96 cadillac unknown problem help

[sdk_89]

hey i got a 96 cadillac deville one day it just wouldent start so i put quick start in it and then it finally starts but it wont start unless i use quick start but when i go to drive it if i push the gas to much it sounds like it's bogging out so i got to barley touch the gas to get it going i dont know what it could be i got codes po171 and 174 which is system to lean bank1 and 2 emission code oxy sensor i took it up to auto zone and they said check the pcv for air leaks and i cant find any at all so they said clean the Mass air flow sensor so i did it but still having same problems so my dad thinks its my fuel pump but it still comes on for about 2 seconds when i put the key in the on position if you have any idea please let me know thanks.

[Cadillac Jim]

I assume that, by a "quick start" are you talking about one of those booster batteries that you get from an auto parts store. Most hook to the battery, but some work through the cigarette lighter socket.

The first line of defense is the fuel filter and fuel pump. I believe that by "bogging" you mean that if you give it more than a little gas the engine stops firing until you come off the gas pedal. That means that it just can't get enough gas. Water in the gas can clog the fuel filter and reduce the capacity of the fuel injectors. This will also throw codes for both banks lean. Did you buy gas just before the problem started? If so, you may have a bad load of gas; I would try siphoning it out and putting in a tank of top-tier premium gas to see if it will carry the water out of the fuel system (aftermarket "dry gas" additives other than GM Fuel System Treatment, P/N 88861011 (in Canada, 89020804) may harm your fuel pump). If it just happened without warning, then your fuel pump is suspect; you should check your fuel pressure. Even if it runs it may not be giving enough pressure.

The "bogging" behavior doesn't sound like a vacuum leak, but the lean bank codes are most often caused by a vacuum leak. The PCV valve hose cracked or popped off of the PCV valve, stuck open, or a loose or missing oil filler cap or dipstick can cause these codes. However, if you are having trouble starting, and it's worse with a cold engine, then you have a much larger vacuum leak than the PCV valve could account for. Look for loose or missing vacuum hoses, and see if you can hear a hiss under the hood while the engine is idling.

Barring vacuum hoses or a PCV valve out of the valve cover, a vacuum leak in the intake manifold gasket can cause this. The fact that it happened suddenly, with starting problems and drivability issues, sounds more like a vacuum hose came off or cracked somewhere.

[sdk_89]

yea actully i did buy gas before it started doing it and 30minutes later thats when it started and yes thats what i mean about bogging and im talking about quick starting fluid, thanks for your reply. and i might sound stupid but where do i check the fuel pressure at?

[Cadillac Jim]

If it did start right after buying gas at a filing station that you normally don't use, I would start by trying fresh premium gas first. If you are below 1/2 tank at this point you might be able to simply fill up. It may take siphoning and a change of fuel filter if there is more than a trace of water in the tank. You could start by siphoning a quart or so from the bottom of the tank into a glass jar and looking at the gas. If it's cloudy, or if it has visible "bubbles" of water at the bottom, it's the culprit. Gas you siphon, then let sit, then pour off the water at the bottom, can be put back into the tank or used in a lawnmower, motorcycle, or whatever.

Water in the gas is looking like the most likely problem, and fixing that can be almost free. However, if that isn't it, your AutoZone mechanic should be able to check your fuel pressure in a few minutes.

[growe3]

To get water out of the gas you normally just need some alcohol, to add to the fuel. It will bond to the water, and then the water will then get burned with the fuel. I would start with some "gas dryer", it is available at most auto parts stores. Avoid buying fuel at the station where you think that you may have gotten contaminated fuel.

Do not forget to check your air filter. If it got wet or is very dirty it can cause similar problems.

-George

[Cadillac Jim]

If you do use an aftermarket "dry gas" additive be sure and run the tank out quickly, the same day if possible but not more than three days. I've used STP Gas Treatment in the past but we've been warned here that the fuel pump is immersed and that some additives can dissolve the insulation on the solenoid.

[BodybyFisher]

yea actully i did buy gas before it started doing it and 30minutes later thats when it started and yes thats what i mean about bogging and im talking about quick starting fluid, thanks for your reply. and i might sound stupid but where do i check the fuel pressure at?

There is a schrader valve on the fuel rail, pull the beauty cover off and look the fuel rail over, I have a 96, but I forget where it is. Mike

[Cadillac Jim]

According to the 1997 FSM, page 6-676, it's on the fuel rail at the left front of the engine. The left rear has the FPR. The inlet is to the front, where the Schrader valve is, and the fuel return line begins at the FPR. The fuel pressure should be 48 psi to 55 psi.

[navion]

Here in Illinois, we have mandated 10% ethanol in our gas. So adding "dry gas" to our "corn enhanced" fuel won't help. Check to see if the fuel you bought has ethanol already in it.

In SDK 89's situation, My recommendation is that he should drain the tank and replace the fuel and the fuel filter.

My '94 SLS had a ball in the filler pipe that effectively prevented any siphoning from the fuel fill pipe.

If your fuel sending unit is original, it may have a fuel drain line that is capped off and bundled together with the fuel supply and return lines that go to the engine. You will find this under the car, close to the left front of the fuel tank.

If it was my vehicle I would not attempt too run bad gas through the engine. You never know what you may have pumped into your tank.

If the station was a major brand, they may have insurance that would help pay for draining, cleaning, new filter and possibly replacement fuel. Getting them to admit that they sold you bad gas may be a bit of a problem though!

Another possibility is that your insurance MAY cover the expense of draining and cleaning your fuel tank. It never hurts to ask!

I have never tried this on cars, but it works very nicely on aircraft. I have taken the fuel line off from the engine and then used the in-tank pump to pump the fuel into approved and GROUNDED containers. I DON'T recommend it to someone who does not have a fair amount of mechanical experience. If you do try this, remember, moving fuel can cause static electricity to build up. A spark from static electricity while handling fuel can ruin your day!!

Once you get the fuel out of your car's tank, you can look at it to see just what you have. Water will be laying at the bottom of the container. If it is only water, you can let it sit overnight and carefully pour the fuel into another container while leaving the water in the first container. That way you may save the fuel and reuse it. In the old days, we used to strain suspect fuel through a chamois to remove the particulates. HINT! Use a REAL chamois! Artificial chamois will NOT work!

There is a slight possibility that you got some fuel with diesel in it. If so, it will feel slightly oily. If there is diesel in your gas GET IT ALL OUT! Diesel in gas has been known to melt pistons. It also smokes and knocks and is hard to start.

I always avoid buying fuel from a station that is getting or has just gotten a load of fuel dropped. Filling a station's bulk tanks stirs up the crud that lays in the bottom. If you pump fuel into your tank before that crud has resettled, you can pump it directly into your tank.

I would avoid using starting fluid in these engines.

[Ranger]

Here in Illinois, we have mandated 10% ethanol in our gas. So adding "dry gas" to our "corn enhanced" fuel won't help. Check to see if the fuel you bought has ethanol already in it.

I'm surprised to hear that you have 10% ethanol down there. I thought it was only in the Chicago collar counties. I can buy non ethanol if I go one county west.

[lothos]

I don't have a choice here, all the gas in Minnesota has ethanol in it:

Minnesota has led the nation in ethanol use. All of the state's gasoline is E-10, and Gov. Tim Pawlenty wants the state's gas to contain 20 percent corn-based ethanol by 2013.

[Cadillac Jim]

Most States use 10% ethanol in the gas, at least part of the time. My 1997 owner's manual states that my car (Touring package, 300 hp Northstar) is designed for up to 15% ethanol. Much more than that can cause problems, and there is a very extensive fuel system clean-out process in the FSM.

[PAUL T]

Check your fuel pressure first. You might find out like me that the fuel pump is only pumping at 30 psi and in need of a fuel pump.