air fuel mixture

kidsusukigsxr · 02-07-2007, 04:25 PM

Hello

can anyone tell me about the emissions control system diagnotic code 25 air-fuel raio rich malfunction. I don't know which sensor i need to change.

thanks

pwpanas · 02-08-2007, 12:43 PM

Quote:

Originally Posted by kidsusukigsxr

...can anyone tell me about the emissions control system diagnotic code 25 air-fuel raio rich malfunction. I don't know which sensor i need to change...

Diagnostic code 25 is "Air-Fuel Ratio Lean Malfunction" (i.e. not "rich" - that'd be code #26)
Possible areas of concern are as follows (listed roughly in decreasing order of likelihood):

- Main oxygen sensor (a likely cause)
- Air/vacuum/boost leak (also a strong possibility)
- Water temp sensor (sensor corroded, due to infrequent coolant flushes)
- Ignition system (old spark plugs (copper?))
- Air flow meter (dirty/oily (from k&n oil?))
- Fuel line pressure (eg. bad fuel pump)
- Injector (dirty)
- Open or short in main oxygen sensor circuit
- Open or short in Injection circuit
- ECU

Of course, other members of the forum please feel free to correct, re-order, or add to this list.

kidsusukigsxr, please answer the following questions:

What year is your Supra? ...and is it turbo or n/a?
What modifications were done to it?

kidsusukigsxr · 02-09-2007, 01:06 AM

yes your correct. I miss wrote. thank you.

I'll looking into the things you listed.

ok your asking so I'll tell ya. before i knew anything about supra's I bought a book and jumped in,learning as i go.

I blew the engine i bought the car with then went to the salvage yard a picked up the engine that I now have. I didn't know what i was buying nor did he savage yard know what they were selling. Because i got it for $450. I got a 7M-GTE and put it in.

so i have a 7M-GTE engine in a 1989 manual supra. Now whats very strange is that this engine didn't have the turbo in it or else the salvage yard would have known. Did they make non turbos with 7m-gte engines without the turbo? Or someone pulled if off.

· No modification

· 89 7M-GTE engine with out the turbo

Thank you

IHateHacks · 02-09-2007, 03:04 AM

7MGTE were turbo only

7MGE were non-turbo only

Thats what the T means, turbo. Someone swiped it before you bought it.

So if I understand this correctly, you have a 7M GTE engine with a 7M GE exhaust manifold bolted on, correct? I just have one question, are the turbo oil line bosses blocked off? (where the turbo oil line would bolt to the block, one is a 2 stud/nut flange, one is a 17mm union bolt)

I'm guessing you are using the injectors that came with your GTE?

I'm also guessing you are using your GE ECU?

What did you use from your blown motor to make the GTE run?

kidsusukigsxr · 02-09-2007, 03:53 AM

WOW u know your sh........... lol all of you guys in here know your stuff.

well i'm going way back about 6 years ago. a buddy who knew about cars helped me and if my memory serves me correctly we used the existing harness and ecu, he swapped one or 2 plug and we connected the harness and engine (i can't remember let me look into it and get back to you).

I can't rememeber if we used the same harness.
For sure we swapped out the exhaust manifold.
using existing ecu

IHateHacks · 02-09-2007, 03:27 PM

Im guessing you are using your GE MAF sensor? (the sensor right after the air filter)

If that is the case, I think that is your problem. GE and GTE MAF's are very different, not just in resistance values and voltages, but they are physically different also. GE MAF's have 7 terminals and GTE MAF's have 5. Even if you spliced a GTE MAF connector into a GE harness you would still have problems. Correct me if I'm wrong but so far you have GE MAF, GE ECU, GTE engine right?

Really need to know if you are using the GE or GTE injectors.

02-07-2007, 04:25 PM	#1
kidsusukigsxr 3" Exhaust Join Date: Dec 2006 Location: Orlando, Fl Posts: 52	air fuel mixture Hello can anyone tell me about the emissions control system diagnotic code 25 air-fuel raio rich malfunction. I don't know which sensor i need to change. thanks

02-09-2007, 01:06 AM	#3
kidsusukigsxr 3" Exhaust Join Date: Dec 2006 Location: Orlando, Fl Posts: 52	Code 25 yes your correct. I miss wrote. thank you. I'll looking into the things you listed. ok your asking so I'll tell ya. before i knew anything about supra's I bought a book and jumped in,learning as i go. I blew the engine i bought the car with then went to the salvage yard a picked up the engine that I now have. I didn't know what i was buying nor did he savage yard know what they were selling. Because i got it for $450. I got a 7M-GTE and put it in. so i have a 7M-GTE engine in a 1989 manual supra. Now whats very strange is that this engine didn't have the turbo in it or else the salvage yard would have known. Did they make non turbos with 7m-gte engines without the turbo? Or someone pulled if off. · No modification · 89 7M-GTE engine with out the turbo Thank you

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02-09-2007, 03:04 AM	#4
IHateHacks 20psi boost Join Date: May 2006 Location: New Haven/Hamden Posts: 793	7MGTE were turbo only 7MGE were non-turbo only Thats what the T means, turbo. Someone swiped it before you bought it. So if I understand this correctly, you have a 7M GTE engine with a 7M GE exhaust manifold bolted on, correct? I just have one question, are the turbo oil line bosses blocked off? (where the turbo oil line would bolt to the block, one is a 2 stud/nut flange, one is a 17mm union bolt) I'm guessing you are using the injectors that came with your GTE? I'm also guessing you are using your GE ECU? What did you use from your blown motor to make the GTE run?

02-09-2007, 03:53 AM	#5
kidsusukigsxr 3" Exhaust Join Date: Dec 2006 Location: Orlando, Fl Posts: 52	WOW u know your sh........... lol all of you guys in here know your stuff. well i'm going way back about 6 years ago. a buddy who knew about cars helped me and if my memory serves me correctly we used the existing harness and ecu, he swapped one or 2 plug and we connected the harness and engine (i can't remember let me look into it and get back to you). I can't rememeber if we used the same harness. For sure we swapped out the exhaust manifold. using existing ecu

02-09-2007, 03:27 PM	#6
IHateHacks 20psi boost Join Date: May 2006 Location: New Haven/Hamden Posts: 793	Im guessing you are using your GE MAF sensor? (the sensor right after the air filter) If that is the case, I think that is your problem. GE and GTE MAF's are very different, not just in resistance values and voltages, but they are physically different also. GE MAF's have 7 terminals and GTE MAF's have 5. Even if you spliced a GTE MAF connector into a GE harness you would still have problems. Correct me if I'm wrong but so far you have GE MAF, GE ECU, GTE engine right? Really need to know if you are using the GE or GTE injectors.