Fuel pump dying? '99 Rodeo - Anyone?

Hello everyone,
I'm back for another round. The forum has been great for feedback and I've enjoyed helping others via e-mail and phone calls and with procedures for jobs I've successfully tackled as well.

I have a 1999 Rodeo, 3.2L V6, M/T, with 142K miles on it.

Driving home tonight from a 200 mile trip, all of a sudden the car started to lurch. I immediately thought it may be running out of gas, but I had stopped 35 miles earlier and put in a 2 gallons just to make sure I wouldn't run out (I use my trip meter as the fuel gauge quit years ago and was never very accurate/liner anyway). I then thought that maybe those two gallons had been contaminated somehow. It did pump in REALLY slow.

The lurching would come and go over the next few miles. I pulled into a gas station and filled up thinking that maybe if those 2 gallons were bad somehow, I could dilute it enough to clear it out.

I made it down the street a few hundred yards (normally), and then it started to lurch again, and within a few hundred more yards I had to pull over when it died altogether. It seemed to me that it may be a fuel delivery problem, so I let the car sit for a few minutes so that I could hear that familiar fuel-pump whine when I turned the key to the second click (one click shy of starting the engine).

I didn't get the familiar high-pitched whine. It sounds rougher than that. But, after 5 minutes or so it started up and I was able to get home the last quarter mile without incident, although it did lurch some.

I backed into the driveway and listened a few more times. I don't get the familiar high-pitched whine, just a rougher sound that's hard to describe. I can now start it up though and accelerate without putting it under a load (sitting there in neutral) and it seems fine. It doesn't hesitate. It's dark now so I don't want to road test it. The pump doesn't sound right, but it's obviously working.

I hear buzzing under the hood as well when turning the key to the 2nd click, and that appears to be the various fuel-injectors buzzing. I swapped the heater and fuel-pump relay positions just to see if that made a difference, but it didn't (too easy).

I'll check the external fuel filter in the morning, but I've never had one clog. Has anyone else? The shop manual states that the in-tank fuel filter doesn't require maintenance but I guess anything could happen. I have a locking gas cap so no-one would have been able to put anything foreign into the tank.

I'll listen for the familiar high-pitched whine in the morning as well. Having a funny sound there indicates that I'm likely having a fuel delivery/fuel pump problem, unless by some miracle it's just a clogged filter.

I'll road-test it as well if it starts and runs OK unloaded.

Has anyone else had to replace a fuel pump? Were the symptoms the same (sudden, heavy, intermittent lurching, with a loss of the familiar high-pitched whine from the fuel pump pressurizing the system)?

Thanks,

Mark

check the fuel pressure via a guage. mike

$20 for a fuel pressure tester that'll plug right into the Schrader valve (looks like a bicycle tire valve stem) in the fuel line up by the fuel rail.

Good idea. I'll check the fuel pressure. Any idea what it should be? I'll look through the shop manual. It's got to be in there.

The pump does sound very strange.

Thanks,
Mark

The pump does sound very strange.

Thanks,
Mark
if it has been over worked due to restricted flow, a "bad" sounding fuel pump is not unusual? you do keep over 1/4 tank in it to prevent fuel pump over heat i hope! 142,000 is decent mileage out of any fuel pump, but i have seen alot last into 300,000 mile range with a new fuel filter ever 15-20,000 miles. mike

p.s. also there is away to measure the amp draw from fuel pumps at the relay location to see if your fuel pump is pulling acceptable amps (i assume amp values are in the fsm) but i do not know how to do this!

Thanks for the input. Very much appreciated.

I'm in the process of checking it out. I'll post the results once I know what the verdict is. And I'll post more questions before then if I have them.

I've called around to price fuel-pumps just to have an idea what they may cost, and I've found prices from $182 (Airtex), $227 (Master), and $637 (Bosch). I'm curious to know the dealer prices but will have to wait until Monday for that, and hopefully by then I'll know I won't need one.

Back to it.

Mark

unless you are going to sell the vehicle soon airtex (bigbox auto parts) is junk and so is master. bosch make very good fuel pumps! but i am unsure if they are oem. ac delco might be oem. i would stick with the bosch or the oem. keep in mind that the fuel sender on the fuel pump module had alot of problems on this unit. make sure a new sender goes in with the new pump! you don't wnat to do the job twice! and last replace the fuel pump relay (under 20 dollars). if your pump is pulling alot of amps the contacts in the relay are toast and will not relay the proper volts amps to the new fuel pump. but then again if you are selling soon airtex or master might get you through! mike

Thanks Mike. Very much appreciated.

I'm not selling it, so I don't want to go for the bottom of the line pump. I know through experience on this vehicle that some of the dealer parts are worth the extra money since the quality is way above the after-market stuff.

And I don't want to do this job twice. I opened the fuel filler line right at the tank so that I could siphon the fuel (had a full tank with only 1 mile on it).

Changing the fuel relay is a good idea. That's about a 5 second job.

I've done tons of maintenance on this vehicle, even changing the tranny and rear axle oil every 15K miles, but, stupidly I've never changed the fuel filter. I changed it today and it seems pretty clogged, not totally, but enough to where it likely killed the pump prematurely. Stupid on my part. There's no other explanation. :>)

I'm going to check dealer prices for the pump in the morning since they're closed today. I'm sure that the Bosch pump is a good one, but $637 is a little steep. I'll go there if I have to, but I'll check the dealers first.

I really appreciate your input on the Airtex and Master parts as well. I'd never heard of either brand, though I had a bad feeling.

Thanks a million.

Mark

It was the fuel pump.

The cost at the dealer was $375 plus tax. The dealer also said, that as far as he knew, the after-market brands weren't complete units (fuel gauge sending unit etc...). Not sure whether that's true.

New fuel filter, new fuel pump, new fuel pump relay.

And it's sure NICE to have a working fuel gauge again. No more flashing "low-fuel" warning light that's been on for years. Very nice. I hope this one lasts. Hopefully the new unit's design is improved.

All is well.

Thanks for all of your help. The forum is always a great place to give and get help.

Mark

Dingobait,

Can you tell us how hard it was to change, how you did it etc. I've never looked into the fuel pump even though I've done a ton of work on my '98 myself (timing belt, waterpump, brakes, shocks, alternator, etc.) How long did it take you to do, etc?

As long as you have a floor jack its not difficult at all. HERE (http://www.planetisuzoo.com/articles.htm?id=116&Replacing_the_Fuel_Sending_Unit_on_a_2nd_Gen_Isuzu _Rodeo) is a write up on replacing the fuel sending unit. Same basic steps as replacing the fuel pump. I did mine by myself in a parking lot in a couple hours.

Wow - thanks for the link; that was a nice write-up w/ pics..... My fuel gauge is about 50% reliable; sometimes when I fill up it will work right, others it won't. Thanks again!

-Scott

the problem with the fuel sending unit is the sulfer in cheap gas contaminates the sending units, but i also understand their was some engineering problems with the sender too. do you know what brand the oem pump was? mike

It isn't a tough job, as you already know. I had to siphon gas out of my tank since it was totally full. To do that you need to open the big fuel inlet line at the tank since trying to snake a siphon hose from the gas cap to the tank is nearly impossible due the the 90 degree turn and the distance to the tank.

It's easier to open the big line about a foot back from the tank. Other than that there are a few other small lines to disconnect at that same spot, and 2 up front near the fuel filter, and then just a couple of connectors at the pump/sending unit along with the snap-ring that holds it all in place.

In my case, the pump/sending unit assembly from the dealer was $404 once tax was added in. Due to the demands of my job, I've forged a good relationship with an independent mechanic 2 blocks away from home.

He knew that I knew it was the pump, how much it cost, and what it took to put it in. He got the pump from the dealer I had called, and only charged me $100 to put it in.

So, I paid $504 total and he did it up on his lift and had it done in an hour and a half. I then went to work and never skipped a beat. And since he put it in the repair is under warranty.

It was worth the $100 extra just for the convenience, though it did feel strange not to do it myself. This guy's a great mechanic and does quality work though, so I wasn't going to pass up the chance to get back to my regular life quickly and help him make a living as well.

I'm not sure what the oem brand was. Forgot to ask him.

Thanks for all of the feedback.

Mark