what went wrong on my pass

[workingdan]

I was making a pass and had some detnation and Looking at my powerlogger log, it looks like the O2 senser went haywire. I ended up with a broken piston. I have not torn down my motor yet. But I would like to know what caused it. Thanks for any help.

 

[TurboDave]

I'm looking at the run traces and don't see anything unusual
The O2 trace is flat as a billiard table. What part of the run is worrysome?

 

[Blazer406]

I was making a pass and had some detnation and Looking at my powerlogger log, it looks like the O2 senser went haywire. I ended up with a broken piston. I have not torn down my motor yet. But I would like to know what caused it. Thanks for any help.

I am looking at it now.... It doesn't appear lean at all.....the times it spiked lean... you were not on the gas at all...the majority of the time she was real rich... .900 or so...

It is hard to make alot out of it because the throttle was never really matted for only a second or so for the entire run..... wierd things happen on datalogs when the throttle isn't planted....

 

[workingdan]

Crap I posted the wrong file. I dont have it on this computer, I will repost when I get home. Sorry.

 

[TurboDave]

I am looking at it now.... It doesn't appear lean at all.....the times it spiked lean... you were not on the gas at all...the majority of the time she was real rich... .900 or so...

It is hard to make alot out of it because the throttle was never really matted for only a second or so for the entire run..... wierd things happen on datalogs when the throttle isn't planted....

What file are you looking at????? Take a look at the picture I posted of the file right above your post.

.900????

Throttle was 4.66 the whole run.

You must be looking at the burnout portion. Ya need to go further into the recording.

 

[workingdan]

here is the right one. Sorry

 

[notacarlo]

Did your fuel pump crap out? 5150 rpm @ 28 psi and the 02 was at .031!

 

[notacarlo]

33 Knock counts and 7.1 degrees of retard. 15 degrees @ 1550 TPS 4.66. I'd say your fuel went somewhere.

 

[notacarlo]

How much fuel was in the car before that run? Your 02's came back on the top side. Or the alky pump went south.

 

[workingdan]

How much fuel was in the car before that run? Your 02's came back on the top side. Or the alky pump went south.

Not sure. I felt the car start to slow down. The fuel pum is new and the alky kit is new also. I have put about 8 passes on the new set up and all of a sudden this happend. The only thing differant was i had to pull the cam senser to prime the motor after I pulled mu pan to replace the rear main seal.
I had a half tank of freash 93 octane.

 

[TurboDave]

Dude. IMHO, alky and 93 octane are NOT going to support 29# of boost, not for long anyway.
But it does look like you maybe lost the fuel pump or something along the fuel delivery equation.

 

[workingdan]

Ya it was a little higher than I wanted. I was shotting for like #26.

 

[Slow91z]

Now why is that Dave...I have run a Bunch of passes at 28 psi and a few at 30 psi with no knock on 93 and meth.

It's just like anything else if you sneak up on it there's no reason this isn't as safe as race fuel.

I'm even running 26* of timing.

(Disclamer: This doesn't mean anyone can turn the boost to the moon and be ok, careful tuning and a car in good condition is required)

 

[TurboDave]

Now why is that Dave...I have run a Bunch of passes at 28 psi and a few at 30 psi with no knock on 93 and meth.

It's just like anything else if you sneak up on it there's no reason this isn't as safe as race fuel.

I'm even running 26* of timing.

(Disclamer: This doesn't mean anyone can turn the boost to the moon and be ok, careful tuning and a car in good condition is required)

I've heard such claims (30psi, 26°, 93+alky). I suppose there are a rare occurance of folks getting away with that. I'd say you're lucky, but I certainly would not recommend it as regular fair for most.

 

[Blazer406]

What file are you looking at????? Take a look at the picture I posted of the file right above your post.

.900????

Throttle was 4.66 the whole run.

You must be looking at the burnout portion. Ya need to go further into the recording.

Yes... I looked at it quick... (shhh I was at work).... and only was looking at the burnout portion....

On the correct datalog.... during the run.... the pulsewidth was 16.x mS.... this is similar to the incorrect file he first posted.... O2's on the incorrect file were in the upper 700's alot... for about 27 psi boost.... The newer correct file.... the 02's bottomed out near 0. I concurr that the fuel pressure must have gone completely away.... cause it shouldn't have gone that lean... with similar pulsewidths...

IMHO... Your fuel pump is likely the direct cause of this failure..... however.... I assume you had no audible knock detector... or you might could have heard this... and got out before she cooked...

Good luck tearing into it... and getting back on the road...

 

[notacarlo]

In my opinion, 25 psi+ should be done on race gas and a supplement such as meth.

You will find more than not when bad things happen the finger gets pointed at fuel issues.

 

[notacarlo]

I felt the car start to slow down. The fuel pum is new

If you don't mind me asking, where did the pump come from and which is it?

"I felt the car start to slow down" - right about that point, is a good time to lift for future reference. Obviously if the tires break loose you will know that, but for any other undetermined reason....lift.

 

[Slow91z]

I've heard such claims (30psi, 26°, 93+alky). I suppose there are a rare occurance of folks getting away with that. I'd say you're lucky, but I certainly would not recommend it as regular fair for most.

I don't think it has anything to do with luck...Just being careful.

I will agree with not being regular fair because I don't think most will take the time to tune it that much.

 

[workingdan]

If you don't mind me asking, where did the pump come from and which is it?

"I felt the car start to slow down" - right about that point, is a good time to lift for future reference. Obviously if the tires break loose you will know that, but for any other undetermined reason....lift.

It came from full throttle. not sure witch one it is. The worst part is there was a good pump in there and I changed it because I didnt know how old it was.

Ya I should have. happaned about the time I flipped the switch to lock the converter and I had never done that before and I thought that was what I was feeling.

 

[workingdan]

"IMHO... Your fuel pump is likely the direct cause of this failure..... however.... I assume you had no audible knock detector... or you might could have heard this... and got out before she cooked...

Good luck tearing into it... and getting back on the road..."

I dont have a audible detector. And I was running a open dump and running next to a car with open headers.


Thanks, The worst part was it happened a week before I was to do Pinks all out.