Instrument to find gas leak

[chunstone]

I have strong smell of gas and I cannot figure out where the leak is. I see on online that several gas leak detectors are available. Prices start at $120. Anybody have experience with these instruments. VG 30 engine......

[qwik510]

The gas tank on the 510 had a recall from the factory way back when. There are 2 fittings on the bottom of the tank that were capped from the factory. These caps rot out over time. If you pull the back seat, you should be able to see them and/or a puddle under there.
Check that first.

[RMS]

what year wagon are we dealing with ? is it the stock fuel system ?

[qwik510]

Duh, sorry. I didn't see that it was a wagon.

Lots of hoses on a wagon that could be leaking and the later ones have the evap system too.

Good luck.

[510rob]

The late wagon tanks with the "evaporative emissions" stuffs have a bazillion hoses to rot and fail and leak and stink...

Pre-evap type

datsun 510 wagon gas tank simple.png (248.79 KiB) Viewed 3656 times

Post-evap type

datsun 510 wagon gas tank complex.png (239.39 KiB) Viewed 3656 times

In the second picture, look specifically at item #23 "ASSY-TANK RESERVOIR, WAGON EVAPO" and at all of the rubber hoses that connect it to the gas tank. A nightmare of rotten hoses!

Rumor has it that some people turn the post-evap setups into pre-evap setups by removing #23 and then welding various ports closed on the gas tank (but I would imagine that you must retain some kind of vent tube like #6 in the first picture!). There is also the issue of vented gas caps on wagons

non evap gas caps = 17251-22902, 22903, 22904
evap gas cap = 17251-A5900

Someone who knows - Did the early gas caps seal or vent? How about the late gas caps?

[Byron510]

I know I did seal up these evap lines on my late wagon, missed the fact that the cap wasn't vented and collapsed my tank in a 45 minute drive, so beware.

Hoses #26 in the second drawing are very prone to failure and are an absolute PITA to access as they go through a hole in the bodywork in the car. I have had to replace these on a different wagon and it was a nightmare as access with my large hands just wasn't there.

Also, your car has been converted to EFI, what was done to the send and return lines at the tank? I know this was an issue when I did the EFI conversion on my second wagon. I ended up removing these and welding in a larger one for the feed line. Just in case this hasn't been done, and you end up removing the tank to fix the other hoses anyways....


Byron

[okayfine]

If you're going to explore in the area of the wagon gas tank and associated hoses, do yourself a favor and pressure-wash the underside of your car. Decades of road grime will rain down on you as you wiggle hoses.

DQ 9.1 documents both the early and late fuel systems and hoses for replacement. Worst job I ever did on a 510.

[chunstone]

Opps, my bad for not describing my fuel system/engine. I appreciate the diagrams submitted as I have the evap system of 1972.

I have a custom aluminum fuel tank, filled with foam that was modified to vent and a fill tube that hooks up to the stock filler componets.

I have tried to see and sniff everywhere I believe there might be gas evaporating from, thats why I am interested in an instrument to sniff out the leak.

I have heard that VG 30 engines had injectors that had a recall for leaking....

I see if I can get some photos of the fuel system, this was a system that someone else installed.
Thanks.Neil.

[chunstone]

"Re: Lialee, VG 30 wagon, 4 link suspension" See in Project Builds. Sorry Computer

[okayfine]

Should be fairly obvious if the fuel smell is coming from the VG/engine compartment or from the gas tank area. If you've eliminated the stock evap system, then you've reduced the number of joints by a lot. Going over each and checking the tension on the clamps shouldn't take long. Is it worse when the tank's full, cold/hot, left hand turns, etc.?

To your OP, I'd spend an hour checking over connections before dropping $120 on a detector gadget. And if you still couldn't find the source, better smog testing shops used to have those detectors to sniff out evap/emissions leaks.