dpn941

I have an 87 Mazda RX7. In a hard left turn at high rpm the engine cuts out for a second or two and then comes back on. This does not happen in a right turn.

satch

iTrader: (1)

There is an item in the fuel tank called a baffle and it can possibly cause your problem.

misterstyx69

iTrader: (142)

It is also signs of a clogged up fuel sock.(on the pump in the tank)..so If you have to access the tank(lift rear carpet,undo 4 phillips screws on plate then take sender assembly off with 8 phillips screws) then you can check both suggestions.

dpn941

Thanks for the suggestions. I do have a question though. The problem only happens in a hard left turn - it seems like a clogged fuel sock would cause the problem in right turns and in straight line driving also. Is the baffle idea that the baffle has come loose, or what would have happened with it. The problem is the same with lots of fuel in the tank and with low fuel ~ 1/4 fuel.

satch

iTrader: (1)

Baffle coming loose.

dpn941

I still have the problem. We took out the fuel pump and checked the baffles and they are in place and appear to be in good shape. We also replaced the screen on the fuel pump. It was somewhat dirty. (The fuel tank had been taken out and cleaned about a year ago. It was quite dirty.) The screen may not have been replaced when the fuel tank was cleaned.

The problem has not been solved. In a hard left turn the engine suddenly cuts out, then suddenly comes back on. There is no sputtering or anything like that. It is full power then no power then full power. This only happens in a very hard left turn. It does not happen in a normal driving left turn and it does not happen in a right turn.

Any suggestions?

satch

iTrader: (1)

When you say it does not occur in a right turn does that mean a hard right turn too?

dpn941

Yes, it does not happen in a hard right turn. These are turns like one might have in an autocross. Only happens with the left turn.

satch

iTrader: (1)

I am not 100% familiar with the location of the pump in the tank, but I believe it is towards the left side. Is that correct. If that is so then maybe the pump is weak because in a left turn the fuel gets sloshed to the right side of the tank leaving the pump in a harder position to pull in fuel.

dpn941

Yes, the pump is on the left side. I don't remember the fore-aft position. There is a baffle surrounding the pump, kind of like a bathtub. The problem has occurred with various fuel levels in the tank.

To me it doesn't seem like a fuel problem. The loss of engine power is sudden and the return of power is sudden. For a fuel problem I would expect there to be some sputtering or something like that when it loses power and/or when it comes back on. Note, I am not saying it is not a fuel problem, just how it seems to me.

If the fuel pump should not be getting fuel would that instantly stop the injection of fuel into the engine or would the fuel in the fuel line and filter continue to run the engine, maybe at reduced power, for a bit?

Trinityevo13

iTrader: (1)

Hey dpn941,

A friend of mine had a similar issue (not an RX7, but still may help). What was happening, was that only in a left turn something was rubbing against the wire loom and shorting out some wires. His engine would sputter and then once out of the left turn, came back to life. Never happened with right hand turns.

Maybe check to see if any rubbing is occurring on the steering column or around any wires, any wires that may be bruised etc...
Hope you solve it soon

dpn941

Thanks for all the help so far. At least we have checked some things.

Am I right that the fuel pump in the tank supplies the pressure for the injectors, there is no other injection pump? If this is right, then an interruption, for whatever reason, in the fuel pump in the tank supplying pressure would instantly stop fuel from being injected, or at least it would not be injected properly. Thus the engine would instantly lose power and when the pump again applied pressure the engine would instantly respond and have full power.

In the hard turns that we have been doing we are in first or second gear with the throttle wide open or close to that (over 6000 rpm) and turning as short as we can without skidding out of control. The engine runs in the start of the turn, then it is like a switch was turned off for a second or two, maybe three and then the switch turned back on and the engine has full power by this time we are coming out of the turn.

04Green

++ Trinity's comment.

To test, fill the tank completely and test. If it still does it, not the fuel pump. Unless you are pulling about 4 G in the turn, the pump should be covered.

Then start looking for a short. Likely in fuel pump wiring. I suggest this because I had to trace every stupid wire in a 1985 camaro to find the one that bounced against some flashing on the transmission casting when I went over a particular rail road crossing. It was the fuel pump SENSE wire, and would blow the fuse.

Good luck.

satch

iTrader: (1)

If need be you could hard wire the pump to see if it's an electrical problem.

Kman Art

iTrader: (1)

Once you are under 1/4 tank and you make a hard left turn, the fuel starves and your car dies. I have the same problem.

Just make sure your car is above 1/4 tank, or search for aftermarket baffles.

I have a RHD FD if that matters at all.

DWNUNDR

iTrader: (1)

is it a Nascar model and you should only be turning right

TitaniumTTRE

Anything under 1/4 tank in a stock FC is going to cause the fuel sock to be exposed, cavitate, loose pressure and sputter for a second.

Three solutions
Fuel Cell
Surge tank
keep the tank above 1/2

Even my 8 is susceptible to this. Running the tank to 1/4, and with a saddle tank it's really 1/2 full on the left side, going through the left hander @ LRP, by the time I would hit no name straight the car was dead but come back to life quickly... Again, the solution is ti run more fuel, or run a surge tank

TitaniumTTRE

If you're looking for something that's relatively easy to install and plumb, Radium makes a nice one that can be mounted in the trunk. Personally though I built a fuel cell with an intank surge tank and it solved every last one of my fueling issues