per Guide, vacuum gaugae between egr valve and egr modulator at normal operating temperature says it should be low vacuum at 2500 rpm,0 vacuum when it's below temp.

this seem to be the case for my 1995 camry manual trans. I connected R port of EGR modulator to the intake manifold and got high vacuum at 2500rpm

both seem to satisfy the Test and also confirm VSV is working.

Now what I am not sure is what vacuum should I get between EGR Valve and Modulator when I am running in the Freeway, 70mph at 2800rpm.. so far I am getting a steady vacuum of 1.5-2 in HG ,sometimes it jumps to 5inHg.

placed vacuum gauge between the modulator and VSV and I get 2inHg on the freeway and jumps to 5inHG but sometimes jumps to 10inHg..

at IDLE removed EGR Valve hose and connected to a vacuum gauge and as as raise the rpm, vacuum rises to up to 10inH without any problem- meaning VSV is also open.

BUT if I put the gauge between the hose and EGR using a 3-way connector, i only get 2inH at 2500rpm, again it satisfy the test.

1. does the vacuum at egr port really should be at 2inHg at normal operating procedure? or should be higher than that

2. not sure if EGR valve has a leak or very tight.

I guess I need to take it off the car and do some testing and check for clogs too but would like to know If I really need to if the tests indicates say it is ok.

reason am doing this is it failed the smog check and failed only for High Nox, rest of the tests passed.

1. EGR could be closed and not letting enough exhaust gas form entering but no Engine light.
2. mpg seem to be ok.

- I guess i need to make sure chamber does not have too much carbon coz it will make the engine hotter than usual. dont want to just change cat converter if it's not really the cause of high NOx.

did notced too spark plugs is whitish all around which indicates engine being hot? - timing checked ok but looks like still running lean?

will test EGR valve but hoping someone here has any insights if only NOx is high for the emission and every else is well within the limits...

I am about 200 above the Max of 450 i think. and thinking engine is just too hot.

thanks

 

What emissions spec was the car built to, California or Federal? There should be a sticker on the car, check under the hood.

High combustion temps can cause high N0x, check:
Coolant temp, dash gauge needle should be slightly below the mid mark.
Ign timing
Bad 02 sensor
Engine air intake system leaks, check hoses, etc.
EGR

A quick test of EGR valve function is to apply vacuum directly to the EGR valve to open it at engine idle. This should cause the engine to stumble or die.

The EGR is off at coolant temps below 140F, low engine load and idle, RPM above 4400 and deceleration.

The VSV is powered on/off by the computer (12v). When on it allows vacuum to go to the modulator from the throttle body. The modulator compares vacuum from two sources to control the position of the EGR valve. The EGR system may also have a exhaust temp sensor screwed into the EGR valve to signal the computer.

It does happen the EGR valve gas passages, tube, etc plugs up with carbon.

White plugs may not mean hot but normal.

 

EGR tests are all fine- my engine stumblied/die when i applied vacuum.
coolant temp is just below the mid mark- but i might need to drain and refill - CAN I do 60/40 ration instead of 50/50 to make engine cooler?
ignition timing is on the mark
O2- sensor? - downstream is pretty new- i might need to replace the upstream if it fails smog again
Air intake sysm are also fine.

Will go ahead and check egr system for carbon deposits
will have to disconnect VSV and test manually,even tho the vacuum test says it's ok.
Will Have to put the old TPS/IACV I replaced with a 96 camry TPS/IACV bec it was clogged before, 96 version looked the same but the hole where it closes and open is bigger than the 95 version by about ~50%

I guess the engine and combustion chamber had a lot of carbon deposits as I also see it on the engine oil cap... I am putting premium gas and lucas oil right now hoping to clean things up.

I also put marvel mystery oil to clean the engine but will have to change oil again before my next smog test.. BUT not sure if it's ok to mix the marvel mystery oil before smog bec label says it helps it keep engine form getting hot too....

I dont have performance issue,rough idle or hesitation,gas mileage drop or anything other than I do think engine is hotter since spark plug is white- from the tip to the edge of the thread- dont see it that way on all my previous cars-usually only the tip that extends on top of the Pt tip-the edge of the thread should still be the same color.

It's a very old car and when I bought it- the IACV was clogged and hoping putting the old IACV will bring down the NOx level then after the coolant change- will have another smog test see if it improves.

thanks for the response

 

my camry is a CA emission system.... and I am not how to see if the EGR temp sensor is working... I guss if not engine light evrything should be working fine regarding sensors.

 

Would look into any reasons for higher combustion temps.

What were the emissions test result readings for all gases tested?

EGR code trips if gas temp is 158F or below for 50 sec under the following conditions:
Engine coolant temp 176F or more
EGR operation is possible under the defined computer parameters

The EGR temp sensor can be tested by measuring the resistance as follows:
122F 64-97k ohm
212F 11-16K ohm
302F 2-4K ohm

You can heat the sensor by using oil in a heated container, use a cooking thermometer.

Check for plugged air filter on EGR modulator.

Check modulator.
Disconnect vacuum hoses on EGR from ports P,Q and R.
Block ports P and R.
Blow air into port Q and determine if air passes through the air filter side freely.
Operate engine at 2500 rpm and repeat test above. Check for strong air resistance.

When you ran your tests did you jump the TE1 and E1 terminals in the diagnostic box?

Check large engine air intake hose where it clamps to the throttle body, this area can crack completely around. Also check the area of the resonator can for leak.

For coolant temp, the radiator fans should start when temp is above 199F.

60/40 coolant is Ok but if coolant temps are not excessive this may not help. If changing coolant flush out the engine and radiator with a garden hose.

 

changed coolant
vsv working when 12v applied on the temrinal- air goes to the filter.
changed the vacuum hoses.
cleaned egr- found it to be clogged 80%

now the car idles high, 1200-1800, it fluctuates at first after starting but it's either 1200 or 1800..
i guess there's vacuum leak somewhere- i do hear a little hissing sound before and now i think it's a bit louder... no problem driving tho.- i had this high idle when i just bought the car and ithought the 96 version iacv fixed it- due to failed smog- tried putting the old part back and at least that one i got 1000-1100 idle, so i put back the 96 iacv back and now it's even higher idle.

i need to remove the TPS and adjust the iacv manually see if idle goes down. if it odes then iacv position is set at 50% open

since i dont have the idle screw- the computer sets the idle by controlling the idle speed.

is there a key combination to reset the TPS?- not sur eif it has that option as the new cars do.

ignition timing is at 10deg- but will check again after going home since i drove it on the freeway but idle still the same

I do hope the clogged EGR port will solve my smog issues.- will deal with the idle separately.

 

The clogged EGR may be the problem with N0x.

If not yet done so, reinstall the 95 IAC valve as the 96 is the wrong part for the 95. If dirty clean using a throttle body chemical cleaner safe for plastics.

Check IAC valve operation by applying 12v DC as follows:
Center terminal of IAC electrical plug is B+ (positive 12v)
Connect positive 12v to this terminal then negative to top of bottom terminal to move IAC valve air vane one way or the other.

There appears no way to drive the valve via the computer, etc using a connected diagnostic tool, etc.

Check ohm reading between B+ and upper and lower terminals, should be 19.3-22.3 ohms at 68F.

Once you find the air leak and install 95, IAC check IAC operation as follows:
With engine at operating temp, jump TE1 and E1 terminals in Diagnostic box.
Increase engine idle between 900-1300 rpm for 5 seconds and release throttle.
RPM should return to normal idle which is 750 +/- 50 engine hot.

If hearing hissing find the cause! An intake air leak can cause high idle AND high N0x. Use a section of hose as a stethoscope to narrow down the noise area.

Can also use an unlit propane torch, the gas will be sucked into the engine. Remove the electrical plug from the TPS to force computer in open loop mode when doing this check.

The computer sets the idle speed, the screw on the throttle body is for the throttle plate stop setting which does not need adjusting.

Timing seems OK.

Make sure the throttle plate opener dashpot rod is retracting. This is the small can near the throttle arm having a vacuum hose running to it. If not retracting will can cause high idle.

Check TPS setting by taking ohm readings at various set clearances between throttle throttle lever and throttle stop screw. Make sure throttle opener is retracked to allow throttle lever to seat on throttle stop screw.

0 in clearance. Ohm reading between terminals VTA-E2 = 0.2-5.7k ohm
0.020 in IDL-E2 2.3K ohm or less
0.028 in IDL-E2 infinity
Throttle valve full open VTA-E2 2.0-10.2K ohm

VC-E2 2.5-5.9K ohm

To adjust retract throttle opener:
Loosen screws on TPS
Insert 0.024 in gauge between stop and lever
and check ohm reading between IDL and E2.
Turn TPS CW until ohm meter deflects
Recheck continuity between IDL and E2 as follows:
0.020 in continuity
0.028 in No continuity

With TPS bolted to throttle body and mounting bolt flange of TPS oriented on the right and looking directly at the electrical terminals in plug. From top to bottom terminals are
VC, VTA, IDL, E2

Find air leak as this can cause higher N0x.

 

with the 96 IACV, idle settled donw at 1000-1100 rpm, dont know why, but i used it for two years and it was always at 800rpm- but anyways, put the 95 IACV and am back down to 800rpm. Vacuum while on the freeway between egr and vsv looked better now...
will run some lucas fuel system cleaner then go back for testing.

thanks for all the help.

 

Great!

Post back with the results of the smog test.

 

will post when i get the result- hopefully it passed, just that i cant still find an info about the vacuum between egr and vsv when it's running, I supposed it's going to be about 2inHg at 2500rpm for the camry? since that's the vacuum you looking at to test the vsv at 2500rpm?

if it opens at 2500rpm, smog test is at 15mph and 25mph, and saw last test was only 1200 and 1800 rpm at those speed, how is that supposed to work, am sure they know where to put the gear if it's manual transmission....

before cleaning egr, on freeway

between egr and vsv - steady at 2inHg with burst to 5inHg at times.
between modulator and vsv - 3inHg and burst up to 12inHg

after cleaning the egr- now vacuum matches the modulator and vsv result on the previous test- 3inHG and burst up to12inHg.

seems to accelerate better now also.. been reading a lot of mixed info regarding the usage of gas. Camry manual say 87 or up for 5sfe...

some say use premium before the test because it's cleaner, some say dont because it burns longer and will leave unburned fuel on the combustion chamber ,will make the temp hotter and overwork the cat and will give you high readings.

some say use lower octane because it burns faster and keeps the temperature down

i already used premium on the 2 previous gas fills so i decided to go in the middle, used 89 with the lucas fuel system cleaner. then I guess will go back to 87 before smog test because it will burn faster?

am only 200 above the max limit and hopefully this will do it... and be good for 2 years although am not sure if the car will last that long.