Cyber_RX7

Hey guys, I was wondering if any of you could help me. I got my RX-7 a couple of weeks ago and I have already had to fill it twice (£60 each time). My speedo has been converted into miles but the trip meter still reads in km. I got 160km on a full tank and that was without going stupid and foot heavy? Surely this is not right? That means I only got about 100 miles to a full tank??

If this is wrong (its got to be lol) then does anyone know what it could possibly be and what I would need to check for? I have noticed that when I do put my foot down or I'm setting off that I can smell the fuel but I don't think I have a leak? On idle, it does seem to pop a little bit and I am sure that it is over fuelling but wouldn't have a clue about how to sort it out

Thanks guys

dgeesaman

iTrader: (7)

Do you smell fuel under the hood?

Either way, take fuel leaks very seriously with this car. Many FDs have gone up in flames with the symptoms you have. There is a spot on top of the engine that can collect a big puddle of fuel just waiting for ignition. Do not start it or drive it until it's been properly diagnosed. It is possible to pressurize the fuel system without starting the engine; I recommend you do this before starting the car again. Just go into the diagnostic box between the battery and wheelwell and put a wire (paper clip) in jumpering the F/P and GND connectors. Then set the ignition to On. Start poking around looking/smelling for fuel.

Dave

Cyber_RX7

jumpering the F/P and GND connectors?? Is this what they will titled in the diag box?

Thanks for the fast reply (I am getting worried now )

Cyber_RX7

Right I figured the diag box out anyway. I just did it and all I could here was a slight errrrrrm hissing type noise but I assume this is the noise of the fuel under pressure?

I couldn't smell any fuel whatsoever under the hood so that is a good sign I hope.

I know I need a new exhaust system fitted as the current one is really crappy and rusty. It also has quite a large hole in the back box and is blowing. I don't suppose this could be one of a few reasons it is over fuelling?

Thanks again.....

fendamonky

iTrader: (6)

The only hissing should be coming from the boot. That would be your fuel pump, but it's gotta be a pretty big one to actually hear it in the cabin.. If there is hissing in the engine bay than you may have trouble. I'm no expert though.

pauli311

iTrader: (2)

sounds like it is putting more fuel into the engine.. how is your idle?

Do you have a boost gauge to check vac with?

Cyber_RX7

It wasn't hissing as in air. Its the only way I could describe the noise. It sounded as though the fuel was travelling through one of the fuel lines at speed? lol. Sorry, nits really hard to explain. Surely when the fuel is under pressure, there will be some noise?

sickboy2345

told you after ur first post mate, this rex was on ebay for ages...and noone bought it for some reason...

anyway im not gonna help you with technical advices - my one is gonna be:

pay 30 quid for the recovery truck and get it checked by the specialist, i wouldnt play with fuel leaks if i was you...(just my opinion)

and talking about fuel consumption - it costs me about 1GPB a mile :] - you do the math :] (but my foot is sooooo heavy )

Cyber_RX7

Thats the thing though. The engine sounds sweet as a nut. There is no way that anyone could have known that it was drinking fuel after a test drive, so there is no reason it was on the bay for any length of time. Not that I can see anyway as it does drive well and looks immaculate inside and out.

Why would the vac have any thing to do with petrol consumption (sorry I might be being stupid). It is funny you should say that though. One of the vac lines on the the second turbo is a vac pipe at the top of the engine (the one where there are 2 right next to each other. The other one next to it is blocked off with a blocker pipe. The vac for the 1st turbo goes somewhere underneath the strut brace. I have been having problems with this vac. Basically if I start the car up, both the BOV's open up. When I turn the car off, one of the BOV's stays open and the other closes. If I remove the pipe that is connected to the one that remains open it hisses out a load of built up pressure? I am assuming it shouldnt do this. Should I connect the BOV to the vac at the top of the engine and see how it goes?

Sorry, its hard to explain.

Really appreciate the help guys

TwilightRotary

iTrader: (3)

im not sure how important these factors could be but how modified is the car? is there any colour/smells to the exhaust fumes?

Cyber_RX7

Its not modified at all. The engine is totally standard. I have not checked the exhaust fumes so will check them next.

She has been low on oil since I got her (but above the low mark). I dropped the oil yesterday and filled her back up. I am not mechanically minded at all so I don't know if low oil would have any impact on MPG??

Really do appreciate the help everyone

dgeesaman

iTrader: (7)

The vacuum you were asked about is the vacuum reading of the engine at idle. You need a boost gauge installed to read this. Vacuum gives you a rough idea of whether the engine is running poorly.

The vacuum you found under the hood is stored vacuum (or pressure). To control the turbochargers and other widgets, the FD has a stored vacuum tank and pressure tank. They are part of the "rats nest" control system. It is normal for both the pressure and vacuum storage tanks to remain charged after the car is stopped, and is unrelated to your idle vacuum level.

Cyber_RX7

oh

My brother has a boost gauge I could probably take off of his supra just to try it on mine? What would I be looking for.

I really do apologize about all the questions. I just want to do everything that I can 1st before I take it to a specialist.

Thanks

dgeesaman

iTrader: (7)

I've also been wondering if you're speedo is working out right. 16km/gal is about 10mpg, so I would check the speedo/odometer against a known distance. Highway markers perhaps.

Yes, the boost/vac gauge is what you need and you can rig it temporarily. There is info in the FAQ about how to do that. I think it's under the buyer's guide information, but you should work on reading the whole thing.

One thing I need to repeat - if you smell fuel shut the engine off! Fuel smell and missing fuel are two scary things to hear about. If you're smelling fuel, get it towed to a specialist!!

Dave

MrNizzles

iTrader: (5)

So if a tow truck is a "recovery vehicle" ... then what do you guys call a Ambulance?

Cyber_RX7

Thanks a lot. I will have a look it at the weekend with my brother. He knows a lot more than me about turboed engines although he has very little knowledge on rotaries. We will have a look. Think I am going to take it to WGT in Cheshire for a checkup

fendamonky

iTrader: (6)

Best. Idea. Possible.

Pip knows his stuff and will be MUCH better able to diagnose and fix your problem than your brother will.

fd0

iTrader: (8)

One other thing you could do is fill up your tank and drive back and forth to two known points that you know the distance. Figure out how many times it takes before you lose all your fuel. Then fill up your fuel tank to full and see how many liters it takes to fill up. Divide the total distance in kilometers by liters and you should have your average gas mileage in (km/l). You can then convert that into miles/gallon.

I believe an average FD RX-7 is roughly 15-20 MPG.

Good luck! How much is petrol now in the UK? Last time I was there it was around 121p/litre.

Six Rotors

iTrader: (17)

I just did a 500km round trip yesterday,2 up and used 50.2 l of fuel.So,10km/l,about 30 miles per imperial gallon or 25 mpUSgal.
Driving conservatively on country roads with the odd spurt thrown in.
I have a stock motor,BNR turbos,JDM DP,RB Twin cat back,stock ecu,E-01 boost controller set at 10.5 psig.

moconnor

iTrader: (14)

That's actually very decent for this car.

Six Rotors

iTrader: (17)

Yes,better than my RX8 and about what I could do on my TIIs driving in a similar style.

Dudemaaanownsanrx7

iTrader: (23)

also i might add that you should get a permanent boost/vacuum gauge mounted in the car, it will help trouble shoot turbo issues and other problems along the road

Cyber_RX7

Cheers guys! I am going to get a boost gauge tomorrow. I am also going to try a different vacuum source for one of the BOV's as I don't think the current one is opening and closing the BOV as it should be whereas the 1st one is fine. I am also going to phone WGT tomorrow and see if they can get me booked in for a checkup to see why my fuel consumption is so bad. Might even get a few other bits and bobs done if the manage to sort the fuelling out

Thanks again