I Messed Up- ST SIG HELP
#1
I Messed Up- ST SIG HELP
Hey guys, I did something stupid. I started my car with the ST SIG 10A fuse still in. I have a DIYPNP V1.5. Which transistor, and possibly anything else, did I most likely fry? I think it is the one in spot Q17 but I'm not entirely sure.
Side note, why does my car only idle when the fuse is in place and not when I take it out? The IAT sensor does go into pins 1 and 6 of the AFR pigtail, yeah?
Cheers!
Side note, why does my car only idle when the fuse is in place and not when I take it out? The IAT sensor does go into pins 1 and 6 of the AFR pigtail, yeah?
Cheers!
#4
Boost Czar
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it was working because the AFM controls the fuel pump, since you probably blew the transistor on the MS and it sounds like you still have the AFM in place.
But it also depends if you bought your DIYPNP with that circuit populated/wired or not.
But it also depends if you bought your DIYPNP with that circuit populated/wired or not.
#7
Boost Pope
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I'm going to take a wild guess here and say that until you replace the damaged transistor on the MS board, the car isn't going to run (with or without the ST SIGN fuse) after you remove the AFM.
With the transistor blown, the MS isn't able to control the fuel pump. With the ST SIGN fuse in, the starter circuit is powering the fuel pump during cranking, then the mechanical switch inside the AFM takes over once there's airflow.
You could work around this problem by placing a jumper wire between pins A and B of the AFM connector, or between pins F/P and GND of the diagnostic connector under the hood on the drivers side shock tower, which will cause the fuel pump to run all the time when the key is on. This creates a potentially unsafe situation wherein the fuel pump will continue to run in the event of a ruptured fuel line.
I am, admittedly, taking some liberty in translating your original post, presupposing that when you say "why does my car only idle when the fuse is in place and not when I take it out?" what you really mean is "why does my car only START when the fuse is in place..."[/i] With the AFM still installed, I'm guessing that you could have started the engine with the fuse in place, then removed the fuse and the engine would have kept running.
With the transistor blown, the MS isn't able to control the fuel pump. With the ST SIGN fuse in, the starter circuit is powering the fuel pump during cranking, then the mechanical switch inside the AFM takes over once there's airflow.
You could work around this problem by placing a jumper wire between pins A and B of the AFM connector, or between pins F/P and GND of the diagnostic connector under the hood on the drivers side shock tower, which will cause the fuel pump to run all the time when the key is on. This creates a potentially unsafe situation wherein the fuel pump will continue to run in the event of a ruptured fuel line.
I am, admittedly, taking some liberty in translating your original post, presupposing that when you say "why does my car only idle when the fuse is in place and not when I take it out?" what you really mean is "why does my car only START when the fuse is in place..."[/i] With the AFM still installed, I'm guessing that you could have started the engine with the fuse in place, then removed the fuse and the engine would have kept running.
#10
Boost Pope
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TypicalSteve responded to me via PM, which I post here so as to retain one single thread of conversation:
Two options occur to me:
1: The transistor isn't blown, however your ECU was clearly assembled at a shop located directly above an Indian burial ground, or
2: Are you sure about that full minute?
Reason I ask is that once the fuel system is primed and the engine running, it'll take a little while for the fuel pressure to drop and stall the engine while it's just sitting there idling. Not a full minute by any stretch of the imagination, but maybe 10-20 seconds of runtime after the fuel pump is shut off might be plausible before the engine sputtered to a halt.
Originally Posted by typicalsteve
Hey Joe,
I am bit confused about what you said earlier. Just to clarify, my AFM is removed and I have the IAT sensor installed. Last night, my car would not start or idle with the ST SIG fuse taken out. After I put it in, it would start and then it idled for about a minute. What can explain this? And I still cannot seem to find the transistor that is blown.
I am bit confused about what you said earlier. Just to clarify, my AFM is removed and I have the IAT sensor installed. Last night, my car would not start or idle with the ST SIG fuse taken out. After I put it in, it would start and then it idled for about a minute. What can explain this? And I still cannot seem to find the transistor that is blown.
1: The transistor isn't blown, however your ECU was clearly assembled at a shop located directly above an Indian burial ground, or
2: Are you sure about that full minute?
Reason I ask is that once the fuel system is primed and the engine running, it'll take a little while for the fuel pressure to drop and stall the engine while it's just sitting there idling. Not a full minute by any stretch of the imagination, but maybe 10-20 seconds of runtime after the fuel pump is shut off might be plausible before the engine sputtered to a halt.
#11
The car was most definitely on and idling for at least a minute. I then shut it off, though, and it was unable to maintain idle after that. But it did do it once.
Is there a sure fire way to tell if the transistor is blown or not? Shouldn't I be able to test the continuity with a voltmeter or something?
Is there a sure fire way to tell if the transistor is blown or not? Shouldn't I be able to test the continuity with a voltmeter or something?
#12
Cpt. Slow
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When you key the car on, it should prime the fuel pump for 3 seconds. If it doesn't, that transistor is blown out, and you'll have to solder a new one in, ~$14 from DIY.
If you need the car to run, jumper FP and GND in the diagnostic box. The FP will be on when the key is on, which is annoying, but it'll work.
If you need the car to run, jumper FP and GND in the diagnostic box. The FP will be on when the key is on, which is annoying, but it'll work.
#14
Boost Pope
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The NB having a returnless fuel system, you can't hear fuel moving under the hood as with the earlier cars. Easiest way is to open the fuel filler and stick your ear against it while someone turns the key on.