Engine harness problems...

[kmckiness]

I have a pretty bad problem.

I currently have a 1988 Supra turbo automatic and just had my entire engine and trans rebuilt / upgraded. My engine harness that I was using is shot. It is missing connectors, the wire is brittle, and you can hear it breaking if you bend it slightly etc. I was planning on getting a new harness but found out that the 88-89 auto ones were discontinued. My mechanic that is working on my car has been in touch with Toyota and has been told different stories about being able to get one from Japan, that they have one on the way, or that they were not sure. I have been waiting on it for at least 3-4 weeks now without much on a positive outlook. I just found out that Toyota does have the 90 and newer engine harnesses in stock for the auto.

My question is would a 90 auto 7mgte harness work on an 88 auto 7mgte? I understand that it might need to be slightly modified and such but would be better to cut and crimp / solder different connections in certain spots than to try and use my old garbage harness.

If it wont work then what would be the best way for me to get my car back up and running?

Thanks in advance,
Kevin

 

[SublimeSupra]

As far as i know the only differnce between years is the connectors and a few sensor but im not %100 sure someone else would surely know though.

 

[ross1]

did you check suprasport.com they sell new harness that are matched to VIN number, i'd say call them and see, if not you may have to change a few sensors for the 90 harness but most importantly you'd have to get a new ECU the has the same plugs as the 90 harness on the inside...

hth

ross

 

[kmckiness]

Thanks for the responses.

I tryed emailing suprasport about a month or so ago and got no response on the 88 auto harness. They also updated their site a bit ago (it looks as if after the email) stating "All 1988 & Prior Automatic ECU / EFI Wiring harnesses have been discontinued from TOYOTA".

Every time I call them it always goes to a voicemail message as well.

I am just getting a bit annoyed with the Toyota dealers due to the fact that it seems that they are stringing along myself and my mechanics. They had us prepay for the harness and they were not even sure they had one to begin with. I might ad that the pre-payment was around 970ish bucks. I know it is rediculous for a harness but if it is new and will prevent my car from having electrical issues down the road then I will bite the bullet and pay that price.

 

[kmckiness]

So, if I got a 1990 ECU for the auto 7mgte supra then a 90 harness should work for my car with a slight bit of modifications to the end plugs on the harness?

 

[supra90turbo]

Stick with the 88 harness and ecu. Even though you may not be able to get a brand new one, you should be able to get a good used one.

Have you tried Jeff Watson? He should be able to get you a new one.

Changing to 89+ is going to be a pain in the ass

 

[Halsupramk3]

I am not sure about 88 harnesses but doesn't the harness plugs that go to the body harness differ from 88 to 90. I tried a 89 harness on my 90 and one large square plug was different and would not connect. Of course the 89 did not have the white air bag plug. Also there are different colors used for the wiring between the years and probably plug wire layout for various pin electronics. If you could convert the wiring configuration from 88 plugs to 90 plugs that would be a feat and help out many members. Of course i am talking about the 3 or 4 plugs that goto the body harness and not the ecu. You would just use a 89+ ecu and correct engine sensors. I have not compared my 90 wiring manual to the 88 to see if the plug pins are a different layout. I am so glad i bought a new harness for mine 3 years ago for i think $470 or so? I dont remember. A new harness is one of the best mods to do especially if you plan on keeping the car.

 

[kmckiness]

I already tryed Jeff and Toyota no longer carries the 88 or even 89 auto harnesses. They have the 88 manual harness but that does not help me. The autos are discontinued (except for 90 and newer) so I would have to attempt to track down a used harness but I am concerned with using a used one due to the fact that I am likely to run into the same problems that my current one has. The internal wires are brittle along with the plugs and easily break.

I just spent around 3 grand having my motor fully rebuilt and some minor head work done with oversized valves along with another grand for a fully rebuilt trans with a higher stall plus stronger clutch packs. I definitely plan on keeping this car for a very long time. This car was my first one that I ever owned and I got it back in the summer of 2001.

This is why I am trying so hard to find good replacement parts and re-doing all of the used mechanical parts that are worn out.

Where would you recommend that I get a good used harness from?

 

[bigaaron]

I think I can get the harness for you. We have purchased 5 new Toyota harnesses in the last few months. We have a Toyota insider :icon_wink
I'll find out on Wed.

I did put a early 89 harness in my 88 car so I could use the newer ecu. It has all the right body connectors, but there are a few differences in the pinouts, one of which will damage your headlight control relay and cause the headlights not to work! I have it all working now, but the lower redline just sucks with a turbo that wants to pull way past 6200 rpm!

I do have an auto harness that is in better then average condition. It looks a little dirty because it was sitting on my patio and got cat hair on it, but it's really not bad. It needs just the connectors for the coolant temp sender and the oil press sender but I can put those on for you. I was asking $120 shipped for it, lmk if you are interested.

 

[kmckiness]

I think I can get the harness for you. We have purchased 5 new Toyota harnesses in the last few months. We have a Toyota insider :icon_wink
I'll find out on Wed.

I did put a early 89 harness in my 88 car so I could use the newer ecu. It has all the right body connectors, but there are a few differences in the pinouts, one of which will damage your headlight control relay and cause the headlights not to work! I have it all working now, but the lower redline just sucks with a turbo that wants to pull way past 6200 rpm!

I do have an auto harness that is in better then average condition. It looks a little dirty because it was sitting on my patio and got cat hair on it, but it's really not bad. It needs just the connectors for the coolant temp sender and the oil press sender but I can put those on for you. I was asking $120 shipped for it, lmk if you are interested.

Would you be able to get me a new 88 auto harness?

Is the used one for an 88 auto?

If so, I would be interested in either the new or used one.

Also, what do you mean about the lower redline? Do the newer ECUs have a lower redline than the 88 ECUs?

Thanks,
Kevin

 

[ross1]

yeah, i think it's late 89's and newer are 6250 instead of 6500 or something around there had something to do with weighting of balancing of the crank.

ross

 

[lagged]

as long as you keep the year of your harness and ECU in the same range (ie: 87-88 harness with an 87-88 ECU, and newer 89 - 92 with the later89-92 ECU) you should be fine.

 

[3p141592654]

Didn't the transmission connectors change as well on the 90+ harnesses?

 

[bigaaron]

Would you be able to get me a new 88 auto harness?

Is the used one for an 88 auto?

If so, I would be interested in either the new or used one.

Also, what do you mean about the lower redline? Do the newer ECUs have a lower redline than the 88 ECUs?

Thanks,
Kevin

I found out the 88 auto harness was discontinued in '04 from Toyota. I can still get the early '89 harness, but you will need the newer ecu also. The used harness I have is the same thing. The used harness is not very crunchy and is in good shape.

 

[lagged]

i can refurbish engine wireharness for a reasonable price. i had to completely rewire my harness after the engine fire and not only does it look great, but whats more important is that it worked on the first try, not that i was worried it wouldnt .

if anyones interested.

 

[kmckiness]

How much would it cost roughly for a refurbished engine harness?

What is replaced on it when you refurb it?

Thanks,
Kevin

 

[lagged]

How much would it cost roughly for a refurbished engine harness?

What is replaced on it when you refurb it?

Thanks,
Kevin

i think around 175 would be a fair price.

anything that needed to be replaced. if the insulation is damaged on any wires, that wire would be replaced. any plugs that were damaged, as long as i can source them would also be replaced. all soldering would be done by an EXPERIENCED person (me, ive been making repairs like this for a long time now) and all of the loom would be replaced by high quality automotive grade wire loom.

it would look like new from toyota.

you pay to ship it to me, and ill pay the shipping to get it back to you.

i could also beef up the knock sensor wiring since that code is a common problem, espcecially with older harnesses. i would include chassis ground straps for the sheilding. no more KS code! this would be for an additional 15 dollars.

 

[Halsupramk3]

as long as you keep the year of your harness and ECU in the same range (ie: 87-88 harness with an 87-88 ECU, and newer 89 - 92 with the later89-92 ECU) you should be fine.

Lagged:

You need to read this post a little bit closer. Getting a good harness for 88 down will be a problem. If you switch the engine harness from 88 to 89 or 90 you will need a 89+ ecu but the other plugs will not plug n play into the body harness plugs that the engine harness uses. The connectors for the ecu will be fine but it is the other connectors that plug into the body harness from the engine harness that will be different. Some of the plugs are different/uncompatible and some of the pin outs of these plugs are different. I could not plug one plug from the late 89 harness i bought into the corresponding body plug of my 90. Of course the ecu plugs worked but the rest of the harness did not. When you rewire the harness i guess you use the same plugs for the body harness side. Sounds like a difficult procedure.

Lagged do you have access to pins and the small female tips for the wires in the plugs?

Are 87 to 88 5 speed turbo engine harnesses still available from toyota?

It would be easier to switch to 5 speed than rewire the harness i would guess but i have never done that. Year 89 harnesses are in two styles, early and late. the 90 harness has a air bag and will not work PnP for late 89. I think 91 and 92 are the same but different from 90.


Saddened to hear that toyota is not making these harnesses any more but for the late years.

 

[bigaaron]

Lagged:

You need to read this post a little bit closer. Getting a good harness for 88 down will be a problem. If you switch the engine harness from 88 to 89 or 90 you will need a 89+ ecu but the other plugs will not plug n play into the body harness plugs that the engine harness uses. The connectors for the ecu will be fine but it is the other connectors that plug into the body harness from the engine harness that will be different. Some of the plugs are different/uncompatible and some of the pin outs of these plugs are different. I could not plug one plug from the late 89 harness i bought into the corresponding body plug of my 90. Of course the ecu plugs worked but the rest of the harness did not. When you rewire the harness i guess you use the same plugs for the body harness side. Sounds like a difficult procedure.

Lagged do you have access to pins and the small female tips for the wires in the plugs?

Are 87 to 88 5 speed turbo engine harnesses still available from toyota?



It would be easier to switch to 5 speed than rewire the harness i would guess but i have never done that. Year 89 harnesses are in two styles, early and late. the 90 harness has a air bag and will not work PnP for late 89. I think 91 and 92 are the same but different from 90.


Saddened to hear that toyota is not making these harnesses any more but for the late years.

Ok, the early 89 harness has all the correct connectors for the body harness of the 88 car, with the ecu connectors for the 89+ ecu. There are only 2 or 3 wires on the big square connector that must be moved to a different position on the same connector they are in. There is one more connector that you may need to change but all the colors are exactly the same and it is also very easy to do, a LOT less work and a LOT less money then a 5 speed swap. As long as you have the late model ecu its all good. If you change to a late 89-up harness then there are some major differences. The harness I have has no cracked wiring at the connectors and I have plenty of split wrap and electrical tape if you want it cleaned up before I ship it. Honestly though, this harness is not something I need to sell, it's worth more to have it here for when it's really needed.

 

[Halsupramk3]

Ok, the early 89 harness has all the correct connectors for the body harness of the 88 car, with the ecu connectors for the 89+ ecu. There are only 2 or 3 wires on the big square connector that must be moved to a different position on the same connector they are in. There is one more connecotr that you may need to change but all the colors are exactly the same and it is also very easy to do, a LOT less work and a LOT less money then a 5 speed swap. As long as you have the late model ecu its all good. If you change to a late 89-up harness then there are some major differences. The harness I have has no cracked wiring at the connectors and I have plenty of split wrap and electrical tape if you want it cleaned up before I ship it.

good to know. It sounds like the early 89 harness is basically an 88 with the 89+ ecu. confusing that a car made for 5 years has 5 different wiring harnesses. Screwing around with the pinouts of a 89+ engine harness to add the 88 body plugs so it would fit the body harness would be a PITA.