2000 Buick misfire ??????????

[Yankee Transplant]

I KNOW THIS IS A LOT TO READ BUT IM LOST

I need some help .. I have a 2000 Buick LeSabre it misfires and hits so hard that it will set off the knock sensor ..... I have bought 1 new coil and replaced one coil pack at a time (it has 3) its a 3.8 v-6 with no change in the misfire . so it is not any of the coils... I replaced the plugs and wires plugs look like new ones (clean) still will hit hard enough to stall out car when idling in town . took it to a parts house and his computer picks up nothing . other than knock sensor . Which is because it almost dies or it does die .. Took the module off and had it tested and it passed , infact we tested it 6 times in a row . to maybe make it heat up , with no luck still passed . put new fuel filter on (thinking water ) nope. clean gas in the filter too . [S this miss dont happen like a bad plug every time a cylinder fires just maybe skips 5 times in a mile or maybe drive it 5 miles and dont skip , then skips every 100 yrds or so ,, (crank censor , cam , idle air , Kind of ruled them out .. It is not as noticeable going down the road (it has overdrive) but its there (random) even in park it will do it . it took 7 min. to do it a while ago in park with the car in rev. and air condition on (just to put a strain on the engine) last night I put it in 1st gear and run it up to about 35- 40 mph , and it jumped pretty bad about 6 times in about 1/4 mile . any body know what to do .. The last computer it was on was a $1500 one ( i guess it was supposed to be a good one ). Again I know this is a lot to read but I appreciate any help thanks Kelly


I know this is for Rat rods and Ill take the post down if y'all want , but I have exhausted all the brains that I know around here ..

 

[donsrods]

We just had a somewhat similar problem with a 93 Buick my Son bought to flip. Changing the underframe fuel filter helped somewhat, but it turned out to be the electric pump in the tank. Fuel pressure was supposed to be about 54 pounds but it was only 32 pounds. After replacing it the car runs like new.

Not saying that is your problem, but put a fuel pressure gauge on it and see if it is within specs.

Don

 

[Yankee Transplant]

I just priced a gauge ,, the cheapest one was $54 , so I backed off that for now ,, maybe I can find some body to barrow one from .. you say if its 54 pounds its ok .. Hey thats how much the gauge was I had thought about that even put my hands on the injector pump thinggy ,, hoping to feel it quit for a second or two but no luck ... thank you donsrods this will be my next step .. I new Id find some other ideas on here [cl

 

[Tripper]

Ask your friends if they have a pressure gauge or maybe the parts store has 1 you can borrow. When I really can't figure it out I break down & take it to the dealer which around here is usually about $100 but it beats replacing a bunch of parts & still not fixing the prob!

BoB

 

[Yankee Transplant]

Ask your friends if they have a pressure gauge or maybe the parts store.

BoB

Just called the parts house $ they want $120 to rent it , if you bring it back they will refund your money .. may have to do that ..

 

[donsrods]

Harbor Freight sells them cheaper than that, you don't need SnapOn quality for what you are checking.

Don

 

[Yankee Transplant]

Harbor Freight sells them cheaper than that, you don't need SnapOn quality for what you are checking.

Don

this $54 was at O'reillys I guess store brand , the others were $124.00 I didnt need it for about 10 min.s The $124 was the brand they rented out . and the fuel pump is about $280 plus tax. Kinda hope I dont need it , but kinda hope I do ,, so this problem will be fixed . trying to get in touch with a couple of race car building friends..they should have one I can get .

 

[ssimpala]

It doesn't throw any codes?

 

[donsrods]

this $54 was at O'reillys I guess store brand , the others were $124.00 I didnt need it for about 10 min.s The $124 was the brand they rented out . and the fuel pump is about $280 plus tax. Kinda hope I dont need it , but kinda hope I do ,, so this problem will be fixed . trying to get in touch with a couple of race car building friends..they should have one I can get .

Rock Auto is your friend. I wouldn't buy the cheapest pump (if that is what you need) because they do fail quicker than a name brand. But RA can save you some money. Check out these prices:

http://www.rockauto.com/

Don

DELPHI Part # FG0180 Module Assembly
To Chassis No Y4120966 Or No YU145189

Part Image
Choose:
$127.99
SPECTRA PREMIUM / COOLING DEPOT Part # SP3518M {Click Info Link for Alternate/OEM Part Numbers} Module Assembly Includes Pump, Sender, Float, Strainer and Fuel Reservoir One of our most popular parts
2nd Design; From VIN # Y4120967 or YU145190; w/ Module Code CRL; Wiring Harness Included; Float Arm Included & Shipped Detached. Reattachment Required. Instructions Included. (Only 2 Remaining)

Part Image
$133.79
AIRTEX Part # E3518M Module Assembly; Includes Fuel Pump, Sending Unit, Float, Fuel Reservoir, Fuel Strainer, Wiring Harness and Upgraded Electrical Connector. Includes Sending Unit One of our most popular parts

Part Image
$139.79
SPECTRA PREMIUM / COOLING DEPOT Part # SP6278M {Click Info Link for Alternate/OEM Part Numbers} Module Assembly Includes Pump, Sender, Float, Strainer and Fuel Reservoir
1st Design For Use On VIN # Y4120966 or YU145189 & Prior.; Wiring Harness Included

Part Image
$149.89
CARTER Part # P74917M {#19180115, 25335955, P74983M} Module Assembly; Features CleanScreen Technology

Part Image
$174.79
BOSCH Part # 67313 {Click Info Link for Alternate/OEM Part Numbers} Fuel Pump Module Assembly (Only 3 Remaining)

Part Image
$183.99
DELPHI Part # FG0162 {Click Info Link for Alternate/OEM Part Numbers} Module Assembly
Contains Internal Pump Strainer

 

[Yankee Transplant]

It doesn't throw any codes?

no codes other than the knock sensor

 

[Yankee Transplant]

donsrods the airtex is the part they sell for 280 ,, also heard that brand dont last very long .

 

[Sniper]

Crank sensor is what I would hold suspect, it's your ignition trigger. It can be triggering a lot more often than you know. If it triggers a coil to spark in the exhaust stroke you would never feel it. But when it triggers a coil to soon and fires the air/fuel charge on a compression stroke it likely deadheads against another cylinder that just fired as it's supposed to. Now you have two cylinders momentarily trying to turn the crank in opposite directions causing your "hard hit". Cam sensor I would give it a way out there maybe. Crank sensor is the one I'd bet on. You didn't mention how you ruled out the sensors, but I would give it another look.

 

[Yankee Transplant]

I didnt think the crank sensor would work then not work all in about 2 seconds , same as cam , but your saying it could fire more than it should , I didnt know that could happen My mothers van just quit and it was the crank sensor, Never thought of it firing to many times . is there any way to test this sensor ? You have to pull the balancer off to get to it . this is about a $118 guess .

 

[Sniper]

MY dad had a Buick that acted the exact same way, his was an older model but had the crank trigger and multi coils. I don't know why they go bad and just trigger at random but they will. His wouldn't set any codes either so it was a bit of a hunt to track it down. I'll see if I can find if there are any perimeters or possible ohm tests that can be performed. I don't have the answer just off the top of my head. Let me see what I can find.

 

[JBailey]

I would also check the fuel pressure regulator on the fuel rail. Sometimes the diaphragm can get a hole in it and make the vehicle run like crap because its sucking fuel through the vacuum line. Usually you can just pull the vacuum line off while its running and see how it reacts or if there is moisture in the vacuum line. That won't usually throw a code either. Just something else to check lol.

 

[Yankee Transplant]

Hey Sniper I just re-read what i said , and I didnt mean to sound like you were guessing ,, Im sorry it sounded like that , I know (zero) about this new stuff , just trying to use common sense and its not coming out to well for me .. so far all Ive done spent on it was for nothing , cause ive still got the problem , I was holding a crank sensor in my hand yesterday. but I figured they either worked or they didnt . I did walk under the car and blow the sensor and the pulley out last night (hoping maybe a leaf or something was flipping around in there . but nothing come to think of it if the pump was low pressure it would cut out at high speed not idling right ?

 

[Yankee Transplant]

I would also check the fuel pressure regulator on the fuel rail. Sometimes the diaphragm can get a hole in it and make the vehicle run like crap because its sucking fuel through the vacuum line. Usually you can just pull the vacuum line off while its running and see how it reacts or if there is moisture in the vacuum line. That won't usually throw a code either. Just something else to check lol.

It runs smooth as a new car ,, just when it misfires it will almost shut the motor down then the next 2 or 3 seconds its running smooth as a whistle ... but it is sounding more like two cylinders firing at the same time , now that Sniper said about the crank sensor could be double firing .... sure going to look into this . if I can get it off without pulling the pulley , I may just see if I can go by a junkyard and get one to try it out.

 

[Sniper]

Hey Sniper I just re-read what i said , and I didnt mean to sound like you were guessing ,, Im sorry it sounded like that ?

No biggie, sometimes an educated guess is all you have to go on. The situation is just about a carbon copy of what happened to Dad's car. Googled some test procedures and found a few good ones that are right up your alley. You can't use an ohm meter because it's Hall Effect system, there is no resistance to check. But you can test for pulses with a volt meter and see if the voltage is correct.Try the Google approach, you should find what you need. Best of luck.

 

[Yankee Transplant]

Thanks Sniper

 

[donsrods]

While my Sons and I are fair on older cars, when it comes to newer stuff with computers and fuel injection we are lost. Luckily, we have a very honest, good mechanic who has a shop 3 doors down from our shop and we take him stuff on our newer cars, or work we don't want to do.

My Son just took a 95 Towncar down to him because the airbag light was on and my Son can't legally sell it that way. Mark diagnosed it for $70 and told Don it was the Airbag control module, but Lincoln wanted $ 480 for the part ! I took one of my days off and went to a local pick and pull and found the identical car, removed the part, and paid $ 26.50 for it. Plugged it in and the light is out.

So what I am suggesting to you is that rather than just starting to throw parts at it, maybe find a good local mechanic and have him look at it for you. Sometimes the hour or two labor can save you a lot of money and headaches.

Don