bad knock sensor? bad gas??? (updated again)

[Mephisto]

went for a DM run tonight to see if heat shielding the IC and running the IC hoses through the drivers side fender well would help drop my temps... and this is what i got....

i dunno wtf is goin on here... but 15.3* just aint happenin! my intake temps dropped a lil bit (used to be at 130* all the time), all ignition stuff is pretty fresh, i got shitty 91 oct in the tank but ive never gotten that much knock from 91...

 

[sy112]

holy KR batman

just by looking at the frame there I see only one thing that really stands out, maybe 2.

1. your o2's are low, my truck likes right at around 930 or so, anything lower than that and it lets me know real quick, and that's with 93 octane.

2. your TPS is only at 32.5%, now I am assuming that this is because you were letting out of it after seeing the knock. I know my truck acts weird under part throttle acceleration, that's why I usually just firewall it 8) Under part throttle it spools hard but after i get to some boost then it starts to knock, and my o2's are kind of low like yours. I ws told that it is because of Power Enrichment under WOT, just makes things a little richer across the board since you are beating on it. Makes sense to me, under part throttle I run lean in boost, under ful i run about perfect. And like others, mine feels real strong under spool up cause of the lean condition until the knock sets in then falls flat on it's face.

kind of hard to pick it apart though cause of it not being zoomed and all.

 

[Mephisto]

well the o2's are a lil low, youre right... how else do you get the o2's up without raising fuel psi? because when i raise it, it tends to drive real sluggish...

second the tps is at 32% because i did this on the freeway, i was in 3rd and just gave it some gas... the boost went up, and i looked over at the comp and the knock was goin just as high as the boost... so i let off... i dont even wanna know what it would look like if i went WOT. something is definitely goin wrong though.

 

[Tooky]

This kinda stuff nearly gives me nightmares just thinking of recollections of my own.. but anyways, first thing I would do is check plugs and distributor cap and rotor, if they look slightly worn replace them as long as you have them out, just in case the problem persists so you can say without a doubt "Its not the plugs or cap and rotor since I did those yesterday". My plugs can go to crap in 1 month depending on the gas I run, and I'm sure you drive your truck more than I do.

I would try increasing FP also and see how it is, if the knock goes back to normal but your driveability is sluggish, at least you proved it's a fueling problem right?

The other thing, it looks like you're getting full boost at like 30% throttle - do you have a manual boost controller installed? I would try running 10 PSI Boost at WOT and see how your knock is. If it's flat 0 like the small boost areas of your run (the ~5PSI sections) then the problem is either your paltry 91 octane gas or too high of timing.

EDIT: I gave it one last look, the fact that your STerms are 144 suggests it is in fact lean, so try turning up the FP first!!!

 

[Typhoon #1133]

If you can, email me that DM file. i would like to take a look at it.

 

[Mephisto]

This kinda stuff nearly gives me nightmares just thinking of recollections of my own.. but anyways, first thing I would do is check plugs and distributor cap and rotor, if they look slightly worn replace them as long as you have them out, just in case the problem persists so you can say without a doubt "Its not the plugs or cap and rotor since I did those yesterday". My plugs can go to crap in 1 month depending on the gas I run, and I'm sure you drive your truck more than I do.

I would try increasing FP also and see how it is, if the knock goes back to normal but your driveability is sluggish, at least you proved it's a fueling problem right?

The other thing, it looks like you're getting full boost at like 30% throttle - do you have a manual boost controller installed? I would try running 10 PSI Boost at WOT and see how your knock is. If it's flat 0 like the small boost areas of your run (the ~5PSI sections) then the problem is either your paltry 91 octane gas or too high of timing.

EDIT: I gave it one last look, the fact that your STerms are 144 suggests it is in fact lean, so try turning up the FP first!!!

well my cap/rotor/plugs have maybe 1500 miles on em... and my wires seem to be holdin strong... oddly enough before this run, my truck was idling really well holding at 600 and not bouncin around like it normally does. i have a manual boost controller and the ITS mini gate. my ultimate is at T1-22 and the boost controller is set to about 16-17 lbs...

ill set it to base boost tomorrow and turn the fuel psi up a bit, and see what happens... im hoping that will help, and that the real problem is just the shitty 91 oct. (i still wanna know why they lowered the oct here in cali yet the price remains the same as 93)

also seems as though i got a kink or an air bubble in one of my IC lines... my intake temps got up over 180* tonight without even gettin on it. :x

thanks for the tips Josh! much appreciated!

 

[Mad Mike]

Lets see a screen shot of your o2 volts and spark retard.

 

[Mephisto]

my o2's look like a richter scale... but i think thats cause im not WOT and just waivering the pedal... ill drop the boost, up the fuel psi, and do a WOT run, then post it... the o2's here and just too confusing.

 

[Tooky]

Why is your BAROmeter reading 18? Unless your testing was done on Mount Everest, that sounds totally b0rked up, I would be concerned if your MAP sensor is reading proper values, perhaps a vacuum hose problem.

 

[Mephisto]

Why is your BAROmeter reading 18? Unless your testing was done on Mount Everest, that sounds totally b0rked up, I would be concerned if your MAP sensor is reading proper values, perhaps a vacuum hose problem.

well the barometer reading was at 18 cause i had it set in hg not kpa...

today i turned the manual boost controller all the way down, and set the fuel psi back to 50psi... upon changin the fuel psi i heard a "psssss" sound when i was fooling with the vacuum hose... and sure enough the lil rubber elbow on the back of the manifold was cracked... fixed that and the barometer reading went back up in the 90s... heres a look at 2 runs i did...

this run you can see the changes from adjusting the fuel psi, but the knock is still there... im really starting to think that these gas stations here are putting 87 in the 91 pump.

this run is pretty weird considering my intake temps are outta control, yet the knock is lower... and ive never had knock like that before. was the knock lower cause my TPS was higher, hence giving it more gas?

 

[Mephisto]

ok well if theres anything ive learned from all of this its...
1. my CCHE is a POS!!!!
2. 91 octane no matter what brand is CRAP!

look at the intake temps on this run! and i really dont understand the knock pattern im getting...

i dont know what else to do to get my intake temps down... ive tried rerouting the lines into the drivers side fenderwell, insulating the intercooler, and a spal fan. the system flows fine, it just doesnt work. im fresh outta ideas other than gettin an alky, but i feel thats more of a band aid than fixin the prob.

 

[Maverick87]

Are you sure the pump is working? How about kinks in the lines? Is the scoop still there? I can beat the crap out of mine and never get near the iat. What is the ambint temp? Is this still the stock turbo?

 

[Flyin Ryan]

Just a guess but couldn't it just be the coolent temp sensor?

 

[Mephisto]

Are you sure the pump is working? How about kinks in the lines? Is the scoop still there? I can beat the crap out of mine and never get near the iat. What is the ambint temp? Is this still the stock turbo?

the pump does work... i pulled the lines off and ran the pump; and water flows out of the hoses. theres nothing clogging the lines, because i put a garden hose up to one of the hoses and turned it on full blast, and water came shootin out the other hose... ive messed with this thing making sure to get any air bubbles out, and i can feel the water goin through the hoses, when its all hooked up... i dont know what else to do. something has to be wrong somewhere, cause my IC has never done the 'tornado' when i take the cap off. everything on my truck is stock, except for the usual safety mods etc... and i dont really have a scoop just that lil rubber flap

Just a guess but couldn't it just be the coolent temp sensor?

boiling water in the IC cant be wrong hehe

 

[Sy769]

If you still have the stock vac lines you need to replace all of them.

If you addressed any of this and I missed it I apologize.

Here are some things to check


IC pump should be hotwired.
EGR should be disabled.
I don't know how you routed the hoses but many heater hose installs are suceptible to kinks after the engine is warmed up. Make sure there are no kinks with everything bolted up in place. The hoses down around the cche are prone to kinking.
Ditch the stock pump.

The stock IC system can work very well. Mine does pretty well even here in TX. Heat soak is probably it's worst enemy.