41 replies to this topic

[nanbar]

Gday All

Still got bad a fuel smell in the cabin whilst driving.

I have had the Rochester rebuilt so it virtually new. Its been tuned but I reckon its still using too much fuel but more on that later.

I have replaced the sender unit (and gasket) as the old one appeared to be cracked where the main fuel line goes in.

I propose to do the following:

1. Check the fuel cap gasket. Its got a Valiant Charger flip top cap, looks cool but dont know if its sealing properly.

2. Check the vent line (again), it should discharge to atmosphere somewhere above diff correct? I will also check it for blockage.

3. Check the fuel line from the tank to the carry (again).

4. Block all holes in the firewall, there is one un-grommet 12-15mm hole I can see. I will plug it and any other ones I can find.

5. I read somewhere (here I think) that someone had fuel smell problems and they adjusted the back of the bonnet down so it seals properly. Mine sits up a bit, I suspect its been set up that way so the air cleaner does foul the inside of the bonnet. It makes sense I guess, if it isn't sealed properly, air will go from the engine bay into the air grills in front of the windscreen right?

 

Have I missed anything ? That is, any other suggestions?

 

Re the fuel usage, pre carry rebuild, it was using around 52 L/100km (based on figures from short runs.

Since the rebuild, its down to 38 L/100km which is still too high for a fairly standard Holden V8. I intend to get the bloke who rebuilt the carby to retune it on his machine. The carby was fitted and tuned by my mechanic but I don't think he did a very good job with the tune.

Any thoughts?

Cheers

Nanbar

[Dr Terry]

My guess is that it is a combination of 2 things.

 

Firstly 38L/100km is ridiculous, the whole engine bay will stink of fuel. My 5.7 LS1 Adventra wagon uses 20L/100 km & i think that is over the top !!

 

That coupled with the rear edge of the bonnet sitting high will put heaps of fuel vapour straight from the engine bay into the air vent intake.

 

Dr Terry

[RallyRed]

Wowsers!   that's 2km to the litre? 

Our track LJ 6 cyl. with 48mm triples get that...wide open around a racetrack....you must have a leak that's pretty big? 

 

Back in the day, even the hottest of the hot GT Falcons on the street around here were getting 12mpg...yours is around 6mpg!   Reckon you'd better find that leak ( assuming it's got one), but with my limited knowledge, I wouldn't have even thought it would run if that much was going into the manifold?

[gtrboyy]

That is worse economy than my vh sle with 750dp f280 355 stroker,4500rpm stally 4.56 gears...it could do 18-20ltr/100km cruising with occasional jandal.

 

Baby cammed mild mods efi 304 vp ute does 14-15ltrs now but still think has some unkown issues.

 

My lc gtr with in 6cyl & v8 had the rear of bonnet raised only time ever smelt fuel was when pipe in sender unit cracked.

 

Pinhole in fuel cap blocked?

 

Wrong type of fuel hose?

[nanbar]

That is worse economy than my vh sle with 750dp f280 355 stroker,4500rpm stally 4.56 gears...it could do 18-20ltr/100km cruising with occasional jandal.

 

Baby cammed mild mods efi 304 vp ute does 14-15ltrs now but still think has some unkown issues.

 

My lc gtr with in 6cyl & v8 had the rear of bonnet raised only time ever smelt fuel was when pipe in sender unit cracked.

 

Pinhole in fuel cap blocked?

 

Wrong type of fuel hose?

Thanks for the reply, as I said I have only fuelled it up after short distances and I assume the odometer is correct.

8.4L for 12.1 miles

14.9L for 24 miles

Its still s-house no matter how you look at it.

Pinhole in the fuel cap blocked - What you you mean by this?

Wrong type of fuel hose - How would this effect fuel economy? Do you mean it could be perished and leaking?

[RallyRed]

Is the fuel smell worse at the front of the car? or the back?, inside? underneath?

[nanbar]

Is the fuel smell worse at the front of the car? or the back?, inside? underneath?

I'd say even all around. It doesn't smell real bad like it was coming out of a bowser but its its noticeable when your outside the car in garage and in the cabin when driving. Its also in the boot.

Edited by nanbar, 02 November 2023 - 07:22 PM.

[nanbar]

Thanks for the reply, as I said I have only fuelled it up after short distances and I assume the odometer is correct.

8.4L for 12.1 miles

14.9L for 24 miles

Its still s-house no matter how you look at it.

Pinhole in the fuel cap blocked - What you you mean by this?

Wrong type of fuel hose - How would this effect fuel economy? Do you mean it could be perished and leaking?

As mentioned, I replaced the sender unit as it looked like the fuel pipe was cracked.

Edited by nanbar, 02 November 2023 - 07:28 PM.

[rexy]

I dont think you can make an economy assessment on such a small sample.

 

Leaving that to one side, the smell is not uncommon in the small toranas with the tank and fuel line in the boot.

 

If the rubber fuel lines are old then replace them, its cheap to do and all the connections will be tight.

Leaks in the boot are harder to solve. Filler neck rubber, hard line connection and vent hose can all be a problem.

 

When updating mine I fully sealed the boot from the cabin which solved the fuel in cabin smell problem.

[Indy Orange]

Is the black o ring seal where the sender unit goes into the tank intact?

[nanbar]

Is the black o ring seal where the sender unit goes into the tank intact?

Brand new with the sender about 2 months ago.

[nanbar]

Checked a few things:

1. Timing seems to be around 4 to 6 deg BTDC

2. Checked the vent line off the fuel tank, it goes through the floor as it should and the rubber is not perished. The line was clear. I added some cable ties around the the hose ends.

3. I checked the fuel cap, there is no evidence of fuel leakage from there, the rubber is in good nick and seems to seal. As I said, its a Valiant Charger flip cap and it has a 2mm hole in in the centre that appears un blockled.

4. Rubber Fuel lines in the engine bay all appear in very good condition.

5. I checked the odometer on a little drive and found it to be around 11% out (under, ie 4.99km odo, actual distance was 5.63km) 

6. Pulled the dizzy cap off and it and the rotor look ok. Pulled a plug out of no. 1 and it looked ok also.Plug Leads look in excellent condition.

7. I blocked the hole in the firewall with some tape.

I went for a drive to buy a new timing light and check the odo, I dont know if its my imagination but there is no fuel smell in the cabin!

I dont know if it what I did with the tape and vent line or if its to do with the lower fuel level in the tank.

I will continue checks and try and get to the bottom of the poor fuel economy.

[Bruiser]

I was just about to ask what your plugs are like, then read no. 6 above
Hard to believe they look alright with such high fuel usage.
If you only pulled one plug, the rest may need a check too, they could be super black,
you never know.
If they all look ok, it isn’t rich. (?)
Does your exhaust stink of fuel and hurt your eyes?
Can you see the smoke in the headlights of cars behind you when you floor it?
I suppose you would have noticed a leak from the tank or lines to the motor by now
Don’t know where else the fuel could disappear to
Local kids with siphons?

[nanbar]

I was just about to ask what your plugs are like, then read no. 6 above
Hard to believe they look alright with such high fuel usage.
If you only pulled one plug, the rest may need a check too, they could be super black,
you never know.
If they all look ok, it isn’t rich. (?)
Does your exhaust stink of fuel and hurt your eyes?
Can you see the smoke in the headlights of cars behind you when you floor it?
I suppose you would have noticed a leak from the tank or lines to the motor by now
Don’t know where else the fuel could disappear to
Local kids with siphons?

Thanks for that, much appreciated. Ill pull all the plugs out over the weekend and change them all anyway. The plug I pulled out was dry on the tip with the tiniest smidge of oil on the thread. Id say they all need looking at as you say. Its gonna be fun pulling all of them out let me tell ya.

The exhaust smells a little fuely but not where it hurts your eyes. Been driving a modern cars and diesel Prado for years so I am getting used to the old car smells and runs all over again.

I haven't noticed smoke in the head lights but I haven't thrashed it all that much.

Kids with siphons would have to find the thing first, its well tucked away..

[claysummers]

Testing consumption over short distances is fraught with inaccuracies. See how far you get on a tank. I wouldn’t be surprised if the consumption turns out not as bad as what you are saying.


Sent from my iPad using Tapatalk

[gtrboyy]

As others have said take it for a decent drive then report back.

[Bruiser]

Thinking about the rich smelling exhaust idea, the mixture at idle could be ok, and the part or full throttle jetting
is hosing fuel in while you are driving
Maybe lift off the carb after a drive to see if your plenum is overly wet
Could smell the dipstick to see if there’s fuel in the oil, too

[nanbar]

Testing consumption over short distances is fraught with inaccuracies. See how far you get on a tank. I wouldn’t be surprised if the consumption turns out not as bad as what you are saying.


Sent from my iPad using Tapatalk

I haven't done it to date as I cant trust the gauge (it all over the shop - separate problem). Ive now got 10L of fuel in jerry can in the boot so I intend to drive it till its empty.

[nanbar]

Righto, update time:

Went for a drive to buy some tools I needed and new plugs, on the way home, the old girl started surging and missing and my thoughts immediately turned to running out of fuel. I was literally in front of a servo so I darted in and filled it up. Only 17L went in. I was lazy to start but drove home with it cough and spluttering and proceeded to pull the plugs out. I'll post pics of the plugs later but Ill recant the comment that I made earlier saying they looked ok.

After pulling all but one of the plugs out and cleaning, I went to start it up and it was dead. Checked the battery and a terminal had come loose as hell. Thats probably what made it misfire and splutter.

Back to the plugs, black as all get out, see attached pics.

 

I also pulled the fuel gauge out and set up a test rig on the bench with my old sender unit. Works exactly as it should so nothing wrong with it. I have added another earth wire from the sender unit to the body of the car just to make sure.

Attached Files

•  cyl 1.jpg   51.72K   1 downloads
•  cyl 3.jpg   107.43K   1 downloads
•  cyl 5.jpg   106.15K   1 downloads
•  cyl 2.jpg   140.56K   1 downloads
•  cyl 4.jpg   97.7K   3 downloads
•  cyl 6.jpg   106.02K   1 downloads
•  cyl 8.jpg   107.17K   3 downloads

[claysummers]

Yes, plugs don’t look rich. Best go around the car and tighten all loose nuts and fasteners. It actually says to do it regularly in the owners manual as I recall from my first car, a 90,000 mile HK Kingswood wagon. Hopefully it will run ok now. Get out on the highway and run up some miles. Maybe update your roadside assist first.


Sent from my iPad using Tapatalk

[RallyRed]

They look rich as, dont they?

Edited by RallyRed, 04 November 2023 - 06:41 PM.

[nanbar]

They look rich as, dont they?

claysummers reckons not, I sent them to a mate and he also said the electrode tips dont look like its rich. FIIK.

[RallyRed]

...seems to be way too much black gunk?

[Indy Orange]

What fuel are you using?

[nanbar]

What fuel are you using?

BP 98