mikepayne

As the title states I had a mishap with a cheap wheel in my 94 LS. I'm a rookie to this forum and this is my first post which makes me hope you guys can help out, as I've seen lots of great info floating around here from members like PD when I'm out searching around.

Back to my problem had a wheel break in two (****ty scenario) in the moment it took my car to stop a few wires (15) were stripped from their insulation. Causing a fairly big short, and blowing a handful of fuses as well as disconnecting the ground from the negative terminal of the battery. I've spent the past week trying to run my head around the issue and searching my *** off (possibly not searching the obvious) my car gets no spark which I don't know why, my fuel pump is getting no power (thought it was the fp ecu swapped it still nothing) my engine control is getting power on a handful of pinouts but when ignition is turned to on no check engine light (not burnt out already checked) I also looked over the ecu took the plates off for inspection no burn marks and didn't smell like it got hot, just checked the harness where it rubbed, yet again and there are no breaks in the wires so i shrink wrapped them instead of tape and I replaced all fuses that blew but still no spark no fuel. The car cranks just fine but wont wake up. I think a relay or two can be the culprit but when the ignition is on I definitely hear them up front. If this has been talked over a hundred times I apologize for my ignorance; I must have missed it but any help would be greatly appreciated, trying to get it running again before I ship out to basic.

Thank you for any help

mikepayne

Here is a photo of what I'm working with, it is NOT electrical taped as it sits now

PureDrifter

iTrader: (10)

did...did you just twist the wires together and then cover them in electrical tape?

or is there some proper solder/splice work going on that i can't see...

to start with, repair the harness properly, that means NO visible copper, and matching all the wires, repairing where needed with the right gauge/type of wire, solder, and heatshrink. then after that you can move onto the fuses, relays, fusible links, and ECU(s).

how did you break a wheel in half?

mikepayne

Thanks for the reply, but no.. I'm definitely not an idiot, I understand that is a lot of info to retain I probably should have worded it differently and used a different photo but that is the only one I have at the moment.

The harness by no means needed to have wires spliced in since no wires actually cut or frayed only the insulation was damaged. This photo was taken while I was taking the tape off to shrink wrap everything; only reason why I taped in the first place was to transport the vehicle without further damage. Harness is now repaired using shrink wrap although the first time when taped no copper was visual that's besides the point. Checked the harness and it has continuity and NO breaks NEVER did (until cut for shrink wrap tubing)

Since i didn't need to really do anything to the harness except reinsulate everything i've checked all the fuses inside and out which are good. I seem to check those more often than anything in hopes I forgot or missed one. The fusible links were tested for power all of which do.

Which leaves me to my relays and controlling units, no idea if these are bad but car isn't starting at all and as I said no spark no fuel, no power to fuel pump.

Driving home some punk got to my front right fender and started getting into my lane while slamming on his brakes, causing me to hit the brakes I swerved a little and it pointed at a curb at 45-50. Not happy about the situation should have just hit the dood.

mikepayne

Wires are soldered where need be and no **** electrical tape covering wires.

timmy0tool

iTrader: (7)

sorry to hear about this. fixing this current harness does not guarantee the rest of the harness up and down are ok as well. a short can cause other sections of the harness to fail elsewhere. and where to start is very difficult. do you have access to a factory service manual? i would check what that harness provides then check all that is connected to it. a quick test is to also obtain another ECU just in case your current one is toasted. good luck!

PureDrifter

iTrader: (10)

you really should have replaced any wires with insulation missing more than a couple milllimeters, just because there's continuity doesn't mean the signal is clean and clear.

mikepayne

So what you're saying is though they're now re insulated the right way I should have just replaced the wires though they didn't break?

LScowboyLS

you likely just have a circuit breaker open or a relay smoked that is critical to the starting process, you did check all under hood fuses, right? are you sure you checked all fusible links, how do you know?

if you have multimeter, and your car's battery, you can test any relay pretty easily

you can goggle the Nippon Denso or Toyota relay number and get the pinout, so each relay's schematic makes sense, and many of the relays even have their schematic printed right on the relay itself for you!

I would also clear the codes and reset the ECU to its default state by disconnecting negative battery for a while and then rescan the DTC codes using the instructions here, the codes will likely tell you which relay or circuit breaker is causing the no start condition, but there aren't really that many anyway that could cause it.

Let's all say a prayer that his ECU hasn't been damaged, it is fairly well protected from these type of events, but it is certainly a possibility, though a low probability.


his fix is not optimal, but not enough of a problem to cause a no-start condition, as long as "no wires were actually cut or frayed" as he stated, this part is fine for now for the purposes of getting it going.

PureDrifter

iTrader: (10)

that's the best and preferred fix.

messed up insulation can screw with expected resistance values for sensors and such.

LScowboyLS

I am sorry, but this is just incorrect information

if you don't believe it, take some wire, strip off the insulation and measure it both ways yourself

LScowboyLS

another thing to consider, is that you may not think you have damaged any wires, other than their insulation, but with the kind of force it takes to strip off insulation, you may have damaged a wire in some area that you cannot see or are aware of (such as broken it further up the harness) - so that would be the next thing I would investigate after the circuit breakers, fuse links, relays

this is where the DTC codes will help, say you get a code for crank position sensor, then it is likely a wire leading to it was broken further up where you cannot see (inside the loom)

you may well need to get this document ordered on ebay tonight

PureDrifter

iTrader: (10)

yes in a clean lab environment you can run an uninsulated multistrand copper wire without ill effects.

Try doing that in an open, dirty area like a car's wheel-wells and see how well the wire conducts after some exposure to the elements, provided it doesnt short against the chassis first.

I'm not even going to get into the shielded signal wires, and what happens when the shielding is damaged...

LScowboyLS

no one has advocated that he run the car with uninsulated wires, he re-insulated them, and while perhaps not identical to the way Toyota did, his insulation being a bit different than stock is not what is keeping this car from starting, nor is it changing the resistance of the wire, as you previously erroneously stated.

and btw, where are any shielded wires in his photo above?

mikepayne

I've checked the fuses, and fusible links, haven't checked the relays because I wasn't sure how. The ecu has been reset because I had to remove the batter to clean up the harness. I can't read the codes though because my check engine light won't light up and being an OBD1 car that's how I've read any codes. Not entirely sure where the breakers would be either (sorry for my ignorance) I haven't had any mishaps with the car until now. I definitely looked further in he harness than where the wheel rubbed through but didn't see any breaks, it is a possibility that I could have pulled a wire from it's pin though. Originally I taped tr harness back up to see if I could get it to start as well as shield the wires some while I towed it home. That wasn't the perminent fix as I've shrink wrapped everything now and still no start. So no my car hasn't ran since the wires were stripped of itheir insulation. The photo above was taken while I was pulling the tape off to shrink wrap, I haven't left the wires bare at all.