Popping and misfire when under boost

[Quick6'n'-K.C.]

No disrespect to you Mr. K.C. but you should know better than that.

Better than what? Im not following what your saying.

The cam sensor sends info to the module, then to the ecm. If there is a failure or the cam sensor is unplugged it goes to batch fire and the injectors are all on, not sequential. You get code 41 with this failure.

Maybe you can learn me something new today


Anyway, customer dropped off his car thursday for a popping and studdering issue, he just had a new front cover installed by a buick guru here in town.

Whats wrong with this picture guys?
I will even give you the instructions

Car is fixed runs better than ever

BW

 

[Mike70gtx]

I've had a busy week. I'll be able to check it out on Monday and will let you know what the story is on mine.

 

[BenPutnam]

Cap was loose and cracked, I screwed it back down but it still pops and misses, it has a crack in the side so I probably need to get a new one.

 

[BenPutnam]

Anybody know where I can get just the sensor without the whole assembly?

 

[Mike70gtx]

Update: I unhooked cam sensor and there was no difference. Put on the fuel pressure gauge and the pressure was down to 37 from 43 with line off. On acceleration it would go to about 47 (vacuum back on) and then it would drop. My fuel pump was bought new two years ago from full throttle it has about 10,000 miles. Could it be fuel filter? Could the sock have collapsed or is the pump bad? When the car was running good, the first sign that I had was Basically a loss of power under full throttle.It would run strong and then the nose would drop. Now it pops, I guess from lack of fuel.

 

[bmackinnon]

Better than what? Im not following what your saying.

The cam sensor sends info to the module, then to the ecm. If there is a failure or the cam sensor is unplugged it goes to batch fire and the injectors are all on, not sequential. You get code 41 with this failure.

Maybe you can learn me something new today


Anyway, customer dropped off his car thursday for a popping and studdering issue, he just had a new front cover installed by a buick guru here in town.

Whats wrong with this picture guys?
I will even give you the instructions

Car is fixed runs better than ever

BW

Agree KC.... and that one's 180 out...

 

[bmackinnon]

Update: I unhooked cam sensor and there was no difference. Put on the fuel pressure gauge and the pressure was down to 37 from 43 with line off. On acceleration it would go to about 47 (vacuum back on) and then it would drop. My fuel pump was bought new two years ago from full throttle it has about 10,000 miles. Could it be fuel filter? Could the sock have collapsed or is the pump bad? When the car was running good, the first sign that I had was Basically a loss of power under full throttle.It would run strong and then the nose would drop. Now it pops, I guess from lack of fuel.

DOH! One of those... probably bad pump. Better stay the hell out of the boost, or the next 'POP' you hear will be the head gaskets....

 

[BenPutnam]

Anybody know where I can get just the cam sensor without the whole assembly?

 

[FreeBoost]

Anybody know where I can get just the cam sensor without the whole assembly?

Caspers/ Kirban

 

[BenPutnam]

Cam Sensor

Caspers/ Kirban

Cool, thanks.

 

[Quick6'n'-K.C.]

Anybody know where I can get just the cam sensor without the whole assembly?

I have a used one if interested

BW

 

[Beamer]

Update: I unhooked cam sensor and there was no difference. Put on the fuel pressure gauge and the pressure was down to 37 from 43 with line off. On acceleration it would go to about 47 (vacuum back on) and then it would drop. My fuel pump was bought new two years ago from full throttle it has about 10,000 miles. Could it be fuel filter? Could the sock have collapsed or is the pump bad? When the car was running good, the first sign that I had was Basically a loss of power under full throttle.It would run strong and then the nose would drop. Now it pops, I guess from lack of fuel.

Here you go...

http://www.turbobuick.com/forums/general-turbo-buick-tech/263358-walbro-fuel-pump-update.html

That is exactly what I was thinking when I saw the thread. Been there and living it right now. I have a bad pump in my car now with a BRAND NEW FTS PUMP in the trunk that I can in no way trust to install. And to top it off, Mike appears to be a "stand up guy", but once he has your money, you're screwed. Basically in a nutshell the only way to put it.

I truly do not know what is eventually going to happen but I would recommend staying out of the throttle. In other words, park it until you get another pump that you can trust. I say that because if you are like me, you can't stay out of the throttle, LOL.

Good luck and keep us posted on your progress.

Mike

 

[Mike70gtx]

Thanks. I found the walbro thread. Mike said he didn't have any pumps in and was waiting for the new design . He wanted to test them first. I'm deciding whether to wait or get the one from Racetronix. I think it is the old walbro design.

 

[Quick6'n'-K.C.]

I tried ordering a few 340m pumps today from racetronix, i just had one small question about the 86 harness.

Ive had great luck with the 340m in the past, no reason to discredit the good old fashion pump that never had any problems, just the "newer" ones had issues

BW

 

[BenPutnam]

Replaced cam sensor...problem solved.

 

[BenPutnam]

Out of Phase, out of luck.

I installed my cam sensor out of phase, I realized it when I installed it but did not think it mattered. After reading a bit I decided to go install it correctly and my backfiring is back.

Somone said if unhooking the cam sensor fixed the problem then I needed to replace my crank sensor. Is this correct, if so why?

 

[SloGN]

Did you replace the entire cam sensor? If you just replaced the cap the bottom part can have excessive wear on it causing it to move around just enough to make a change in the cam sensor postion thu causing it to run like crap.


Also might want to check the gear to see if it's got some wear on it as well

 

[BenPutnam]

It seemed pretty tight.

 

[TurboBuRick]

I installed my cam sensor out of phase, I realized it when I installed it but did not think it mattered. After reading a bit I decided to go install it correctly and my backfiring is back.

Somone said if unhooking the cam sensor fixed the problem then I needed to replace my crank sensor. Is this correct, if so why?

Quick6nK-C, care to elaborate?

 

[gndrager]

i had poping one time on my car, i had the wife get in the car with it jacked up and put in drive and rev it and i put a volt meter to the pump my volts where droping down to 11 volts i fixed the voltage prob and poping was gone