I keep blowing my ecm1 fuse (LSx)

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Boost27

Member
My on going problem is that i keep blowing my ecm1 fuse on my 92 typhoon. I have gone threw the harness and unplugging any thing on this circuit. I found out it is unplug the harness just above the ecu the fuse stops blowing. here is a picture of the connector. I'm hoping this can get me closer to finding out what is the problem.
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here is a picture of the engine side of the plug.

[URL=http://imageshack.us/photo/my-images/10/img0338vk.jpg/]
there is only 4 wires on this side
From what is looks like have a the last two is what there might be a problem, i have been tracing wires on diagrams i haven't found the green wire yet thought that i would post this before bed. Thanks in advance for any help i can get.

engine side - truck side

brown - brown
white - white
purple - green
green - pink with black strip
 
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The Bronze

The Bronze

New member
Re: I keep blowing my ecm1 fuse

Re: I keep blowing my ecm1 fuse

I edited the hell out of this post after chasing the diagrams for an hour.

I tried like hell to track the pink/black to green at the C101 connector you are showing but I didn't ever see it be any color but pink/black (even with the syty supplement). With that in mind, the book is probably wrong and that green wire is what comes from the fuse box. You could check that by keeping the connector unplugged and installing a new fuse. You should have power at the green wire side if I am looking at the diagram correctly.

I have 3 different wiring diagrams and they show things a little differently. The SyTy supplement shows ECM1 (pink/black) as powering the PCM at Pin A6, The O2 sensor heater, the turbo boost cut-out relay (both the control side and the switching side (continuing onto the wastegate solenoid) and the CAC relay (switching side only- The CAC pump has it's own dedicated circuit to power the pump). Try removing each one of those items individually.

The connector you took a picture of is C101. It continues the power to the keyless entry module- disconnect the 3 wire connector there to isolate that, then the audio alarm module in the convenience center (7pin connector), the rear window defogger timer relay and then the rear window defogger switch. Basically, if it has a pink/black wire, it needs to be removed from the circuit one at a time. If you are going to get tired of blowing fuses, you can always put a resetable circuit breaker in it's place for testing purposes, but no bigger than factory, which is 10A I believe.

The pink/black wire also runs to your alternator (field). That is what I would check first- even though I typed it last....wierd, huh? The best way to do this (and safest) is to pull all the components listed and start plugging them back in one at a time until you blow a fuse the first time (I am assuming it blows a fuse immediately all the time).

For added reference, if you owned a Syclone, you would be only doing the engine components and PCM. The Sy doesn't use any of the interior dohickies like defogge and audio alarm module.
 
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B

Boost27

Member
Re: I keep blowing my ecm1 fuse

Re: I keep blowing my ecm1 fuse

(Note this has and current performance wiring a set up for lq4 and 4l80e trans)
l ready had a circuit breaker in the fuse spots. Well i played with it today after work. I unplugged everything on the engine and trans harness except for the 2 speed sensor and the c212 plug that I showed a picture of early. So the only thing left is the ecu, I unplugged the blue part of the harness and no change. So I moved on to the red harness and unplugged it and the fuse stop blowing. I going to try to get the ecu tested with that person that reprogrammed the ecu for me.
 
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B

Boost27

Member
Re: I keep blowing my ecm1 fuse (LSx)

I under stand this is a LSX swap truck and question. Sorry it was late and i just want to post to help find out what connector that was so i can track it down. I'm more interested in the chassis side of the harness. I know the harness is new and the ecu was good about 6 months ago. Sorry again for the confusion. Now that i know what plug it is i can track it down in the dash to see if there any bare wires or mouse nest in there. thanks again for your help
 
T-Bone

T-Bone

Active member
Re: I keep blowing my ecm1 fuse (LSx)

Replace your 15 Amp ECMB fuse with a 20 Amp or 25 Amp one and I bet you your problem will be solved. You are currently running fuse Amp ratings designed for a V6 instead of a V8.

If I am correct, your fuse will most often blow when you apply your brakes (approaching a stop sign/stop light or when parking)....correct?
 
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Boost27

Member
Re: I keep blowing my ecm1 fuse (LSx)

Quadrajet72 said:
I thought you said it does NOT blow the fuse if you disconnect that connector. IF that is TRUE, the short is in your engine harness.
Click to expand...

Yes correct, it doesn't blow when I unplug it that connector. I thought that would tell me that the short was in the part of harness that I unplugged. Could it be my gauge cluster? I'm going to find out the origin of those 4 wires in the lsx harness and see what there are connected to. Then see if i can match them to what they should be be on the side of the ty harness. I did what you said to do and look up the posts from davep and I found this.

C212 by the ECM. 10-pin natural colored connector.

Pin K lt grn = boost ga
Pin H wht = tach

li green should go the the map sensor correct? just brain storming

Quadrajet, Thanks for that tip.
 
B

Boost27

Member
Re: I keep blowing my ecm1 fuse (LSx)

T-Bone said:
Replace your 15 Amp ECMB fuse with a 20 Amp or 25 Amp one and I bet you your problem will be solved. You are currently running fuse Amp ratings designed for a V6 instead of a V8.

If I am correct, your fuse will most often blow when you apply your brakes (approaching a stop sign/stop light or when parking)....correct?
Click to expand...

fuse blows son as you turn the key on. I will stick with the 10amp fuse right now and see if i can figure it out. I don't want to burn it to the ground if i stick a higher amp fuse in there.
 
The Bronze

The Bronze

New member
Re: I keep blowing my ecm1 fuse (LSx)

I couldn't sleep thinking about this connector, so I ripped the masking paper out of the door jamb, removed the lower cover and checked out the connector on my truck.

I don't want to confuse this any more than necessary, but I have put a little time into this. From what the SyTy wiring diagram (page 441 of 454) and connector id pages indicate (and alldata, since it is GM info as well), the connector you guys are talking about is C101. I even verified by the wiring colors in the picture.

C101 is the 10 pin connector by the DRAC and ECM. On an original wiring set-up there would be C101 by the ECM to C200 near the dash and then C202 at the cluster. I can't seem to find C212 at all. It certainly doesn't make any difference at this point in the thread, as all parties are looking at the same connector, but I thought that I would report what I found.

With the connector issue resolved in my own head, I went back over the diagram. DaveP is spot on with the rest of it....and by memory too. I am impressed.

I think I can sleep now.
 
T-Bone

T-Bone

Active member
Re: I keep blowing my ecm1 fuse (LSx)

Boost27 said:
fuse blows son as you turn the key on. I will stick with the 10amp fuse right now and see if i can figure it out. I don't want to burn it to the ground if i stick a higher amp fuse in there.
Click to expand...

Ummmm, ok. Didn't know the fuse blew the instant you engage the key. I had a LSx Sy that would blow the ECMB fuse randomly but it happened when stopping or sitting at a intersection (always when under a load on the amp draw). A local wiring genuis recommended upping the AMP fuse to 20-25. Never had a problem since. All the best finding your gremlin.....wiring issues like yours are often nightmares.
 
T-Bone

T-Bone

Active member
Re: I keep blowing my ecm1 fuse (LSx)

Quadrajet72 said:
Yeah, right. I'm outta' here. T-Bone has this under control.
Click to expand...

Pffffttttt. You are light years ahead of me in this category. My LSx swap Sy had a similiar fault but not as soon as the key was engaged. That's a much more serious issue and way above my elementary level of expertise.
 
WyoSyclone

WyoSyclone

Active member
Re: I keep blowing my ecm1 fuse (LSx)

One other troubleshooting trick is to disconnect battery pos and neg.

Take the harness connector in question and use an ohmmeter to check for resistance between each wire and ground. Some wires may show a typical 1k or 5k value if going through a board. If a wire is shorted to ground its resistance will be very low (0 ohm, 1ohm, 10ohms, etc.).

This could help you at least rule out a dead short to ground.
 
B

Boost27

Member
Re: I keep blowing my ecm1 fuse (LSx)

Quadrajet72 said:
100% correct. Now think. Where is the power coming from? The pink/black! so when you disconnect the connector, the short must be on the green wire, or some component it powers. Because the pink/blk is still hot.
Click to expand...

Your right, I don't know what i was thinking. That green and black wire is grounding out, and it is connected to pin 20 on the lsx ecu. Now on to that problem.
 
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Boost27

Member
Re: I keep blowing my ecm1 fuse (LSx)

Will one of the other syty lsx owners take a picture of that plug for me? I have been trying to get a hold of the guy that mad the harness for me and have had no such luck yet.
 
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B

Boost27

Member
Re: I keep blowing my ecm1 fuse (LSx)

Just figure i would give and update, I sent the harness back with the factor harness. He fixed a few problems he found with it. Last night i put the harness back in and the truck fired right up.
 
Throws

Throws

Active member
Re: I keep blowing my ecm1 fuse (LSx)

Sweet! Sucks that you had to send it off, but at least you know it's done right.

-P
 
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