1995 toyota celica st usdm

i just reinstalled my 7afe after ripping out the ecu wiring harness and motor
replaced the block with a jdm 7afe and used my head and intake manifold of my stock usdm
had the head reseated and reserved installed it all back in and now i have no spark?

i had some spark when i used the jdm ecu but with my stock ecu it didnt fire at all
the jdm ecu made the the ground wire on the passenger side burn up where the wire was showing so i replaced it
but now it didnt wanna fire at all. i know the jdm ecu was for coil packs but i thought i could try it anyways hopefully i didnt f something up

what do i need to do? replace ECU and Wiring harness and distributor all at once and try to start it up again?
i really dont wanna have to buy anything i dont need i did find a guy with a 94 celica st that said he would sell me his wiring harness and ecu for 150 buck


i need some help thanks

jdm engine install

my old ecu no spark after reinstall

Jdm ecu sparked at first but after i continued to try and start it it died

the engine after i put my old head back on with distributor

another pic

another pic

The ECU is grounded to the intake manifold. There is a ground wire coming off of the firewall that needs to bolt to the intake manifold. When you turn the ignition key to the ON position, the Check Engine Light will light up and remain on until the engine is started to show that the ECU is recieving power. If the check engine light does not come on with the other warning lights your ECU is not powering up.

Get out your multimeter and check for continuity between the SOLID BROWN wire going into the ECU and any grounded metal part of the body. If there is no continuity then you have left the ground wire off, a very common mistake. You can either check this brown ground wire at the plug going into the ECU or at the small clear/white connector that is capped off next to the ECU. This small connector is a diagnostic port. Make sure that when you remove any wires from the ecu to turn the car off and disconnect the battery. With the battery reconnected, the key 'ON' and the harness disconnected from the ECU check the SOLID PINK wire using your multimeter for 12volts against any ground on the vehicle. The pink wire is your power wire. Also check the EFI fuse and relay, these are the main source for the ECU's power

yep there is no check engine light

Check the power and ground. The brown wire for ground and pink for power
I bet you a chocolate covered doughnut that you left the ground wire to the back of the intake manifold off, because thats precisely what happened to me when I removed my cylinder head LMAO. Tens of hours checking EVERYTHING and reading the electrical schematics 50 million times. Then in a moment of clarity I remembered the ground strap and the sucker started right up.

At least your oil system is primed real well after all the cranking with no fire, just make sure to run it at 2000 rpm for about 20 minutes so your cylinder head wears in properly. And baby it for a couple hundred miles. I would also suggest double checking the valve shim clearance after you get it broken in.

Good luck dude and Im here if you need me




*EDIT*
Ok I just crawled under the car to verify(damn now im dirty), and on the 5SFE the ground strap actually comes out of the harness that is by the fuel injectors. It drops out of the harness between cylinder 2 and 3 injectors and I have it attached to the bolt that goes through the support bar( the one that goes from the block near the oil pan to the intake) on the intake. Hopefully that is your problem, the engine will come to life, angels will fly down from heaven and all will be good.

This post has been edited by Special_Edy: Apr 17, 2012 - 3:34 PM

there are Two brown wires...

They are both the same, they run together later in the wiring harness. Infact the white wires with a black stripe run into the browns too.


Here is a picture of the wires, the brown wire at the ECU plug is at the top left and the Check Connector is at the bottom right. You can test them at the check connector.

so.... what happens to a ecu if you forget to unplug the battery?

i tested for a positive current and i was getting power pink wire , by the way i thought that plug was for the transmission not the engine? the pink wire goes into the 12pin connector that goes into the ecu...

im sorry if im being difficult im still learning alot.

That check connector has all ground wires in it I believe. To my knowledge it is specifically for checking the grounds not the transmission.

Yes the pink should be in a different connector The fact that iit has power means that the ignition, relays and fuses are okay. And the grounds are the brown and white with black stripe. But its the brown wires that you want to check


edit***
I checked the wiring schematic and pink should be pin 2 on the 12 pin connector, at least it is on the 5SFE. Ground wires will be the pins along the outter edges of the 26 pin plug. In the schematic all the computer's grounds, white with black stripe and brown, all run together to the ground strap on the intake manifold.

If you are getting good ground here then I am going to say you have a bad ECU. If you are not getting ground through the Brown and W-B(white-blackstripe) wires then you are potentially 10 minutes away from fixing it and starting the engine. Stick one lead of the multimeter into the Brown or W-B wire at either the ECU plug or at the white check connector. Now hold the other lead of the multimeter to a good ground on the vehicle and check for continuity( the arrow running into a plus sign symbol). Make sure that you are using a good ground for the test, as every surface of the car is treated with a protective coating such as paint which does not conduct electricity and isnt a good ground. You might check for continuity between two bolts screwed into the floorboard under the dash(possibly good grounds) to verify that you have indeed found an acceptable ground (one of the two bolts) for the test. Let me know how the test goes I might make a video for this tomorrow if you want to wait till then

This post has been edited by Special_Edy: Apr 19, 2012 - 9:59 PM

im going out side to check them now stay online lol

http://buy1.snapon.com/catalog/item.asp?P6...amp;dir=catalog

i have a test light

Tester, Circuit, for 6 and 12V Systems, Green

and i used it to test both power and ground

i clamped onto a ground to test the power

and i clamped onto a power source to test the ground wires and none on that connector worked so somewhere i have a bad ground

is it possible that the jdm ecu when i tried to start it and when it burned up the ground wire that ran to the passenger side fender from intake manifold that it also burned up another ground wire? maybe inside the harness

i replaced the ground wire from the intake manifold to the fender with alot bigger ground wire

This post has been edited by stormmage88: Apr 19, 2012 - 9:54 PM

They all run together so it wont matter if you test it at the ecu plug or check connector. Do you know which wire you burnt up?

all i know was the ground wire from the intake manifold that ran stright to the passenger side fender got hot and burned the plastic off the wire

im thinking that i hooked up a ground to the wrong thing

there is a box cover over some of the harness thats under the intake manifold and there is one wire coming out of it and i think i have it bolted to the block... i think thats a ground wire and that spot isnt a good ground so im gonna try and bolt it to the support that bolts to the intake manifold and the block

if that doesnt work could i just run a ground wire to that connector?

Well to be honest I ran a 10 guage wire from the white check connector to a bolt on the intake manifold once I found there was no continuity. It worked great but I didnt trust the connection to the check connector( I just crammed the wire in there). Also I reattached the ground wire to the intake so the problem was solved.

If its simpler for you- with the ecu completely disconnected, turn the ignition on and test for 12 volts between the pink and brown wire, brown on the 26 pin and pink on the 12 pin connector.

Make sure to spray some cleaner when you reattach the ground to the intake(oil kills electrical connections) and get it to bite into the metal real well. Ive had the ground wire from the alternator valvecover/alternator bracket to the pass fender(5sfe location of the wire that burnt on you)try to burn up but that was because an alternator wire frayed. I think the intake to computer ground would burn first since it is a smaller gauge

This post has been edited by Special_Edy: Apr 19, 2012 - 11:51 PM

it started right up after i ran a ground straight to the brown wires lol but now after i started it like 10 times the starter went out lol

anyways THANKS FOR YOUR HELP it sounded wonderful with my new exhaust on there just gotta finish her up so i can get her on the road now.

No problem man. Glad I could help save you the headaches. My car set for like a year after I rebuilt the head because I was so frustrated with the no spark. Double check your DIY ground strap from time to time to make sure its holding up, or find the break in the original ground strap and fix that.


This post has been edited by Special_Edy: Apr 20, 2012 - 12:46 AM