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Old 05-26-2008, 11:56 AM   #1
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Default Problem while upgrading to 'No AFM'

I've been running a MSPnP (Latest firmware) on my 1993 (CA Spec) car for a while and decided to remove the AFM. Since doing this, the car won't start anymore and I'm not sure how to proceed:

More details:
* Basically the engine cranks, but doesn't seem to fire up (revs stay below 300 rpm, and I don't hear any 'explosion' sound')
* I believe I've followed the instructions from http://ozmx5.com/viewtopic.php?f=4&t=13 using the HR images from the same site. As this didn't work, I've also tried to flash the DIYAutotune versions (Both with and without AFM), using the same process and with the same results.
* If I replace the MS with the stock ECU (and put the ST IGN fuse back), the car will start fine (Idle is not perfect as there is no AFM, no IAT signal, and the VTPS confuses the ECU... but it does work).
* I seem to be getting some spark with the MS installed (hard to check without any help, but the timing light does flash a bit when cranking)
* There seems to be some fuel going into the engine (my WB goes to full rich and back to full lean if I push the throttle down)
* I've tried to make adjustments to the default maps to account for my setup (WB O2, MAPDaddy with baro correction, VTPS) but doubt that this matter much until the engine starts

I'm not sure what to do next (What I'm also wondering is if the MSPnP has been flashed correctly... although Megatune seems to work fine and connect to it).

Thank for any suggestions.

Eiffel
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Old 05-26-2008, 01:22 PM   #2
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The odd thing here is that, so far as I can tell, the only different in the DIY MSPNP setting between "With AFM" and "No AFM" is the IAT sensor itself.

Since you've changed a bunch of stuff, I'd suggest that you go back to a working, baseline configuration (with the AFM) and check the following:

1- Upon removing the AFM, without making any other changes other than installing the new IAT (Yes, it will be wrong) does it run at all? Do this while the engine is warm, so we don't have to worry about cranking PW and ASE quite so much.

2- While doing so, take note of whether or not the fuel pump is running. Try the test with a jumper placed between F/P and GND in the diagnostic box.
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Old 05-26-2008, 02:23 PM   #3
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It sounds like you still need to change the settings in the configurator to the mapdaddy sensor, i had the same issue.
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Old 05-27-2008, 06:38 PM   #4
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Guys, thanks for the help (Joe had it right!)...

After ripping all my mods (I think I was too confident the first time ) flashing various versions with a computer with a serial port rather than a USB adapter, etc., I think I got it: the fuel pump is partially disabled when unplugging the AFM!

I just need to find which pin on the AFM connector to jump (Alternatively I could follow Joe's suggestion above, but I'd prefer a stealthier solution).

From the enthusiast manual, I gather that the IAT sensor is connected between the THAa and E1 wires, and it would seem that connecting E1 to Fc would do the trick. Hopefully this won't fry anything!

I wish the MSPnP manual would make mention of this, as it means I would have been able to enjoy the long weekend a bit more... but I'm glad a solution is in sight (It seems that the MSPnP manual should indicate that one should short wires 6 and 7, in addition to connecting the IAT between wires 1 and 6... although I haven't tested this mod yet).
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Old 05-27-2008, 06:51 PM   #5
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hmm interesting.. subscribing to know what to do.
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Old 05-27-2008, 06:56 PM   #6
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Interesting. The 90-93 MSPNP triggers the fuel pump by providing +12 on the violet ST SIGN wire which hits the ECU at pin 1C. It's normally an input to the ECU (to tell the ECU when you are cranking), and this hack is the reason that the ST SIGN fuse must be removed prior to installing the MSPNP. I wouldn't have thought this was different in the CA cars.

Anyway, here's the relevant section of the wiring from the FSM. The red line I drew indicates the normal operating path for the fuel pump relay. When the AFM moves off the stop, the switch between pins A and B closes to ground, completing the circuit for the relay to ground. So at the AFM, you can jumper the green wire to the black wire, and the FP will run all the time. It'd be nice to have it work properly, but that will do for now.

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Old 05-27-2008, 07:09 PM   #7
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Joe,

Thank you for the instructive diagram (and quick response!). I'll try your suggestion tomorrow and will report on how it works afterwards.
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Old 05-28-2008, 09:33 AM   #8
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Quote:
Originally Posted by Eiffel View Post
I wish the MSPnP manual would make mention of this, as it means I would have been able to enjoy the long weekend a bit more... but I'm glad a solution is in sight (It seems that the MSPnP manual should indicate that one should short wires 6 and 7, in addition to connecting the IAT between wires 1 and 6... although I haven't tested this mod yet).
I'm sorry you're having this problem; it sounds as if the fuel pump drive circuit in your MSPNP is not working correctly (when it is working, there is no need for any external jumpers like that - that's why there is no mention in the manual). Let me know how this goes; we may need to arrange to have the box repaired.
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Old 05-28-2008, 05:47 PM   #9
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Ok, it works!

I connected the Black and light green wires together on the AFM connector (Based on the picture in the MSPNP 9093 manual, this means connecting pins 6 and 7 together (with the IAT wires going to pin 1 and pin 6). This seems to yield the same results as connecting F/P to GND in the diagnostic connector. Removing the fuel pump connection stalls the engine.

I'm not sure if there is any drawback to this additional wiring (Expert views welcome!).

I have always followed the instructions to install the MSPNP (removing ST IGN fuse, etc), so I'm a bit puzzled as to what this happened (My MSPNP has already crossed the Atlantic three times as the 93 CA wiring mod had not been done when I got it), and, as I have owned this car since new, I know the wiring hasn't been touched by anybody but me.

Eiffel

Last edited by Eiffel; 05-28-2008 at 06:01 PM.
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Old 05-28-2008, 05:56 PM   #10
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I am also running MSPNP 9093 along with IAT and never had to ground or fiddle with any wires at all. I was actually running the car at first with the AFM, but when I did the turbo install then I removed the AFM and installed the IAT. The car started right up without any issues. You might have bad unit (MSPNP).
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Old 05-28-2008, 06:04 PM   #11
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Quote:
Originally Posted by Eiffel View Post
I'm not sure if there is any drawback to this additional wiring (Expert views welcome!).
If you crash the car in such a way that the fuel line is ruptured, the fuel pump will continue to operate, emptying the entire contents of the fuel tank into the blazing inferno, killing you slowly and painfully, and leaving nothing more than a charred cinder for your distraught widow to bury.

Apart from that it works just fine.
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Old 05-28-2008, 06:24 PM   #12
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Quote:
Originally Posted by Joe Perez View Post
If you crash the car in such a way that the fuel line is ruptured, the fuel pump will continue to operate, emptying the entire contents of the fuel tank into the blazing inferno, killing you slowly and painfully, and leaving nothing more than a charred cinder for your distraught widow to bury.
Well, sound like a fine tradeoff, although I need to meet the future widow first!

Thanks for your help!
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