A mechanic at work commented on my recent car problem ('car is dead' thread below) and suggested that my old pump was maybe killed by a lack of free enough flow in the fuel return line, like a kink or an obstruction, causing the fuel pump to make a vacuum in the gas tank and have to force harder and harder to get the gas pumped back towards the engine.
I told him our cars are supposed to have that pressurization in the tank, he said his Mustangs and Honda didnt do that.
When my fuel filler tube sprung a leak way back when I noticed first that even after passing a whole tank of gas, when i took the gas cap off it would no longer 'whoosh' as air went in. So I bought a new gas cap...same problem.
After I replaced the fuel filler (which had a mean corrosion hole in it on the weld seam) it repressurized fine...but then my tank sprung a leak, and we replaced that, too.
I'l pretty sure the normal state is a pressurized gas tank, and I wouldnt be suprised if you left the gas cap off, the CEL came on. I'll see what I can dig up in the FSM, I dont recall seeing too much about it though.
EDIT: there is a vacuum relief valve on the gas cap, so there shouludnt be a vacuum on the tank at all
True true but perhaps the relief valve only relieves the pressure to some set amount of vacuum - I have read that if the gas cap is bad it will indeed throw a CEL (at least on B14s?)...
Does anybody else's cap go WHOOSH a bit when you open the gas tank?
True true but perhaps the relief valve only relieves the pressure to some set amount of vacuum - I have read that if the gas cap is bad it will indeed throw a CEL (at least on B14s?)...
Does anybody else's cap go WHOOSH a bit when you open the gas tank?
D
yeah, every time I open mine, it blows out air as I open it. Even after sitting for 30-40 minutes it still hisses some.
My friend has an Oldsmobile Alero, and his does the same thing, pressurize the fuel tank to check for leaks. I dont know if there is a code for that on the B13 or if it is there just so you can listen for a leak etc...
Yep, mine releases pressure once opened. Freaked me out at first, as my other cars have vented fuel caps.
I don't know if there's supposed to be vacuum or not, but I would assume so, if the caps aren't vented. Mine is an OEM cap, so I know it came with the car, or was replaced with the same cap from the dealer.
I am pretty sure it should be sucking air IN, but not a lot...
...so my car stalled again yesterday. In thinking about a possible fuel system bug I went and unscrewed the cap whoosh...then drove on. It stalled not 5 minutes later and the cap WHOOSHED a lot again after I unscrewed it again.
We tried driving it with the cap just barely tight/loose so that the pressure could equalize easier, no stall! My temp fix is to then do this before driving, and when I park, screw it on to 2 clicks.
So I took back the cap I bought last October, to Nissan and explained that their faulty cap broke my pump and please give me another one...today I'll get it. I do suspect thatthe vacuum relief valve on the cap is faulty. Oh, my CEL came on thim morning on the way to work but I'm not sure of it's because of my hacked off EGR or the loose gas cap...I'll check the code after work.
Is it normal for the pump to whirr loudly? I think I may have reinstalled it improperly and it is transferring vibrations into the tank bracket or something...and I still have yet to see about the FPR and fuel pressure in general.
Fuel pressure testers are like $60 at Crappy Tire...a guy I know told me he can sell me a good aftermarket FPR with a gauge built in for probably the same or less...I dunno what to do.
I hope it is just the gas cap because I am dead tired.
WAIT NOW: Is it possible that my Walbro 190 (low pressure) fuel pump is too powerful for my i/h/e GA16DE setup? In the sense that it pumps so much it somehow creates more vacuum (that really doesnt make sense to me, since as I understand the vacuum in the tank should be created not by flow of gas but by the gas being used up and since there it is capped the vacuum is supposed to slowly release from the gas cap to make sure that not so much vacuum builds up in the tank that it would make the pump have to force harder and harder to work until it failed...either permanently or temporarily, either which would result in a stall!)
I still don't get this. Could I put a gas cap from another car that would have a vacuum release valve that could handle more vacuum release (that is, if its not my gas cap that I have that is the problem)...
...I still am not clear why a restriction/obstruction on teh fuel return line could cause the gas tank to overpressurize. I have a new fuel filler tube - is it possible the little 'breather' tube that runs beside the filler tube could have a problem with it?
I need to print out the entire FSM, make coffee, sit down and carefully look over this stuff. I can't stand not knowing what is going on here.
Thanks again for all the help though guys. It was enough to make me finally pony up some dough for the nice webmasters of NF. hehe
What if the evap canister in the engine bay was clogged or worn out somehow? This summer once when I parked my car after hard driving gas spilled out of somewhere up there and left a big puddle underneath the bay...just remembered that.
Can that canister go bad? Would it have anything to do with project: dead car and the stalling even after pump replace...hmm....well when I get my new gas cap today we'll se what that does.
What if the evap canister in the engine bay was clogged or worn out somehow? This summer once when I parked my car after hard driving gas spilled out of somewhere up there and left a big puddle underneath the bay...just remembered that.
Can that canister go bad? Would it have anything to do with project: dead car and the stalling even after pump replace...hmm....well when I get my new gas cap today we'll se what that does.
My brain never stops grrrr
I have heard of evap canisters filling/clogging and needing to be replaced on other vehicles. Air leaks on the purge and vacuum lines can cause hesitation according to the trouble diagnosis in the EC section of the FSM. Not sure if that would stall it however... Are you still on that same tank of gas? It also says to disconnect the fuel pressure regulator vacuum hose and plug the hose. If that fixes the stalling then "check fuel properties"
If you have the means to print out the FSM, go for it, or at least the EF&EC section for your engine, I just wouldnt attempt that on a poor ol inkjet.
Car is only throwing code 32 (EGR system; because the tbe is hacked off near the header). I got the new gas cap and will resume testing tomorrow; I still have some of the old gas in there but theres some dessicator fuel treatment and an extra 3 gallons of new gas, and I'll also go ahead and dump the rest of my bottle of redline in there too.
If its not the gas cap then I will test the EVAP - one big question I have is that the solenoid for the EVAP vacuum line control is on the BPT for the EGR system - and so is it just mounted there or is it part of teh system? If I remove the whole EGR apparatus and plug associated vac lines, I guess I'd have to mount that EVAP solenoid elsewhere? IS EVAP and EGR independent systems?
And of course follow the suggestions above and check the fuel return lines. $130 CDN for a brand-new EVAP canister from the dealer, 47 bucks for the solenoid. I may just limp until swap time and try the EVAp can from the donor car
Wow I am sure learning a boatload of stuff through these few painful days!! FSM will get printed and hole-punched at the print shop. I have a laser printer but no way am I gonna print 2000 pages on it in one shot.
Gack brain on overload. Time for some pie and ice cream. MMMMMM iiiiice cream.....good night forumfolks.
D
I printed out some FSM goodness and have lots of reading to do. My battery light is also gojng on and off intermittently so I may have a short but more likely my alternator is on its way out. The new one is in the back seat just in case it dies on the road.
Still stalls with gas cap closed so I have some problem with my line; I may try and rent a fuel pressure tester and see what I read.
OK your thinking too much. The pressure in the tank should have NOTHING to do with stalling out. You need to buy a fuel pressure gauge and install it after the fuel filter and see where your fuel pressure is. I can tell you from experience that removing the fuel cap does not release the fuel pressure in the rail.... I just tested this yesterday on my gauge.
Buy a liquid filled FP gauge and see where it is at.
When your car stalls, pull the plugs, are they fouled with fuel?
As far as the EGR and EVAP, I completely removed the EGr stuff and left the EVP in place and have NO CEL. I do have the JWT resistor program for the EGR temp sensor, but other than that all of the EVAP stuff works the way it should and does not throw a CEL. This means you can remove the EGR and still have everything else function properly.
As for your EGR removal, did you just cut the tube going to the intake manifold? Did you plug the IM OR the end of the tube? Tell us what the heck you did so we can try and help make sense of this, you are just thinking yourself in to a corner here!
Hahaha good points all Wes I got too much education and it ruined my brain...the mechanic just hacked of the EGR tube that goes to the manifold and plugged the header but left the EGR tube open.
I didnt think itd be a problem since I thought the EGR needs the pressure of hot exhaust gas to open up and 'suck' exhaust through.
As for the tank, it is weird, but I swear it only stalls when I put the (new or old) gas cap on to 1-2 clicks. If I leave it cracked it works FINE even if I go hard on the car for a while on the highway.
As for the fuel pressure thing...I will try and rent a tester. I cant see dropping 60 bucks to buy one at the moment. If I cant rent one then I'll buy it, but then again why not get an adjustable FPR with a built-in gauge for a few more bucks?
Friday the swap guy is comin by to see what parts I have. I will try and get simple on this fuel thing...a weird thing is my new pump seems noisy, almost like transferring vibrations into teh tank and I worry it popped the braket hold off and is hanging weird in there or something. I'll go see when the gas in LOW.
Gas tank pressurization and fuel return
hmmmm
Linear Mode
