Started car today, now backfiring and misfiring...

[Chrisssssssss]

Hey all,

The car has been running decently at least (trying to chase down a stupid knock problem) but today I started the car and it idled really rough and when I went to drive it, the car sputtered and backfired all the way. Even with very little throttle.

So I replaced all the spark plugs and wires - no improvement.

So now what?

I am reading and searching and am coming up with MAF sensor issues, Cam Sensor issues, coil pack issues... Anything else to check? Fuel injector issues?

Like i said, the car was running perfectly fine last night when I parked it, now when I started it today sputtereing and backfiring all to hell. Sounds like it is running on 5 cyl and smells really gassy (not methane either) lol

what is my course of action now?

Thanks.

 

[TurboTdr3.8]

Did any of the spark plugs look wet or real black ?

 

[Chuck Leeper]

"what is my course of action now?"
Start w/ some basic Scanmaster info?
Fuel psi is?
Start it, unhook the MAF.

 

[Lil Truck]

"what is my course of action now?"
Start w/ some basic Scanmaster info?
Fuel psi is?
Start it, unhook the MAF.

I had a similar issue with my car a few years ago...... Running great one day ........ took it for a test run and got a bad knock....... went to check everything out, everything looked good... but I did not check the fuel psi as the pump, reg and filter were less than a year old.... started it up went 1 block and it ran like you jut stated. So I limped back home, checked the fuel psi and found it was very low. Pulled the gas tank and found the short rubber hose from the pump had a hole in it........fixed it and the car ran fine but a few weeks later I noticed my water was disappearing from the radiator ....... the hard knock took out the stock head gaskets.

 

[Chrisssssssss]

Scanmaster:

410 0.0
AF 05
L8 37
Bat 14.2
Int 128
BL 142
MPH 00
CLt 156
ATS 57
r800
tps .44
IAC 54
cc 111 (going up by 20-30 each update)
MAL 34 (it was 00 before, but I unplugged MAF sensor to see if anything changed now this shows up)

I also have had the top turbo bolt (where it meets the downpipe) back itself out and there is a lot of exhaust coming out of that hole. This happens often with this car and I have just recently got these bolts replaced with new ones that doesn't happen as often now because before the threads were not holding. This has never caused this problem. I have to go back to the muffler shop in the morning and get another bolt - see if this helps. But like I said, this happens frequently and never was a problem.

Also when I went back to start the car to get the scanmaster readings, there was a lot of what looked like water... or raw fuel (didn't smell like fuel) on the ground where the tailpipes exhaust out the back end.

As for the spark plugs... I will have a closer look at them in the daylight.

Thanks

Chris

 

[Chrisssssssss]

Fuel pressure 39ish with the vac line on and 46ish with it off

 

[TurboTdr3.8]

BL is high ,so its adding fuel for some reason

 

[Chrisssssssss]

Usually my BL is around 134

Just in case it is the Head Gasket, how difficult is it to replace?

 

[we4Mateo]

BL is high ,so its adding fuel for some reason

Beet me to it. Probably a vacuum leak somewhere, but there is probably another issue causing the issue stated.

 

[TurboBuRick]

T-top? Did you wash the car?

 

[bpman1234]

x3 on high bl how old is the fuel pump and check all your hoses for leaks cracks dry rotted.

 

[Chrisssssssss]

Fuel pump I would say is about 5-6 years old. From what I remember, it is a Walbro340.

 

[Chrisssssssss]

Yes - t-top and I did wash the car on my way home last night. I have the ecu kinda hanging out and I doubt any water got on it. If you mean the one that the chip sits in. Maybe I will try changing chips and see what happens. I tried reseating the chip but no help. I also tried resetting ecu but didn't help.

 

[Chrisssssssss]

I also just went to run it a bit down the street - no bubbles or anything in the coolant, also oil still looks good.

 

[TurboBuRick]

I would still pull the plugs on the ecm and and have a look inside the sockets. Bet something got wet.

 

[Chrisssssssss]

Well, I went out to fiddle with the car again and now the car is running right again. All I did was fiddle with the plug wires, moveand fiddle with some wiring and vac lines (nothing really) and took out the chip and re-seated it again and like magic... It seems to be running fine. I don't know what the problem was exactly - Maybe the chip needed reseating again (tried it last night - no help) but something worked!! Weird. Well... I will let you know if anything else happens. Thanks for the suggestions. Something somewhere along the lines helped. And it didn't cost me anything (phew!!)

Chris

 

[whitehot1]

Like TurboBuRick said something got wet when you washed the car. Now you know to be careful around the ecm and all the other sensors / electronics on these cars especially when spraying water.

 

[bpman1234]

glad you got it .these cars can make you want to pull your nut hairs out .but after having one and fixing it your self with the help from the people on this site you will get to know your car .

 

[Chuck Leeper]

"113K T-Top" = Water in the ecm.