my name is dave, and my son and i just spent 3 months swapping over a n/a 88 to a fresh new turbo powered supra. it has a t3/4 turbo and intercooler and new/used wire harness from an 87 turbo and an 87 ecu. this thing has dbov, 50mm wastegate, afpr running at 40 lbs. we got this thing to fire right up first try and found the o2 sensor was putting out .03-.07 volts. which is too lean!!!! we purchased a piggyback from apexi and tried every setting but it made no difference. we cant get this to run richer. there are no vacuum leaks so now i am thinking bad ecu??? any ideas out there??
oh i forgot to mention we did install 550injectors and a lexus afm. we do have a new/used afm coming as the one we got tested bad but the car runs (idles) without the afm installed anyway. so i am still hoping someone has a good idea out there. is there a way to test the ecu from a 87, 7mgte??
Last edited by toolmasterdd; 03-06-2010 at 07:19 PM.
Reason: more info
Now, when you say that it's outputting zero volts what are you testing? The 02 signal wire? The VF wire coming from the ECU?
I've said this time and time before, the stock O2 sensor cannot reliably be uses as a measurement of too rich or too lean. It is intended for a single point of reference, 14.7:1 AFR.
If you want a real rich/lean signal, use a wideband O2 sensor with a linear sensor curve. Not a narroband sensor.
__________________
1988 Mk3 Turbo Targa - 17.5psi, 486hp, 494tq.
[img]http://www.**********s.com/supra/rsw_sig_stupidTN.jpg[/img]
Who came up with this 500px wide BS?
I've been PM'ing back and forth on the issues for a few days now too before this post, and it's a little more complicated than just the tune. History: It is a fresh NA - T swap. The car is exhibiting an AFM failure symptom (idles, but wont rev with or without the meter). The OP discovered the CEL bulb needs to be replaced, and will then be able to read the codes to determine if there is a problem with the AFM or the wiring.
I don't remember if he said the car was running stock or not before the mods were entered into the picture, but if the AFM isn't working all the tune in the world won't matter as it sits on the idle without AFM signal map.
I would personally read the codes and get the car running stock first, then put the go fast stuff back on, but if the AFM issue is the only problem, perhaps you could get that working and then as Jeeves mentioned, head to a tuner with a wideband and a dyno to get it dialed in safely.
The Following User Says Thank You to bgrieger For This Useful Post:
getting new/used afm today. will do further testing. the car was running fine before the mod. i am testing the output at the ox1 terminal on the check conn. thanks for all the help. sound like you guy know what you are talking about. i will be back later today with all i have found out. dave.
ok. replaced afm, but no difference. new unit is a lexus LS400 same as old one. it tested the same as the old one. a little different from what is said in tests for afm for supras. got codes 52, 32. unplugged knock sensor and cleaned afm cleared codes and ran car..... still stumbles upon acceleration... tried bypassing apexi unit still same thing...have been talking to bgrieger, he is helping also! i need a local tuner in puget sound area. i guess he will have wide band o2 sensor to finish this situation... k.. we have to be very close.
Cleaning the AFM is also a notorious way to destroy one, so be careful
Obviously I'd recommend fixing the knock sensor wires. Those are crucial to the way the car operates in boost and with the Headgasket issues these cars have you don't need more detonation.
Quote:
Code: 32
Air Flow Meter Signal(7M-GE)
HAC Sensor Signal(7M-GTE)
(High Altitude Compensation Sensor)
Diagnosis(Air Flow Meter Signal(7M-GE))
•Open circuit in E2 or short circuit between VC and VS.
Trouble Area
•Air flow meter circuit
•Air flow meter
•ECU
Sounds to me like you should look into the HAC Sensor. That's an external little box on the 87 ECU's. Generally you should check: "Open circuit in E2 or short circuit between VC and VS" as it states.
~0v across this pin can mean a number of things depending on when you measured it, which is why it's highly unreliable. I would never use it for an important measurement. A wideband is really the only way to go.
__________________
1988 Mk3 Turbo Targa - 17.5psi, 486hp, 494tq.
[img]http://www.**********s.com/supra/rsw_sig_stupidTN.jpg[/img]
Who came up with this 500px wide BS?
Last edited by Jeeves; 03-08-2010 at 06:30 PM.
The Following User Says Thank You to Jeeves For This Useful Post:
Cleaning the AFM is also a notorious way to destroy one, so be careful
Obviously I'd recommend fixing the knock sensor wires. Those are crucial to the way the car operates in boost and with the Headgasket issues these cars have you don't need more detonation.
Sounds to me like you should look into the HAC Sensor. That's an external little box on the 87 ECU's. Generally you should check: "Open circuit in E2 or short circuit between VC and VS" as it states.
~0v across this pin can mean a number of things depending on when you measured it, which is why it's highly unreliable. I would never use it for an important measurement. A wideband is really the only way to go.
oh ok. more good info. hmmmm... we used mineral spirits to clean the afm and compressed air. we also disconnected the knock sensor and now we have no check engine light even if we tried to rev it, but of course it will barely get above 1200 rpms. but i will check into the hac sensor. i dont remember if we plugged in that extra connector or not.... i will check it tmoro. thanks for the extra info. we ordered another ecu just in case, if we dont need it we can always sell it. i am going to replace the knock sensor wire as described in another blog with coax wire just so we dont have any issue there. lots to do man i want this thing done and out of the garage so i can start another project ///???//////??? haha
interesting way to check to voltage for the o2 sensor... i will examine the schematic to see why the different way. i was just going to the check connector and to ground to read output voltage of o2 sensor with my sensor simulator/testor. i even disconnected the wire from the ecu and checked it that way to see any differences...... will try it that way also. thanks.
Now, I will say that neither the knock sensors, HAC nor the O2 sensor will cause that ~1200 RPM stall. A dead AFM is well known to cause the engine to not rev over ~1500 RPM however.
The AFM works by measuring the vibration rate of a mirror, as seen in this diagram:
They're notorious for their easy death by many cleaning solvents and such because of any traces, changes that they leave, and abuse/damage to the mirror or it's surface or any other components in there. I think I've only ever heard of one or two surviving a "cleaning" .
__________________
1988 Mk3 Turbo Targa - 17.5psi, 486hp, 494tq.
[img]http://www.**********s.com/supra/rsw_sig_stupidTN.jpg[/img]
Who came up with this 500px wide BS?
ok so i checked into getting an o2 sensor and i asked the guy about a wide band with a linear curve and he didnt know about the curve, but did say that the bosch was very popular. but then he asked about what controller i had.... i told him i didnt have a controller, only a tester/simulator. so the question is do i need a controller also and if so maybe i should wait to do any more testing till i get the new/used ecu??? i do know of some race guys over in tacoma but will have to get a hold of them. but they do mostly v8's. will do more checking of this afm and hac system...
Unfortunately, if you have cleaned the afm electronics, you probably destroyed them already. I thought I could do the same thing, I actually bought a can of cleaner that was 25 bucks and sprayed it for a bout a second, and bam, toast. It was a nice clean one too. I was pretty mad at myself for doing that when it really didn't need it. But you mentiond that you used a different wiring harness in your build; perhaps something was crossed when you wired it in? Make sure to check because if the ecu is not getting a signal from somewhere, then that may be your problem......otherwise if all else has been diagnosed, or perhaps you have a stuck injector, it could be the ecu.
Last edited by SupraTuned; 03-13-2010 at 01:27 PM.
Sorry to have mislead you, you can't just use a wideband O2 sensor, you have to have some kind of hardware attached to the back to interpret the signals. That's the controller he's talking about. There are many varieties of many different costs and features:
Most entry packages will not have a display of any type but will have laptop access. MOST will also have wiring configurations so that it will give a 0-5Volt signal (wideband) and a 0-1volt simulated narrowband output so that you could wire it into the stock ECU as well. Some of the software packages allow you to control what range that 0-1v represents. If you'd like the best package for your tuning, you'll need to do your research.
ok question, my afm still tests good. how did you know that yours went bad? .....also, my son does have a gauge installed that reads the voltage off the o2 sensor and tell if it is lean or rich with a wide reading... i am thinking this is a voltage gauge as well... i bet i could test it by using my simulator to give it a reading and check it... hmmm and if so would it work to read the new wideband o2 sensor...hmmm then i wouldnt have to get the controller??? hmmm. well anyway we got the new/used ecu and the car runs the same . that means something else is wrong for sure. wiring, afm... i bet the wiring,,,, not happy about that. i will be checking this for now as a possible problem, opens, shorts, continuity issues... etc etc. oh well...
Those narrow band over the counter air/fuel guages almost never work all that well as a tuning tool...in part because of how narrow a range the standard O2 sensor detects, so all you end up seeing is wild oscillations of the needle or lights. A neat show, but not of much practical value. In essence, they are a volt meter as you suggest. The wideband on a controller will allow you to see more of what is happening.
If the AFM is passing all the tests, I'm not sure other than wiring where to go next. Though if the wiring to the AFM was bad, you would think it would kick out a code as if there was a problem with the AFM itself. I guess you could also look to the cam position sensor or the throttle position sensor as well...
The AutoGuide.com network consists of the largest network of enthusiast-owned enthusiast-operated automotive communities.
AutoGuide.com provides the latest car reviews, auto show coverage, new car prices, and automotive news. The AutoGuide network operates more than 100 automotive forums where our users consult peers for shopping information and advice, and share opinions as a community.
ToyotaNation.com is an independent Toyota/Lexus enthusiast website. ToyotaNation.com is not sponsored by or in any way affiliated with Toyota Motor Sales, USA, Inc. The Toyota, Lexus and Scion names and logos are trademarks owned by Toyota Motor Sales, USA, Inc.
Forum for all Toyota Supra generations.
dave.
. that means something else is wrong for sure. wiring, afm... i bet the wiring,,,, not happy about that. i will be checking this for now as a possible problem, opens, shorts, continuity issues... etc etc. oh well...
Linear Mode
