reborn92rs

Hey all,

Here is a complete recount of everything I have done and gone through to hopefully give someone enough information to tell me what is wrong.

Just replaced my gas tank (sending unit and a walbro 190 pump) because the car reeked of gas all the time. Well first full tank up after the install went fantastically, no problems, no leaks, NO GAS SMELL!!

Heres where things go wrong. I started smelling gas again probably by 70-75miles into the tank of fuel. The fuel gauge was not working, annoying as hell, so I had set the trip meter at the tank up and planned on getting gas at 100 miles (10mpg was good est for tuning driving imo, car did 28mpg highway). As the trip was approaching 92-93ish miles I started for the gas station. 1/4 mile from said station, on an inclined road trying to accelerate from a stoplight the car lurched bad and stumbled. I lifted off the gas pedal and the car caught itself and went back to normal, tried accelerating again and got the same results. Crap, gas was nearly gone I thought so I idled the car up the rest of the hill (tq rules!) and into the plaza next door to the gas station. Stopped the car, walked over and bought a gas can and put 2 gallons of fuel in it. Put it into the car and let the car finish priming before turning it on and heading over to the gas station. Got there and tried to fill the tank and gas would not go in. Got 2 gallons with having to constantly restart the pump as if I was trying to top off a completely full car. Gas was outside the splash flap in the filler neck, it was acting like the car really was full.

Knowing I don't get 50+mpg I headed home and stopped by another gas station. Exact same results, got 1 gallon in before I had to constantly restart the pump to get another gallon back in there. I even tried trickling the gas in, still would not take it.

Once I got home I noticed gas covering my really nicely painted rear panel. Cleaned it off, and got up here and started searching. TGO + the manual told me to check the charcoal canister lines (checked out) and the fuel tank vent valve. Valve arrived today, put it on, drove the car, same results. Gas all over my paint. Tried to tank up, again forced 2 gallons down it.

I have no idea what is going on with this thing. Is there something else that I am missing? I did use a socket breaker bar inserted into the filler neck to carefully bend the neck towards the rear of the car 1/4" to make the plastic shroud fit again. Did that do some internal damage I am not aware of? I looked down my old tank and the new one and I see something near the top that goes down 6" or so, but thats it. Both look the same on the new and old tank. Did running the pump dry for a little harm it? Even if it did, how would that not let gas in when I want it in and out when I don't want it out?

Ideas anyone? Thats all I can think of, sorry for being long.

afremont

It's full. Check your fuel pressure at the rail and make sure it holds when the key is off.

reborn92rs

I cannot believe its full, I was tuning a good bit in the 3-4k rpm range where EBL estimates about 6mpg.

But going on that idea since I have no others, what do you recommend for checking fuel pressure with? Do I have to get a gauge and splice it into the fuel lines? Is it something I can bring inside the car (maybe as an input into the EBL)?

Thanks for the reply!

reborn92rs

Tried letting the car idle and hope to see some leaking happen. After 20 minutes no gas out the filler neck, but there was a gas smell around the rear driver side wheel, I guess the new tank valve was open and venting.

Took the car about 1/2 mile down the road (all left hand turns), pulled over and sure enough gas out the cap.

My original problem was gas smell at the rear of the car, and now with a new tank, new pump and new sending unit, I still have the gas smell. Except perhaps the higher output pump has worsened the problem causing smell plus visual aid out the gas cap.

If I view it as I never solved the original problem then it does narrow things down a bit. I am going to order up a charcoal canister and the vapor valve that sits in front of the CC. I will replace all the little hoses in the area when that comes in. Failing that I just have fuel lines left. $100 a pop for stainless. =/

afremont

I assumed you have a TPI system. If so, then there is a Schrader valve on the intake. It looks like a tire valve and you screw a fuel pressure gauge right on to it. I have one permanently installed. It's like this one, but it came with a bracket to reorient the MAP sensor.
http://store.summitracing.com/partde...5&autoview=sku

RBob

iTrader: (1)

As for the gas spilling out while driving, it may be that the gas cap isn't fully seating. My '92 was the same way from the factory. For some reason the cap was too tight in the threads and would tighten-up & click well before being seated. Sometimes to the point the cap would hold the door open. It was worse in hotter weather.

To fix this I took a flat file and filed down the cap threads a little. This is the peaks of the threads. Then took a round file and filed the troughs of the threads. Not a lot, but enough so that the cap would freely spin on and tighten down.


An issue with the fumes is the filler neck leak. Even has a recall on the tanks ('91 & '92). The soldering of the neck into the tank has pin-holes in it. This causes lots of fumes. Again, my '92 has this issue. Dealer checked it on the recall and pronounced it healthy. Not quite, can even see the gas stains from more then just fumes leaking. This is still a problem and will be repaired at the same time the fuel pump requires replacement.


Speaking of the filler neck, there is a divider that runs down the length of the neck. This allows air out and fuel in via two separate paths. The El Camino has this same style neck. How do I know? POS (Previous Owner Syndrome) struck and the neck had been cut, then put back together with a coupler and hose clamps. Because of this it is difficult to get gas into the tank. If it can't be trickled in the pump shuts off.

CCP: check the solenoid on the cannister to see if air will flow with no power to the solenoid. This is to tell if it is an NO or NC setup (normally open or normally closed). Then set the CCP option bit for the proper operation.

To check this: pull CCP vacuum line off of TB, try to blow through it (or use a vacuum pump). If air flows then it is an NO solenoid. If no air flows then it is a NC solenoid. Setting the option for this is important so that purging is done when commanded, otherwise it will be opposite in function.


There have been some long threads on the fumes issue. Some found that the heat shield above the muffler wasn't present. This causes the gas tank to heat up.

RBob.

SteelTownMadDog

iTrader: (2)

I'm saving similar problem, but a little different. Ever since I took the tank off for another unrelated issue, I can't put more than 9 gals of fuel in the car....ran out of gas, could only put 9 gallons in. The only line I'm using out of the tank is the main fuel supply, and the vent.

reborn92rs

Been a while but finally got the correct parts shipped to me and on the car.

Fuel filter was replaced, found a bum o-ring on the tank side that I replaced as well.
Charcoal canister is replaced as well as the 3 input valve in front of it, new hosing all round it. Canister it a NC (couldnt blow through it) and the CcpNC option is set in the bin.
Also my old gas cap never even sealed onto the tank, this new tank is special or something, the rubber ring wouldnt get anywhere near the filler neck end. I have the new one back on the tank now and it does not get any tighter than when I put it on the car. (On loose, comes off loose, etc)
I have all the heat shielding still under the car, cleaned it up a little while I had the tank out.

Still got tons of fuel down the side of the car. I should know if my gauge broke or if the sending unit is malfunctioning on me this weekend.

I have a TBI setup so does that gauge that afremont posted still apply? It really would be awesome if I could plumb something into the EBL. RBob is this doable?

I'm pretty much out of options now. I think I do need some kinda fuel gauge and a pressure gauge to tell things from here on. If anyone has part #'s or ways to get a good gauge into a TBI let me know. Bonus points if I can tie it to EBL.

Ideas anyone? I really dont want to take it to a mech, I know this would end up horribly expensive.

r62mcmahon

new gas cap

RBob

iTrader: (1)

Regarding the gas down the side of the car, the only thing I can think of is that the gas cap isn't sealing. It should be a solid cap, no venting what-so-ever. Look at the inside center of the cap, should be solid. If you have some modeling clay (play-doh works ) place some on the rubber sealing ring in the cap, tighten it down then remove, did the clay get pressed out?

For a fuel pressure gauge the TBI setups have no access point. Need to add one. Some tap into the feed line where it goes to rubber from the frame to the TBI. Can also tap in at the feed line at the TBI. These are saginaw fittings which has aftermarket pieces to fit.

Autometer sells a 30 psi fuel pressure transducer. The EBL supports it directly (along with the AM 100 psi transducer). Give it +5 volts from the TPS/MAP line, ground to engine block, and signal to ADC on EBL board. Select it in the Preferences dialog (type & channel).

RBob.

quikjeff

I have the same issue with my 91 TA - 305 TPI, 105,000 miles. I suspected issues with the charcoal can up front. Have changed gas caps. I tried a vented cap, a new non vented cap, and still get fuel down the side of the car. Big sucking or blowing sound when you crack the seal on the gas cap, so it must be sealing, pressure must be building in the tank, and somehow fuel is pushed past the cap seal and down the side of the car. I am trying to sell the car and would like to get this figured out.

RicksIroc86

when i bought my car it didnt have a gas cap on it, and i bought one about 2 weeks after driving the car, and i never had any gas run down the side of the car or a fuel smell.