tb3

I'm fixing to just throw in the towel and just accept that I'm going to have the dreaded "fuel smell" linger with the car.
I've done mucho searches on this, and to no avail.

89 2.8 firebird, stock.
Fuel smell is strongest right after shutting the car off, and its coming from the rear-ish.

Heres the things I've checked:

No fuel leaks.

I installed a new fuel pump and filter when I first bought the car several months ago. all new hoses and clamps.

I popped the hood right after shut down and theres no fuel smell up there.

I installed a fuel vent valve after taking it apart and cleaning it. The original vent valve was actually very clean.

The smell seems to be the strongest right around the fuel filler door (go figure), so I swapped the fuel cap with a known good one from my 87 buick (they are the same pn), but that didn't help.

I'm open to any other suggestions.

thanks in advance!

Mark RWC

If you car is running rich the tail pipe will have a smell of gas.

Check the tank and filler neck with the tank full. When I first got my 88 it smelled near the tank when filling up It turned out someone had patched a crack where the tank and filler neck meet with epoxy. The leak was only visable when the tank was full.
There are dyes that can be added to the fuel and show the leak with an ultra violet light. I was looking in to this before I found the leak.

RBob

iTrader: (1)

Check that the Charcoal Canister Purge (CCP) system is working correctly. That system is what prevents fumes from escaping the fuel tank.

RBob.

Gumby

n when those suckers go bad, they can short out a small section of the ECM but the car still runs and wont toss a code.

tb3

thanks guys for replies!
I checked it again with full tank. didn't see any leaks.
I removed the charcoal canister and it seemed to be ok. I checked the filter on the bottom and it was pretty clean. I shook it a little bit and it didnt make any rattle noise (not sure if that is relevant or not).
I cleaned the solenoid on the top of it. Should I put 12 volts to it and see if I hear it operating? The hoses going to it are all in excellent shape.

How else would I check the charcoal canister operation?
guess I need to invest in a maintance manual

Mark RWC

Remove the hoses from the canister. Test the canister by using compressed air from a compressor or a bike pump. You should be blow in and feel the air come out the outlet side of the canister.This should not take alot of air pressure.

When you replaced the pump did you replace the large Oring that sets between the pump and the tank? If it was the original it would be over 20 years old.

Factory service manuals are availble on CD for around $30 plus shipping from
Bishko automotive literature at www.autobooksbishko.com I got mine from Bishko and it it worth every penny.
I think rockauto also sells a CD but I have not seen what is on it.

tb3

thanks!
I will try to blow through the canister this weekend.
I did reuse the old o-ring because it looked to be in real nice shape, and I cleaned and lubed it with o-ring lube. you make a good point about the age of it though. It may have twisted or broke on me when reinstalling the hangar assembly. I will replace it this winter when I pull it back out to troubleshoot my sending unit problem.

thanks for the link on the factory service manual! I'll get one coming

jiyasa

iTrader: (1)

Hey Gumby, to what you were saying about the ECM going bad... earlier this year my car had an awful misfire and smelled like gas whenever I started the car. Shortly after, my car started showing a code 35 and idles super high in park. If my CCP and ECM went bad and the IAC is governed by the ECM, could that be causing my code 35? And if so, if I want to replace my ECM is it as simple as taking out the old one and swapping out the prom and hooking it all back up or is there more to it than that such as programming of any kind?

LarryD

Check your tank again for leaks, you won't necessarily see a leak under the car. Mine was leaking badly where the fuel filler connects to the tank.. Looking under the car I could not find a leak.. That is because the heat shield above the muffler collects the fuel and it won't hit the ground. It either gets absorbed by the dirt and oil or evaporates fast off the heat shield. The best way to check for the fuel filler neck leak (common problem) is to remove the fuel door and the trim pocket around the filler neck.. Shine a flashlight down onto the tank joint and look for wet fuel or stains running down the side of the tank.. Mine did exactly what yours is doing, filled the cabin with gas smell when the tank was full... It would go away after the tank level dropped below the filler neck level... I put in a new tank and the problem went completely away...

Gumby

pull the emc open and look at it, look and smell for burnt sections.

your nose can pick up a fried part easier

tb3

I think you are right.
over the weekend I was under the car installing a alum drive shaft, new shocks, alum brake drums and tubular lowers.
I noticed on the filler side of the tank a wet stain all over the heat shield that wasn't really wet, just "sticky", like a very slow leak.
Now I'm second guessing my hose clamp reinstall on the fuel sending unit tubes when I installed the new pump, or, like you said, I got a leak on the filler neck. This is something new in the last 3 weeks since the last time I was under the car. So its deciding to get worse quicker now.

I guess I know what my next step is, lol!
I'll post back with what I find. It may be a week or two.

Gumby, I pulled the ECM out an hour ago and did take a quick sniff of the inside. Didn't smell or see anything burnt. It also gave me a chance to confirm my ECM # (302). I'm gearing up to do the 730 swap.
I also am rather intrigued by your rear hatch. It made me do some searches on the net and I discoverd the "notchback". Very very cool!!!

Gumby

I wanted one forever but they cost $$$ finally found that one NOS for $150 local by accident looking at craigslist.

only thing else id like is a set of wide body fenders.
But just the rears.

tb3

yep, you guys where right. crack at the filler neck.
I can now officially say that removing the tank is a aggrivating pita!
It's that damn filler neck that just doesn't want to cooperate.
after reading some threads here about the aftermarket tanks not always fitting right, I decided to weld repair mine since it is otherwise in nice shape.
tank is back in and so far so good. thanks guys!