Hi folks,

Just picked up an 81 rx7 project for the car is not running. Today I put a gallon of 91 octane fuel in the car and charged the battery. Upon turning the ignition the engine turned over and gave me a little rumble, seconds later gasoline started surging out of my oil dipstick tube.

So I obviously quit trying to start it after I caught the leak, literally 2 or so liters of gas had poured out. I get all the fuel cleaned up then stick the key back in the ignition (not to try to start it). I hear the fuel pump click, and gas once again starts pouring out of the dipstick tube. Keep in mind I did not even try to start the car this time.

Has anyone ever had this problem with your engine? I have never heard or seen such a thing happen.

 

I think the first thing I will do is change the oil tomorrow, the engine probably has to be deflooded as well. going to be a pain because there is probably a lot of gasoline in the oil pan that ill have to collect. I did read that having poor oil rings can let fuel into the oil. But as much as this? Hmm...

 

If gas is streaming out of the dipstick tube it is not coming from the fuel injectors. The fuel injectors should not flow enough fuel to allow 2 litres to spill out while cranking. IIRC the charcoal canister vents into the crankcase, is it possible the vent and pressure lines have been switched, the charcoal canister is completely filling then overflowing into the crankcase and spilling out the dipstick tube?

When you get it figured out I would change the oil once, run the engine for a few km, then change it again. There will be a lot of gas hiding in there.

Also, I don't think there is any reason to run 91 octane in your 81, higher octane gas burns less quickly and can lead to increased deposits, IMO it is 87 only.

Finally, what part of Alberta are you in?


*EDIT*
You have a 12a not a 13b like I do so it doesn't have fuel injection... my advice might be completely wrong.

 

Hi Zero,

Thanks for your reply! The car is a 12a indeed and is carbureted. I am from Medicine Hat. Hm, 87 you say? The only reason I put 91 in was because my owners manual said thats what the car likes.

Ill let you know what happens when I change the oil.

Chris

 

is it just gas or a gas oil mix?

 

Yes, definitely gas and oil. Whats left of the oil in there at least.

 

Hm, I'm not as familiar with the carbureted cars but I suspect one or two odd things:

1. Floats stuck, flooding the engine massively

2. Maybe someone did something silly like run the PCV vent tube to the carb vent tube?

 

This is an interesting problem, I don't have a 1st gen anymore so I have to go off of the Factory Service Manual and this is just a wild guess, but this valve might be hooked up wrong...

 

hi guys, pretty sure its the needle valve staying open and dumping too much gas in the carb, the car was sitting for 12 years. put some carb cleaner into the openings over the floats. my guess is the carb will have to be taken apart and the needle valves replaced.

 

If it is dumping gas in the carb then how would it be coming out of the dipstick tube without the engine running? It would have to be getting past the rotor side seals and into the oil system, and it would take a lot of pressure to do that. If the carb was overflowing then it would not build much pressure at all and the gas would spill out the top of the carb once the intake filled up, or at least that's how it would work in my head

I think it is being dumped directly into the oil system, probably through the ventilation and check valve as mentioned above.

Do you know anything about what work was done to the car before it sat for 12 years? Sounds like an attempted repair went bad, then the car got put on the back burner for a while.

 

Hi Zero,

The engine was cranking and the car did rumble a quite a bit, but it was flooded. So the car was getting compression. In further tests I only turned the key to turn on the electrical fuel pump, I did not crank it in these scenarios. That was when gas started filling up the carb. It did not touch the oil system after that.

Going to check up on those valves in any case, thanks much!

 

You posted that on the second try it started coming out the dipstick tube on the second try where you didn't crank it, that is what I based my statement on. If it was coming out the top of the carb on the second try then you very well may be right. That said, if the side seals are so worn that it could allow that much gas into the oil system then you may have a second problem

 

Good point Zero,

Got a carb kit on order, will replace the needle valves and what not and let you guys know what happens.

 

Best of luck with it, hopefully it is nothing serious