Fuel cut around left turns?!
 

I've posted this before, and it's still unresolved. Maybe this go-around will fix it.

Sometimes, when I take a real sharp LEFT TURN (sharper than normal ppl drive), I get what feels like fuel cut. Maybe it's spark cut.. But I lose all engine power, the car bucks from slowing down...lasts for about 2 seconds, then the power returns, bucks from the sudden surge of power, and i'm back on my way. Here's what I've found.

First, it's *NOT FUEL SLOSH!!!* It's done it on a 100% full tank of gas, 1 mile after I filled up.

I've found that if I can get the clutch in during this, i save myself the shock of the buck from the power returning. The car does *NOT* die when I clutch like this.

I've taken many, many sharp left turns in neutral/clutched, and it has never died. I don't even think the idle has dropped off.

The voltage guage does not move when this happens.

I don't hear any backfiring afterward, so that leads me to believe that it's NOT a spark cut...

It only seems to happen when i'm "on" the throttle.. If I engine brake around a sharp turn, this doesn't happen--or at least, it's not noticeable.

I regrounded my battery to the the chassis, and regrounded the engine block to the chassis, 6" away.

It used to be really bad...I changed the fuel filter (really, really clogged), and it helped it a whole lot. But it still does it at random..

Yeah.. Any ideas? It's starting to piss me off!
-Tesla

I have no idea, but if the fuel filter worked then try the fuel pump and the little strainer. Just a thought

How about the plug on the air flow meter? Got me.I'm still not 100% sure what causes mine. The full tank helps me and I realize that you still have the prob with a full tank. I think we are experencing the same phenomenem. Its like the ignition just cuts off for a moment then catches as the car straightens out. No back fire. For me only left turns. Not experencing it lately. I'm down to a quarter tank now. I'll write back if I get a clue. It does not sputter cut off, it just flat stops running, then starts again.

this same thing has happened to me! but, it only has happened while at 1/4 of a tank.

It does the same thing to me too. I have had it happen when I have 1/2 of tank and less. If anyone knows it would be helpful.

whoa this is too wierd.......another common problem with the fc.....mine does the exact same thing full tank, quarter tank doesnt matter.....many times ive tried to drift left hand turns and it boggs down then surges back up.......im installing a walbro 255 in soon and will see if it has anything to do with the fuel pump or the filter being dirty....... has anyone else solved this problem??? i only drift right hand turns it pretty funny....all my friends are like you cant drive hahha

this is too wierd my 88 started doing the same thing. TED HELP!!!!!!!!

This might be a clue.....I have a fuel cut switch. While driving in the hood about thirty mph, I switched it off. Within a half second the car had zip power and acted just like the posts that describe how going around left turns kills the car. Is it possible that the flapper door in the air flow sensor is acting under g's and is opening the micro switch that supplies the power path to the fuel pump. Just a guess. EDIT.....Whoa, how about not the door on the afm but how about the plug on the afm. A poor connection might be coming loose due to say the radiator hose hitting the plug or.....you get the idea. If you have a bad wire connection for the micro switch it would act like the fuel cut switch I described above. If you have this problem consistently you could jumper that two wire plug near the r/h strut tower that activates the fuel pump, and leave it jumpered while driving. Then if the problem does not reccur, its likely the harness to the afm. How about that for a thought?

hmmm...I've only had this happen at 1/4 tank, and while auto-x'ing.

so what your saying hailers is to wire a switch to the fuel pump so its always on therefore its unaffected by the micro switch? it seems that it might work but my other question is why only hard left turns????? if this was true why wouldnt right hand turns be affects???...this is quite a mystery

80STYLEFC.....I think what I'm getting at is, if you have this problem consistently, then if you jumper you fuel pump to be on all the time, and then the problem goes away, then the problem must lie in either the door on the afm or the plug to the afm is not secure and you are losing the circuit that turns the fuel pump on(micro switch activated by the door in the afm). My car is getting low on gas and I hope I get this problem in the next day or so. I have not had it for a couple of weeks. Could be the gas level or ????

i think ima do that because having a switch for the fuel pump would also be like an anti theft device on the car.....if i put the switch under the dash ...an unknowning person wouldnt be able to start my car with out turning on the fuel pump....=) ghetto security for those who cant afford a real security system

Ok. I am down to the bottom on the fuel gauge. Needle on the mark. At a stop lite. Goes green. Made an agressive left turn. Car died then came back as I straightened out. Pulled off road. Jumpered the fuel jumper on the r/h strut. Came back to the same stop lite. Same results. So on MY car it is'nt a broken fuel circuit. I'll try the clutch in thing tomorrow. I'm fairly sure my car's problem is just slosh, but I'm willing to keep an open mind. 'Tomorrow, and tomorrow creeps this petty pace........

So far Ive had about 20 FC's, and about 3 of them had this problem. It does so even if you rewire the fuel pump. Ive had success by swapping the fuel pump though. Try that. Also, try rewiring the fuel pump *straight from the batery*, to your switch, to the fuel pump, instead of off the relay.

I have had the same thing happened to my GTUs. However, what I have done in order to prevent this is not to let go of the throttle while making the turn, just keep the pedal down. I think that if you are in a cruse and then punch it while making the turn the cut off happens.
Anyone.....try this and see if it helps.




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89 GTUs
TII Hood
HKS Intake
Racing Beat Header & pre-silencer
Apexi N1 Duals
Engine Balanced to 11,000RPM
Racing Beat Race presure plate
Stock Clutch Disk

This happened once in ny 91 na. Could not get it to repeat. Anybody have a cause/effect or fix? :cool:

I get the same thing in my t2. Left U-turns. I always assumed it was fuel slosh.

SAme problem here always left turns. And its driving me nuts!

Well, it happed to me this weekend while doing solocross. Everytime I took a hard turn the RX would almost cut off, ..sucks!. I also tried working the gas and the brake at the same time but no luck. I will try to ask my friend who is a Mazda mechanic who specializes in RX7s to see if he may know why this is happening.


:mad: :mad: :mad:

Has anybody tried what I suggested?

A) rewire fuel pump directly fromt eh battery, to a switch, to the pump, and reground it at the pump to teh rear hatch area. This ensures there are no electrical gremlins, teh aforementioned AFM flapper safety switch, etc. causing it.

b) replace the fuel pump

I bet if you do one or both it will cure this problem.

Somebody wants to fix it badly enough to try the above and fix their car.

Post the outcome if you try.

my 88 GXL does it on RIGHT hand turns, the idle will dip low and sometimes it'll stall out. I think it's related to the power-steering switch which compensates engine idle for load. However, I've replaced the BAC and even with a full tank it still does it. I need to check the switch, but I've been way too busy. I need to find a solution soon as I'm working on getting the car ready to sell.

been so busy w/ school but i will try replacing the fuel pump and wire it directly with a switch....i already have my walbro sitting here just need to pop the bad boy in hopefully this weekend...i will let everyone know after i have it done if it solves the problem

I'm a bit hesitant to wire it directly from the battery, thru a switch... Then, anyone who drives the car *MUST* remember to flip the switch when starting/stopping.. No big deal for me, but I don't trust mechanics enough to remember to do that... I feel I'd end up with a dead battery. ;) Could I go thru the existing relay under the dash? That way, it would at least work if someone didn't know about it..

Also...the screws holding my fuel pump in are really soft, and i rounded out a few heads trying to get it off a while ago.... Any recommendations for how to remove them?

-Tesla

-Tesla

I just drilled the head off. Removed the pump and grabed the remaining threads with a set of pliers. Didn't feel real bright while drilling the head off. Couldn't decide if a full tank would be better than a part empty. And tesla02.. I just bought and installed a used pump assy yesterday for a totally different reason and I'll try it out tonight. I''m down to a bucks worth of gas. I did eliminate the flapper sw by bypassing it. As you see in an earlier post the car died with an agressive left turn. Agressive as in the right foot is pressing the pedal in the down position all the time. Duh! I've got two other cars that I havn't tried.

Well, what I really mean is wire it up through a switch directly from the battery, OR a switched 12v source fromt eh ignition switch or fusebox would work also, just so you are bypassing the fuel control relays cutoffs, etc. Just for test purposes, like a week or something. I wouldnt trust the fuel pump relay in this situation, because the cutoff switches are in front of the relay, so you wouldnt really be doing anything.

As for rounding off those heads, Ive noticed they are really soft screws, way to small, and usually full of crud. Drain the gastank(1 screw on bottom) then grind off the heads with a dremel. IF youre brave, dont drain it.