So I recently picked up my Bathurst-X, and I've been happy with it. The only thing i noticed is, when the gas tank is at about 1/4, the car will begin to stumble and bog, almost like it's out of gas to the point its impossible to maintain a freeway speed. As soon as I fill the tank up (about 13.00~ gallons is what it takes before full at this point) the problem goes away completely. Once it gets down to around 1/4 tank again, it will resurface.

The shop that looked at the car when it landed in the states said they put a walbro 450 I want to say in it.

My thoughts:

1) is the pump overheating? My RX-8 did this when the tank would get low, the pump would overheat. I'd fill it up, and it'd be fine until it got low again.

2) Dirty tank/sock. The rotary shop said they replaced the tank, I find it hard to believe they wouldn't check these parts out.

Anyone have any insight or thoughts into what may be causing this?

Also, Has anyone had any experience with their bearings on their pulleys going bad? The car makes a noise that to me, sounds like metal scraping almost at idle. It didn't do this when I picked the car up, but started and gradually got worse when I put some miles on it. Revving will increase the sound. However, driving at highway speeds you don't notice it, though at idle its bad. I'm 90% sure it's coming from the PS or PS idler pulley, or at least that general area. I did look at the PS belt, and on the top surface, it almost looks like a fraction of the surface has been worn off on the side closest towards the engine, its not a uniform smooth surface like a new belt should have. Just curious as to if anyone has seen this as well, I'm looking at ordering a new Idler pulley but I'm wanting to make sure thats what it is. The other drive belts are fine.

 

On the gas tank thing, any reason they put in a Walbro 450? that seems like way overkill - isn't the car stock or near stock?

You'll need to pull the fuel pump and check things out in there.

On the noisy pulleys, remove the engine belts and run the car and see if the noise goes away. You don't want to run like this for long since the water pump /alternator won't be turning but for a few minutes you'll be OK. See if the noise goes away. If so go from there.

Dale

 

It is basically stock. It has a Blitz NuR catback. It does have a power FC, but the rotary shop that did the inspection when it arrived stateside found no other kids that would effect engine performance. It does have a power FC, and has been likely tuned for japanese 100 octane (their octane system not ours.)

I planned for this, however, and have calculated that half 100 octane (unleaded) and half 91 will be 95.3 octane, which is .3 above Japans 100 octane when converted to our system. But like I said the car runs fine when not low on fuel.

I'm looking into the pulley situation, I'm assuming it's likely related to the pulleys on the PS belt, because of the missing uniform amount/pattern about of the top surface of the belt.

 

You're also assuming the PFC has been tuned. Quite possibly still on the base map.

BTW, the Blitz NUR spec is one of the more obnoxious exhausts on the FD, really is just loud and doesn't sound that great. Probably not as bad if everything else is stock but it's pretty obnoxious.

Dale

 

Agree with Dale you gotta pull the pump assembly to check things out. For the idler pulley, if the pulley itself is in good shape you can get just the bearing from Ray, it's easy to swap with a press at home.

 

Might check the the idler pulley installation and lip orientation.....if you believe Mazda depictions, it seems to have reversed at some point and could contribute to belt wear. As long as you don't have long hair, a big screwdriver stethoscope might tell you something before replacing parts *****-nilly, a bad bearing is pretty easy to pick.

Would hope it's only a 255 walbro installed on the pump. Fuel starvation isn't unknown if throwing G at the car around that level, sounds like the car must have sat a long time if the tank was effed-up and had to be replaced.

 

Could be, I'm not sure what the drivability is on a basemap, but I want to say the shop told me it had been tuned or very likely was, and they didn't have time to re turn it for american pump gas before I had to leave.

I'm not a huge fan of the NuR. It's not the most obnoxious exhaust I've heard, but I'd much rather prefer a Racing Beat Dual.

 

Lip faces the back of the car as opposed to being closest to the front. I was told by the shop that looked the car over when it got here that they put a 450 in it. Seemed like overkill to me. Its rather low mileage, 48k~, so I imagine it did sit for a bit here and there. I just don't know what else it could possibly be. Only happens when fuel is low, if its gets low enough you can't even maintain a constant crusing speed before it starts heitating, and any attempts to give it more throttle just result in it bogging more.

I suppose the next plan is to pull the pump assembly out, and check the pump, sock, and tank for any sediment.

Does anyone happen to know if the FD tank has a drain on the bottom? I don't believe it does, but I figured I'd ask.

My hair is on the long side, I imagine i can source a screwdriver stethoscope and try. The issue is, the noise is horribly loud. I think it may drown out anything i"d hear or isolate with the stethoscope. I do notice the noise gets lower when I turn the AC on, but still audible.

 

Remove the belt and spin the pulleys by hand, some time it will be pretty obvious which one is making the noise, plus you should change that belt anyways if it is wearing unevenly.

 

The screwdriver should be pretty good - short of an ear piercing screech where you can't hear anything at all.

Replacing the tank, excepting NOS or secondhand, all the new ones, won't have a drain. If they've done a complete fuel system swap and installed a big pump as you state, with a stock FPR(?), that makes me a bit dubious, and I might check the fuel sender arm.

92 wreck engine components here had the lip at rear, Version III-on cars seem to have lip front https://mazda.epcdata.ru/rx-7/ajfa05..._cooling/1580/.....I'd let the belt happiness dictate!

 

I think the fuel gauge is accurate, every time It got down to where it was hesitating (1/4 tank mark) I would put in about 13 gallons before the pump would cut off. I don't believe they've done a complete fuel system swap, just the pump from what I remember them telling me.

Also, I believe the issue may be with the AC compressor. I started the car and looked at the compressor closely, it seemed to be where the noise was coming from (but the noise is so loud its hard to tell.) When the compressor kicked on, the noise definitly became lower. The compressor clutch activated, spun, then stopped after a few seconds. This would repeat.