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4.0 L spark knock
I have a 00 TJ - 4.0. I am getting what I call spark knock at lower RPMs under
light acceleration. This is a fairly recent development and I have gotten little help in identifying the cause of the problem. The engine is stock except for the following: Avenger Supercharger with associated larger than stock injectors. A 700R4 AT which has the crank position sensor relocated to the front crankshaft pulley. I burn hi-octane fuel exclusively. I cannot see how the supercharger install would produce this effect, as the engine is not showing boost when the knocking appears. In my old car days I would suspect the timing to be at fault but this computer ignition system is way beyond me. Does anyone have experience with this or suggestion where I might direct my search? tia dw |
Re: 4.0 L spark knock
The obvious would be a bad tank of gas. Does that block have a knock sensor
in it? My 88 does but I dont know about your y2k. Maybe the knock sensor isnt connected? KH "Dalewhite" <dalewhite@aol.com> wrote in message news:20041109110628.11961.00000273@mb-m16.aol.com... >I have a 00 TJ - 4.0. I am getting what I call spark knock at lower RPMs >under > light acceleration. This is a fairly recent development and I have gotten > little help in identifying the cause of the problem. The engine is stock > except for the following: Avenger Supercharger with associated larger > than > stock injectors. A 700R4 AT which has the crank position sensor relocated > to > the front crankshaft pulley. I burn hi-octane fuel exclusively. I cannot > see > how the supercharger install would produce this effect, as the engine is > not > showing boost when the knocking appears. In my old car days I would > suspect > the timing to be at fault but this computer ignition system is way beyond > me. > Does anyone have experience with this or suggestion where I might direct > my > search? > tia dw |
Re: 4.0 L spark knock
The obvious would be a bad tank of gas. Does that block have a knock sensor
in it? My 88 does but I dont know about your y2k. Maybe the knock sensor isnt connected? KH "Dalewhite" <dalewhite@aol.com> wrote in message news:20041109110628.11961.00000273@mb-m16.aol.com... >I have a 00 TJ - 4.0. I am getting what I call spark knock at lower RPMs >under > light acceleration. This is a fairly recent development and I have gotten > little help in identifying the cause of the problem. The engine is stock > except for the following: Avenger Supercharger with associated larger > than > stock injectors. A 700R4 AT which has the crank position sensor relocated > to > the front crankshaft pulley. I burn hi-octane fuel exclusively. I cannot > see > how the supercharger install would produce this effect, as the engine is > not > showing boost when the knocking appears. In my old car days I would > suspect > the timing to be at fault but this computer ignition system is way beyond > me. > Does anyone have experience with this or suggestion where I might direct > my > search? > tia dw |
Re: 4.0 L spark knock
The obvious would be a bad tank of gas. Does that block have a knock sensor
in it? My 88 does but I dont know about your y2k. Maybe the knock sensor isnt connected? KH "Dalewhite" <dalewhite@aol.com> wrote in message news:20041109110628.11961.00000273@mb-m16.aol.com... >I have a 00 TJ - 4.0. I am getting what I call spark knock at lower RPMs >under > light acceleration. This is a fairly recent development and I have gotten > little help in identifying the cause of the problem. The engine is stock > except for the following: Avenger Supercharger with associated larger > than > stock injectors. A 700R4 AT which has the crank position sensor relocated > to > the front crankshaft pulley. I burn hi-octane fuel exclusively. I cannot > see > how the supercharger install would produce this effect, as the engine is > not > showing boost when the knocking appears. In my old car days I would > suspect > the timing to be at fault but this computer ignition system is way beyond > me. > Does anyone have experience with this or suggestion where I might direct > my > search? > tia dw |
Re: 4.0 L spark knock
'91 and later wranglers do not have a knock sensor. Knock comes about from
running too lean, too advanced, or too hot, or not enough octane. Dino's adjustable map sensor: http://www.angelfire.com/my/fan/MAP_adjuster.html will allow you to play with your mix under different throttle conditions, which when combined with adjustments to fuel rail pressure, should allow you to dial it in pretty well. Since the blend of additives in gasoline changes based on the season, you may need to have a different calibration for summer and winter, especially given your extensive modifications. -- jeff "Kevin in San Diego" <kevin_hedstrom@yahoospam.com> wrote in message news:sV6kd.39869$SW3.36094@fed1read01... > The obvious would be a bad tank of gas. Does that block have a knock sensor > in it? My 88 does but I dont know about your y2k. Maybe the knock sensor > isnt connected? > KH > "Dalewhite" <dalewhite@aol.com> wrote in message > news:20041109110628.11961.00000273@mb-m16.aol.com... > >I have a 00 TJ - 4.0. I am getting what I call spark knock at lower RPMs > >under > > light acceleration. This is a fairly recent development and I have gotten > > little help in identifying the cause of the problem. The engine is stock > > except for the following: Avenger Supercharger with associated larger > > than > > stock injectors. A 700R4 AT which has the crank position sensor relocated > > to > > the front crankshaft pulley. I burn hi-octane fuel exclusively. I cannot > > see > > how the supercharger install would produce this effect, as the engine is > > not > > showing boost when the knocking appears. In my old car days I would > > suspect > > the timing to be at fault but this computer ignition system is way beyond > > me. > > Does anyone have experience with this or suggestion where I might direct > > my > > search? > > tia dw > > |
Re: 4.0 L spark knock
'91 and later wranglers do not have a knock sensor. Knock comes about from
running too lean, too advanced, or too hot, or not enough octane. Dino's adjustable map sensor: http://www.angelfire.com/my/fan/MAP_adjuster.html will allow you to play with your mix under different throttle conditions, which when combined with adjustments to fuel rail pressure, should allow you to dial it in pretty well. Since the blend of additives in gasoline changes based on the season, you may need to have a different calibration for summer and winter, especially given your extensive modifications. -- jeff "Kevin in San Diego" <kevin_hedstrom@yahoospam.com> wrote in message news:sV6kd.39869$SW3.36094@fed1read01... > The obvious would be a bad tank of gas. Does that block have a knock sensor > in it? My 88 does but I dont know about your y2k. Maybe the knock sensor > isnt connected? > KH > "Dalewhite" <dalewhite@aol.com> wrote in message > news:20041109110628.11961.00000273@mb-m16.aol.com... > >I have a 00 TJ - 4.0. I am getting what I call spark knock at lower RPMs > >under > > light acceleration. This is a fairly recent development and I have gotten > > little help in identifying the cause of the problem. The engine is stock > > except for the following: Avenger Supercharger with associated larger > > than > > stock injectors. A 700R4 AT which has the crank position sensor relocated > > to > > the front crankshaft pulley. I burn hi-octane fuel exclusively. I cannot > > see > > how the supercharger install would produce this effect, as the engine is > > not > > showing boost when the knocking appears. In my old car days I would > > suspect > > the timing to be at fault but this computer ignition system is way beyond > > me. > > Does anyone have experience with this or suggestion where I might direct > > my > > search? > > tia dw > > |
Re: 4.0 L spark knock
'91 and later wranglers do not have a knock sensor. Knock comes about from
running too lean, too advanced, or too hot, or not enough octane. Dino's adjustable map sensor: http://www.angelfire.com/my/fan/MAP_adjuster.html will allow you to play with your mix under different throttle conditions, which when combined with adjustments to fuel rail pressure, should allow you to dial it in pretty well. Since the blend of additives in gasoline changes based on the season, you may need to have a different calibration for summer and winter, especially given your extensive modifications. -- jeff "Kevin in San Diego" <kevin_hedstrom@yahoospam.com> wrote in message news:sV6kd.39869$SW3.36094@fed1read01... > The obvious would be a bad tank of gas. Does that block have a knock sensor > in it? My 88 does but I dont know about your y2k. Maybe the knock sensor > isnt connected? > KH > "Dalewhite" <dalewhite@aol.com> wrote in message > news:20041109110628.11961.00000273@mb-m16.aol.com... > >I have a 00 TJ - 4.0. I am getting what I call spark knock at lower RPMs > >under > > light acceleration. This is a fairly recent development and I have gotten > > little help in identifying the cause of the problem. The engine is stock > > except for the following: Avenger Supercharger with associated larger > > than > > stock injectors. A 700R4 AT which has the crank position sensor relocated > > to > > the front crankshaft pulley. I burn hi-octane fuel exclusively. I cannot > > see > > how the supercharger install would produce this effect, as the engine is > > not > > showing boost when the knocking appears. In my old car days I would > > suspect > > the timing to be at fault but this computer ignition system is way beyond > > me. > > Does anyone have experience with this or suggestion where I might direct > > my > > search? > > tia dw > > |
Re: 4.0 L spark knock
Hi Dale,
Just after you crack the the butterfly you're going to be under eight pounds, if you can't find a gas station with high enough octane then you're going to have to retard the spark. Even the stock computer is programmable, but it takes DRB-III scanner: http://search.ebay.com/DRB-III_W0QQs...ectZ1QQfromZR8 Maybe the shop that sold you blower will pull it back for free. God Bless America, ßill O|||||||O mailto:-------------------- http://www.----------.com/ Dalewhite wrote: > > I have a 00 TJ - 4.0. I am getting what I call spark knock at lower RPMs under > light acceleration. This is a fairly recent development and I have gotten > little help in identifying the cause of the problem. The engine is stock > except for the following: Avenger Supercharger with associated larger than > stock injectors. A 700R4 AT which has the crank position sensor relocated to > the front crankshaft pulley. I burn hi-octane fuel exclusively. I cannot see > how the supercharger install would produce this effect, as the engine is not > showing boost when the knocking appears. In my old car days I would suspect > the timing to be at fault but this computer ignition system is way beyond me. > Does anyone have experience with this or suggestion where I might direct my > search? > tia dw |
Re: 4.0 L spark knock
Hi Dale,
Just after you crack the the butterfly you're going to be under eight pounds, if you can't find a gas station with high enough octane then you're going to have to retard the spark. Even the stock computer is programmable, but it takes DRB-III scanner: http://search.ebay.com/DRB-III_W0QQs...ectZ1QQfromZR8 Maybe the shop that sold you blower will pull it back for free. God Bless America, ßill O|||||||O mailto:-------------------- http://www.----------.com/ Dalewhite wrote: > > I have a 00 TJ - 4.0. I am getting what I call spark knock at lower RPMs under > light acceleration. This is a fairly recent development and I have gotten > little help in identifying the cause of the problem. The engine is stock > except for the following: Avenger Supercharger with associated larger than > stock injectors. A 700R4 AT which has the crank position sensor relocated to > the front crankshaft pulley. I burn hi-octane fuel exclusively. I cannot see > how the supercharger install would produce this effect, as the engine is not > showing boost when the knocking appears. In my old car days I would suspect > the timing to be at fault but this computer ignition system is way beyond me. > Does anyone have experience with this or suggestion where I might direct my > search? > tia dw |
Re: 4.0 L spark knock
Hi Dale,
Just after you crack the the butterfly you're going to be under eight pounds, if you can't find a gas station with high enough octane then you're going to have to retard the spark. Even the stock computer is programmable, but it takes DRB-III scanner: http://search.ebay.com/DRB-III_W0QQs...ectZ1QQfromZR8 Maybe the shop that sold you blower will pull it back for free. God Bless America, ßill O|||||||O mailto:-------------------- http://www.----------.com/ Dalewhite wrote: > > I have a 00 TJ - 4.0. I am getting what I call spark knock at lower RPMs under > light acceleration. This is a fairly recent development and I have gotten > little help in identifying the cause of the problem. The engine is stock > except for the following: Avenger Supercharger with associated larger than > stock injectors. A 700R4 AT which has the crank position sensor relocated to > the front crankshaft pulley. I burn hi-octane fuel exclusively. I cannot see > how the supercharger install would produce this effect, as the engine is not > showing boost when the knocking appears. In my old car days I would suspect > the timing to be at fault but this computer ignition system is way beyond me. > Does anyone have experience with this or suggestion where I might direct my > search? > tia dw |
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