Constant backfire-Timing?

[jnianekeo]

Hey everyone,

I just finished my 1J swap into my 1988 Ma70 5spd Non-turbo and when I first started the motor it ran and idles great! But now, when i try to step on the gas, it just backfires constantly. its like vrooom pop. if i hold it it will sound like a machine gun. It's seems very hard to get it to rev any higher than 3k.

motor is out of a Soarer.
I followed AF1JZ wiring write up.
A few wires were not used ?, but I followed it exactly. if this makes a difference???

for example...

For the Eb1 and Eb2 plugs, mine were cut off, but i was left with 3 wires untouched all on the same harness.
brown, and two smaller gauge black/red wires.

I didnt wire the B2 plug because my wires didnt match up.
Wiring the B2 plug
• Blue – White from IK1
• Green – Green from IK2
• Yellow/Blue Red IJ2

Wiring the B1 plug is mainly for ignition and fuel
&#8226; Black/Blue &#8211; Black from IK2 (NSW)<-------- i had no Black/Blue on my B1 plug. so i wired to pin 15--->(NSW to cruise control clutch switch (MT)- black/yellow)
&#8226; White &#8211; Blue from IK1 (AT Switch)<--------also had no white wire, so i didnt wire it either


If not wiring.....

Im thinking it could be
- timing? (how do you adjust timing ?)
- O2 sensor
- Bad ECU - leaky caps?
- Misfire? bad spark plugs?

I've rechecked all my connections and I have 2 ECUs which i swapped. still not running straight.
Timing was never touched, tps looks untouched.
no odd noises, idles smooth. no vacuum leaks.

The motor is completely stock with 3 inch exhaust, intake, and FMIC.

Any Ideas on where I should start?

I'll be replacing the spark plugs tmrw. and checking the coilpacks for cracks, and connectors for corrosion.

I'll try to upload a video (56k ftl).

 

[ToyotaFear]

If you did'nt change the plugs when you got it you should. Change the wire well you're at it. Timing It will probably help i'll let someone else explain that IDK what it's suppose to be set at on a 1jz.

 

[jnianekeo]

If you did'nt change the plugs when you got it you should. Change the wire well you're at it. Timing It will probably help i'll let someone else explain that IDK what it's suppose to be set at on a 1jz.

I have a set of NgK-R 6097 on order. Hopefully it helps.

 

[jnianekeo]

UHM.... :weak: soooo I noticed that I removed my gas cap prior to the swap and I never put it back on... until a few minutes ago, when i was about to call it a night.... I put my gas cap back on... started it, and revved for the heck of it... and what do you know..... no more backfire! and I can rev past 3k! :icon_razz...

Is this even possible? was I not building enough pressure in my tank or something? :aigo:

 

[bluemkiii]

I was just about to tell you maybe your gas cap is off:biglaugh: j/k

btw is your car 5spd or auto?

 

[jnianekeo]

I was just about to tell you maybe your gas cap is off:biglaugh: j/k

btw is your car 5spd or auto?

My supra is 5spd. the motor is an auto.

 

[jnianekeo]

Just kidding... :cry: it didnt work...

I started the car, and drove it normally out of my development. I kept the revs low initially, and then I gave it a little more throttle, i was in second and boost came on... I shifted at around 5k and went to third and coasted... thats when things turned to poo... as soon as i gave it gas, all the symptoms came back and it started to backfire and bog... it wouldnt die though. I could give it wide open throttle and it wouldnt die, just sound like a machine gun.... popopopopopo....

Could it be that I wired something wrong? and its in boost cut mode? I feel like when it saw boost, it went to safety mode or something.... is this possible?

The motor is completely stock with 3 inch exhaust, intake, and FMIC.

:1zhelp:

 

[jnianekeo]

Here's a video if it helps


http://s34.photobucket.com/albums/d124/jnianekeo/?action=view&current=MOV00127.flv

 

[tlo86]

doublecheck your timing, make sure everything lines up at TDC. if it doesn't redo the belt

 

[jnianekeo]

hey yall, I made some progress on the problem, I double checked timing and installed new spark plugs, my coil packs look fresh, no cracks. everything seems to be in check. I undid my EB1 and EB2 wiring. and tried to mess with the two black/red wires, and when i connected all the black/red wires together, the idle dropped to about 900 and it revved freely.

But when i pull the throttle all the way open, it would bog and die.

I've spent hours trying to try differnt combonations of the 3 differnt black/red wires to C1 black/red. and still cant get it to rev wide open throttle.

I feel like my EB1 and EB2 wiring is jacked.

Heres how i have it hooked up

??? is where i have those 3 different black/red wires that are unmarked/cutoff.
----------------------------------------
There are two plugs on Driver side near Junction Block #2, a 3 wire plug and 7 wire plug.

also a brown wire was not mentioned or used...

3 wire plug EB2

• Black – yellow from old alternator plug and black from EB1<---done
• White – white from old alternator plug<---done
• Black/Red – Black/Red from C1 plug and Black/Red from EB1<---???

7 wire plug EB1

• Blue –Blue from old AC connector<--- no AC so not connected.
• White – White of C1 plug<---done
• Black/Red – Black/Red of C1 plug and Black/Red of EB2<---???
• Black – Black of EB2 and Yellow of old alt plug<---done
• Black/Orange – Black/Orange of C1 plug<---done
• Black/Yellow – Black/Yellow of C1 plug<---done

-----------------------------------------------

Im sure everything is correct and the problem lies with this wiring.

Sorry bout all the confusion, I'll try to post some pictures tonight.

-Josh:1zhelp:

 

[jnianekeo]

Ok, after hours and hours of endless searching for the problem, I think i found it. There was a vacuum/boost check on the Map sensor (one of those things that allows vacuum but no boost. I thought these were filters, but I was wrong. I feel like a huge dumbarss..:stickpoke right now. I redid my C1, EB1, EB2 wiring and it runs smooth now.

I'll be testing it out tonight, I'll post of results or any mishaps later tonight.

 

[tlo86]

well good thing youve seemed to clear it!

 

[91T breezen']

Seems to run fine to me! Great seeing you up and running strong Josh.It's pretty cool that I just happened upon you on the I-5. I've actually gone several weeks, without having another MkIII going the same way on the freeway with me! Mad props on quite possibly the speediest Soarer to Supra 1JZ swap ever!!!:icon_bigg See you again soon for Centralia.

 

[jnianekeo]

Seems to run fine to me! Great seeing you up and running strong Josh.It's pretty cool that I just happened upon you on the I-5. I've actually gone several weeks, without having another MkIII going the same way on the freeway with me! Mad props on quite possibly the speediest Soarer to Supra 1JZ swap ever!!!:icon_bigg See you again soon for Centralia.

Thanks TOM! I was about to post but you beat me to it! here is my update:

SHE RUNS GREAT!!!

Like the picture said above, I had a check valve on my MAP sensor so it would only read vacuum. I also redid my EB1 and EB2 connections and everything seems to run fine except for my idle. For now I'm using the idle screw to open the throttle a tiny bit. without it i would idle at 400. Other than that

I AM AMAZED by how well it runs, I'm running ~11-12psi right now - according to my trusty SUNPRO Boost guage lolz. but ya,

Noticed that it drives extremely smooth throughout the pwr band, I'm not used to the redline being beyond 6k so I was a little hesitant at first.

While driving to school, I noticed another mk3 speeding up behind me... and I was about to show him up, but as he got next to me I noticed it was TOM! Nate, Duane and Ron's friend in Everett! A really weird coincidence that I ran into another 1jz especially when Tom was there the day i got the motor from Nate. It was nice seeing Tom's car all finished too! LOOKS AMAZING!

So ya, we caught up, and had our supra talk in teh freezing cold here in WA. but ya, I'm totally stoked right now that its running and running really well.

Another thing - suspension

The Tein Coilovers are really nice, STIFF but not too bad, I love the feel, but I couldnt get on it too hard in the corners, because it is wayyyyy too low. My buddy Nick slammed it and convinced me to stay low, but after driving it and scraping everywhere, it needs to come up! I need some spacers, and my fenders rolled and i should be good to go.

Its been a long day and night, Im off to bed.

Thanks for all the help!