New Fuel Pump-New Problems

[DonK]

The Fuel Pump in my 97 Astro 4.3W finally decided to give up! I guess after 145,000 it was due! Had the new pump installed because it's WAY too cold to tackle it myself. Now I've got a whole new problem. It's running like crap! Some days it'll humm right along and then for no apparent reason it just decides to run REALLY bad. The first time it happened was after about a 10 mile run @ 60mph. The CEL came on and I had NO ACCELERATION! The engine never died, it just wouldn't accelerate! After shutting it down for a few minutes I fired it back up and managed to make it home. Had acceleration but still missing really badly!
I've had it back to the shop 2 times and they say they can't find anything wrong! The code say's it's running lean (O2 Sensors) but my gas mileage is TERRIBLE and I can smell gas sometimes in the cabin. Even when it's running "GOOD" I can feel a miss in it.
Changed the Cap and rotor but didn't help! Now the CEL will come on for a while and then reset itself??
Anybody got any Ideas what to do next?
Thanks- Glad to see the Forum back up and running! Great Group of people and it's saved my wallet quite a few times!!!

[Matrixx]

Hi DonK
I Don't know where you had the pump replaced at, and it doesn't matter how many times you take it back, the key is did they test and or replace the pump properly. All of this started when the pump was replaced, then that's where I would be heading back to and don't let up until they fix it. You might want to get a second opinion in this particular matter just in case the first shop isn't trying to 'Hedge" out of replacing the pump again. Ask what name brand of pump that they replaced it with and watch carefully how they respond, body language tells a whole story in itself. Hope this helps.

[nitropyro]

could be an o2 sensor took a crap but i would check fuel pressure first and see what that reads.
Danny

[DonK]

Thanks for the replies. I checked the fuel pressure and it's reading 55-60 (which is correct I guess) I normally do ALL the work on my vehicles myself so I wasn't sure where to take it. It died on the way to work (26 miles from home) so I got a recommendation from one of my drivers on where to go!
The intermittent lack of power is driving me CRAZY! It feels like a bad Dist. Cap but I just bought a new one from NAPA (brass) and it runs the same no matter which cap I have on it!
I don't get why it keeps throwing a code and then clears itself after driving for a while!
All they say at the shop is that they can't find anything wrong and to bring it back if it happens again! OF COURSE IT'S GONNA HAPPEN AGAIN they didn't do anything to it!!

[Matrixx]

Hi DonK
Yes that is correct. The key here, is does it have that same pressure when the problem Arises? You need to leave the pressure gauge on and try to induce the "Intermittent" you now have. Whether the code goes away or not, it should still be stored in memory and should be read. An 02 sensor won't be that bad if it does fail. It could be a faulty "Temp Sensor" IF everything checks out with the fuel pressure. The Temp Sensor will really make things smoke and stink if it does go faulty and resorts to a Cold Engine reading than a Hot engine reading for the computer to see. Also Vacuum Leaks can cause problems as well but not usually that bad as you described. MAF and IAT can be culprits as well, they are both located in the intake tube just behind the air filter (2-separate Plug-ins). Hope this helps.

PS: Just a suggestion to people interested. I have recently purchased a product called ScanGauge II. This has been a very valuable tool for my van and I feel worth every penny for it. Thanks to the members from the old forum that suggested it to me. Here is the info on it, please read. Very easy to install and use (Personally speaking).
U.S-http://www.scangauge.com/products/
Canada-http://giffordautomotive.com/
And no I don't get a commission, hehe.

[allwhite1100]

sometimes the miss fire will send a code and the engine will run ruogh until it thinks the problem is fixed the clear the code but in any case it should be stored and able to retrieve when scanned if all this started when you had work done they probally messed something else up and are scared to say ive worked at shop and seen them run motors dry no oil causing damage then put oil in it and tell the customer something was wrong when it came in some shops are just not honest. ive seen alot of big name shops like treadquarters tirekingdom ect where the person behind the counter doesnt know anything about a car good luck

[dcarlson12]

Try to get the code read before it resets itself. Then go from there....

[DonK]

I keep on hoping it'll throw the code on the way into work! Then I can drive it right over to them and have it looked at. I was thinking about the MAF sensor because the parking lot @ work is gravel and dirt! When the wind kicks up it COVERS the van in dust. I've changed the Air Filter twice in 6 months. It just seems to coincidental that it started acting up as soon as I had the pump changed. It's drivable now but IT AIN"T RIGHT and I can't stand knowing it's not running right!(kinda anal I guess, but that's the way I am) Not to mention at $3.26 a Gallon now is NOT the time to be getting crappy fuel mileage!

[DonK]

Okay, this is just crazy!! The van's been running fine for 2 weeks and then "poof" it starts running like crap again! I just don't get it! I have NO acceleration. It'll go thru 1st and 2nd OK but when it gets into 3rd there's nuthing! It just starts spitting and sputtering! If I take a turn and the tranny doesn't kick down, I can't accelerate. If I pull over and turn off the ignition for a few minutes, it will at least accelerate a LITTLE when I fire it back up! But after about 3 miles of stop + go driving it gets so bad that I have to pull over and shut her down again! The SES light is on again (don't know the code yet). Does this sound like a Sensor problem of some sort? I was thinking about pulling the MAF in the morning and cleaning it up. I did notice a faint odor of Gas in the cabin just b-4 it started acting up again. I don't understand what could be so intermittent?
Any thoughts or ideas on what to look for?

[DonK]

Went to A.Z. and had the code pulled. It read P0131
"The PCM has determined that the input voltage for oxygen sensor 1 in bank 1 is too low for current operating conditions"
Definition:
HO2S-11 low voltage (Heated Oxygen Sensor Bank 1 Sensor 1)
Explanation:
The powertrain control module uses the oxygen sensor to calculate the air/fuel ratio in the exhaust. The computer is receiving a low voltage indicating the system has a high content of oxygen.
Probable Causes
1. Oxygen sensor defective
2. Fuel System running lean-check other codes first.
3. Engine vacuum leak or misfire-repair
4. Low fuel pressure-fuel pump defective

Do you think I should spend the money and get a new O2 sensor OR do you think it's too much of a coincidence that it started throwing a code after I had the new Fuel Pump installed and that it's a problem with the fuel pump??

[davesyo]

I would check fuel pressure first before you buy a sensor.How long has it been since you changed the fuel filter ? If it's been a long time I'd suggest replacing it .

[DonK]

Fuel Pressure reads good. I checked it and the shop checked it. The only thing that hasn't been checked is weather the Fuel Pump is working correctly ALL the time! It's only been checked by turning on the key on the initial start-up. Just because the O2 sensor is telling me something is wrong doesn't mean the sensor is BAD does it? I thought that's what they're supposed to do!
Supposedly the shop put a new filter in it when they changed the Fuel Pump, but I don't trust ANYBODY unless I see them do it with my own eyes.

[davesyo]

Maybe you could try driving the van around a bit with the gauge hooked up and check the readings and also hook up a scan tool and check fuel trims when the problem occurs.

[DonK]

Well, I managed to limp it back to the shop AGAIN and showed him the code readout that A.Z. gave me. He replaced the O2 sensor ($142.00) and told me that my Cat. might be plugged up! He recommended that I drive it "softly" for a couple of days and maybe it would clear itself out! I didn't get 5 Miles down the road when the SES Light came on and it started doing the EXACT same thing again! Took it back to A.Z. to pull the code and Surprise, Surprise it pulled the Same One P0131, but now it's also showing P0151. Same thing different O2 Sensor!!
I'm usually a pretty easy going guy and things don't upset me too much but this guy is beginning to P** Me Off. I'm no Mechanic but, I think I got a bad Fuel Pump!!! I'm not giving this guy another DIME until he can show me whats wrong!! I don't mind paying $142.00 for a $50.00 O2 Sensor because I know he's in business to make money but I'm not gonna keep throwing parts at the thing unless I know why!!
I know he's gonna want to put a $400.00 Cat. on it next but, I don't think that's the problem!
Am I Wrong??

I think I'll take the advice and run it with the pressure gage on and watch the reading!. Should I be looking for a STEADY Pressure or will it fluctuate?

[davesyo]

According to my chilton manual it says key on engine off 58-64 psi ,engine running at idle the pressure should decrease 3-10 psi When I checked my fuel pressure a few weeks ago My engine idled in the mid to upper 50s from what i can remember
and during acceleration I believe it stayed in the low 60s

[DonK]

Thanks for the reply and Info. Of COURSE today there's a Winter Storm Watch up so it won't be too easy watching a gage and the road at the same time.

[DonK]

Got it back to the shop yesterday, for the 4TH Time. He gave me a little attitude when I gave him the slips from A.Z. with the codes on them! He said that he would just throw a new Fuel Pump into it since the guys at A.Z. and me know more than he does! That did it!!! I told him that I didn't want him to keep throwing parts at it without knowing what was wrong! He could replace the Cat. since he was convinced that was the problem BUT, if he did, and that didn't fix it, I wasn't paying him a RED CENT!!
I went to pick it up after work and guess what... He replaced the FUEL PUMP!!! Said that the pump was showing good pressure @ idle but it would die out under a load! Must be a pin hole or something in the line. (Boy, I wish I'd of thought of that).
Drove it home with that feeling of Impending Doom but the SES never came on!!!! Still runs a little ragged, but I'm hoping it will clear itself up in time! I wonder if running so lean has damaged any of the plugs or electronics?
Thanks for all the help!! That was the first and LAST time I take it to THAT Shop!!

[Matrixx]

Hi DonK
I would be walking lightly with a big stick for awhile before coming to any
conclusions. Lean won't hurt things as badly as Rich will, but like I said, just wait
for awhile to make sure everything is fine. It is a bit odd he made that comment to
you after replacing the pump for a second time (Yes In Fact their was a problem with
the pump). From what I have gathered over the years about these motors, is if you
don't run a High Grade Top Tier full, expect to be repalcing O2 sensors and EGR's on
a regular bases. I found this out the hard way, once I switched to 92 octane (Chevron)
9 or more years ago now, not a stitch of trouble from any of them. Original O2 Sensors
except bank-1 Sensor-3, original EGR, original Cat, and it just passed Air Care with
flying colors (Very Surprised actually) but it did, that's with over 500,000 kilometers
on the clock. Food for thought. Please keep us updated, Thanks.

[DonK]

Well, after a few drive cycles, it seems to be clearing itself up a bit! Still have a miss when running at a constant speed but that's been an off and on problem for the last few years. I think when the weather breaks (if ever) I'll be putting Plugs and Wires into her. I've been putting it off cause I still have the scars from changing the plugs on my 86 Safari. Now if only that "Pucker Factor" would go away every time I start up from a Stop Light

[davesyo]

Sometimes a simple tune up can solve a lot especially if your due for one