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Ballast Resistor Lifespan?

8

88XJSport

NAXJA Forum User
Location
Michigan
How long are our ballast resistors supposed to last? More specifically, the Renix era? Are they like a fuse, where they die when it gets stressed, and if not they will last forever, or do they actually crap out?

And no Im not gonna just bypass it, I want things hooked up like theyre supposed to be.
 
Well you certainly know when they go. Start, release key, die, repeat.
I only replaced one in eight years, then had three junk yard ones go in a year. Now, I have it jumpered with relay, Trail fix.
 
Not to be a smartass, but they last until they wear out. They're not fuses - they have a theoretical "lifetime" life, but the do live in a harsh environment.

The ballast resistor on the fenderwell was added to the fuel pump circuit ca. 1988, and was offered as a "voluntary recall" for 1987 models. It is not necesary to emissions or driveability - my 1987 did not have it, my early 1988 had one (with the "Recall Performed" tag - when the resistor failed, I simply installed a bit of wire between the terminals instead,) and every 1989-up should have them.

And no, not having the ballast in place on my 1987 or my early 1988 had any effect at all on emissions. They make the rig a touch noisier, but I like to know things are running anyhow (if I wanted "quiet", I'd have bought a Caddy!)
 
According to my '88 Jeep Cherokee Field Service manual, the only purpose of the "ballast resistor" is to solve customer complaints of "noise coming from the rear". Reducing current flow through the fuel pump (the purpose of the resistor), slows the pump's RPMs, reducing pump noise.
I've been using my stock 4.0L pump without the resistor for a number of years now, supplying fuel to my Chevy; no problems. I like hearing the pump when I turn on the key. Any noise from the pump while moving is indiscernible, considering my tires, engine, etc.
 
The resistor was dropped again later. I am pretty sure my daughter's 93 has none. My 95 certainly has none. It doesn't seem to affect pump life judging from the 262K miles I have on the 95, and the 218 or so on the 99.
 
Matthew Currie said:
The resistor was dropped again later. I am pretty sure my daughter's 93 has none. My 95 certainly has none. It doesn't seem to affect pump life judging from the 262K miles I have on the 95, and the 218 or so on the 99.
Click to expand...

They probably either changed the pump or the mounting then.

Pity people think trucks are supposed to be quiet...
 
5-90 said:
They probably either changed the pump or the mounting then.

Pity people think trucks are supposed to be quiet...
Click to expand...
The pump and mounting changed in 97,, but as far as I know there's no difference between 87 and 96. The 93 certainly has run just fine on an 89 pump for several years. The 95 has the same pump and mounting.
 
Just for info, my 93 has one. It is a very convenient place to tap in for a wire to trigger an ignition-on relay.
 
Matthew Currie said:
The pump and mounting changed in 97,, but as far as I know there's no difference between 87 and 96. The 93 certainly has run just fine on an 89 pump for several years. The 95 has the same pump and mounting.
Click to expand...

No extra bushings or anything? I wonder if there's a segment of "resistance wire" in place of the traditional ceramic ballast, then...
 
Pelican said:
Just for info, my 93 has one. It is a very convenient place to tap in for a wire to trigger an ignition-on relay.
Click to expand...

I've always wondered EXACTLY when the ballast resistor was phased out. Does anybody have the answer to this question? I know that it went on for a few years post-Renix, but what year did they stop installing them??
 
I think my ballast resistor is shot. I'll be going tomorrow to pick up a new one, but I cant find it in the on-line NAPA parts catalogue ( I have much better luck getting what I need when I go in with a part number )

Any idea what else the fuel pump ballast resistor might be called?

Sal
 
sflasal said:
I think my ballast resistor is shot. I'll be going tomorrow to pick up a new one, but I cant find it in the on-line NAPA parts catalogue ( I have much better luck getting what I need when I go in with a part number )

Any idea what else the fuel pump ballast resistor might be called?

Sal
Click to expand...

It's a ballast.

Take a look at the one you've got - you should see a small number stamped on one of the spade lugs, right up against the ceramic. This is a resistance value, and is typically something under 5.0 ohms. If you know that number (or just take the thing in with you and your counterman knows what he's about,) you can find it without needing the application information.

Or, you could just get a bit of wire (12 or 10AWG,) put 1/4" spades on it, and eliminate the ballast entirely.
 
2 years now with no ballast resistor and no issues on my 90'. The ONLY time I hear the pump is when I get below 1/4 tank.

I see no difference in drive ability, mileage, or durability. Just one less thing to go bad and leave me wondering what it is!
 
xjtrailrider said:
2 years now with no ballast resistor and no issues on my 90'. The ONLY time I hear the pump is when I get below 1/4 tank. I see no difference in drive ability, mileage, or durability. Just one less thing to go bad and leave me wondering what it is!
Click to expand...

I think the ballast resistor was designed simply to reduce noise on the fuel pump, shouldn't have any affect on anything critical. And I do agree with you about one less thing to go wrong; there are actually quite a few posts about problems/failures with ballast resistors. Seems like jumpering is not a bad plan.
 
birchlakeXJ said:
I think the ballast resistor was just to reduce noise on the fuel pump, shouldn't have any affect on anything else I don't think. And I do agree with you about one less thing to go wrong; there are actually quite a few posts about problems with these.
Click to expand...

That's what I've been saying all along!

Added mid-1988 for NVH complaints, voluntary recall for vehicles made before. My 1987 didn't have one in the first place, my 1988 had one added, and I removed it when it failed.
 
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