Lean Spike

[cuda6pak]

Finally logged a pass on the new setup and had the car go lean for a split second right at the end of the 1/4 mile giving me some knock. Nothing in the powerlogger that I can see indicates what caused it. I did not do any back up runs after this. This is with a TT6.1 chip and WBO2 AFR tracking. Attached is the powerlogger file...see frame #2593

Full info on my setup can be found here

http://www.turbobuick.com/forums/threads/dyno-numbers-guesstimate.382646/page-3#post-3115388

 

[cuda6pak]

Here is another PL file which was my last dyno run....I do notice that during my 1/4 mile run my Fuel Pressure seemed to be all over the place I didn't have my eye on the actual gauge itself to verify that, but it sure looks that way. Could the volt booster have caused some weird stuff going on?

 

[Ttype6]

If you weren't watching your gauge,what makes you think your fuel pressure was all over the place?

 

[cuda6pak]

If you weren't watching your gauge,what makes you think your fuel pressure was all over the place?

Pressure(4) on my logs is the fuel pressure. From the logs my FP was bouncing from 50-60psi during the run, whereas the dyno was 54-56 or so.

 

[jasjamz]

From my observations:
Too much alky being used
Fuel pressure too low-hi injector duty cycle
Better check the plugs for black peppering-knock at the finish
What plugs are you using?

 

[kidglok]

double check the fuel pressure with a good mechanical gauge to verify its set at 43psi with the line off. Then look at the powerlogger and make sure it matches, that way you can trust the sending unit. Also those lean spikes you see are indications of a failing coil pack/module.

 

[cuda6pak]

I checked the fuel pressure and it was 39psi with the line off, so I bumped that up to 43psi. Duty cycle dropped considerably. I believe the plugs are AC R42's.

I went and did two back to back runs with the new fuel pressure setting, backed boost down to 21psi, and alky down to 5.5.

First run - quicksave wasn't working so I didnt get a chance to save it before I realized it However according to the logs my fuel pressure was bouncing up and down anywhere between 58-72 psi at WOT. I saw a few ~11.0 AFR spikes as well. Zero knock to about 120mph.

Second run (attached) - I disconnected the volt booster. Fuel pressure was much more stable around 60-63psi at WOT. However I got a tiny bit of knock and let out immediately (AFR around 10.4).



Can the voltage booster have any actual effect on fuel pressure? Or is it some sort of electrical interference with the sending unit?

 

[cuda6pak]

Still lost on this issue....if anyone has any ideas I'm all ears!

 

[turbo nasty]

I didnt look at the logs since i dont have a PL on this terminal.
Voltage to pump drasticaslly affects its output.
A boost leak somewhere can cause issues like this.
Time to go over everything...electrical connections, vac lines, IC hoses, etc.
Leave the alky on six.

How old is your fuel pump?
When was the last time your alky pump was service/checked?

 

[Eric Stage I]

I don't see any lean condition. If you're talking about those tiny spikes in the wideband signal, that's very typical of an LC-1 data trace. Everything looks great regarding fuel.
You could add some octane and see if it goes away, just to see if its real or not. If it's real, you might need a tad more alky.

Eric

 

[cuda6pak]

The fuel pump is new - DW. The alky pump does need to be serviced (bought in Feb 2009), and may be acting funny with the extra voltage supplied by the volt booster.

Eric - all of my WOT pulls without the volt booster do not show such high spikes in AFR as compared to the runs with the volt booster. Which is why I am trying to figure out why adding the volt booster causes my steady WOT fuel pressure to suddenly jump around 58-72psi up and down.

I'm going to check my fuel tank ground strap tonight.

 

[Razor]

The fuel pump is new - DW. The alky pump does need to be serviced (bought in Feb 2009), and may be acting funny with the extra voltage supplied by the volt booster.

Eric - all of my WOT pulls without the volt booster do not show such high spikes in AFR as compared to the runs with the volt booster. Which is why I am trying to figure out why adding the volt booster causes my steady WOT fuel pressure to suddenly jump around 58-72psi up and down.

I'm going to check my fuel tank ground strap tonight.

Your messing with a live gernade with a close to 4 year old pump. God knows i'd love this stuff to last 20 years.. but cars that are heavily modded are way more sensitive to stuff like this..

That knock is accumulative.. its like straw on a camels back.. sooner or latter.. you pack enough straw it collapses.

Two items I never mess with.. fuel pumps and alcohol pumps. Both must be current when tuning. Or at the least tested..

 

[dynoman]

Get Razor's alky pump tester , it will tell you if that pump is getting up to full pressure (when you really need it !!!). I got one and found that my pump was working but the pressure was low, sent it to Razor for rebuild and now all is well . Sam

 

[cuda6pak]

Your messing with a live gernade with a close to 4 year old pump. God knows i'd love this stuff to last 20 years.. but cars that are heavily modded are way more sensitive to stuff like this..

That knock is accumulative.. its like straw on a camels back.. sooner or latter.. you pack enough straw it collapses.

Two items I never mess with.. fuel pumps and alcohol pumps. Both must be current when tuning. Or at the least tested..

Alky pump rebuild is on the list of things to do this winter, I'll be sending it to you sooner rather than later. FWIW it has only been used for maybe 1.5 years, it sat for the rest of the time...

Still doesn't explain the wacky fuel pressure with the volt booster, however.

 

[dynoman]

Check your fuel pressure @ WOT with a mechanical gauge Tywrapped to the windshield wiper. I work with pressure transducers almost every day and the vibraton at WOT could give you those wacky readings if it's mounted on the rail. Also what is the voltage @ WOT with the volt booster hooked up? Sam