We changed the fuel pump about 25 miles from my house this past Sat,ran great all the way home.Sun evening took her out for spin and every time I slowed down she started missing and almost dieing till I would step on gas pedal.Got to my parents house and while parking it knocked off.When I tried to start it no fuel pressure.Let her sit and Mon morning started and idled perfect.After work 2night started & idled great till she warmed up then started missing and knocked off/no fuel pressure.Did I get a bad pump or is the pump shorting out?Has anybody had this problem!


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86 IROC mods:T.E.S.,Flowmaster muffler
T.P.I.S. airfoil,Dan Burk ported intake system,,March
pulleys,Accel 8.8wires,ign.mod,Crane PS-91 coil,Crane HI-6S ign.box
RAM AIR induction,gutted MAF,
B&M shift kit,3.73 rear gears,Accel afpr,Hypertech stage 2 chip,Random Tech.cat.,Lakewood lower control arms,Lakewood adj.panhard rod,mac subframe connectors
"The more I learn about women,the more
time & money I spend on my IROC"

 

BTT

 

I've known more than one person that has gone through the huge ordeal of changing out an intank pump. I also know people who have paid $700+ to have it replaced by a mechanic. In both instances I know of cases where the new pump failed in a weeks time or less.
That's why I would never run an intank pump, nor would I recommend anyone else to.

I know this does not answer your question or explain your problem, but I hope it gives you some good insight to the situation that you have created.

good luck
ODB

 

as far as your problem goes.
most of those pump problems are electrical

caused by a faulty ground or flakey relay.

another remote possibility is a blocked off fuel tank vent. To test for this simply remove the fuel filler cap and drive. If you still have the problem then it wasn't the vent.

 

Could be your oil press switch. This thing kicked my *** for a long time. Put 2 pumps in before figuring it out. Not to mention the original was good. If your car has fuel press when could and as sonn as the oil gets hot has none this very well could be your problem. Its the sending unit above the oil filter going into the block. Cars with high miles have this thing get cruded up and when the oil gets hot and thin the fuel pump gets shut off. Wish someone would have told me about it 5 yrs ago.

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87z 383,afr 190's, crane hyd roller(224/230-.509/.528,112 sep),Ported and polished mini ram, 30lb inj, 3.42 gears, strange 12 bolt, tremec 5spd, , 1,3/4" slp headers.
"Just remember children, no man can beat you once youv'e found the cliterous." 'chef'

 

Fuel tank vent? When I remove my filler cap it makes a de-pressurization sound. I thought this was normal...

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89 GTA G92
305 TPI WC 5spd w/3.45
Accel Cap & 8mm Taylor's
Custom 4" Cold Air Induction
Jet Airfoil
K&N Airfilter
160 deg stat/fan switch TB Bypass - Steel Rad
Cat back 3" Exhaust w/Terminator Muff.
HiGh FlOw Dynomax Cat
Spohn LCA's - KYB GR-2's
Autometer Vac+Oil Temp

 

87Z-ya both oil pressure sending units were replaced last July.Guess I'm going to replace pump this Sat.

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86 IROC mods:T.E.S.,Flowmaster muffler
T.P.I.S. airfoil,Dan Burk ported intake system,,March
pulleys,Accel 8.8wires,ign.mod,Crane PS-91 coil,Crane HI-6S ign.box
RAM AIR induction,gutted MAF,
B&M shift kit,3.73 rear gears,Accel afpr,Hypertech stage 2 chip,Random Tech.cat.,Lakewood lower control arms,Lakewood adj.panhard rod,mac subframe connectors
"The more I learn about women,the more
time & money I spend on my IROC"

 

Did you try running 12v to g on the alcl?

 

keep forgetting about that oil pressure switch because I never ran one. Thanks for bringing that up.

well if there is vacuum in your fuel tank then your pump has to work that much harder to pump fuel out of it. This is why a lot of pumps fail...besides them being junk in the first place.

I've seen too many racers at the track go through all kinds of mess thinking that they need a huge fuel pump and 1/2" fuel lines etc.. because their carb bowls would empty at full throttle. This was usually caused by them forgetting to vent the tank or blocking off the vent when they removed their charcoal-canister.

 

I thought the oil pressure switch was just a backup to the fuel pump relay... if the switch is bad, the relay should still drive the fuel pump.

Or at least that's how it's been on my car for the past, oh, 4 years; I don't even have that oil pressure "backup" switch installed. I plumbed my mechanical oil pressure gauge into it's hole by mistake, instead of using the hole for the idiot-light switch. Oops. That's a repair for a warmer month.


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
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