liljon285

My 1987 seemed to always run a bit odd but still very good. then last night after a nice drive out for valentines, on my way home i heard a hummm from the back instead of like a usual buzz from the fuel pump and suddenly when that happens the car starts to bog and like cut off on fuel. It did that all the way till i got home, i would start it throw it in first gear and go...how i made it home i dunno probably cuz its chevy. So today i replaced the fuel filter and it drove perfect to my friends house, i left it parked there for a while then when i went to leave it did again, but then stopped. Then like halfway home it started doing it AGAIN but this time a lot worse, it took me a good hour to get it home in a distance that usually takes like than 2 minutes. Then when i got it home i parked it for a while went inside all frustrated then an hour later i went outside to see if i can put it away in the garage, and it started right up normally. I am confused could it be the pump or just the tank that has dirty fuel and clogs up the lines. The cars last owner did have it parked for a long time so that could be the cause. What should i do?

irocboy8292

BUMP!

Q's 91z28

your not alone. my car is doing the same thing. I replaced the fuel filter and no luck. Last night replaced the fuel pressure regulator and the car is still boging down on me. I was about to ask if it may be my fuel pump cause it does sound kind of loud. Seems like we're on the same boat. Hopefully someone out there has an answer.

pwdbychevy

Do you also smell gas fumes when this happens? It sounds to me the tank vent valve is not doing it's job and not allowing the gas tank to vent properly. The humming may be coming from the vent valve which is white and located above your rear axle on the driver's side. You may need to replace it. I had this happen to me a long time ago with the humming and car bogging and cutting off. I opened the gas cap and the car fires right up every time after the pressure release.

liljon285

Yea i think that may be it because the more i let it sit for a while, the more it would run better. Yea you smell gas and you can here the gas in the tank bubbling as if it was a bunch of pressure in there. I will replace that and see what happens. Thanks a lot!

84redta

iTrader: (34)

Usually when the whining starts, the fuel pump is on it's way out. Deal with the cheap stuff first, then get ready to drop the tank...

liljon285

Yea i wanna do it anyway....but the problem is im not driving the cars, they dont have tags or insurance yet, i have to sell my current daily first =/ so when i get my tag on it that will be the first thing i do.

IrocZ_85

iTrader: (1)

I have had a similar issue with my car, can some one put up a pic of the vent valve on the car?

pwdbychevy

I got this from another thread. Yellow arrow is pointing at it.

IrocZ_85

iTrader: (1)

Thanks, do the usual auto parts stores carry this?

liljon285

Wow thats what it is lol, hmmmm doesnt seem like a big laborious job. Ill see if i can pick it up somewhere.

pwdbychevy

I believe so.

IrocZ_85

iTrader: (1)

Thanks, I will try to locate one. Does warmer weather tend to aggravate this problem?

liljon285

Went to advance and they didnt have any =[ i hope autozone has them. My dad said to "just cut that **** off"...thats not a good idea isnt it lmao.

pwdbychevy

Yes because the heat increases tank pressure. I never had a problem in cooler weather.

liljon285

No wonder its happening. Im in freakin miami!

pwdbychevy

Not a good idea because that acts as a check valve. It allows air in but not out. It keeps the tank pressurized which helps the fuel pump operate more efficiently. If you cut it off then the tank won't pressurize and the pump will have to work harder to deliver fuel. If AutoBoneheads don't have it then you'll have to go to the dealer and get it.

liljon285

Dealer=$$$$$$ =[ i hope autozone has it, i got hooks up..20% discount lmao

IrocZ_85

iTrader: (1)

OK, did some searching here and on the web an found the part number 10033125 and a link to buy it:
http://www.gmpartsdirect.com/results...umber=10033125

Its cheap, only $23 on the site. I will try to stop by a local dealer and pick one up first.

regal301

just cut it off !!!!!!!!! its a one way valve to prevent fuel from spilling out in case of a rollover,if you roll over your car fuel spillage will be the least of your worries.it has nothing to do with your fuel pump. mine is off and been off for years.

pwdbychevy

very good advice regal liljon is trying to fix it the RIGHT way

jv9999

iTrader: (1)

It also works with the vapor canister to keep gas fumes from escaping. If you're in a state that does emissions testing, you'll likely fail the gas cap test.

liljon285

Yea i dont want anymore problems i want to fix it the right way lol.

regal301

vapor canister...................hmmmm, threw that in the trash, got in the way of the air intake.

these cars dont check the evap system.and a gas cap test is just that,a test of the gas cap.i happen to have an inspection lic. and mass and ri have almost identical procedures.
not looking for a war,i just enjoy a good argument.

IrocZ_85

iTrader: (1)

Why rip a part off when you can just replace it so cheaply? I picked up a new check valve at a local GM dealer for $28. I will have to put it on before it starts to get warmer, my car started acting up when it was about 75 degrees out. Now what its back in the 50s its been fine.

chads89ta

iTrader: (6)

if you are careful it can be taken apart and inspected ,cleaned

pwdbychevy

Compare the operation of the old one with the new so that you can see the difference. When I replaced mine I checked the old one and couldn't blow through it but I could on the new one.

IrocZ_85

iTrader: (1)

I will, probably wont get a chance to replace it until next weekend..........

liljon285

I couldnt find the part in autozone! AHh no one has it locally =[

jv9999

iTrader: (1)

There was a guy on here a couple weeks ago that couldn't pass CA smog because of the check valve. They do check that the tank holds pressure. Not sure about other states.

regal301

california ............ i believe it............ probably have to have a cat converter on your lawnmower,and bring it in for a dyno test too....

here (new england) we check the gas caps on old cars,and the obd 2 cars check the evap system on there own.

Slowridr

iTrader: (1)

My car is doing the same thing I found this thread and looked for the check valve and found that it was removed. Can not having it on the car cause the same problems as having a stuck/faulty one?

Please give me some knowledge here!!! Been chasing this for a month now and this car is my daily driver.

pwdbychevy

It's a strong possibility. I haven't had a problem since I replaced mine. There is another valve thingy located near the CCP canister that looks like a UFO with a vacuum line connected. That is also a check valve. Hook a vacuum gauge up to that one and see if it holds. I believe the Chilton manual has a test for that. It's supposed to hold vacuum for a certain amount of time.

Slowridr

iTrader: (1)

Is that the carbon canister you are talking about. Is you car a TPI?

pwdbychevy

Yes, the valve is located near the canister. It should be located to the left side of the washer bottle if you look at it from the front.

liljon285

Ok so i put the vent valve from my 89(since ima have it parked for a long time and im gonna build it) and the car seems to not be doing it anymore. The old vent valve was wide open, so i put the new one and it seems to be running different, now when u step on it it chokes for a millisecond then takes off, i guess since the tank actually has pressure now. But runs good nonetheless. I hope it starts doing the failing it would when the other vent valve was on. Im trusting it now!

liljon285

Guess what guys....it is still doing it! I am thinking it is the Fuel Pump Relay connector. It looks real bad, and i got one that was better(not good enough but better) than the old one from a junkyard and it helped but it still does it once in a while. Could it really just be the plug? I put the relay new too and also that helped but still, it still does that dam humming. It cant be the pump though because it would of given up by now! Please help this is going to be my daily in less then a week and I dont trust the car, I get scared to drive it.

jv9999

iTrader: (1)

You can always solder the wires right to the relay.

liljon285

Nah the relay has a plastic surrounding so unless i break it it would not look very nice. I want to buy the plug and I will but I dont wanna keep buying things to be in the same situation.

jv9999

iTrader: (1)

You can easily solder it without damaging the relay with a low temp iron. Tin the contacts and the wire first. A little shrinkwrap and it will look great.

liljon285

Ok Ill try taking it apart tommoro when i get home since i wont have to drive it in the afternoon.

Slowridr

iTrader: (1)

Dude ive been trying all the same stuff you have and still no fix for me as well. I am anxiously waiting to see what happens here!!!

Ive been told to change the MAF so I bought a used one to try it next.

liljon285

Lol nah it cant be that for me...mine is purely a gas problem. But it cant be the pump because it drives perfect 99% of the time.

irocboy8292

jon try to buy new plug and vent valve from GM and that should solve it iam going to get a new one so i wont have those problems

pwdbychevy

He did already. He has a different problem.

liljon285

Well i should. Ima buy the plug, a NEW one and see if it helps...i also am gonna see how much the vent valve from GM is, cuz i put the one from my 89 so its not really NEW either. Im just tight on money so im just trying to do things to see if it solves the problem so then later on i can buy everything new.

IrocZ_85

iTrader: (1)

I hate to quote myself, but you really seem hung up on the price of a new vent valve. I bought one at a local dealer for $28.

pwdbychevy

I thought you bought a new one already. You may want to now.

rough

How bad are your cars bogging done, i just recently replaced my pump and such thinking that was the problem, ended up being a clogged cat, it was so bad it was sending exhaust through the TBI !! Drove home 30 mi like this, and no gaskets blew !


All I did was mod my TBI unit slap it back on, and I guess the car god pimp smacked my cat and clogged it so i had no power then eventually making it hard to reach 20 mph.

liljon285

So today driving it home i stopped by a friends house to say hello and then when i went to leave it did the humming noise for about two seconds so i turned it off and on again and it went away. So i started driving and noticed it ran a bit weird, then the SES light cam on and go figure i cant rev past 2800rpms or so, it would just choke or cut out. So i bought the fuel pump today and im installing it tommoro. Ill keep you guys updated.