1996 Mazda will not show readinest for polution test

MADMAN

Full Member
Joined
Oct 27, 2008
Messages
68
Likes
0
Points
6
#1
Can any body can help me find out and tell me what this means, thanks

1996 Mazda 6, V6. automatic, 131000 miles and runs well! but here in Illinois it will not pass the polution test because it shows that system monitors :

1) Catalytic Converter EFF, "NOT READY"

2) EGR Flow, "NOT READY"

3) Oxygen sensor, "NOT READY"

once a code P0400 (EGR flow malfunction? what ever that means?) poped up, but then cleared and hasnt come on again and no light on at test.

any one can give some thoughts to what is wrong? how would i fix this? thanks all!
 

billr

wrench
Staff member
Joined
Mar 12, 2007
Messages
6,340
Likes
76
Points
48
#2
Lots of possibilities here, do you have a way to look at live-data? One simple possibility is that the engine coolant temperature (ECT) sensor is bad and the PCM thinks the engine isn't getting warm enough to go into closed-loop and run the "readiness" tests.
 

MADMAN

Full Member
Joined
Oct 27, 2008
Messages
68
Likes
0
Points
6
#3
no way to get "live data". i just have a cheapy nova scan tool from wally world. does great on reading codes, but thats about it. did check for engine coolant level, thats fine. also car has good heat and warms up as normal. and it doesnt smell to be running rich. but that is a thought!!! would'nt that pop a temp sensor code?
 

billr

wrench
Staff member
Joined
Mar 12, 2007
Messages
6,340
Likes
76
Points
48
#4
Some sensors, including the ECT, can fail "in range" and not necessarily set a code. However, by '96 it is likely the PCM diags were sophisticated enough to conclude the engine hadn't reached temp in an appropriate time, or the ECT sensor wasn't keeping up with the IAT or trans fluid sensors and deduce it (the ECT) was probably bad. Point is, there are some really inexpensive ways to get OBD2 live-data via a laptop. Do a search for "elm 327" and wait for "nickb2" to chime in here.
 

nickb2

Wrench. Diagnostic Tech.
Joined
Nov 22, 2008
Messages
9,253
Likes
161
Points
63
Location
St-Hyacinthe, Quebec, Canada
#5
Best thing to do here is erase memory since these masdas were not so finicky. Do a drive cycle and see what post back.

You have three codes here and masdas at 100000k were programmed to code a O2 sensor.

Egr valve should be cleaned, masda had huge issues with sticking egr valve stems.

As for the cat code, you may need a new one. But first, check switching of the O2. These engine did not have heated ones.
 

MADMAN

Full Member
Joined
Oct 27, 2008
Messages
68
Likes
0
Points
6
#6
Thanks BillR and NickB, I cleared the only code (P0400) and went for a drive cycle, little city type drive to get to an expressway, then 55/60mph for 5 min. let it come down to 20/30 for a tad then back to 55. I think thats what book said. did this while leaving my nova reader pluged in and still not ready! those 3 still blinking not ready, and yellow light (if you know what i'm talking about on this code reader). turn car around and started the same drive cycle back home, and after reaching 55/60mph for the 3rd time... pop! code P0400 again! check engine coolant and right to top, but i'm going to try and get a ECT this week and change it, maybe that's all it needs? I'll write back when i get this done. just want to say thanks for your help.
 
Joined
Nov 14, 2006
Messages
1,590
Likes
17
Points
38
Location
Nothern California
#7
Why not work on the coded information that the computer told you, PO400, EGR flow ? you may not even need a ECT.

The EGR seems to be a very common problem on this car. The following person wrote an article about it.

http://mazda626.net/topic/41067-egr-inspection-cleaning-1993-2002/
 

nickb2

Wrench. Diagnostic Tech.
Joined
Nov 22, 2008
Messages
9,253
Likes
161
Points
63
Location
St-Hyacinthe, Quebec, Canada
#8
EGR valve stem sticks in carbon, can be removed and cleaned, I have done this several times, key word is several, and they still come back with the P0400. I think the valve stem and egr valve bore get pittied, and after a short time just end up sticking again.

Best to check this, remove the 12mm bolts from the egr, and us a small pick or screwdriver and see for yourself how these stick. I have found that a new one is better because I usually work under warranty. But you can de-carbonize it with some carb cleaner, or just let it soak overnight, and work it free with said pick or small screwdriver.

See my skills in sceenshot. I am not good at drawing. 8)
 

Attachments

MADMAN

Full Member
Joined
Oct 27, 2008
Messages
68
Likes
0
Points
6
#9
i was thinking and leaning towards the egr, or some place in egr circut, including the solinoid. all vacum hoses are good, however the ect seem kinda a thought since the 3 different things where showing up not ready all the time. would a problem with egr sticking cause the flashing of not readiness for the Converter EFF and oxygen senors too? thanks
 

MADMAN

Full Member
Joined
Oct 27, 2008
Messages
68
Likes
0
Points
6
#11
just a thought though... as Bill mentioned, if computer doesnt know the engine temp, will it sent the voltage to operate the solinoid to open and allow vacuum to pass and operate the egr valve itself? if by some chance its not reading correct engine temp, i can see signal to servers not functioning properly. But i guess removing throttle body and trying to get this egr out and visualy checking it would maybe be the best before buying unneeded parts.
 

nickb2

Wrench. Diagnostic Tech.
Joined
Nov 22, 2008
Messages
9,253
Likes
161
Points
63
Location
St-Hyacinthe, Quebec, Canada
#12
Maybe my previous picture was not representative of your egr exactly, but still they stick at the same place, in your case do as this screen shot, in a vise, apply vacuum and see if pintle/valve moves.

On these, you could creep in your finger and manually move the egr diaphragm, if the engine died, most likely that pintle was not stuck and you had other issues. You need to get your hands dirty here.
 

Attachments

MADMAN

Full Member
Joined
Oct 27, 2008
Messages
68
Likes
0
Points
6
#13
yep, i can remember reaching under some older GM (chevy) and pushing up to it stumbled or killed the engine. just all this computer controll stuff still gets to me. I'm a retired outdoor equipment mechanic, was my trade... years ago! been thinkin again if i could get to the vacuum hose if i can use the vacuum pump in the same manner if i would get the same results. stumble or kill engine.. good? no effect... bad egr? thanks
 

nickb2

Wrench. Diagnostic Tech.
Joined
Nov 22, 2008
Messages
9,253
Likes
161
Points
63
Location
St-Hyacinthe, Quebec, Canada
#14
@MADMAN< you should see the crazy stuff I deal on a daily basis with, just on the phone or here. Adaptive steering response sensors and or now with distance sensor interacting with braking.

Wish I would have stuck with lawnboys. :D

Now I am embarking on a new trade, quality control systems for the food industry. :D What am I getting myself into. School starts in a week, scared to be the old guy in class. Hope they don't see my bald spot. :eek:
 

billr

wrench
Staff member
Joined
Mar 12, 2007
Messages
6,340
Likes
76
Points
48
#15
Why so much focus on the EGR sytem? This could well be the O2 sensor(s). If you don't want to do it the easier way, looking at live-data, then you could read the O2 sensor outputs with a multimeter. But, you may need two meters, to read both upstream and downstream sensors simultaneously, and won't have other data along with those readings. With live-data resolving your present problem will take a certain amount of guessing, without live-data it will take a lot of guessing with probably some "parts swapping". I'll ask again... do you have a laptop available? If so, those ELM thingys are under $20!