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6G Celicas Forums > 6th Generation Celica > Engine/Transmission/Maintenance
m2736185
Picked up another celica today! However it needs work...a lot of work. I am trying to get this one running and make it my daily driver so I can prepare the 95 vert for the 3sgte swap.

Anyways, here is the story behind this celica...apparently the engine was sputtering over 45MPH so this lady was having her (crazy) fiance work on it. Things ended badly and he didnt want her driving the car so he unplugged and did god knows what to every wire in the engine. I will try to post pictures tomorrow. I am familiar with 5s engine, but the 7A seems foreign to me.

The celica is a 1994 GT the 7a, however the engine was replaced with a 1996 7a engine and tranny.

I tried starting it today, but the starter would not engaged. The lady stated it had started before.
Bitter
7A engine you mean?
m2736185
Yes, of course. Isnt that what i said tongue.gif
stephen_lee
id check egr stuff. does it accel smooth?
m2736185
Got it started today...idles really rough. As you guys can see the engine harness is a mess any help would be appreciated if you guys know where or what these plugs are.

1. Here is the distro. I know they took the original one off and put this one on here


2. No idea what this is. I followed a wire that was held down by a fuse and found it spliced into one of thse wires.


3. Here is a close up of #2


4.?


5. ?


6. ?


7. ?


8. ?


9. ?


10. ?


11.?

richee3
Ouch.... That looks painful. I'd be tempted to go to a junk yard and find another 7A, rob the harness, and start from scratch.

#2 is the fuel pump. Check the wire you traced and see if it has constant power. Could be an issue. #6 looks like a spark plug wire coming from the dizzy. Where is the other end? I bet that has something to do with the rough idle.

I wish I could tell you the rest but sadly, it might be a case of tracing each and every wire to see where it ends so you know what each one is for.
Bitter
I'd venture a guess that the fuel pump wasn't getting power so they ghetto rigged it.

run the vin, make sure that didn't have a 5S engine in it originally or something, I've never seen any 7A with external coil.
m2736185
QUOTE (Bitter @ Feb 21, 2012 - 8:41 PM) *
I'd venture a guess that the fuel pump wasn't getting power so they ghetto rigged it.

run the vin, make sure that didn't have a 5S engine in it originally or something, I've never seen any 7A with external coil.


Yea, its an odd case I thought every GT came with the 5s. The trunk says GT the hood says 7A, but the rear also has drum brakes. The vin Reads JT2AT...i believe thats a 5s Vin

Ohhh that makes sense. Yea, the fuel pump was rigged to one of the fuse panels, but I ripped outt he wire and it still starts so I guess the fuel pump isnt the problem

Yea, I think #6 went to the old distro. It musta been the ground or something, but the new one doesnt have a spot for it.

Hopefully, I can find a 7A in the junkyard.

Can someone confirm this the 7A changed in 95 so if its a 94 with a 96 motor I will need to look for a harness from a 7a 95+?
mandrek
QUOTE (m2736185 @ Feb 21, 2012 - 9:27 PM) *
QUOTE (Bitter @ Feb 21, 2012 - 8:41 PM) *
I'd venture a guess that the fuel pump wasn't getting power so they ghetto rigged it.

run the vin, make sure that didn't have a 5S engine in it originally or something, I've never seen any 7A with external coil.


Yea, its an odd case I thought every GT came with the 5s. The trunk says GT the hood says 7A, but the rear also has drum brakes. The vin Reads JT2AT...i believe thats a 5s Vin

Ohhh that makes sense. Yea, the fuel pump was rigged to one of the fuse panels, but I ripped outt he wire and it still starts so I guess the fuel pump isnt the problem

Yea, I think #6 went to the old distro. It musta been the ground or something, but the new one doesnt have a spot for it.

Hopefully, I can find a 7A in the junkyard.

Can someone confirm this the 7A changed in 95 so if its a 94 with a 96 motor I will need to look for a harness from a 7a 95+?



it changed in 96
m2736185
ohhh thats right...thats when OBDII started. Perhaps that explains some of the wiring? What type of modifications would be necessary to drop a 96 7a in a 94 GT celica?
mandrek
QUOTE (m2736185 @ Feb 22, 2012 - 3:24 AM) *
ohhh thats right...thats when OBDII started. Perhaps that explains some of the wiring? What type of modifications would be necessary to drop a 96 7a in a 94 GT celica?

i am in the process of doing that exact thing right now.

all that you need is a your 94 intake manifold, and TB.... and harness/ecu... and dizzy
m2736185
TB...timing belt?

Mandrek: I am heading to the junk yard now....so what you are sayiing is I need to use the 94 harness/ecu and distro and not the 96? Doesnt the 96 distro have the cam sensor built in?
Smaay
wait a minute? you have a GT with a 7A in it? dude nothing is going to work right. why are you even messing with a 7A? put a freaking 5S in there like it belongs! you know if its really a GT by looking at the firewall. the chassis number is stamped in it. if it says ST204 then its a GT, if it says AT200 then its an ST
m2736185
Smaay, I picked it up to use as my DD so I can prepare my 95 GT for a 3sgte swap in the summer. I thought it was gonna be an easy fix, but it turned out to be a little more complicated that I thought. Ill check on the firewall....idk what they did to this poor car.
mkernz22
If there are drums in the rear, then it's an ST with a GT emblem slapped on there.

TB = THROTTLE BODY.
just for a future reference
m2736185
ah I will remmeber that. So the stamp on the firewall confirms its a ST, however the vin decoder states in a GT, but I will go with the stamp.

I am confused about the need to keep the 94 TB, intake manifold, engine harness and TB.

Would it not run better if you swapped a 96 engine WITH the 96 ecu, engine harness, manifold, TB and dizzy.

Any idea how to tell what year the intake manifold and TB is from? I tried looking for a part number or vin, but I couldnt find one. I am going to finish removing the dash and glove box so I can see if I can tell what year the ecu is from. Here is a pic of the Diagnostic port...thats def not OBD II so I am gonna assume the ecu and harness is obd I



Bitter
Get the part number on the ECM and use Toyodiy to see what year the PCM is. You want everything the same year.
mandrek
yeah at that point it may just be easier to just get a whole new motor harness and ECU.. sounds like allot, but if you are changing everything over then it will make the swap allot cleaner. and easier to make sure that things are going where they should.... and plz dont take offence to this.. but DAMN!!!!!! i havent seen a hack job engine bay like that since the last honda meet i went to.. (back when the B18c was top dog) yup a clean slate may just be the best thing for you... all comes down to $$..
m2736185
Ha ur tellin me the wiring looks worse in person and this isnt the car im doing the swap in. The swap is going in my 95 GT Vert. This one is suppose to be my DD while I work on it. So I am planning on fixing it the cheapest way possible. It would be awesome if it was a 5s then I could just refer to my GT, but it doesnt help I have never seen under the hood of a 7a. I am going to tear the dash apart today and see if I can get some damn part numbers so I have an idea of what they did in there.
m2736185
AHHHH, wtf. So i just spend about 2 hours removing my dash and breaking one of the brackets in the process and as I was about to remove the LAST wireharness I followed it to the ECU which was just by the passenger kick panel.

I used toyodiy and I believe it says its a corolla ECU.

It is Labled
89661-1A860
175300-0621 12V
4AG-MT
m2736185
Im heading to the junkyard tomorrow....with the assumption that they used the 96 intake manifold can I use a 96+ engine harness and ECU? will all the plugs fit into the ecu?
mandrek
well, if the manifold is an indicator then, there is a chance that it is indeed a 96 motor.. best way to check would be to see if there is a sensor on the crank (on the oil pump housing) and if the dizzy is just a straight bolt in, or if it has elongated holes that would allow for it to be rotated some.. if it is the straight bolt in then it is a 96+ for sure. if not.. well, it could be that they put an OBDI dizzy on it to try to make it work...

if all the signs point to it being a 96 then yeah, a 96 harness and ECU should be the key for you..
m2736185
The motor is indeed a 96. I got the vin number off it. The dizzy was changed by the previous owner trying to fix the problem so that wouldnt be much help. I am not sure the difference between the 94 and the 96 intake manifold or TB so I havent been able to check that.
m2736185
Here are some pictures idk if anyone can identify the year the intake manifold or TB is from pictures









ECU found in the car

Looks like they did some modification to the harness
mkernz22
i don't believe the car should have a 4a-g ecu in it, but i've never see a 7a before.
mandrek
OMG!!!

well that is defiantly an OBDII mani.. as far as i know any harness and ecu from 96+ would work for ya.. Smaay should be able to give you a more definitive answer. as he has worked on SOOOOO many 7A's....


QUOTE (mkernz22 @ Feb 24, 2012 - 2:07 PM) *
i don't believe the car should have a 4a-g ecu in it, but i've never see a 7a before.

yeah lol, that may be an issue as well. lol
m2736185
Yea, that was the first person I thought of asking, but he said he doesnt know if the ECUs have the same number of plugs.

Doesnt seem like many people have any experience with the OBDI -II swaps.

Well, I guess I have a complete 96 engine and tranny swap...then who ever did the swap realized the ECU wasnt gonna work so they assumed one from a corolla would.

Since everything in the engine is 96 I would really prefer to just swap a 96 harness and ecu on there, but I need to know if its gonna work....otherwise im gonna have to track down a 94/95 ECU, harness, TB, mani, dizzy.

Can anyone shed some light on this? It will be one extra celica saved from the junk yard
mandrek
QUOTE (m2736185 @ Feb 24, 2012 - 5:58 PM) *
Yea, that was the first person I thought of asking, but he said he doesnt know if the ECUs have the same number of plugs.

Doesnt seem like many people have any experience with the OBDI -II swaps.

Well, I guess I have a complete 96 engine and tranny swap...then who ever did the swap realized the ECU wasnt gonna work so they assumed one from a corolla would.

Since everything in the engine is 96 I would really prefer to just swap a 96 harness and ecu on there, but I need to know if its gonna work....otherwise im gonna have to track down a 94/95 ECU, harness, TB, mani, dizzy.

Can anyone shed some light on this? It will be one extra celica saved from the junk yard



no just get the 96 harness and ecu..
m2736185
I guess that's the best option. If the interior doesn't plug in I suppose I will have to rewire the interior. Where can I get a wiring diagram if the worse comes to that?
mandrek
there are some in the online BGB in the stickies.
m2736185
Most of the online BGB are down.

Well, my harness came in today. Came from a 97, but it was cut at some point. I gotta figure out what part was cut.

I got it running today, but it was running really rough with the rpms jumping. Im guessing that is more an issue with the distro that the ECU. Now the fun begins gonna try to identify all the conncections on the wire harness before I proceed. I will update with some pictures.
m2736185
I got the harness today, but there is a nice piece of the sections that was cut. Ill see if I can get a pic
Kwanza26
Holy crap that b!tch is jury rigged... anyway... all i was gonna say is... JT2AT vin code is Celica ST. J for japan... T for toyota... 2 for vehicle type... A for engine type (A for celica ST... S for celica GT)... T for chassis/model. This is universal for most Toyota models originating prior to 1996.
ricochet1490
I cannot shed any light onto the the wiring harness problem, but if you are still using that 4age ecu, that would be the FIRST thing I would change. my .02$
m2736185
Yes, the ECU is going to be changed, but it wont do any good until I can make sense of this wiring.

I wish the previous owner would have left the 4age in there.

Anyways I think the reason I dont see a few of the connectors is...the harness has been cut. I have been unable to locate the MAP sensor, o2 sensor, sensor on tranny and a few others. Here is a pic if anyone can identify this part.

mandrek
QUOTE (m2736185 @ Mar 4, 2012 - 1:37 PM) *
Yes, the ECU is going to be changed, but it wont do any good until I can make sense of this wiring.

I wish the previous owner would have left the 4age in there.

Anyways I think the reason I dont see a few of the connectors is...the harness has been cut. I have been unable to locate the MAP sensor, o2 sensor, sensor on tranny and a few others. Here is a pic if anyone can identify this part.


that big bundle of wires with the white plastic clip on it looks like the harness bundle for the Diagnostics port.
m2736185
I think you might be right. I just looked at my GT and it has a similar plastic clip that splits into the diagnositc port....and the igniter...i might need that.
toyotatech3
QUOTE (mandrek @ Mar 4, 2012 - 6:40 PM) *
QUOTE (m2736185 @ Mar 4, 2012 - 1:37 PM) *
Yes, the ECU is going to be changed, but it wont do any good until I can make sense of this wiring.

I wish the previous owner would have left the 4age in there.

Anyways I think the reason I dont see a few of the connectors is...the harness has been cut. I have been unable to locate the MAP sensor, o2 sensor, sensor on tranny and a few others. Here is a pic if anyone can identify this part.


that big bundle of wires with the white plastic clip on it looks like the harness bundle for the Diagnostics port.


there is a pic of it in my profile. mine is a 97 st
m2736185
So I wish that was just the diagnostic port, but the wires for the igniter is also in that bundle and the 2 wires to the left are for the MAP sensor.

Anyways the harness i bought is also missing the battery cables so I have to splice in my own. I noticed there are 2 wires running to the 100 amp fuse in the fuse block. One is white and one is black. I am guessing one of these go to the battery and then there is another cable somewhere that goes to the starter and alternator?
m2736185
She Lives!

I put in the new ECU for the 7A, fresh gas, checked the pressure of the gas (26-34 PSI). With the help of starter fluid and a few tries until the battery was almost dead it started up. Runs 100x better with the 7A ecu. I guess the previous owners that had the blacktop in there left the exhaust the had on there. Its super loud it make the 7a feel like its faster than my 5s.

Only scary part was after I ran the car for a test drive around the block...I took the key out of the ignition and you would think the car would turn off right? Nope, I ran over to the battery and unhooked the battery cables and still nothing. I was about to pull the cables from the dizzy but it finally turned off.

Still gotta put in the new harness
Figure out why the fuel pump doesnt turn on without my jumping it.
mandrek
QUOTE (m2736185 @ Mar 18, 2012 - 12:47 PM) *
She Lives!

I put in the new ECU for the 7A, fresh gas, checked the pressure of the gas (26-34 PSI). With the help of starter fluid and a few tries until the battery was almost dead it started up. Runs 100x better with the 7A ecu. I guess the previous owners that had the blacktop in there left the exhaust the had on there. Its super loud it make the 7a feel like its faster than my 5s.

Only scary part was after I ran the car for a test drive around the block...I took the key out of the ignition and you would think the car would turn off right? Nope, I ran over to the battery and unhooked the battery cables and still nothing. I was about to pull the cables from the dizzy but it finally turned off.

Still gotta put in the new harness
Figure out why the fuel pump doesnt turn on without my jumping it.


GRATS!!!!!

and as to the pump.. do tell!!!
Smaay
i thought i had posted earlier. that ECU is for a corolla or MR2 with a 4A-GE in it. no wonder you were having so many problems. looks to me like someone thought they could get more power by using that ECU. who knows???
m2736185
Yes, who knows why the ingition doesnt turn it off, but I am going to install the new harness and corss my fingers that it solves all the problems.

BTW it could just be the exhuast making me feel like I am going faster than I am, but it feels faster than my 5s.

Smaay: They had a blacktop swap in the car. It took me a whole to figure out, but it makes sense why they have the ae111 ecu and an external blacktop coil mounted next to the igniter.

The oil is the dirtiest oil I have ever seen and I think it may have been contaminated with gasoline. I bet its the same oil thats been in the engine since it was swapped out of whatever car it came from.


I still need to pick up a map sensor, igniter connector and diagnostic port from the junkyard then I can start the rewiring.

It doesnt seem too difficult. I hope I dont end up eating those words.
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