Intake Backfire

[faviles]

Hello everyone!

So I finally pieced back together my 7mgte after changing the head gasket. It took a couple of tries to get it started but once it did it shot fire out of the intake manifold where the 3000 pipe connects to the S looking pipe. After getting the $*** scared out of me I turned it off immediately. It also sounded like the car was accelerating on its own.

The timing is set at TDC (crank at 0 and cams were lined up with the notches on top; tps was also lined up with notch and ridge on the gears.) which was followed by a video on youtube "timing a 7mgte".

What exactly could it be that caused this? Prior to the engine being taken apart this did not occur. Is this normal until I get the timing done correctly or should I begin to worry about other things? Like I said I did not let the car run for too long. The burst of flame shot out right when the car started and stopped immediately after and the car ran for a good 20 seconds. I'm not to sure if it was in an accelerated position or if that was the normal sound of the 7M.

Thanks for the help in advance!

 

[A-to-the-J]

Did you line up the CPS correctly?

Sent from my SAMSUNG-SM-G900A using Tapatalk 4

 

[faviles]

I tried my best! It felt like every time I inserted it back in the camshaft gears would make it turn a bit. I'm going to try to line it up perfectly today.

 

[A-to-the-J]

I tried my best! It felt like every time I inserted it back in the camshaft gears would make it turn a bit. I'm going to try to line it up perfectly today.

http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=IG&P=24

 

[faviles]

Okay guys, so I went ahead and checked over everything. The spark plugs are lined up in the correct order on the coilpack and the plugs are lined 1-6 from front to back on the cylinders. The markings are all lined up on the cams and crank as well. Crank is set to 0.

Here's the thing, my father and I were arguing whether or not it could be the fact that we do not have the full intercooler piping on the car. The only air the intake is getting is the air from the 3000 pipe outlet. His reasoning is to leave it all off so that we have space to work in case something around the turbo goes wrong.

Could it be that the car is not getting the right amount of pressure from the turbo? The codes were checked as well and I pulled up codes 24 and 51.

The car turns on and stays on when it wants to. However when you open the throttle a bit, it seems like it wants to go off or it hesitates and makes a popping sound. I really need your help with this one guys! Prove my dad wrong haha.

 

[hvyman]

24 is afm. Is the afm hooked up?
51 is tps or you had the ac button pressed when checking for codes. But it sounds like it might not be set correctly.

It should run without the ic piping but needs all the sensors plugged in. Also the intercooler piping is very easy to remove and to do anything on the top it's only the top pipe.

http://www.cygnusx1.net/supra/techtips.aspx

 

[faviles]

Thanks hvyman, I'm going to play around with the alignments one more time, if not time to recheck to see if everything is connected to where it really needs to be.

I did not check to see if my A/C was on or off, but I do know that my MAF was correctly connected.

thanks again and I will keep you updated

 

[hvyman]

ya incorrectly placed and timed cps can also do that was well.

 

[3p141592654]

I'm confused. Is the throttle body connected to the AFM, or is the piping missing?

 

[supranewbie]

I'm confused. Is the throttle body connected to the AFM, or is the piping missing?

This.
Hard to believe people are serious sometimes.

 

[hvyman]

Car will still run and drive without ic piping as long as the afm is hooked up.

 

[supranewbie]

Sure it can. But you can't expect the afm to tell the ecu the truth if it has no idea whatsoever what the truth is.

 

[atmperformance]

:opcorn:::opcorn::

 

[hvyman]

That's why it uses the tps...


Have you never blown an ic pipe off? The runs and drives fine. It just won't go anywhere if you try to boost. Blown off pipe is the same as no pipe.

 

[3p141592654]

Not my experience. It runs if the AFM is disconnected and code 31 is set, but it does not run fine with the afm reading no air. That's the primary input to the fuel calc. Anyway, the OP should hook up the plumbing and try again.

 

[super51fan]

^^^ 3P's is correct with AFM being primary input to ecu. THW second and all other sensors minor input changes. Why not hook everything up the way it supposed to be before trying to start. Have faith if you follow the repair manual that it will run properly.

 

[faviles]

All the intercooler piping is being connected today as well as one final check over timing. Sorry for all the confusion. Let's hope it starts with everything put together.

 

[Nick M]

What exactly could it be that caused this? Prior to the engine being taken apart this did not occur.

I know you think this is cruel, but why would you try this when you don't know what you are doing in the first place? As already stated, hook everything up.

 

[faviles]

I don't think it's cruel I just thought it would be possible to do with a large amount of recording and picture taking of the work. Everything is where it needs to be besides the intercooler piping. I basically recorded the whole process with my GoPro head mount and did everything backwards when putting the car together.

 

[Emeraldage]

Car will still run and drive without ic piping as long as the afm is hooked up.

It's funny how true this is. When I was first driving my car the hose that connected to the 3000 pipe blew off on boost cause we forgot to clamp it back on.. Car still started and idled at 600rpm.

I'd check CPS as well when I was getting my car together I had it off 1 tooth and it sounded like a muscle car and would not rev at all. I also had a backfire once but that was during my first startup try. When you pull the cps out you just align the gear inside with the notch, press it in and it should turn one tooth forward. (Assuming everything is set at 0 degrees).