86 Fuel Pump replacement
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
I thought you had a 1984??? What are you going to do for help with Crossfire problems? Your car is speed density, that book is for a MAF system. Yes, it would be just as good for a fuel pump, but you know how to replace that, now. If you can get it for next to nothing go for it, but don't let that delay you getting one for YOUR car. www.helminc.com It costs about the same as replacing a fuel pump you don't need.
RACE ON!!!
RACE ON!!!
Le Mans Master
Joined: Jan 2003
Posts: 5,858
Likes: 7
From: Santa Maria CA
Originally Posted by Pete K
11.7 volts at idle is bad. Should be about 13.9 or so. I would investigate and solve your charging issue first. Low voltage causes hundreds of problems on these cars.
Last edited by 86PACER; Jan 8, 2006 at 12:54 AM.
Le Mans Master
Joined: Jan 2003
Posts: 5,858
Likes: 7
From: Santa Maria CA
Originally Posted by MNorlander
First it was the alternator, then it was the coil, now it's the fuel pump.. 
Don't be surprised if that shop manual you are looking at gets bid up close to the cost of a brand new one. They are worth every penny though.
Last edited by 86PACER; Jan 8, 2006 at 01:26 AM.
Racer
Joined: Feb 2004
Posts: 265
Likes: 1
From: Irwindale Ca
to test, I jumped one of the aldl leads with a hot wire from the battery and heard it run while the car was off. It is explained in the manual how to test. The best way is pulling out the pump and manually putting 12 volts to the positive wire and grounding the negative wire. You bypass any relays and test the source.
2nd Gear
Joined: Jan 2006
Posts: 2
Likes: 0
From: Lecanto Florida
yes it is that easy...
be carefull about the flow of a factory or oe replacement fuel pump if you have a highly modified early c4... only good for engines making under 350-400hp... when i put a 383 in mine, i'd burn lean on the e-way... very bad! I replaced mine with a high-flow internal from ecklers and have not had a problem. (with one hand, in 15-20 min)
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
If you do determine it's the fuel pump-I'm with CFI, get the sock with the pump and also a new in line fuel filter. I'm just curious how these guys determined your fuel pump was losing pressure-what test did they use? because if they hooked a fuel pressure guage to the schrader valve and it lost pressure this COULD mean leaky injectors.And with these guys telling you that you need to drop the tank to replace the fuel pump-who knows how they tested the fuel pump. Hope you get your Helms soon.
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Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by madmike
to test, I jumped one of the aldl leads with a hot wire from the battery and heard it run while the car was off. It is explained in the manual how to test. The best way is pulling out the pump and manually putting 12 volts to the positive wire and grounding the negative wire. You bypass any relays and test the source.
Originally Posted by MNorlander
no I have an 86. says so in the title. this thread is cursed.. people misreading all over the place.
Have you charged the battery? Didn't you say that you replaced the alternator???
RACE ON!!!
Racer
Joined: Feb 2004
Posts: 265
Likes: 1
From: Irwindale Ca
[QUOTE]If you are talking about testing the fuel pump, jumping at the ALDL bypasses the relay, also.
If jumping the ALDL doesnt start the pump I would still check after pulling itCould be a bad connection . Always good to check ground zero. Saves alot of money.Im not sure if the relay grounds the pump also or just provides 12 volts positive. Could be a bad wire between the ALDL and the pump. Highly unlikely but it could happen...
If jumping the ALDL doesnt start the pump I would still check after pulling itCould be a bad connection . Always good to check ground zero. Saves alot of money.Im not sure if the relay grounds the pump also or just provides 12 volts positive. Could be a bad wire between the ALDL and the pump. Highly unlikely but it could happen...
Pro
Joined: Oct 2003
Posts: 506
Likes: 12
From: Savannah GA
Buy the shop manual period! If you can't fix it with the Helms manual here are the reasons why:
Don't have time
Don't have tools
Can't read
Even if you can't fix it, if you read through the trouble charts you can probably figure out what is wrong with it by the symptoms!
Heck, get a can of starting fluid and shoot some down the intake, if it sputters and tries to start you can figure it is a fuel problem. You can actually check the fuel pressure with a tire gauge if your back yard enough. If you have fuel pressure and starting fluid makes it run a little you can have a bad ECM because that would make you think the injectors weren't being pulsed. If it still doesn't try and start go back to spark tests.
JS
Don't have time
Don't have tools
Can't read
Even if you can't fix it, if you read through the trouble charts you can probably figure out what is wrong with it by the symptoms!
Heck, get a can of starting fluid and shoot some down the intake, if it sputters and tries to start you can figure it is a fuel problem. You can actually check the fuel pressure with a tire gauge if your back yard enough. If you have fuel pressure and starting fluid makes it run a little you can have a bad ECM because that would make you think the injectors weren't being pulsed. If it still doesn't try and start go back to spark tests.
JS
