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Blown fusible link, no start, no ecu diagnostic lights, power light flashing


Cuong Nguyen
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So I've been having some running issues with the truck lately and so figured it was time to do some much needed maintenance.
Cleaned the MAF sensor. Soldered in a new MAF sensor plug harness with a separate ground wire attached. Original one broke and had some corrosion. 
Replaced the fuel pressure regulator vacuum hose and replaced all fuel injectors. I had one bad so went ahead and replaced all of them.
Attempted to start it and heard a pop and smoke near the battery (had hood open). One of the fusible links blew.
Took a look at the ecu and did not see any lights and could not pull codes.
Also the power light was flashing like 16 times (guessing limp mode) for transmission?

What I am trying to figure out is what would cause my fusible link to just pop like that?

I traced the wire (White) from the fusible link and it took me to the ECCS relay (via electrical diagram).
Is the ECCS relay the Main Relay or the Check relay under the hood on the passenger fender wall?

 

https://imgur.com/tgzbnA3

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Double-check your MAF wiring. If you grounded the wrong wire, that could be what popped the fuse link, taking out power to the ECU (hopefully before anything else was damaged). The trans computer gets its TPS and engine speed data from the ECU, so it might just be pissed that it's not getting that. Should be one flash, then ten flickers, with one longer flicker corresponding to which circuit it thinks is damaged. If the Power light flashes continuously, it's got a power issue. Could be the TCU lost a power feed when the ECU's fuse link blew. In any case, the flashing power light seems like a symptom, not a cause. If the MAF ground checks out, check the injector wiring harness. Something is shorted out.

 

ECCS is the first green relay (looking from the front). Labelled main relay on the fuse box cover in mine. The blue check relay is bulb check, for the idiot lights I think.

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15 hours ago, Slartibartfast said:

Double-check your MAF wiring. If you grounded the wrong wire, that could be what popped the fuse link, taking out power to the ECU (hopefully before anything else was damaged). The trans computer gets its TPS and engine speed data from the ECU, so it might just be pissed that it's not getting that. Should be one flash, then ten flickers, with one longer flicker corresponding to which circuit it thinks is damaged. If the Power light flashes continuously, it's got a power issue. Could be the TCU lost a power feed when the ECU's fuse link blew. In any case, the flashing power light seems like a symptom, not a cause. If the MAF ground checks out, check the injector wiring harness. Something is shorted out.

 

ECCS is the first green relay (looking from the front). Labelled main relay on the fuse box cover in mine. The blue check relay is bulb check, for the idiot lights I think.

Would the low oil, hand brake, and low battery light staying light mean anything in this case? Usually bad alternator but it's not running for it to stay on. I guess I'll pull it and take it to get tested.

No fuses popped under the dash. 

 

Guess I'll rip open the maf plug job to verify everything again for peace of mind. 

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If it's not running, it's not making oil pressure, and it's not charging. I would ignore those lights unless they stay on once the short is sorted out and the engine is running again.

 

 

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Well if I disconnect the the alternator plug the battery and brake light turn off.....lol
Fuel pump is not priming either so that lead me to think ecu.

Had some time after work to pull the ecu out. Opened the covers and sure enough, I found a burned spot.

Anyone with FAST can help me ID which ECU I can use? I need a non California model. I have a 93 2wd. 4wd could work. Anything before 94 with the electric speedo.05b5a690ffa96c671043f1a58515c701.jpg0f77922def997ff449f9e4c96f8fd9c9.jpg

Sent from my SM-N960U1 using Tapatalk

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Oof. Yeah, that's good and roached. Find the short yet?

 

I would expect any federal/square dash/MPFI/auto trans computer to work, but I'm no help on the numbers.

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Posted (edited)
On 6/26/2021 at 5:16 AM, Slartibartfast said:

Oof. Yeah, that's good and roached. Find the short yet?

 

I would expect any federal/square dash/MPFI/auto trans computer to work, but I'm no help on the numbers.

I hooked the wrong black wires together.  Mistook the black with white to be ground on the TPS harness after I had did a clean cut and splice with solder. The black with white was ignition hot....... Crazy thing is, this was how it was hooked up for the past decade or so and ran fine as far as I can tell but had some corrosion/oxidation on the wiring.

Just ordered a 93 4wd Auto ECU so well see how it goes. If it starts running again, I'll start diagnosing my @!*%ting running issue (suspecting Chinese eBay injectors at fault, currently)

 

Super lucky and thankful for JWT for creating a chart of ECU IDs based on part numbers.  It's only limited but points me in the right direction. Nissan FAST only lists NISSAN part numbers and do not indicate Hitachi's part numbers as that is the only identification on the ECU casing. 
When searching, you have to rely on the VIN numbers and seller's description of vehicle it came from.
http://jimwolftechnology.com/wolfpdf/ecu-id.pdf

Edited by Cuong Nguyen
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I hope so too. I have been continuing my unlucky streak of misfortune. Thieves stole the cats off my Tundra while I was at work Monday and there's a rental shortage here due to the pandemic so I'm carless at the moment and other crap went downhill because of this nuisance. Toyota is backlogged on orders and wont expect shipments of converters for another 3-6 months.

 

My new ECU should be here Friday. 

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  • 1 month later...

I did the same thing running a ground for my maf years ago. Luckily i didn't toast the ecu. Tracked my issue down to misinformation in a factory wiring diagram and i didn't confirm wires before i hooked it up. 

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