supercharged xj troubleshooting
#16
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Year: 1999
Model: Cherokee
well the map i have made was working just right. But the problem begins when it gets hot. When i open the hood after a while it stops bouncing and the throttle works correctly! I think i have a map sensor problem! is the only thing i have not changed. It might got burnt out! I have a wide band installed together with an AEM Fi/c! I talked with AEM and i don't need resistors for the injectors.
#18
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#19
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So an update! The sensor did not make anything! My tuner told me that it is not electrical or vacuum lines leak. I am disappointed i don't know where else to look!
#20
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one thing i noticed but i think its ok is that after installing a faster water pump and a 3 row cooler my electric fun does not start at all but the temp gauge is all the time at the first quarter! Might that be the problem?
#21
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Year: 1999
Model: Cherokee
I'll tell you again... It is a fuel map related issue (not map sensor). I can't tell you how many times I've seen a bouncing idle.
Your noticing it change when it get's hot simply because the engine will be using a different cell value than when it's cold.
#22
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Year: 1998
Engine: 4.0L 162,000
Compressor Surge, No bypass valve used, Extreme Examples...
https://www.youtube.com/watch?v=LziDXhy2fxs
https://www.youtube.com/watch?v=9mQIG-e1how
Sound familiar??
https://www.youtube.com/watch?v=LziDXhy2fxs
https://www.youtube.com/watch?v=9mQIG-e1how
Sound familiar??
#23
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Year: 1998
Engine: 4.0L 162,000
Try pulling the vacuum hose off the Fuel Pressure Regulator and cap the hose, and see.
With the compressor surging, the intake is seeing fluctuating vacuum, up and down, and in turn the FPR is seeing fluctuating vacuum and fuel pressure is going up and down and 'richening/leaning' the mixture.
With the compressor surging, the intake is seeing fluctuating vacuum, up and down, and in turn the FPR is seeing fluctuating vacuum and fuel pressure is going up and down and 'richening/leaning' the mixture.
#24
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Your looking for a mechanical issue when there isn't any.
I'll tell you again... It is a fuel map related issue (not map sensor). I can't tell you how many times I've seen a bouncing idle.
Your noticing it change when it get's hot simply because the engine will be using a different cell value than when it's cold.
I'll tell you again... It is a fuel map related issue (not map sensor). I can't tell you how many times I've seen a bouncing idle.
Your noticing it change when it get's hot simply because the engine will be using a different cell value than when it's cold.
Try pulling the vacuum hose off the Fuel Pressure Regulator and cap the hose, and see.
With the compressor surging, the intake is seeing fluctuating vacuum, up and down, and in turn the FPR is seeing fluctuating vacuum and fuel pressure is going up and down and 'richening/leaning' the mixture.
With the compressor surging, the intake is seeing fluctuating vacuum, up and down, and in turn the FPR is seeing fluctuating vacuum and fuel pressure is going up and down and 'richening/leaning' the mixture.
I can not find find a by pass valve for my sc in greece!
#25
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Compressor Surge, No bypass valve used, Extreme Examples...
https://www.youtube.com/watch?v=LziDXhy2fxs
https://www.youtube.com/watch?v=9mQIG-e1how
Sound familiar??
https://www.youtube.com/watch?v=LziDXhy2fxs
https://www.youtube.com/watch?v=9mQIG-e1how
Sound familiar??
#26
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Year: 1998
Engine: 4.0L 162,000
IDK, This is the problem with a "Momentum Motorsports" Jeep SC Kit.
You need a bypass valve.
You need proper fueling.
You need boost timing retard.
You need a 'Tune', not just bigger injectors.
You need intercooling.
In short, you need a complete kit and not just a mounting plate and piping.
You need a bypass valve.
You need proper fueling.
You need boost timing retard.
You need a 'Tune', not just bigger injectors.
You need intercooling.
In short, you need a complete kit and not just a mounting plate and piping.
#27
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I have a vacuum leak on the evaporator canister. Would that be a problem?
Last edited by gsamakovlis; 08-21-2015 at 11:06 AM.
#28
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IDK, This is the problem with a "Momentum Motorsports" Jeep SC Kit.
You need a bypass valve.
You need proper fueling.
You need boost timing retard.
You need a 'Tune', not just bigger injectors.
You need intercooling.
In short, you need a complete kit and not just a mounting plate and piping.
You need a bypass valve.
You need proper fueling.
You need boost timing retard.
You need a 'Tune', not just bigger injectors.
You need intercooling.
In short, you need a complete kit and not just a mounting plate and piping.
If i were in the States believe me i would be on your list 5 years ago! I think that is when i first saw your site.
I tried to find a way to buy your ki but with the taxes and customs i would have paid more than 12.000 $ to get it. The point is that i am trying to make an xj for what i want it to be. Experimenting and doing my best, for the spare time i have.
#29
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Year: 1998
Engine: 4.0L 162,000
The vacuum leak can cause the idle surging, but usually leaks cause a fast idle.
I feel your frustration.
If you barely crack the throttle does it still surge or does it smooth out?
Only when hot, it does it?
I feel your frustration.
If you barely crack the throttle does it still surge or does it smooth out?
Only when hot, it does it?
#30
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Thread Starter
When is hot is bouncing!
I have found some other staff that are installed incorrectly the vacuum hose that goes to the fuel pressure stabilizer is on the manifold and takes both pressure and vacuum, so i have to change all the vacuum lines and put them before the SC.
I will leave only the MAP and AEM vacuum lines on the intake manifold.
I am trying really hard to figure this out but there is no free time as i am working everyday 12-14 hours. even on weekends.
I have just changed all the vacuum lines i have just found out that the Intake Air Temperature sensor is dead! :-(
Last edited by gsamakovlis; 08-22-2015 at 07:43 AM.