Race Ready 7M Code 51 Now 32

[Van]

I'm getting code 51. 7MGTE idles smoothly about 1000 RPM, on the stock Tach and ECU.
I'm getting this Supra ready for Road Racing: So, I removed all the Air Conditioning in the car including the relays and sensors, before I set the ignition timing.
TSRM lists: Code 51 may indicate no "IDL" signal, "NSW" signal or, A/C signal to ECU, during diagnosis check. Would my having removed the A/C relays and sensors be the cause for the slightly elevated idle?
Another symptom: while setting the ignition timing per TSRM, with TE1 and E1 connected in the Diagnostic Block, the idle would only go down to 1200 RPM at 10 degrees and no lower, until I moved the timing to 8 degrees and idle went down to 1000 RPM, which is where I set it. After disconnecting the jumper from the diagnostic block, the timing light showed the timing was around 10 degrees or more, and the idle RPM about 1200.
I next set the TPS, which lowered the idle to 1000. I reset the TPS to lower the idle even more, but then the throttle response was dodgy, causing a hesitation on accel, as if there was a dead spot. Moving the TPS back to the previous setting eliminated the hesitation.
Cold start is very good; starts up in a couple seconds and idles up to around 1800 RPM, then fall slowly down to 1500 in a few seconds, and then gradually down to around 1000 at warm idle. No raw fuel smell noted despite doing a Lexus/550 mod, with AFM by-pass screw out all but the last three threads.
I replaced the old O ring on the by-pass screw, to asure no "pirate air" gets past the opening. I have all new Toyota intake & throttle body gaskets, new HTS silicone couplings and T-bolt clamps, plus new vacuum hoses from Toyota. I used Toyota FIPG on all the gaskets, to assure there are no leaks.
The only thing I will do to test for leaks is to spray some ethanol around all the fittings, while it idles, to see if it idles up.
Any suggestions for what to do next?
Thanks. Van

 

[northwestsupra]

Idl signal is from maf check to make sure that the connector is fully connected. Its also part of the tps sensor. You said you adjusted it. Did you clear the code after you adjusted ? No codes? Besides 51

Didn't see but do you have like a safc wired at all?

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[SupraSean]

code 51 is a self clearing code i believe. i have it as well, after removal of a/c. where is your idle screw set?adjust it?

 

[Van]

No SAFC on the car...

---------- Post added at 10:56 AM ---------- Previous post was at 10:42 AM ----------

I'll pull the EFI fuse to reset the ECU. I have no plans to adjust the idle screw on the throttle body. Would vacuum leaks produce a code 51 (no "IDL" signal, "NSW" signal or, A/C signal to ECU, during diagnosis check)? Thanks. Van

---------- Post added at 11:06 AM ---------- Previous post was at 10:56 AM ----------

TSRM indicates a Code 51 is a switch condition signal, system problem; that I should chack the A/C switch, circuit and amplifier (all have been removed from my Supra). I think I need to jumper a couple of pins on the ECU. No?
Thanks. Van

 

[Van]

I ruled out vacuum leaks, on the intake, by using 91% Isopropol Alcohol in a spray bottle. Test spray on the air filter caused mild increase in RPMs. Next, I'll pull the EFI fuse, wait a minute to reconnect, start the Supra, then check for codes. Van

 

[northwestsupra]

I ruled out vacuum leaks, on the intake, by using 91% Isopropol Alcohol in a spray bottle. Test spray on the air filter caused mild increase in RPMs. Next, I'll pull the EFI fuse, wait a minute to reconnect, start the Suprs, then check for codes. Van

And codes?


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[Bmettie]

This happen to be a MT swap from an auto????????
I get this code every time. But for me it because I did an auto to R154 sway and have the NSW (Neutral Safety Switch) wired to my clutch switch. At first I thought the same thing, TPS or something but I put a rocker switch along with the clutch switch and now when I pull codes I just hit my rocker switch.

Remember "Code 51 may indicate no "IDL" signal, "NSW" signal or, A/C signal to ECU, during diagnosis check" So this code can only be created During the diagnosis check, so if you have IDL signal to the ECU and AC off during the check then i'd lean towards NSW.

 

[IwantMKIII]

This is a very well covered issue. but once again, code 51 99% of the time is the IDL signal and lack there of. Your TPS should NOT be used to adjust your idle so long as you are not getting a code, what is the theory behind this idea?? It doesn't make any sense? This is a REAL TIME code, it will go away when the issue is fixed, it will NOT store in the ECU mem. Your high idle is not related to 51 unless it's just severely out of spec which is also a possibility because of you idle adjustments with the TPS though if anything it would probably just make your car run like crap rather than an increased idle as much as yours. My guess would be it is your TB itself being out of adjustment and not fully closed IF you in fact have no vac leaks.

 

[Van]

I pulled the EFI fuse: The code 51 went away. Now I'm getting a code 32; according to TSRM, could be an open circuit in E2 or, a short circuit between VC and KS (ref., FI-57). I had a spare AFM, hooked it up, pulled the EFI fuse, still get code 32. :1zhelp:

Last night, I noticed the CPS leaking oil into the sensor and awash in oil, from oil coming down the shaft. I replaced it with a used CPS, that is in spec, along with a new oil O ring. I reset ignition timing and It's still idling around 1000 RPM when set according to TSRM.

Also, the TPS still has a dead spot in it, so I'll be ordering a new one from Toyota. I have installed on the motor, a new engine harness from Toyota. So, I doubt it is wire related prob. Likely, the replacement AFM is also bad. I'll be checking it tomorrow w/a volt-ohmmeter.

Thanks for the help. I couldn't have done this w/o the tips and direction. In the past I'd have taken it to a mechanic to fix.
Van

 

[IwantMKIII]

You can get a TPS at autozone or something like it for half the price. Im not sure what you're not getting, pulling the efi fuse will have zero, none, natta, zip effect on code 51. You did something to make it go away.

 

[Van]

...pulling the efi fuse will have zero, none, natta, zip effect on code 51. You did something to make it go away.

:dunno:
Is there a relationship to the new prob: Code 32? See, I'm new at taking care of my own auto, so, there is a lot I don't get... about my Supra, that is. :icon_razz
In the future, I'll be more systematic and not do so many repairs together, that I'm not sure what I did or didn't do. Van

 

[Van]

Tonight I checked out the AFM, with an ohmmeter and it is working w/i spec, 2338 ohms at 68 degrees (TSRM: ohm 2000 - 3000).
I ordered a new TPS. One of the EFI, H2O temp sensors was broken, (on the H2O neck), so I ordred a new one as well. Hopefully, I'll soon have a normal idle... Van

 

[IwantMKIII]

how much vac are you pulling? In in-Hg? 18-20 is good, 20 being ideal, anything lower than 18 and something is leaking. I would test this both on a cold and hot motor and see if you notice a difference

 

[Van]

how much vac are you pulling? In in-Hg? 18-20 is good, 20 being ideal, anything lower than 18 and something is leaking. I would test this both on a cold and hot motor and see if you notice a difference

Thanks for the tip... I'll see if I can borrow one from my neighbor, or Auto Zone.

Tomorrow, I plan to install the new Toyota TPS and EFI H2O sensors. Van

 

[Van]

how much vac are you pulling? In in-Hg? 18-20 is good, 20 being ideal, anything lower than 18 and something is leaking. I would test this both on a cold and hot motor and see if you notice a difference

Cold Vac is 19.7. Rev to 4000 RPM and snap the throttle closed, raises Vac to 25-26in/Hg. I'll be making a run to the store and will recheck the Vac numbers afterward. Van

Hot Vac is 20, snap throttle closed it rises just above 25in/Hg. There is a hesitation from off IDL and the Vac drops to between 13 - 15in/Hg, depressing the throttle enough to get to 1500RPM it recovers to just above 19 then settles up to 20in/Hg. Depressing the throttle gradually, increasing it from off IDL through 400RPM, the Vac slowly rises from 20 to 22in/Hg, snap the throttle closed, it jumps up to 26-27in/Hg (when there is no hesitation then there isn't any loss of Vac.).
I hope this is useful information. Ignition timing is per TSRM. Thanks. Van

 

[IwantMKIII]

right on target, next check the resistance of the ISC and ensure proper functionality. Look in the TSRM for proper testing procedure.

 

[Van]

The ISC is within spec per TSRM. I cleaned it up as well as checked its functionality, per TSRM. This afternoon, I adjusted the throttle body stop screw for the throttle plate and was able to set the ignition timing per TSRM. It now idles at 750 RPM and advance is 10-12 degrees, with paper clip removed from diagnostic block. Removed EFI fuse for more than a minute and it throws code 32. Next step: check the ECU. Van

 

[IwantMKIII]

I warned you a long time ago that your throttle plate was out of adjustment, maybe next time you'll tune in more to what I suggest

 

[Van]

The ISC is within spec per TSRM. I cleaned it up as well as checked its functionality, per TSRM. This afternoon, I adjusted the throttle body stop screw for the throttle plate and was able to set the ignition timing per TSRM. It now idles at 750 RPM and advance is 10-12 degrees, with paper clip removed from diagnostic block. Removed EFI fuse for more than a minute and it throws code 32. Next step: check the ECU. Van

Now the culprit has come out of the wood work... The ISC stopped working yesterday (no clicking sounds). That code 32 may have been thrown as the ISC was having intermittent malfunction. I'll bench test it Saturday, to see what's wrong. I may be in the market for a rebuilt one, as new is $529! (11 in the States according to Toyota). Van

 

[jetjock]

Code 32 has nothing to do with the ISCV. If you have a GTE it also has nothing to do with the AFM. I'd have thought during all this time someone would have pointed that out...