose end)
  • BARK TEST 2, (EGR main removed and cleaned and Main tested by hand fully)
  • No vacuum sucking, engine cranked at the EGR vacuum port, proves that path clogged.
  • Live test passes, ( many still fail on quad port intake manifold) On newer cars, the speedo must show above 0 MPH to activate the Live test and no at idle.
  • The EGR thermal probe usually works, if you just clean off the tip at bark test 2.  The newer MPI engine has a EGR MAP, just clean its vacuum port)
  • Usually the stall test passing and live passing on a monoport system , cures P0400/51 DTC's
  • The monoport system has a SST side tube on plenum right side you can do a stall bark test here, with it disconnected, end to end. then clean the monoport easy.
  • The monoport is superior ! (easy to prove bad, 10x easier to clean)
Keep in mind , the total restrictions end to end must not be less than  9-11 mm. (if it is?, it needs cleaning)

Basic facts about the system:
Folks come here for 4 reasons. (not to mention, EGR cracked or base gasket bad and sucking fresh air like mad!)
  • It fails via the DTC stated above, or the engines stalls.
  • You need to pass a smog test.  40% of USA cars need to.
  • You want it to work right, so the exhaust valves run, nice and cool and last for 100k + miles.
  • That CEL glowing all the time drives, me nuts, and I always wonder what other DTCs are hiding , under the 51s,  (PITA factor?)

Some nice examples:  Hand vacuum pump is best, no burns. But you can use soft wood stick, to push the diaphram ring.
On early cars pre-1996, the live test is easy.  Hot engine, gun the throttle, and see the EGR diaphram move, no need for car moving.
In 1996, you have to be above say 2 MPH to get EGR action.
Here is one man, doing the stall test (8v) in a new video.

A fast Review of all years:
  1. The 16valve MPI  quad port intake manifold EGR system was phased out in  mid 1995.
  2. These Old intake MAN'S were phased out  VIN S640124~ or VIN S4102048~ (S=1995) !
  3. Different factories, used different years to phase out. quad port 16 intake manifolds.
  4. The new 1995.5 Intakes are now a mono port EGR injected, at the rear of the Throttlebody until 1998.
  5. Do not mix California EGR parts (and ECU's ) with the Federal parts. (or get code 53 or 51)
  6. The EGR valve,  only lowers the NOX pollution by 1/2 the TWC gets the remainder,  for your Smog, failing cars.
  7. The EGR tests can fail, even though it is perfect,  (lean running, or any air leaks to the plenum can cause the EGR tests to fail)
  8. The EGRT (thermoprobe years) do not use vacuum readings to do tests, the ECU, Just looks 1 time, to see of the probe gets hot.
  9. If the EFI won't hold closed loop at idle and light cruise then , or run rich , the EGR pathes, will pack in carbon again, fast.
  10. Any part can fail or clog, end to end. Some do carbon packup 100 % end to end.
  11. If the EGR thermo probe (Calif, style) wire fell off , it you will get 53  or 51 DTC EGR failures. Same with mixing Calif and FED,  ECU's.
  12. If the CAT is missing the EGR modulator will be dead, (stuck open,sucking air) and EGR dead totally.
  13. if the EGR modulator , air vent is blocked, the modulator will over flow (excess) exhaust and cause hesitations accelerating.  Easy to clean it.
  14. Excess EGR flow, results in very bad combustion.

end review, now specific generators  of EGR:

The USA generations of EGR are here, with full testing for each.
Pick one?:
   All years below:
       Have a Missing Catalyst Converter? (or rodded out, broken out, etc)?  This will cause 89-98 EGR modulator valve to fail. (all years 89-98, 1.6L and lower)

Keep in mind, The many tests, and some very simple time saving logic. (not applicable to GEN 4,Suzuki Sports , for gen4 just clean it)
In each generation, there are 2 holes under the EGR main the bark hole, and the vacuum suck hole. (MPI , is the engine side left hole)
The barking can be called the Putt Putt holes or pathes. It happens engine cracked or running.
This is just a review below see your generation EGR above for details.
  • Do the STALL test !  Do it only, on a HOT engine, that means 180F + coolant temp. and 800 RPM idle. (stalls or nearly so..)
  • If the stall test fails,  make sure the EGR main, is not packed in carbon or jammed,   then  do the bark test , while main is removed.
  • You pull the EGR main to mod valve rubber hose and it must bark. If not it is clogged., so next remove the main.
  • The main is off, make sure the bark nipple is clean. The diaphram is not cracked (vacuuum leak down test) and the main valve is not jammed up.
  • While cleaning the EGR main, make  sure (Calif. style) the EGR thermoprobe device"EGRT", is not packed full of carbon (heat insulated, with carbon)
  • Do the bark test 2, main off (vacuum port plugged with a cork. The exhuast port must bark loadly.
  • If the bark test fails now, the Exhaust port #4  , head tunnel or the "S" bend turn in the intake  is packed. (3 places to clog. S bend, head tunnel and exhaust port 4.)
  • If the bark passes, but the stall still fails (good EGR main, cleaned and tested) then the EGR Main output side path (vacuum) is blocked (intake manifold, paths)
  • If the bark passes and the stall  test passes , then do the live test.
  • And more see your generation links above.
If the car stalls at stop lights it might be  the EGR main is sticking !!! Clean the EGR-MAIN valve.

My Advance EGR modulator testing page, for all Kicks, 89-98 1.6L . 

History and other, complex issues , and facts:

How to Clean the EGR main.
Warning ! do not use more that 5 foot/pounds of reverse  force on the EGR 6mm screws, or they will SNAP off. GO EASY HERE !
Spec. is 89 inch/ pounds (7foot/lbs) but after 20 years of no service, I'd not go past 5 foot/lbs torque removing it.  
Use lots of penetrating oil, even over night soaks. And jog the bolt head, CCW ,the CW, back and forth (jog)  to get it free.
Use heat on this 6mm bolt, if you can't get it loose. (propane torch: get screw real hot, then turn , or jog it.)

There are 5 systems used, 89 to now. History...

  1. Calif EGRT EGR. (thermoprobe sensor based)  89-95'.  (code 51)
  2. The Federal cars, adopted this Calif EGRT in 1994 years.  (DTC code 51)
  3. In 1995.5 Suzuki junked the 4 EGR injector intake manifold and created the Mono-port EGR , with SST side winder tube , seen on all 1996 to 98'
  4. IN 1996, the EGRT is dropped, and a new EGR MAP sensor   is added. First year of DTC P0400s, too.
  5. In 1999 , the whole system is junked, and a simple electric motor EGR is used, ( and on all 1.8L engines (or bigger) made 1996+ seen in the Suzuki  Sport model.)

The secret rules for the EGRT thermoprobe device, are here. (introduced on California cars only in 1989)

A stuck open EGR can wreck hot idle, speeds, not 800 RPM Hot but 400.  And shakes like a wet dog , hot. Hot means Coolant at 180F+
The EGR Main can leak exhaust or air, the gasket can suck air or the casing can crack and suck air, and this causes idle controls,  to fail too.
The 1995.5 and newer the side winder tube can have missing SST gaskets and this will suck air, and make the engine run lean and slow idle. (or surging)
Why EGR:?
The EGR cools the exhaust valves , They last LONGER those  valves. ! but cleaning it is a royal PITA. (a love /hate deal)
This Smog device, reduces Nitrous Oxides (NOX) and the resultant acid rain and river pollution. (bla-bla....)

Getting Error Code 51 or P0400's DTC 

 (A bad idle can also be bad TPS idle switch bad, or sticky ISC)

Do not touch the casing of a hot EGR or its piping, please, don't get burned or caught in the fan blades or belts of the motor.

If these concepts , make  no sense to you, then read this first.

Some years, pre 92' and some Canadian cars have no code 51 EGR tests at all..  and will not fail 51s ever.
Those cars, you will not notice a stuck closed EGR, but stuck open , this will stall the engine.
When I say stall this means , stall or near stall at  400 RPM, an strong motor can run real  slow, so ' a GOOD SIGN that it can.

Some "JDM" cars, have no EGR at ALL!  (< see the CarbonMonoxide "CO" adjuster here, on those cars. Not used in USA at all.!)
Nor 02 sensor at all, No Cat converter either.
Look for them, and see unique p/n on ECU.?

See Duanes VIDEOS !

#1 Public Offender the EGR main valve. Bench cleaning and testing!


The EGRT is expensive,  and so is the main valve  about $300 a set.  But is easy to clean that probe, see it? and the most easy to test.
The sensor reads   near 10,000 hot and about 250,000 ohms cold (un-plugged)
Just open the main valve any way you can (hand vacuum) on a hot 800 RPM idling engine, and see the ohms drop to 10k range.
That means it works.
Removing the probe from the body , can break  it, so try to clean it , in place,
It is just  a classic NTC Thermistor sensor .  It is very crud  and is not calibrated, its just shows, yes, I'm hot now,  not an exact temp.
See that nipple above in the main vavle (goes to MOD) @5pm, it too must  bark running, or its clogged, somewhere.

Before starting you need a digital multi meter and a Vacuum hand pump.
Carb / induction / MAF  cleaner in a spray can.
These Items are Critical to all DIY repairs on all cars and trucks.

Jargon? Unclear ?  :

Rev: 10  major edits,  3-28-2013