Mazda MX-6 Forum banner

1 - 20 of 27 Posts

·
Registered
Joined
·
149 Posts
Discussion Starter · #1 ·
97 MX-6 M edition....
Flew from New Orleans to Houston to buy this car and sold my 94 4 cyl auto to get the 6cyl stick. The head lasted exactly long enough for me to get back home. I rebuilt the head, had done it on my other 6 with no problems. After getting it all back together I got problems:
The car wont idle and threw multiple error codes that were not there before the fix. All O2 sensors, Mass Air Flow Sensor, throttle position sensor and many others....Now I have the damn check engine light flashing at me. I'm obviously suspicious and wonder what I could have done wrong to make it throw so many codes. The most obvious symptom is that the car wont idle regularly. It idles down and down until it dies. This is much worse with the A/C on and the higher I put the A/C the worse it is.....
I dont believe that it 'suddenly' had most every sensor go out because I rebuilt the head....On the road (RPMs above 3k) the car runs great and gets excellent gas mileage. I can easily rev up to 5k+ rpm without incident and 0 to 100 mph is pretty quick.

Any ideas where to look first??? This is my dream 6 and I want to get it running right so I can go on with the turbo project and body work...
 

·
Premium Member
Joined
·
5,189 Posts
First, the m-edition was 96 only, second, it sounds like a massive vacuum leak. Some people test for the vacuum leak by running the car and spraying starter fluid along the vac lines, but I've heard others use propane also.
 

·
Registered
Joined
·
149 Posts
Discussion Starter · #3 ·
First, the m-edition was 96 only, second, it sounds like a massive vacuum leak. Some people test for the vacuum leak by running the car and spraying starter fluid along the vac lines, but I've heard others use propane also.

Thanks for the input Paul, I probably got the year wrong....my bad...

I've checked the vac system using the starter fluid method, then suspected that I may have put some line in the wrong place so a mechanic friend and I put a 626 with the V6 Mitsu engine side-by-side with my 6 and checked it out. The wiring and vac hoses appear to be installed correctly and spraying it with starter fluid had no effect.

Another suggestion someone had was that because it idles much worse the higher I put the AC fan that it may be some electrical drain somewhere but I dont know where to start looking for such a problem. This seems like its possible since I have so many sensors screwing up. I put a voltage meter on it and it is pulling 12v through the system but that doesnt tell me how many amps are available to different portions of the system.

So far I've changed the Idle control sensor and MAF sensor but no effect and the codes are still trippin on those sensors.

can you tell me what it means when the check engine light flashes instead of staying on solid? I think I'm going to go buy a compression meter just to cover my bases but it runs so good at high speeds and high rpms that I dont think that could be it. possible gasket problem on the throttle body?
 

·
Registered
Joined
·
737 Posts
check all your fuses

i would put a scan tool on it, write down every single code that comes up. clear the codes and see which ones come back.

also, make sure everything is plugged in.

a vacuum leak will not set a code for your O2 sensors unless they are unable to toggle fast enough. i doubt that is the problem though considering it did not have a cel on before.
 

·
Registered
Joined
·
149 Posts
Discussion Starter · #5 ·
check all your fuses

i would put a scan tool on it, write down every single code that comes up. clear the codes and see which ones come back.

also, make sure everything is plugged in.

a vacuum leak will not set a code for your O2 sensors unless they are unable to toggle fast enough. i doubt that is the problem though considering it did not have a cel on before.
Thanks Mx6Girl. I put a scan tool on it and cleared the codes and it came back. I've done this a few times. I dont remember all of the codes but they were extensive where I had none before the head rebuild. Everything is plugged in, no extra wires or harness connections unplugged. No vacuum hoses unconnected and starter fluid doesnt cause a revving when sprayed. It is my understanding when having this many codes that on can cause a fault in another and it could be a cascade effect. Could one bad sensor/component cause cascading faults? Possibly the onboard computer?

Thanks to everyone for helping on this. I think with the MX-6 knowledge base here we can figure this out.... I'd hate to re do the head rebuild to make sure I didnt get something wrong. The mechanic I had check it says the cam is correctly installed and its in time. The cam was what I was most worried about originally....and I dont really have much faith in mechanics around here. how can I check the cam shaft position other than timing the engine. Dont have a timing light but that should show up in the codes.

Going back to autozone to have them check the codes for me again and write them down again so i can post them here.....
 

·
Registered
Joined
·
149 Posts
Discussion Starter · #6 ·
error codes

I have 2 O2 sensor codes and another that is a feedback loop to the O2 sensor. any idea where I can get them cheap???

EVAC control system purge valve (p-40443) (VACUUM LEAK??? but I cannot find it)

Closed trottle position switch (checked this with voltmeter and it appears bad, voltage is either -4.99 or +6.87 when moved at all it should be .5-1.0 at closed and 5.0 fully opened)
 

·
Registered
Joined
·
737 Posts
do not go buy two new o2 sensors until you get this all figured out. unless you're rich and can afford to throw parts at this thing. you didn't have a code for bad o2's until now, along with half the other sensors on your car. it's obviously an electrical problem unles you did something wrong.

go buy a timing light before you spend a couple hundred dollars on o2 sensors.
 

·
Registered
Joined
·
149 Posts
Discussion Starter · #8 ·
Ok, it gets better, I began checking the entire vacuum system and noticed that with the engine warm and manually revving the throttle, the vacuum actuators that activate the secondary throttle valves were not moving. I took the vacuum line off of them and manually checked them and they are good. Its not getting a vacuum to them to activate them. Next I checked the vacuum solenoid valves and noticed something. The vacuum lines run from the solenoids to another set of solenoids and the guy that helped me put the vacuum lines back together after redoing the heads (why they were not labled when I removed them was becuase he took them off, not me) evidently didnt get the lines back on right because this other solenoid is supposed to mount to two studs on the firewall but its not. IT WONT REACH because the vacuum lines are not long enough. That would be a dead givaway that they are not the right lines going to the right place. NO MORE MECHANICS HELPING ME....

NOW, can anyone tell me where to get a GOOD vacuum hose diagram? The one under the hood is a joke. There are 5 solenoids total and most have three lines coming and going. Thats 15 vacuum hoses plus the ones coming off the intake manifold and other places.

There is no vacuum coming off the charcoal canister (either side) No vacuum on the lines going to either vacuum actuators. Hopefully the vacuum canisters are not screwed up and its just the lines are in the wrong place. I doubt if all of the solenoids are bad all at once.......

If I cannot find a diagram I will have to find another 6 and trace the damn lines down that way.....
 

·
Registered
Joined
·
149 Posts
Discussion Starter · #9 · (Edited)
Ok, it gets better, I began checking the entire vacuum system and noticed that with the engine warm and manually revving the throttle, the vacuum actuators that activate the secondary throttle valves were not moving. I took the vacuum line off of them and manually checked them and they are good. Its not getting a vacuum to them to activate them. Next I checked the vacuum solenoid valves and noticed something. The vacuum lines run from the solenoids to another set of solenoids and the guy that helped me put the vacuum lines back together after redoing the heads (why they were not labled when I removed them was becuase he took them off, not me) evidently didnt get the lines back on right because this other solenoid is supposed to mount to two studs on the firewall but its not. IT WONT REACH because the vacuum lines are not long enough. That would be a dead givaway that they are not the right lines going to the right place. NO MORE MECHANICS HELPING ME....

NOW, can anyone tell me where to get a GOOD vacuum hose diagram? The one under the hood is a joke. There are 5 solenoids total and most have three lines coming and going. Thats 15 vacuum hoses plus the ones coming off the intake manifold and other places.

There is no vacuum coming off the charcoal canister (either side) No vacuum on the lines going to either vacuum actuators. Hopefully the vacuum canisters are not screwed up and its just the lines are in the wrong place. I doubt if all of the solenoids are bad all at once.......

If I cannot find a diagram I will have to find another 6 and trace the damn lines down that way.....

and NO I am NOT rich.....lol

I LOVE YOU GUYS!!!! Found the best vacuum hose diagram I've ever seen!!!!

http://www.mx6.com/forums/2g-mx6-other-performance/206978-vacuum-hose-routing.html

Now to check if I'm getting a vacuum off the vacuum chambers and route them correctly.....stringing up lights outside now...did i mention I'm a little obsessive about my car? you guys are probably the only ones who would understand the frustration of being broke and your car you wanted forever not working right......

'nix
 

·
Registered
Joined
·
737 Posts
I have a vacuum diagram for that very system (had to work on it and replace a couple things recently myself) from alldata. i will go get it now and scan it for you. i damn near have all those vac. hoses memorized i've had to take them off so many times.

brb with a pic
 

·
Registered
Joined
·
737 Posts
nevermind. i see you found the same pic i was going to throw up.

only thing i don't agree with on there is the "vacuum source"...i don't know why they labeled it where they did but the source of vacumm is from the manifold. :shrug: not that it really makes a difference because your problem was not ehe source of the vacuum.

anyways, good luck
 

·
Registered
Joined
·
149 Posts
Discussion Starter · #12 ·
THRILLED!
Almost ALL of them were wrong. Thats what I get for letting someone else work on my car. It idles now. Also runs smooth at all RPMs. I had an incident with the solenoid that goes to the charcoal canister. the tip broke off when I was removing the hose. got to get another. just clamped off the hose and went on. I think that just recycles gas vapors or something like that. Not that critical. I do need to get all new hoses as some are a little loose and I want to re run them so that I can get the secondary solenoid back on the firewall where its supposed to go.

The TPS seems to be working now. I'm going to reset the codes and see what happens after I fix that other solenoid. This was not fun, im a pretty big guy and my hands just do not fit back there easily. Had to do the contortionist thing to get all of the hoses rerouted.

Thanks for the help.. I'll let you know how the code check goes. Bet that was all of the problem...if that isnt right your not likely to get a good reading on any other sensors....IMO

Nice to have my car back. Now to fix the body. Someone put a remote starter on this car before I bought it and it broke while my g/f was using it and she left it in 1st gear when she went into a store. It started itself and ran into an SUV then a Taco Bell..... The remote starter has since been removed from the car......and yes, she still drives itl :)
 

·
Registered
Joined
·
737 Posts
hey don't feel bad. i'm little with squirmy hands that i get almost anywhere. but even i had problems dealing with all of those vacuum lines. i had to crawl up onto the motor to do most of it because i'm not tall enough to have a good view of what i'm doing. half sprawled out over the engine only works so well for some things.

glad you were able to get that all taken care of.
 

·
Registered
Joined
·
829 Posts
After all these years your charcoal canister is most likely fucked anyway. It's just there to collect the gas vapors, then send them free into your IM when you start up your car.

And sorry to hear about the remote start... that exact scenario is why most shops wont install into a manual. Glad nobody was hurt
 

·
Registered
Joined
·
149 Posts
Discussion Starter · #15 ·
hey don't feel bad. i'm little with squirmy hands that i get almost anywhere. but even i had problems dealing with all of those vacuum lines. i had to crawl up onto the motor to do most of it because i'm not tall enough to have a good view of what i'm doing. half sprawled out over the engine only works so well for some things.

glad you were able to get that all taken care of.
I dont know, a woman sprawled out over my engine seems like an intriguing idea to me. :cool:
 

·
Registered
Joined
·
149 Posts
Discussion Starter · #16 ·
Ok, here is where I am now....

Redid the entire vacuum system hoses and they were fucked up... the car does much better now and is kinda fun to drive again. I dont have my own ODBII scanner but the guys as Advanced Auto are cool and I've brought it up there, read the codes, reset them, drove the car for another two days and brought it back today to have them read again.
(I know how to clear them manually but the manual says that resets the computer to defaults and can take a while to rebuild history which would be counter productive for my purposes)

The codes I'm getting now are:
Of course O2 sensors
Idle air control valve
Throttle position sensor

No more EVAC codes :jump:

Idle is much more stable meaning it will idle most of the time vs. never
Now, It wants to idle between 750 rpm and 250. it does at times hold at 1250 for a while before dropping. Raising the idle speed just increases the top to 2k and the bottom stays the same.

Next is to replace the
idle speed control valve (this is a new code since fixing the evac problem)
Throttle position sensor AND
02 sensors

Opinions requested. I have a LOT of things I need to do to the car and for a short term fix what are the odds I will get decent sensors from a wreck? Have one near here that has 3 6s that I've pulled other parts from. Never used sensors from a wreck though but it will let me get a lot of other things going and if they last a year thats fine....

I'm going to post pictures of this car as it was when I bought it (if I can find them) and what it looks like now after it was possessed and drove itself into the taco bell....I want to keep this thread open and let everyone see the entire project as I rebuild the entire damn car. I could get another that is in better shape but I have emotional attachment to this car and how I got it and wont let another M edition die.....

Anyone know where I can have seats redone in leather AND have the M edition logo stiched in??? been wondering about that one for a while...

Thanks for the help as I rebuild Nix's Six
 

·
Premium Member
Joined
·
5,189 Posts
The 96 has 4 O2 sensors, you'll have to find out which ones need to be replaced based on the codes you're getting.
 

·
Registered
Joined
·
149 Posts
Discussion Starter · #18 ·
The 96 has 4 O2 sensors, you'll have to find out which ones need to be replaced based on the codes you're getting.
Right, I need all of them if you believe the codes. I'll check it again after fixing the other issues before replacing them. Looking up parts last night I see the front/rear before CC and one after CC where is number 4?
 

·
Premium Member
Joined
·
5,189 Posts
There's one on each exhaust manifold, one right before the cat and one right after the cat.
 
1 - 20 of 27 Posts
Top