Hey Guys,

I was leaving a friends house tonight which is not too far from mine so i took the long way around to let me car run pretty well for a while before I cut it off. My Temps were normal, plenty of oil, I was around a quarter of a tank on gas and in third gear doing between 25 and 30 at about 2500ish RPM and i look over and the Check Engine Light flashed on, (I feel like I was off the throttlee and then got back on it) and then the light went away, about 2-3 minutes later it did this again but it only flashes on for a second. I searched and found some other threads and apparently it seems that it is either the TPS having at issue at a certain speed/rpm or it is the O2 sensor. I have the warranty info on my car and the TPS was replaced in 1991 (apparently the factory one went bad soon after the first owner bought the car) The car is a 1990 GTUs. Are there any pointers that anyone who has experienced this can give me. I can just pick up a new O2 sensor at an autoparts store? I will need to drive my car this weekend for a good period of time to see if this continues. Ive had the car for a few months now and this hasnt happened before. It kinda freaked me out so I need some comforting words here. Thanks



https://www.rx7club.com/showthread.p...k+Engine+Light

https://www.rx7club.com/showthread.p...k+Engine+Light

https://www.rx7club.com/showthread.p...k+Engine+Light



**Edit, I found this link about checking the codes. Will it show a code if the CEL just flashed or does it have to stay on


http://www.1300cc.com/howto/how2/codes.html

 

It should stay in memory until you clear it by disconnecting and reconnecting the battery. Is your car stock? If some emissions are removed you'll have some codes pop up but they wont cause the CEL to come on so dont worry about those.

 

The Car has a full exhaust and a bonez high flow cat...

 

Those shouldnt cause any codes to pop up, assuming everything else on your car is stock and working/connected. It'll take you a minute or so to get the hang of how to read the codes. As said in the link above the codes will start from lowest to highest and then will cycle again once done. If you arent sure about the code turn the ignition off and back on again to restart it and double check. It's a piece of cake. Good luck.

 

did you actually check to see what code(s) you have?

 

I havnt checked the codes yet. This happened tonight, I so I will probably do it tommorow sometime. Thanks for the help. So I take it this isnt a huge deal?

 

bump** Im going to bed. Im gonna try and pull the code in the am, then Ill continue with this thread, talk to you guys then.......

 

I'd guess pressure sensor...

What codes did the CEL come up with when you checked?

 

OK guys, I tried the wire trick this morning. When I turned the key to "on" however all of the idiot lights came on. I waited the 10 seconds + but the CEL never went off to start telling me a code. Here is a picture of what I did. Do I need a different gauge of wire or do I need an actually connector to plug into the green piece or will a stripped piece of wire work the same.

 

You can't ground through paint. Hook the aligator clip to the alternator bracket or negative battery post or something.

 

Ok well I grounded the aligator clip to the negative terminal on the battery. When I turned the key to on the lights came on and then the CEL went off to start telling me the code. Then it came back on and just stayed on. The code manual says that each time its on for more than one second that counts as ten. So does this just mean it is code ten or what?


**I tried it again and it still does this...comes on blinks off and then comes back on

 

If it is a code 10 the FSM says that that it is the intake air thermosensor inside the AFM. The failsafe function is that the intake air temperature is stuck at 68 degrees F.

 

Yeah thats what I am reading to....

Now what do I do?

*assuming if it is code ten.....which I think it is, cause it only blinks off once and then just stays on

 

Heh, if you have just spare parts hanging around hook up another AFM and see if that fixes that problem.

 

just thought Id give this one last bump to see if anyone else can help out. Thanks for everyone elses help. Im currently ordering an AFM to replace the one I have to see if that is the problem.

 

Before you go and get another AFM, you might want to try the test procedure in the FSM. I believe it is in the fuel and emissions section.

 

allright thanks

 

ordering one, as in from mazda? that sounds expensive. Try the for sale section instead, can probably get them cheaper there.

 

oh yeah Im getting one from somebody on the forum....

 

Are you able to confirm its the thermalsensor... theres no point in buying it unless you know thas what the code meant.

If its a code ten it will be like this.

Key on and turn to ignition: light on for a few seconds... light off. Ilight on for 1.5ish seconds light off for about 3 seconds, light on for about 1.5 seconds, light off for about 3 seconds...

In otherwords it would be repeating the 10 code over and over. I dunno it seems unlikely you'ld be getting a ten code, AND, 10 codes won't show up while you're driving IIRC... so... so if you saw the light while you were driving, there are other numbers stored...

 

Well then I have no clue whats going on, because when I checked the code it blinked off and then came back on and thats about it. Well I ordered the AFM already. It was only 60 dollars so its not a waste even if its not the problem, Ill just have an extra. Ill need to drive the car some tommorow and see if I can figure out what is going on. LIke I said once I turn the key to on and the CEL comes on, goes off and then comes back on the show the code it just sits there forever and doesnt do anything else.

That is exactly what it does

 

I want to correct myself. Turns out if you don't have the thhermalsensor plugged in, the CEL will show up when the car is running, doesn't jjust save, but actively lights while you are driving...

 

ok thanks for the correction. Im gonna go play around with the car today and see if i can figure it out

 

**Update:

I started my car up this morning and let it idle till it warmed up (as I usually do). I filled it up with gas and then went or a little drive and the CEL never came on. I dont know if the other night was just a glitch, or it was because it was cold or what. But I tried doing the same thing i did that night and nothing happened today. Maybe nothing is wrong, but I will continue to take it easy for a while and see how it goes. At least now I will have an extra AFM if that is the problem or if i ever need one

 

I had the same problem. There are 2 thermosensors. It could be the one in the AFM.
Or, it could be the one screwed into the intake manifold behind the oil filter.
My code 10 was the one in the intake manifold only after replacing the AFM with a spare that I keep. It seems that I must've bumped it while replacing the heater core hose a while ago. Cleaning the spades and reconnecting it eliminated the problem.

Definitely check the thermosensor which is screwed into the intake manifold. It really doesn't have much holding it on---lousy connector.