The always frightening electrical problems

cre · 02-21-2012, 10:58 PM

Going standalone isn't going to be any easier; You'll still have to replace the wiring harness then diagnose and replace any bad sensors (and replace any that are incompatible)... With some setups you'll need to add additional sensors and make modifications to mount them (such as a crank position sensor). Then there's tuning, the cost of adding a wideband (if you want reliability and on-board tuning). The easiest to install standalones use the stock wiring (ie: AEM and Apex'i).

Most wire harness failures are located at or near the connectors or in high heat locations. If you have recurring error codes they'll often point out the most likely suspects. The wiring which passes over the engine (AFM, CPS, oil pressure, temp sensors and O2) are the most susceptible to heat damage. Testing the wiring for voltage drop is a simple procedure once you get the hang of it.

If you opt to get a replacement OEM harness you may find that Toyota no longer has them (probably not too bad as you would then find out they ran around $500)... There is an established wire harness company who has added replacement 7M wiring harnesses to their product line, but I can't remember who and don't know what the pricing is. Personally, I just rebuild them myself, but it's time consuming and getting replacement clips is sometimes a pain.

No error codes coming up?

supraheelfan · 02-28-2012, 07:00 PM

No more codes, I almost drove it for two days; at the end of the second day it broke down on me again. So its back at the shop. The issue with starting it can be remedied, however the fuel cut is still coming on randomly-doesn't matter what boost or rpm it only happens randomly (sometimes it hits full boost and others it can barely boost at all) and still no codes..

ReelBandit · 02-29-2012, 02:55 AM

CRE, if you can remember who has the engine harness can you post it? Mine is shot, connectors are brittle and breaking. I can build a new one but I need the connectors and pins.

cre · 03-01-2012, 11:15 PM

Quote:

Originally Posted by ReelBandit

CRE, if you can remember who has the engine harness can you post it? Mine is shot, connectors are brittle and breaking. I can build a new one but I need the connectors and pins.

I don't recall, I've always just rebuilt my own. If I happen to remember I'll let you know.

02-21-2012, 10:58 PM	#1
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	Going standalone isn't going to be any easier; You'll still have to replace the wiring harness then diagnose and replace any bad sensors (and replace any that are incompatible)... With some setups you'll need to add additional sensors and make modifications to mount them (such as a crank position sensor). Then there's tuning, the cost of adding a wideband (if you want reliability and on-board tuning). The easiest to install standalones use the stock wiring (ie: AEM and Apex'i). Most wire harness failures are located at or near the connectors or in high heat locations. If you have recurring error codes they'll often point out the most likely suspects. The wiring which passes over the engine (AFM, CPS, oil pressure, temp sensors and O2) are the most susceptible to heat damage. Testing the wiring for voltage drop is a simple procedure once you get the hang of it. If you opt to get a replacement OEM harness you may find that Toyota no longer has them (probably not too bad as you would then find out they ran around $500)... There is an established wire harness company who has added replacement 7M wiring harnesses to their product line, but I can't remember who and don't know what the pricing is. Personally, I just rebuild them myself, but it's time consuming and getting replacement clips is sometimes a pain. No error codes coming up? __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

02-29-2012, 02:55 AM	#3
ReelBandit Stock Join Date: Apr 2010 Location: Johnson City, Tn Posts: 19	CRE, if you can remember who has the engine harness can you post it? Mine is shot, connectors are brittle and breaking. I can build a new one but I need the connectors and pins. __________________ 1987 Supra Targa 7MGTE 5 speed

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02-28-2012, 07:00 PM	#2
supraheelfan 3" Exhaust Join Date: Feb 2011 Location: Wilmington, NC Posts: 178	No more codes, I almost drove it for two days; at the end of the second day it broke down on me again. So its back at the shop. The issue with starting it can be remedied, however the fuel cut is still coming on randomly-doesn't matter what boost or rpm it only happens randomly (sometimes it hits full boost and others it can barely boost at all) and still no codes..