headache with my crossfire
Thread Starter
Instructor
Joined: Aug 2006
Posts: 158
Likes: 5
From: New jersey
headache with my crossfire
hello, I have a 82 vette for the past 3 years. It was runing great up till 3 weeks ago, then things went bad...it wont idle, the idle jumps up and down from 6 hundred to around 9 hunderd. It used to start up in one crank but now it takes 5 or 6 and somtimes it will run and somtimes it just stalls rigth out.When it does run it seems to get a little better when it warms up but when I'am driving and i hit the gas it will bog down before speeding up. I took it to the local speed shop and the guy said that the intake manifold was sucking air, he changed it and the gaskets under the trottle bodies but this didnt help. anyone with this motor has ever had this problum please let me know how you worked it out. please e-mail me at headache57@aol.com.....iam new on this web-site and not sure how to answer mail here. thanks
Race Director
Joined: Dec 1999
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there's no idle sensor. It's most likely a vac leak...or worn throttle shafts. Let the car idle and spray some WD40 around the throttle shafts, if the idle changes (don't spray into the bore) you have a leak. Wiggle the shafts with your hand, if you feel play you need to have the TB's bushed.
It can however also be something simple like a loose vac. hose. Remove the 2 hoses from the port at the drivers side back of the manifold (the port looks like an F) and cap those off. Now you only have the vac. ports on the TBs (centers capped off, they are idle adjustment ports). Make sure the thermac hose is also capped off (the one going to the aircleaner base) and check again. If it's running fine now you have a vac. leak on one of the accessories, ranging from brake booster to headlights to interior heater valves and such (common cause is the heater switch under the center console)
If it's still doing it, check the MAP hose (maybe the hose is soft and is collapsing under vacuum and releasing resulting in a surging idle)
It can however also be something simple like a loose vac. hose. Remove the 2 hoses from the port at the drivers side back of the manifold (the port looks like an F) and cap those off. Now you only have the vac. ports on the TBs (centers capped off, they are idle adjustment ports). Make sure the thermac hose is also capped off (the one going to the aircleaner base) and check again. If it's running fine now you have a vac. leak on one of the accessories, ranging from brake booster to headlights to interior heater valves and such (common cause is the heater switch under the center console)
If it's still doing it, check the MAP hose (maybe the hose is soft and is collapsing under vacuum and releasing resulting in a surging idle)
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Le Mans Master
Joined: Apr 2001
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From: Minneapolis, Mn USA
You can get yourself a replacement GM 1982 fuel pump (get it from the $$dealer$$ -aftermarket pumps are known to be crap!!). It should be good for normal driving. They seem to provide only the minimum of fuel volume-thus creating a problem with maintaining the required pressure at your TBI regulator over time at higher RPMs.
There is a movement for installing a 1985 Corvette fuel pump (again GM only). It will provide more volume (excess even) of fuel-therefore allowing better regulation of fuel at your throttle bodies during any RPM loading and is said to give you better throttle response. Your present 1982 fuel pressure regulator will survive the higher volume of fuel.
Its your choice... Either way your probably OK.
Brent...
There is a movement for installing a 1985 Corvette fuel pump (again GM only). It will provide more volume (excess even) of fuel-therefore allowing better regulation of fuel at your throttle bodies during any RPM loading and is said to give you better throttle response. Your present 1982 fuel pressure regulator will survive the higher volume of fuel.
Its your choice... Either way your probably OK.
Brent...
Thread Starter
Instructor
Joined: Aug 2006
Posts: 158
Likes: 5
From: New jersey
ok..here is were iam at.......i replaced the pump with an 85 pump, and i thougth it was going to be the same hook up, but it was a little different........like wire hook up and rubber hose that goes into the top, anyway i got it in and now the car wont start, i guess iam going to have to pull it out and see whats wrong, my qustion this time is, does it matter which wire hooks up to the plugs in's on the new pump, the old pump had little bolts on top, this one has a plug in...........help help help.......and since i changed the filter yestherday, the idle was jumping and the car would staill out untill the car warmed up and the check engine like came on then went out....the car ran much better........iam confused
Race Director
Joined: Feb 2006
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From: Inside the woods living my passion
St. Jude Donor '07-'08
Originally Posted by headache57
ok..here is were iam at.......i replaced the pump with an 85 pump, and i thougth it was going to be the same hook up, but it was a little different........like wire hook up and rubber hose that goes into the top, anyway i got it in and now the car wont start, i guess iam going to have to pull it out and see whats wrong, my qustion this time is, does it matter which wire hooks up to the plugs in's on the new pump, the old pump had little bolts on top, this one has a plug in...........help help help.......and since i changed the filter yestherday, the idle was jumping and the car would staill out untill the car warmed up and the check engine like came on then went out....the car ran much better........iam confused
Melting Slicks
Joined: Jul 2005
Posts: 2,740
Likes: 3
From: Aurora Ontario
Link with instruction and pictures on how th install the 85 pump
http://www.crossfire.homeip.net/cfte...ID=18&CAT_ID=1
If you cross the wires you may destroy the pump.
Jim
http://www.crossfire.homeip.net/cfte...ID=18&CAT_ID=1
If you cross the wires you may destroy the pump.
Jim
Last edited by jdp6000; Aug 23, 2006 at 08:50 AM.
Burning Brakes
Joined: Jan 2006
Posts: 1,154
Likes: 1
From: St Augustine FL
I had a similar problem with my 82 a month or so ago. It was the fuel pump. My car would Idle though it would just bog down under full throttle. Then it got so bad the car would not even start. I replaced mine with an AC Delco pump for an 82 and the car runs well now but I still run rich and have a high idle. I also changed the fuel filter and cleaned the tank ot while the sending unit was removed. Make sure you put a new sock on the pump.
Becarefull with the 85 pump. I have heard stories of success and I have heard stories of rupturing old fuel lines from the increased pressure. The 82 and 84 pump puts out around 13-14 PSI the 85 pump puts out around 45 PSI.
Becarefull with the 85 pump. I have heard stories of success and I have heard stories of rupturing old fuel lines from the increased pressure. The 82 and 84 pump puts out around 13-14 PSI the 85 pump puts out around 45 PSI.
Last edited by bluesilver82; Aug 23, 2006 at 04:48 PM.
Race Director
Joined: Dec 1999
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Pumps don't put out pressure, they put out flow. Pressure is the result of flow through a restriction... the pressure regulator. The TPI pu mp can deliver a much larger volume and is therefore able to cram so much fuel through a restriction to raise the system pressure to the required 45+ PSI for a multipoint system. However, the fuel pressure regulator controls the pressure and no other part (well...if you have a dead head you will see max. dead head pressure resulting from the flow that the pump is capable of delivering or if you have such a large pump/flow that the bypass is bypassing so much fuel that the return line becomes restrictive then the pressure is outside of the regulators control - the lower limit that is...but that won't happen)
A TPI pump will put more strain on the regulator but a regulator in good condition will be more than capable enough to regulate things. The TPI pump has such an overcapacity that it'll be able to feed your TBI system without a strain...unlike the TBI pumps that barely keep up with the required system pressure and really fall off when they get old (or frequently run w/ a near empty tank)
A TPI pump will put more strain on the regulator but a regulator in good condition will be more than capable enough to regulate things. The TPI pump has such an overcapacity that it'll be able to feed your TBI system without a strain...unlike the TBI pumps that barely keep up with the required system pressure and really fall off when they get old (or frequently run w/ a near empty tank)
Thread Starter
Instructor
Joined: Aug 2006
Posts: 158
Likes: 5
From: New jersey
ok, well i must have crossed the wire's last nite, i changed them tonite and the car started rigth up. No rough idleing or bogging down. It ran great, now my next qustion is when would i know if my regulater will hold the extra pressure.....like what would happen, will it ruin anything or is it a matter of just putting a new regulater on so it works with the pump from a 85...........and now would be a good time to ask.....where is the regulater and what does it look like........and by the way thanks alot for all of your help and everyone els who got back to me with this. tonite was the frist time in 4 weeks that i got to injoy my vette, anyone who wants to see it, go to http://bluecollar.myonlinesite.com/ and look up angelo's corvette
Melting Slicks
Joined: Jul 2005
Posts: 2,740
Likes: 3
From: Aurora Ontario
Originally Posted by headache57
ok, well i must have crossed the wire's last nite, i changed them tonite and the car started rigth up. No rough idleing or bogging down. It ran great, now my next qustion is when would i know if my regulater will hold the extra pressure.....like what would happen, will it ruin anything or is it a matter of just putting a new regulater on so it works with the pump from a 85...........and now would be a good time to ask.....where is the regulater and what does it look like........and by the way thanks alot for all of your help and everyone els who got back to me with this. tonite was the frist time in 4 weeks that i got to injoy my vette, anyone who wants to see it, go to http://bluecollar.myonlinesite.com/ and look up angelo's corvette
The pump doesn't create the pressure. Its the regulator in the rear TBI that does that. You'll note the rear TBI is slightly different. As TwiTurbo indicates sometimes the diaphram will leak but thats only becasue its wearing out...nothing to do with the pump. If its not leaking now it likely will not.
Easiest way to understand what you did by changing the pump is this. The stock pump will deliver 9-13 psi to the rear TBI. The regulator in the rear TBI will deliver 9-13 psi to the injectors. The problem occurs when the 1982 fuel pump starts to fail. If its only sending 7-8 psi to the rear regulator the injectors will never get the required 9-13 psi. I think the 85 pump delivers about 40 psi...the regulator will step this down to 9-13 psi.
So drive it and enjoy it.
Jim
Last edited by jdp6000; Aug 24, 2006 at 07:37 AM.