Backfire at WOT

[TrAb]

Hey guys i just recently got my car up and running good again. Just replaced the timing set, crank sensor, coil packs, and ignition module. Anyways i took the car out for a drive and when i go WOT and the boost builds up the car backfires and looses power instantly. Any ideas of what could be the problem? I replaced the plugs not to long ago, and the plug wires are some from Kirban. Also i do not have the air filter on right now (this was a short drive mind you). Thanks

 

[SHADOWII]

Is it ....

possible to have gotten unmetered air around the Ls-1? Also, the filter helps direct the air into the maf and should be a minimum of 4" from the maf if I understood Mike Licht correctly. Were you running Alchy?

 

[TrAb]

Ok i should have specified on my mods. All that is done to the vehicle is 3in catless exhaust, 38lb injectors and FMIC. Everything else is stock, the MAF is stock i just took out the air filter canister while waiting on the LS1 maf to come in. So it just has the 90 degree bend right after the stock MAF.

 

[turbojay]

Vacuum leak?

 

[TrAb]

Vacuum leak?

You think there could be a vaccum leak with the FMIC piping i put on? Ill try to look it over when i get home. Or better yet i may slap the stocker back on and see if the problem continues or not.

 

[Boost231]

check all the clamps going to the intercooler. also ohm your plug wires and coil pack and report back

 

[TrAb]

check all the clamps going to the intercooler. also ohm your plug wires and coil pack and report back

How do i ohm the plug wires?

 

[turbo nasty]

Hey guys i just recently got my car up and running good again. Just replaced the timing set, crank sensor, coil packs, and ignition module. Anyways i took the car out for a drive and when i go WOT and the boost builds up the car backfires and looses power instantly. Any ideas of what could be the problem? I replaced the plugs not to long ago, and the plug wires are some from Kirban. Also i do not have the air filter on right now (this was a short drive mind you). Thanks

You sure you have the cam sensor set right? How did you set it?
Car run good before the timing set, etc replacement?

 

[TrAb]

You sure you have the cam sensor set right? How did you set it?
Car run good before the timing set, etc replacement?

I came home tonight and put the factory air box on and it didnt make a change, well made it idle a good bit better ...

Yes car was running fine before i replaced those. I have the caspers cam sensor tool, where you plug it in and twist the top until the light turns on. Although when i put the sensor down into the front cover i am not sure if it was exactly right or not. In the intrustions with caspers tool it just says that the cap should be just a tad after the 3 oclock position so thats where i tried to get it close to.

 

[Robert Wilson]

If you still have a problem after you have done the other suggested checks, check every spark plug for a cracked or broken insulator. I had experience with a car that idled and drove fine under normal driving conditions but under WOT would miss and backfire. Ended up being a broke spark plug insulator. The owner never thought this could be the problem because he had recently replaced the plugs.....

 

[turbo nasty]

I came home tonight and put the factory air box on and it didnt make a change, well made it idle a good bit better ...

Yes car was running fine before i replaced those. I have the caspers cam sensor tool, where you plug it in and twist the top until the light turns on. Although when i put the sensor down into the front cover i am not sure if it was exactly right or not. In the intrustions with caspers tool it just says that the cap should be just a tad after the 3 oclock position so thats where i tried to get it close to.

Factory air box? Did you mean the factory MAF?

There is more to the sensor than just turning the cap in reference to where you put the sensor in at.
The engine needs to be at a certain place in the cranks event cycle, degrees marked, etc. Your description of the cam sensor adjustment leaves alot to be questioned on whether the items are set and installed correctly.

If the cam sensor is installed poorly and or leaks in the intake system post MAFthen they could cause issues that you described.
the cam sensor can be a bit tricky to get aligned sometimes

 

[TrAb]

Factory air box? Did you mean the factory MAF?

There is more to the sensor than just turning the cap in reference to where you put the sensor in at.
The engine needs to be at a certain place in the cranks event cycle, degrees marked, etc. Your description of the cam sensor adjustment leaves alot to be questioned on whether the items are set and installed correctly.

If the cam sensor is installed poorly and or leaks in the intake system post MAFthen they could cause issues that you described.
the cam sensor can be a bit tricky to get aligned sometimes

Do you have a link to a guide? But what i did was put the engine at TDC, drop the sensor in as close as i could get it to 3 oclock. Then turn the engine backwards the 25 degrees or whatever was specified, then set the cap.

 

[pacecarta]

zero on the compression stroke of #1 cyl then rotate crank clockwise 1.45" (25After TDC #1 comp), then set sensor by tuning clockwise until light comes on then goes out then turn it counter clockwise until light comes back on , clamp it down

the procedure its pretty clear and by now im sure youve been told where to go for info and to read up
steve woods site, specifically .. http://www.vortexbuicks-etc.com/cam_sensor.htm
last time im going to offer advice ...read or learn to use the search feature
only about a hundred threads on how to properly set the cam sensor here

for those that wan to guess here a link to where he came from and where its at so youll be brought up to speed as far as whats what on his car .. http://www.turbobuicks.com/forums/buick-v6-turbo-tech/88432-bought-gn-broke-down.html?highlight=trab

 

[TrAb]

Yeah i read over that guide and it sounds like EXACTLY what i did. Not sure what the problem is, but i will try to set the cam sensor again and see if anything changes.

 

[turbo nasty]

The vague post of how you do things doesnt give much for us to work with. When you say thisng like "I came home tonight and put the factory air box on and it didnt make a change" and "Although when i put the sensor down into the front cover i am not sure if it was exactly right or not."

Reading that kinda stuff questions your ability. Not saying you cant do it ..Just when asking stuff be a little more clear on what you did.

As I asked you before...... what was the deal with the factory air box reinstall?

 

[TrAb]

Sorry for being vauge. While i was waiting on getting a LS1 MAS i took the factory air canister off and left it off the vehicle. This just left the stock MAS on the car and no air filter. So i was just test driving the vehicle this way. I was just saying that last night i put the factory air filter/canister back on the car as i was uneasy about driving around to much with any filter at all.

 

[turbo nasty]

You REALLY need to do your homework on these cars.
Lesson 1 grasshopper...MAF (not MAS) Mass AIr Flow sensor

Does your stock MAF have any screens in it?

How did the cam sensor check work out?

 

[pajo]

cam

It sounds to me cam sensor is out of whack .:biggrin:.

 

[bmackinnon]

You REALLY need to do your homework on these cars.
Lesson 1 grasshopper...MAF (not MAS) Mass AIr Flow sensor

Does your stock MAF have any screens in it?

How did the cam sensor check work out?

He has a LS1 maf... nobody has mentioned the possibility of the car going lean and backfiring... that's always the 1st thing I check, as the consequences are by far the most expensive.... are you sure the fuel pressure is correct and rising 1:1 with boost?

 

[DailyDrifter]

He has a LS1 maf... nobody has mentioned the possibility of the car going lean and backfiring... that's always the 1st thing I check, as the consequences are by far the most expensive.... are you sure the fuel pressure is correct and rising 1:1 with boost?

+1

Op did the car backfire from the intake or exhaust?