How quickly does fuel go off?
 

Hi all,

I've had a bit of a search on this and couldn't find anything.

My FD started (roughly) after 18 months at the first time of asking after quite a bit of work (rats nest, new fuel lines etc). The second time I started her she ran roughly again, the engine was bucking a little and generally not sounding great, after a short while the revs dropped, the car sounded like it was struggling and then cut out. It now won't start.

I had topped the fuel up with a gallon of 98 RON Fuel (I think you are MON in the US so this is 90), there was probably a gallon or a more of 18 month old 95 RON (87 MON). I'm just wondering how quickly fuel looses its properties and if this combined with now being flooded could be the reason for the car cutting out in the first place and now not starting.

I'm going to order some new sparks and do a de-flood this weekend, I might drain the fuel tank depending on what you guys say and get some 99RON in there again as well.

This is a quick video of the engine running, the nasty clunk is coming from the CAT/DP area (I hope) and not the engine (again I hope), the airpump line wasn't plumbed in.

Cheers

Fuel does "Gum" up over time, making it difficult to push trough small holes like injectors, maybe try some injector cleaner in the tank (doubtfull that that will work if the fuel has allready gummed up the system) or maybe pull the injectors, and let them soah in fresh fuel, overnite.... (make sure you use a sealable container as it is a fire hazard)

Sounds like last summer for me.

I pulled the injectors, had them ultrasonically cleaned but not tested (shop didn't have a side-feed rail for testing), and a bunch of other rats nest joy.

Car never ran right after that until I pulled the injectors again and installed a freshly cleaned set from RC Engineering. The set that was causing problems was tested and cleaned again by Witchunter Performance and the before/after testing showed a problem and their cleaning solved it. IMHO, if you take the time to pull the injectors, it's absolutely worth the money to get them cleaned and tested too.

Threads:
https://www.rx7club.com/forum/showth...=bucking+boost
https://www.rx7club.com/forum/showth...=bucking+boost

Anyway, that doesn't mean you have the same problem. Start by unflooding, and starting up with the throttle held wide open. Use fresh plugs (buy the cheap ones not the platinums - only put in the $$ plugs once it's all running good).

Dave

Thanks Dave & DCrosby

I've tried the deflood with the pedal and had no joy at all, so I'm going to pull the plugs this weekend and do it the hardway. I'll also put some red-x in the tanks and run the pump for 10 minutes by shorting out the diagnostics terminal, this should let the injector cleaner get around the fuel system ok :)

If it still doesn't work then I'll have to pull the injectors and get them cleaned up :)

Thanks!

Dave

If the numbers you put up for the UK rating system are correct your octane is way too low.
I would drain the tank and fill with the highest octane petrol you can get to guard against detonation. And yes, gas does go stale. Get some fresh fuel.

^ They may be slightly off as I can't quite remember the conversion, 99RON is the best fuel we can buy over here :)

IIRC the Japs use 100 RON in their cars so there is very little in it :)

...and while I think of it......draining the tank is certainly more thorough and great if you can do it. An easier approach would be to buy a cheap siphon at an auto parts store. You'll get enough out so that when you fill it with fresh petrol the old stuff will be diluted to the point it won't be harmful.

Your octane numbers are several points higher than ours in the U.S. but I don't know what the exact difference is.