I got an 87 rx7 as a shell to learn how to put my own car together. My boyfriend has been teaching me as a project.
I need help because i’ve been stuck on this for 2 weeks now. After putting the engine in and sorting all the bugs to get the car to start, it’ll start & the second I take my foot off the throttle it’ll stall out and die.
So far i’ve had my fuel injectors cleaned, checked the afm and it seems good, timing is correct, adjusted tps it’s giving me 1 volt, fixed known vacuum leak(emissions deleted too), adjusting the screw on top of the intake manifold doesn’t seem to change much, etc.. Made sure to add two stroke oil to the gas tank. The car and motor was sitting for a while before I picked up the shell and we are flushing it with straight water and the water coming back out is pretty nasty. Would this possibly be an issue of clearing fuel lines & cleaning out my fuel tank? Not sure what else to try. I added in a video of how it sounds when i’m holding the throttle. The second i let go it shuts off. It’ll stay on as long as i hold it for.
This is how the car is sounding (has multiple exhaust leaks atm):
https://screenpal.com/watch/c06vr1VEHDO

Any suggestions for what to try next?

 

i know you said you checked, but i think you should keep checking for a leak somewhere.

with your foot on the throttle, will it run at a reasonable idle RPM, or does it have to run higher?

 

I can let it fall with my foot on the throttle to maybe 800 RPM, the lowest i’ve gotten it to is around 500 before it’ll instantly shut off. It typically stays on for as long as i’ll hold it.

 

It is hard to tell as it is so loud. It does sound like it is running rough though. Hopefully someone with a racing or more open exhaust can confirm. It kinda reminds me of a piston engine with aftermarket cam shafts and an open exhaust. I do have a similar problem with mine as the idle adjuster does little to nothing.

You really don't want rusty fuel running through the system. Drain the fuel if needed and look in the through the top of the tank in the trunk. If you see white in there the tank is failing. You might be able to get away with a little rust after cleaning but I personally wouldn't. Those screws are tricky on the tank for the pump and sending unit. I had to drill mine, I got replacements at a local store. And please be careful, I would leave the drain plug out so the leftover fuel evaporates before drilling. While the pump is out, check the pickup filter/sock, those can clog. Replace with non OEM, the deseign isn't super great. Replace the fuel filter too, not difficult or expensive. This is probably later in the list of things to try but don't ignore the fuel system. I did and my tank was trashed. Fortunately I have Gas Tank Renu location somewhat close by. $410 for a fully refurbished tank, around half the price of the new ones I found online.

What RPM was this timing adjusted too? Did you have a foot on the pedal or other while doing it to keep the idle steady? Verify you don't have an aftermarket pully, The timing marks are in a slightly different position sometimes, or so I have read on here. Spark has be verified on all plugs? Compression testing completed as well? I would verify compression and spark before anything else personally.

With so much deleted from the engine before install it could be a bit harder to diagnose, at least for me anyway. Like the above poster stated, having to keep your foot on the pedal is almost always a vacuum leak. Not sure what with so much deleted though.

Edit: Looking at the pictures, the spark plug wires look routed kinda different?
T Coil = Top of engine
L Coil = Lower part of engine
The #1's go closest to the fan.
The #2's go closer to the firewall.

 

I finally got my 87 GXl out of the garage since June. Replaced all rear end bushings, gas tank and others. The front end and exhaust are next. See below for a refrence video of an idle at 2000rpm with no exhaust. It was incredibly loud and didn't want to disturb the neighbors to much to warm it fully. It has a slight miss but sounds way smoother than the clip you posted. Also, I had to start this three different times before it held an idle.