Failed 'functional' Ca. emission test (EGR) ??? - Page 5

Nathan_Rd · 04-25-03, 12:02 AM

Did you mean it stumbled while you're actually DRIVING the car or while you were revving the motor in Neutral?

theGodfather · 04-25-03, 12:28 AM

It stumbled on IDLE when I applied vacuum to OPEN the EGR valve. Sometimes it stumbled, sometimes it completely stalled which is perfectly normal behaviour for an operational EGR system.

G

Nathan_Rd · 04-25-03, 03:53 AM

Well see if you can get a reading on the vac gauge while driving the car. T in that gauge and go for a drive with the gauge duct-taped to the windshield. If it shows 0" of vacuum while you doing 15-25mph then that explains the NOx problem.

theGodfather · 04-25-03, 07:14 PM

Nathan, you are pretty much on the right track.

Today I ran the car on the dyno again and cleaning the fuel injectors made absolutely no difference to emissions.

We took the cover off the EGR controlling components and started checking vacuum levels and making the car stall. Everything seemed to work fine except when having the vacuum gauge atatched to the hose that controls the EGR valve, on reving the engine we get 8-9 in of vacuum for 2 seconds and then it drops. I always thought this was fine that the valve will open adn close depending on load and RPM.

My mechanic put the car on the dyno to do a 26mph run and he put a T-connector to get a gauge in there. Under load the EGR system will apply 9in of vacuum to the vavle for 2 seconds and then drop to no vacuum. Only way to get it back is to put it into neutral and rev it back into gear and it will repeat the same thing.

The system is not holding the vacuum. He said the EGR valve should be open during the entire time the car is running 26mph in 3rd gear (about 2600RPM).

He ran a test with the EGR valve about 40% open the entire time (using hte vacuum pump bypassing hte control system) and NOx levels dropped to 28 PPM!!!!

However both CO and HC were way over the limit! (car was running too rich.. probably because the ECU had no idea the EGR valve was open like that so it wasn't able to compensate with fuel).

Checked the voltage on the EGR valve position sensor and the voltage is within spec (1.2V when closed... around 4.6V when open).

Shop had to close up by this point so the mechanic will continue to work on this on Monday. He has no clue exactly what is causing it to drop vacuum. There are no leaks with the hoses.

BTW.. how do you test whether a knock sensor is working properly? He took the resistance reading of the two knock sensors and found two different readings. If no ECU light is on, is it safe to asume the knock snesors are working? What test can I do to them? My manual does not specify any specific resistance range they should be in like how O2 sensors have to be between 10-20 Ohms.

G

Merlin the Wrench · 04-25-03, 11:43 PM

according to the Chilton book, there is a solenoid that controls vacuum to the EGR valve.

That can be tested by disconnecting the wires and applying 12v+ to where the blk/yel attached "A" , and vehicle ground to where the white wire was "B". Book says that the blk/yel goes to No 22 fuse which controls 12V and the white goes to the ECU which provides ground when it wants the solenoid to function.

If this makes the EGR work then the problem is either with the ECU, another sensor or the PCM which Haines says requires special equiptment to test.

The PCM (powertrain control module) compares all the data and determines how far the EGR should be open as well as how other smog items should then operate.

You might try to reset the ECU and other computers by disconnecting the battery for about 10 minutes. Besure to have your radio code as you will need it to get the radio working again when the battery is reconnected.

This is REALLY STUPID but have you checked the fuses? It looks like fuse #5 in the interior fuse box controls the ECU and #20 in the engine fuse box controls ETS. The Chilton book says #22 fuse controls 12V+ to the EGR solenoid The book is unclear which controls the PCM.

FutureX 2001 · 07-02-05, 01:13 AM

What was the conclusion to all this? 2 years later

Sean L · 07-02-05, 12:12 PM

Depends on who you're asking. I was the original poster, and the conclusion was that I fixed my car for less than $10 and it passed smog fine. I'm getting ready to sell it as I've had it for 4 years and I'm bored.....it's time to get something made in this century.

theGodfather · 07-02-05, 04:28 PM

CONCLUSION: Bad O2 Sensors.

A bad O2 sensor will not always put out a "check engine" light. So long as it's operating within the proper voltage range, the ECU thinks it's fine. However in my case, if the A/F mixture was supposed to produce a voltage of 0.4V let's say, the O2 sensor would be putting out something differnt like 0.6V or 0.2V (both within range of proper working O2). So the engine would go on the wrong A/F mixture values to control fuel, etc.. and thus produce a lean condition (my case was my O2 sensors were showing richer conditions than reality) which would cause high NOX values.

My emissions were perfectly fine even with the 1 cat only which shows that we do not need the 2 pre-cats on the Type II motors.

04-25-03, 12:28 AM	#62 (permalink)
theGodfather "the Don" Join Date: Jan 2002 Location: Toronto, ON, CANADA Posts: 1,002 Car 1: 1995 Carbon Black Metallic 6-Speed Coupe iTrader: (2)	It stumbled on IDLE when I applied vacuum to OPEN the EGR valve. Sometimes it stumbled, sometimes it completely stalled which is perfectly normal behaviour for an operational EGR system. G __________________ 1995 Legend Coupe 6-speed Carbon Black Metallic 208 WHP @ 6250 RPM 189 FT/LB @ 5250 RPM MUSTANG Dyno 260,000mi and counting WeaponR Secret Weapon Intake - Cold Air Box - Custom 2.5" stainless exhaust system - Remus Rev3 Universal muffler -SPEC Stage II clutch - 5speed flywheel - SR5GUY Chip - APEXi S-AFC - Pullies - MLS copy strut bar - Short Shifter -18" ICON W65 Wheels - KONI reds/Ground Controls - Slotted Brembo Rotors - SS Brake lines - Walbro 255 -ICE

04-25-03, 07:14 PM	#64 (permalink)
theGodfather "the Don" Join Date: Jan 2002 Location: Toronto, ON, CANADA Posts: 1,002 Car 1: 1995 Carbon Black Metallic 6-Speed Coupe iTrader: (2)	Nathan, you are pretty much on the right track. Today I ran the car on the dyno again and cleaning the fuel injectors made absolutely no difference to emissions. We took the cover off the EGR controlling components and started checking vacuum levels and making the car stall. Everything seemed to work fine except when having the vacuum gauge atatched to the hose that controls the EGR valve, on reving the engine we get 8-9 in of vacuum for 2 seconds and then it drops. I always thought this was fine that the valve will open adn close depending on load and RPM. My mechanic put the car on the dyno to do a 26mph run and he put a T-connector to get a gauge in there. Under load the EGR system will apply 9in of vacuum to the vavle for 2 seconds and then drop to no vacuum. Only way to get it back is to put it into neutral and rev it back into gear and it will repeat the same thing. The system is not holding the vacuum. He said the EGR valve should be open during the entire time the car is running 26mph in 3rd gear (about 2600RPM). He ran a test with the EGR valve about 40% open the entire time (using hte vacuum pump bypassing hte control system) and NOx levels dropped to 28 PPM!!!! However both CO and HC were way over the limit! (car was running too rich.. probably because the ECU had no idea the EGR valve was open like that so it wasn't able to compensate with fuel). Checked the voltage on the EGR valve position sensor and the voltage is within spec (1.2V when closed... around 4.6V when open). Shop had to close up by this point so the mechanic will continue to work on this on Monday. He has no clue exactly what is causing it to drop vacuum. There are no leaks with the hoses. BTW.. how do you test whether a knock sensor is working properly? He took the resistance reading of the two knock sensors and found two different readings. If no ECU light is on, is it safe to asume the knock snesors are working? What test can I do to them? My manual does not specify any specific resistance range they should be in like how O2 sensors have to be between 10-20 Ohms. G __________________ 1995 Legend Coupe 6-speed Carbon Black Metallic 208 WHP @ 6250 RPM 189 FT/LB @ 5250 RPM MUSTANG Dyno 260,000mi and counting WeaponR Secret Weapon Intake - Cold Air Box - Custom 2.5" stainless exhaust system - Remus Rev3 Universal muffler -SPEC Stage II clutch - 5speed flywheel - SR5GUY Chip - APEXi S-AFC - Pullies - MLS copy strut bar - Short Shifter -18" ICON W65 Wheels - KONI reds/Ground Controls - Slotted Brembo Rotors - SS Brake lines - Walbro 255 -ICE

04-25-03, 11:43 PM	#65 (permalink)
Merlin the Wrench Registered User Join Date: Jan 2003 Location: sacramento Posts: 863 Car 1: 1995 L sedan; past 1992 L sedan iTrader: (0)	according to the Chilton book, there is a solenoid that controls vacuum to the EGR valve. That can be tested by disconnecting the wires and applying 12v+ to where the blk/yel attached "A" , and vehicle ground to where the white wire was "B". Book says that the blk/yel goes to No 22 fuse which controls 12V and the white goes to the ECU which provides ground when it wants the solenoid to function. If this makes the EGR work then the problem is either with the ECU, another sensor or the PCM which Haines says requires special equiptment to test. The PCM (powertrain control module) compares all the data and determines how far the EGR should be open as well as how other smog items should then operate. You might try to reset the ECU and other computers by disconnecting the battery for about 10 minutes. Besure to have your radio code as you will need it to get the radio working again when the battery is reconnected. This is REALLY STUPID but have you checked the fuses? It looks like fuse #5 in the interior fuse box controls the ECU and #20 in the engine fuse box controls ETS. The Chilton book says #22 fuse controls 12V+ to the EGR solenoid The book is unclear which controls the PCM. __________________ Best Wishes Steve

07-02-05, 01:13 AM	#66 (permalink)
FutureX 2001 L E G E N D Join Date: Jan 2002 Location: Montebello, CA Posts: 4,550 Car 1: '95 Coupe Car 2: '94 Sedan GS Car 3: '90 Coupe iTrader: (2)	What was the conclusion to all this? 2 years later __________________

07-02-05, 12:12 PM	#67 (permalink)
Sean L Sr. Member Join Date: Feb 2002 Location: Bay Area, CA Posts: 314 Car 1: '94 Cashmere LS Sedan iTrader: (0)	Depends on who you're asking. I was the original poster, and the conclusion was that I fixed my car for less than $10 and it passed smog fine. I'm getting ready to sell it as I've had it for 4 years and I'm bored.....it's time to get something made in this century. __________________ Sean in Norcal '05 Infiniti G35 Coupe '94 Mustang Cobra '94 Legend LS Sedan (SOLD) '97 Lex LS400 Coach Edition http://www.mustangmods.com/data/4358/legendsig2.jpg

04-25-03, 12:02 AM	#61 (permalink)
Nathan_Rd hasng w*nd Join Date: Feb 2002 Location: 94620 Posts: 133 Car 1: zenki=funner iTrader: (0)	Did you mean it stumbled while you're actually DRIVING the car or while you were revving the motor in Neutral?

Remove Advertisements Sponsored Links
The Acura Legend & Acura RL Forum Advertisement

04-25-03, 03:53 AM	#63 (permalink)
Nathan_Rd hasng w*nd Join Date: Feb 2002 Location: 94620 Posts: 133 Car 1: zenki=funner iTrader: (0)	Well see if you can get a reading on the vac gauge while driving the car. T in that gauge and go for a drive with the gauge duct-taped to the windshield. If it shows 0" of vacuum while you doing 15-25mph then that explains the NOx problem.

07-02-05, 04:28 PM	#68 (permalink)
theGodfather "the Don" Join Date: Jan 2002 Location: Toronto, ON, CANADA Posts: 1,002 Car 1: 1995 Carbon Black Metallic 6-Speed Coupe iTrader: (2)	CONCLUSION: Bad O2 Sensors. A bad O2 sensor will not always put out a "check engine" light. So long as it's operating within the proper voltage range, the ECU thinks it's fine. However in my case, if the A/F mixture was supposed to produce a voltage of 0.4V let's say, the O2 sensor would be putting out something differnt like 0.6V or 0.2V (both within range of proper working O2). So the engine would go on the wrong A/F mixture values to control fuel, etc.. and thus produce a lean condition (my case was my O2 sensors were showing richer conditions than reality) which would cause high NOX values. My emissions were perfectly fine even with the 1 cat only which shows that we do not need the 2 pre-cats on the Type II motors. __________________ 1995 Legend Coupe 6-speed Carbon Black Metallic 208 WHP @ 6250 RPM 189 FT/LB @ 5250 RPM MUSTANG Dyno 260,000mi and counting WeaponR Secret Weapon Intake - Cold Air Box - Custom 2.5" stainless exhaust system - Remus Rev3 Universal muffler -SPEC Stage II clutch - 5speed flywheel - SR5GUY Chip - APEXi S-AFC - Pullies - MLS copy strut bar - Short Shifter -18" ICON W65 Wheels - KONI reds/Ground Controls - Slotted Brembo Rotors - SS Brake lines - Walbro 255 -ICE

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

Thread Tools
Show Printable Version Email this Page
Display Modes	Rate This Thread
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode	Rate This Thread: