Hey guys! This is my first post as well as my first rotary, so please excuse me for any stupidity coming from my side lol

Long story short, last year I bought a 1981 RX-7 FB (Series 2) that was one owner, which died in 1997. The car stood at a friends garage ever since, until 2021 when I got it. The known issues were seized brakes and faulty fuel pump... turns out the fuel tank was also dead and completely rusted out on the inside. After fixing all the brakes and fixing the whole fuel system (including "new" pump and a tank from a Series 3, which took a lot of adapting), the car was ready for the streets... well, not really.

Now when I start the car when the engine is cold, it runs like a charm, super smooth. Even after reaching operating temperature, I can rev it and the engine seems very happy. But around 5 minutes after I start putting load on it (e.g. driving), the engine dies and won't start, no matter what. When the engine cools down, I can do the whole process again...

Things I have done:
- New spark plugs
- Checked if there is spark on all 4 plugs
- Checked there is fuel being delivered to the carb
- Exchanged the ignition coils (changed the trailing with the leading)
- Removed the fuel tank cap to make sure there was no vacuum building up inside the tank

Am I missing something here? It feels like it's something stupid... the engine can't be dead, right?

I would really appreciate any help/suggestion, I've been dying to see this car on the streets.

If it matters, it's currently spring here in Germany, around 15°C.

Thank you in advance!

 

One thing that works when cool but fails when hot are the igniters mounted on the distributor, aka the J109's. It would be odd for them both to be that close to the edge but not completely dead. I guess check for spark when they are hot...but maybe pull the fuel pump fuse if cranking excessively while hot so that you avoid flooding.

The other thing could be you have enough fuel to idle and drive a bit, but sediment on the carb screens builds up and restricts fuel. An alternative could be sticky needles on the carb floats.

Did you rebuild the carb? A recurring comment here is to not refurb the floats or use the new needles unless you have to because some rebuild kits have sticky needles. If you do have to use the new needles, make sure to burnish the needles and ensure that they move freely in the seats.

Good luck! Let us know here how it goes.

 

My 1980 (after a long winter storage) did the same thing. It was the fuel tank, shedding its insides and plugging the fuel system.
This is what was happening:
-car starts, ran fine.
-once driving, in about 5 min/miles, the car stalled. Turns out the agitation of the sediment in the tank while driving would allow the debris to get sucked up into the the fuel take-up lines, stalling out the car.
-sitting for a while (not running), the sediments settle back down to the bottom of the tank, allowing clear fuel to again be drawn up and the car idles just fine.
Then I drive it again, and in a few miles, same problem.
The debris was probably not even getting OUT of the tank, and into the filter - it was plugging the pick-up tube IN the tank.
Solution was drain, pull the tank, and take it to a radiator shop. Here in the US these shops usually have a big chemical tank that allow you to submerge the WHOLE fuel tank into it an clean it out. THEN I bought a product to pour INto the tank, that reseals the in-sides of the tank, so it will not continue to shed material off the sides and back into the fuel. The product I used here is called POR15:

https://por15.com/products/fuel-tank...l&_ss=e&_v=1.0

Stu A
80GS
AZ

 

Does is cut off suddenly, even if the revs are above idle, as if the engine was shut off?

Or, does it run ok until after some driving you stop and the engine comes down to idle, then dies?

 

Hi!

Have you managed to fix the issue?

 

The last and only time the original poster has logged in was on 10/14/2022

• Last Activity: 10-14-22 06:08 AM