car pinging under wide open throttle
08-31-2003, 03:50 PM
#1
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car pinging under wide open throttle!!!!
ok heres the deal after looking at the fuel pressure these are the numbers im getting,45psi idle 72psi vaccum pulled.but as soon as i turn the car off from idle pressure drops to 22psi and stays there.now if i turn the key just to on position she jumps to 90psi and then comes down to 45psi without starting the car leaving the key on.also as time passes by the pressure goes down to zero overnight,im thinking i have a bad fpr.shouldnt the fuel system stay pressurized all night without losing any?what do you guys think,thats why shes pinging at vtec area because the fuel pressure must be dropping or acting eractically.now remember i cant see the pressure under boost since the gauge is inline under the hood
08-31-2003, 04:13 PM
#2
types1967,
Your FMU should be fine. Your readings all seem to be acceptable, but dropping to 22psi is a little strange. The system will not stay pressurized overnight...it will leak down.
I will speak with Shad at Comptech on Tuesday to see what he says. He may say to take the vacuum hose off and adjust it up to where is shows pulling 74-75...this may help. (try this)
Unless Scalbert can chime in here in the mean time.
Dean
Your FMU should be fine. Your readings all seem to be acceptable, but dropping to 22psi is a little strange. The system will not stay pressurized overnight...it will leak down.
I will speak with Shad at Comptech on Tuesday to see what he says. He may say to take the vacuum hose off and adjust it up to where is shows pulling 74-75...this may help. (try this)
Unless Scalbert can chime in here in the mean time.
Dean
08-31-2003, 04:23 PM
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I think mine depressurizes. The couple of times I opened the system, I was suprised there was very little, if any, pressure. I'm not sure, but I think what your describing is normal. I got your message, fuel is ruled out on the pinging. Next thing you need to do is get that gauge out from under your hood, and see what your pressure does under boost, but stay below 5k RPM.
08-31-2003, 04:24 PM
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maybe i should change the plugs but we will see after i install the fuel pressure gauge electric in the car wed night and see if shes pegging at least 100psi under boost that way i can take it from there that is what brad told me to do and then ill take it from there.i dont mean to be a pain in the ass to smitty,brad,im just so pissed off.also ran the tank to empty and re filled with 94 so i know its not the gas.
08-31-2003, 04:36 PM
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I am almost positive the system cycles a small amount of pressure... when I tapped my fuel pressure gauge into the FPR without DISCONNECTING the battery it seemed to pressurise the system every couple minutes...(i.e. Spraying fuel into the rag I wrapped around the end of the hose.
With your Vacuum off you should see 70-72 psi on your fuel pressure gauge...
I would rule out a fuel issues...since this is your 2nd FPR.
With your Vacuum off you should see 70-72 psi on your fuel pressure gauge...
I would rule out a fuel issues...since this is your 2nd FPR.
08-31-2003, 05:19 PM
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Originally posted by Smitty
I would rule out a fuel issues...since this is your 2nd FPR.
I would rule out a fuel issues...since this is your 2nd FPR.
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09-01-2003, 05:19 AM
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Those numbers sound correct. You will loose pressure after the ignition is turned off eventually dropping to zero. Get an electric gauge in the car and report back on the numbers. That is nearly a requirement IMO.
You can certainly pull and read a plug but concurrently we need to see what the FP numbers are at WOT.
You can certainly pull and read a plug but concurrently we need to see what the FP numbers are at WOT.
09-01-2003, 06:17 AM
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steve brad and smitty just went to sunoco as i was down to a little less then half a tank,it took 9 gallons to be exact of sunoco 100 to fill it so i went for a ride on the highway and shes pulling like crazy in 3rd and 4th with no ping at all!!!!!!!!!!!!! i dont want to have to put 9 gallons of 100 every fill up to get rid of ping.there is no sign of it now at all its an animal.sounds very interesting doesnt it.could it be for some reason my car has more advance then others?what do you guys think?so if you do the math im at 97octane right now since 100-94 and its a little more then half tank
09-01-2003, 06:56 AM
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If I'm not mistaken, Sunoco mixes their highest octane with there lowest octane right at the pump, to get all their midgrades,........ do you trust them? I remember not too long ago, there were some gas stations scamming by volume,....you thought you pumped, and paid for, 15 gallons, but only got 13. They used a switch under the register and selected their victims. I bet it wouldn't be too hard to mix a weeker batch of Sunoco premium all the time, without anyone knowing. Do you go to the same Sunoco all the time? I'm not a cynic, but the whole gasoline industry is full of crooks IMO.
09-01-2003, 06:58 AM
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brad this sunoco staion is legit there is only 1 station in my area that sells the 100 and all the racers use it.the 100 pump is seperate away from all the rest of the pumps
09-02-2003, 04:10 PM
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As mentioned privately and based on the numbers seen, I too suspect the FPR. As snipped from the PM:
The nice part about this is that there are only two components in the fuel system which could be suspect; the pump and regulator. The injectors wouldn't cause this issue nor would the fuel lines. The one remote issue would be voltage to the pump. But we can look at that later.
It is just unusual for the regulator to act this way. What we are saying is that at lower flow return rates (higher RPM and the subsequent higher injector pulse width) the pressure drops. In other words, less return flow amounts to less fuel pressure.
I too had an issue with the FP at higher revs but I am not experiencing knock. But I do have an extra injector being run which works out nicely.
The nice part about this is that there are only two components in the fuel system which could be suspect; the pump and regulator. The injectors wouldn't cause this issue nor would the fuel lines. The one remote issue would be voltage to the pump. But we can look at that later.
It is just unusual for the regulator to act this way. What we are saying is that at lower flow return rates (higher RPM and the subsequent higher injector pulse width) the pressure drops. In other words, less return flow amounts to less fuel pressure.
I too had an issue with the FP at higher revs but I am not experiencing knock. But I do have an extra injector being run which works out nicely.
09-02-2003, 04:15 PM
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Steve #1. Thought you dissabled the extra injector..
Steve #2 I am under the impression that the FP either works or doesn't... what in the upper Rev band would cause that to poop out?
Eric:.. remember what I told you about MARKING the FPR.. that way you know for sure that they swapped it out... I think last time, they just did your pump and told you they swapped the FPR... and just ended up bumping the FPR up in pressure.
Steve #2 I am under the impression that the FP either works or doesn't... what in the upper Rev band would cause that to poop out?
Eric:.. remember what I told you about MARKING the FPR.. that way you know for sure that they swapped it out... I think last time, they just did your pump and told you they swapped the FPR... and just ended up bumping the FPR up in pressure.
09-02-2003, 04:20 PM
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well shes going in tommorow so we will see what happens brad,smitty both agree steve the pressure at wot should be well over 100psi!!! that seems to coincide with what im thinking at that changeover point to vtec shes going lean yikes!!!!!!!! well i hope this solves it.comptech makes a great product so people on the board who read this dont base your assumptions on my issues since me and scalbert are the only 2 who have experienced a bad pfr.well tommorow is the day i swap it out so i will post immediatley what happens.thanx brad,smitty,scalbert for all your time and patience with me as its good to know that we all can help eachother on this board!!!! and the power this board has!!!!
09-02-2003, 04:26 PM
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I then added the injector back in for a single line of thinking. My thoughts were that if there was enough pressure to subdue the knock at the certain 5000 - 5500 range, and then it was too much for all other areas. So I dropped the pressure back down and am running the injector again. Kinda hypothetical but it makes sense.
The FPR is a simple device but can act unusual depending on design. Its role is to limit the amount of fuel returned to the tank. So in some way it is flow dependant. But the idea is that the vacuum/boost pressure applied to the diaphragm should keep the relative pressure equal regardless of flow. But I guess a unit could exhibit unusual pressure control characteristics under varying flow rates.
The FPR is a simple device but can act unusual depending on design. Its role is to limit the amount of fuel returned to the tank. So in some way it is flow dependant. But the idea is that the vacuum/boost pressure applied to the diaphragm should keep the relative pressure equal regardless of flow. But I guess a unit could exhibit unusual pressure control characteristics under varying flow rates.
09-02-2003, 04:48 PM
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Originally posted by scalbert
I then added the injector back in for a single line of thinking. My thoughts were that if there was enough pressure to subdue the knock at the certain 5000 - 5500 range, and then it was too much for all other areas. So I dropped the pressure back down and am running the injector again. Kinda hypothetical but it makes sense.
I then added the injector back in for a single line of thinking. My thoughts were that if there was enough pressure to subdue the knock at the certain 5000 - 5500 range, and then it was too much for all other areas. So I dropped the pressure back down and am running the injector again. Kinda hypothetical but it makes sense.
09-03-2003, 04:12 AM
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Kinda re-mapping; I don't want to flood the lower revs with too much fuel just to take care of the higher RPM areas. So I am running lower fuel pressure which, in theory, should help the lower RPM power and running the extra injector to help the top end fueling needs.
Again, this is all in theory and still needs to be tested on the dyno.
And yes, there are great provisions for extra injectors in the new manifold. 
Again, this is all in theory and still needs to be tested on the dyno.
And yes, there are great provisions for extra injectors in the new manifold.
09-03-2003, 04:14 AM
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well guys if we get that chip by jan we wont have to worry anymore about timing and fuel then its off to the races!!!!!!!!!!.i was just thinking of something why cant we go up one more size injectors and lower fuel pressure but i guess we need a piggyback sorry steve lol to control them efficiently.
then its off to the races!!!!!!!!!!.i was just thinking of something why cant we go up one more size injectors and lower fuel pressure but i guess we need a piggyback sorry steve lol to control them efficiently.
09-03-2003, 04:57 AM
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You could run larger injectors but it isn't buying you too much. But lower pressure could be run. I would wait though until the UniChip is available to make that change.
But with this type of control power gains and better delivery will be a shoe in.
But with this type of control power gains and better delivery will be a shoe in.
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