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Thread: Issues with LNF with Vac and random KR

  1. #1
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    Issues with LNF with Vac and random KR

    So for the past week the car has been having an ANNOYING amount of KR in every gear but not at WOT. In first it's been showing 11.9 kr 2nd 8-12kr 3rd 3-9 and so on. I've also had the vac never go to 20-22 it's always been at 18-20 since the new engine was put in. Currently on full E for 2 weeks before it started happening, didn't put new seals in stock injectors, ZZP LNF fuel lobe cam is in.

    My tuner suggested rotate and re torque knock sensor and I suggested to switch injectors with my brother's old injectors laying around. Rail pressure at WOT is 2300-2450 till 6600, never logged above that.

    I've tried disconnecting the battery for a couple of min, clearing DTC's when there's none, disconnecting EVAP solenoid, and it did run PERFECT for 1 night for like 2 hours until the next morning then it started running like crap again. That was with only disconnecting the battery.

    On the aeroforce gauge I have it shows a max KPA of 255 at wot which is weird, it also shows 22.7 PSI at wot but my factory boost gauge says 25 PSI.

    If you need logs I can get with my tuner and get some. In the mean time I will swap injectors and rotate those knock sensors.

  2. #2
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    fuel trims are doing what? fuel pressure seems a bit excessive.
    The most hated, make the most power.
    93 Ranger. 5.3 D1X. 1069hp.

  3. #3
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    Look at this thread on css net for some logs http://www.cobaltss.net/forums/2-0l-...dom-kr-319356/

  4. #4
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    Get the exhaust to stop rattling. My exhaust rattles on the rear subframe and will do the same thing. Took the exhaust off and I see no knock now, so I have to manipulate it to get off the subframe, somehow.

    Also, I would have changed the injector seals.

  5. #5
    Senior Tuner cobaltssoverbooster's Avatar
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    Quote Originally Posted by mkriebs View Post
    Get the exhaust to stop rattling. My exhaust rattles on the rear subframe and will do the same thing. Took the exhaust off and I see no knock now, so I have to manipulate it to get off the subframe, somehow.

    Also, I would have changed the injector seals.
    Seals are tolerance fit, this should have happened. I was waiting for someone to bring it up, thanks.
    Knock sensors don't really do much as far as position, if it's solidly bolted to the block material at torque spec the signal will be the same. Your exhaust is a big issue since the rattling will set the already super sensitive knock sensors off.
    As for lean idles, the evap sensor likes to leak and I would recheck all the manifold gaskets and clamps that are under pressure.

    Also verify your map sensor data matches the two boost sensors that are installed. This causes data capping. Also if your reading boost on a interceptor the can signal maxes out at alike 257 kpa so it's fairly inaccurate. Plus you can't log your boost pressure along side other data if you only use the interceptor.
    2000 Ford Mustang - Top Sportsman

  6. #6
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    He will be coming back over on Saturday morning to look it over again. When we did the multiple days of initial tuning there was no sign of knock, and the car ran great other than having to limit power due to still using stock injectors. Then about a week or week and a half later he got this 11.9 degrees of steady knock in all cruising gears basically. He came back to me and exhaust was rattling on the car like crazy. I could not determine that there was any actual detonation or real knock occurring so we looked at a few things under the hood. I made the suggestion about checking the knock sensors and to get the excessive rattling to stop.

  7. #7
    Senior Tuner cobaltssoverbooster's Avatar
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    did not know you were involved stevo..as long as he brings it back to you i see this getting solved properly.
    2000 Ford Mustang - Top Sportsman

  8. #8
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    I fixed my exhaust last night and still show some random phantom KR, but nothing serious. At part throttle, it is almost impossible to get the car to ACTUALLY knock, and even harder on Ethanol blended fuel over 15%. GMT even went as far as to say once (if my memory is correct) that even 10% ethanol makes it very hard to make these cars knock. So, my bet is it is all false knock.

    I agree though, I think you will get her figured out Steve. Also, I would change the injector seals. Still think that would cause some of the issues, and if not, they should have been changed regardless.

  9. #9
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    Quote Originally Posted by cobaltssoverbooster View Post
    Seals are tolerance fit, this should have happened. I was waiting for someone to bring it up, thanks.
    Knock sensors don't really do much as far as position, if it's solidly bolted to the block material at torque spec the signal will be the same. Your exhaust is a big issue since the rattling will set the already super sensitive knock sensors off.
    As for lean idles, the evap sensor likes to leak and I would recheck all the manifold gaskets and clamps that are under pressure.

    Also verify your map sensor data matches the two boost sensors that are installed. This causes data capping. Also if your reading boost on a interceptor the can signal maxes out at alike 257 kpa so it's fairly inaccurate. Plus you can't log your boost pressure along side other data if you only use the interceptor.
    When the car's coolant is less than 150F there is 0 deg of KR at any throttle or light boost. Less than 5 psi. but once the engine warms up, KR will go all over the place, 4-6 deg. 11.9. It's annoying.

  10. #10
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    Did Psykosteve get a log?

  11. #11
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    yeah. I think so