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I have an 87 trans am gta 5.7 tpi. Car shut down on me the other day full power loss. Got it towed home and was told that it was fuseable links. Replaced them all with inline fuses and still no power...at all. Did some digging and found a wire that was burnt through on the motor and replaced it and car fired up. My cel light has always been on for maf so I ordered a chip through a tuner that deleted maf and a bunch of other stuff never got to put it on bc ot the car dying so I finally got it running as I said but it kept blowing one fuse which I found led to the maf burnoff (voila) unplugged the burnoff and installed the chip CEL goes off and cars sounds and idles better than ever. Took it for a drive and it popped that fuse again. Is there something else other than the mad burnoff that the particular fuseable link goes to?
That's a valid point. I'll try unplugging the relay and the maf and see if that changes the outcome. If it cant get hot it cant blow the fuse one would think.
THe MAF power relay coil receives power from the fuel pump relay which will put 12v on the red 12v wire going to the MAF sensor. The ecm does not activate the power separately like the burnoff relay. So if the fuel pump relay is on the MAF power relay is on also regardless of the ecm programming.
Now that said, you could also have another issue in the fuel pump circuit as well. As you can see in the diagram that circuit powers the fuel pump itself as well.
Best thing I can do at this point is unplug the maf relay since its obsolete now so it doesnt get power and see if it continues to blow the fuse. If so then I can figure the problem to be as you said Pauly and be in the fuel circuitry.
But even if it has power, if it's not plugged in it shouldn't draw enough to pop the fuse correct?
Yes, its a good practice to make sure the unplugged connector is protected from contamination and coming in contact with anything, basically make sure the connector is clean and tape it off.
I would disconnect the MAF power relay just to take that possibility out of the equation. Then you can focus on the remaining items, which is just power wiring to the relays and the fuel pump components.
found a wire that was burnt through on the motor
Also go back to this location and make sure there are no more damaged wires where this happened.
Alright I'll check on that in the am and disconnect the maf relay. It's just weird that it idles fine but after 1/4 mile driving it pops the fuse. Something is surging and I thought I found the issue but I respect your idea so tomorrow I will go back over that wiring after unplugging. Tape everything up and test it again. If the map has no relay to power into and it's still popping then I can move on to the possibility of it being fuel related. However in hoping it's just the maf lol.
Intermittent electrical issues are the worst. One more simple thing, the fuse should be a 20A if you haven't checked it or didn't know. Also, I have heard people talk about differences in fuses vs fusible links and how a link seems to take higher amperages short term where a fuse may blow with the same load. I haven't personally had any experiences with this as I use links all the time but just something to think about. You could test the amperage draw with a ammeter and see the actual draw to verify you aren't pulling excessive amperage or see that you may simply be exceeding the fuse rated amperage momentarily. I think I am rambling on a bit.
If it is blowing a 30 there is probably a more definite problem somewhere then. The factory calls the fuse a 20A so simple answer is yes, 30 is still protection but you could be masking a more obvious problem with it as well as taxing the wiring with more that it should hold. That could also make it seem intermittent when the higher amp rated fuse is simply handling more before it blows.
You know what, I'm rereading things here and notice we might be looking at two different things. If you look at the diagram, the MAF and fuel are running off an inline fuse already and not a fusible link. You said you followed a fusible link and it lead to the MAF relay; and that is now replaced with a fuse holder and is blowing; so now I wonder if something was modified from stock at some point or just not what it appeared. Can you see or do you remember the wire color the fuse that is blowing is connected to? The problem may be somewhere else altogether.
Ok, thats a bit odd with just one blowing but it does rule out the whole MAF fuel thing. You may need to do some super sleuthing here. Determine what works (if anything) and what does not and match it up with this diagram to see if anything jives with one of the links. I wouldn't expect one of the fuses blowing to take the whole car out, that is the odd part.
Play I said the burn off was completely fried pig tail wires going into it was pride when we took that off the relay it ran longer but it still didn't so I do believe the problem is somewhere in the math area of the circuitry I just have to figure out where exactly the problem lines if it's in the math relay then just unplugging that should fix it but I won't know that until tomorrow morning and itself
Understood, but the MAF isn't run from those links, definitely have a look at the items we talked about earlier but I'm hoping you'll find things like headlights, taillights, power locks if you have them still functioning and its only the key on items that die. Then we can focus on the ignition which would make sense here. If only one fuse blows something else is almost certainly functioning still, you may not be thinking about these other items that are running on the other links. You can also check for power at the MAF relays when the fuse is blown to verify the power for that is on that fuse. I'm betting you will still see power at the MAF relays when this fuse is blown. If it happens to be dead and replacing that fuse restores it then there is something modified from factory and all bets are off, Let us know what you see!
So i went spelunking through the wires to unplug the maf relay and accidentally unplugged the fuel pump relay... i think i found the problem.if not its def a contributing factor. This is the fuel pump relay pigtail.
11-29-2018, 03:30 PM
