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Old 04-19-2012, 12:17 AM   #1
carlck19
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Default ej20g robs knock light

Hi guys,
So i have an ej20g v1 with robs tune on stock injectors.
Every possible maintenance has been done on the motor save for removing and cleaning/flowtesting the injectors
mbc at 15psi
full 3" catless
v2 sti slanty
coilpack conversion
In short the motor runs great and I hear no audible "knocking" at any time but often when I get on it the knock light flashes a significant amount, but I don't hear or feel anything out of the ordinary.
Are my injectors maxed out? Do I need to upgrade to the 550's? Is my knock sensor just overly sensitive/going bad?
In addition, whenever I go on the highway and come off my fans kick on immediately as if the car is running somewhat hot, but the temp needle doesnt actually budge at all. The car is closed deck so maybe it just runs somewhat hot??
Input much appreciated,
Alex
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Old 04-19-2012, 12:22 AM   #2
eg33GC
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any codes?
have evoscan?

It is likely bad gas, a faulty knock or ect sensor.
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Old 04-19-2012, 12:30 AM   #3
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no codes. What is evoscan?
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Old 04-19-2012, 12:37 AM   #4
carlck19
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I have read that the ect sensor is only bad if the fans kick on automatically before even starting the car, with the ignition just turned to the "on" position. Is this true? do you have a p/n for the ej20g knock sensor and do you know where it goes?
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Old 04-19-2012, 12:42 AM   #5
rob
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If you free rev does it flicker? I would recommend trying to lower the boost and see if the frequency drops. You can also run the tank low and put in 1/4 tank of race gas to see if it goes away. My custom code will flicker the CEL once the ECU has determined a real knock event has occurred and is taking action to counter.

One other important note is that one side effect of my code is that when the CEL comes one for a real code, the light does not stay on solid, it flashes real fast (almost looks dim). If you are getting an intermittent CEL, it might look like sustained, severe knocking. In that case you would be able to connect the black diag connectors and have it flash a code as normal.

-Rob
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Old 04-19-2012, 12:47 AM   #6
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free revving hardly makes it flicker, very rare. I will try lowering the boost and see what happens, I was going to try octane booster because i dont have easy access to race gas. Is it possible that my knock sensor is messed up in some way?
The car has no codes, btw.
Also, Rob, when will the z32 tune be ready?!?
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Old 04-19-2012, 12:54 AM   #7
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Another comment I will make is the stock temp gauge is near useless. The needle will basically stay parked in the same "normal" spot between 160-220F.
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Old 04-19-2012, 12:55 AM   #8
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Quote:
Originally Posted by carlck19 View Post
Also, Rob, when will the z32 tune be ready?!?
How dare you.





























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Old 04-19-2012, 12:55 AM   #9
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if turning down the boost fixes the knock light issue, do you think I should upgrade injectors?
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Old 04-19-2012, 12:56 AM   #10
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How dare you.




























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Old 04-19-2012, 12:56 AM   #11
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no, figure out why youre knocking.
I assume you NAW YAWKAs don't get the creme de la creme of fuel.
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Old 04-19-2012, 12:58 AM   #12
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Quote:
Originally Posted by eg33GC View Post
no, figure out why youre knocking.
I assume you NAW YAWKAs don't get the creme de la creme of fuel.
i suppose not. but I don't hear the motor knocking and it runs fine, I don't see what there is to figure out...
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Old 04-19-2012, 01:02 AM   #13
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you can't hear knock inside the vehicle while driving. it is not rod knock, it is pre detonation in the cylinders.

knock has a few causes:
fuel
air temp
oil reducing octane
timing
exceeding mechanical limits, ie too high boost, too lean, too much timing, too much fuel
faulty equipment- faulty maf/tps (that are the load basis of the ecu), ect (dictator of fuel and timing allowances)

We also have a very lean throttle tip in value, so it is not coincedental this happens right when you get on it
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Old 04-19-2012, 01:09 AM   #14
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Quote:
Originally Posted by eg33GC View Post
you can't hear knock inside the vehicle while driving. it is not rod knock, it is pre detonation in the cylinders.

knock has a few causes:
fuel
air temp
oil reducing octane
timing
exceeding mechanical limits, ie too high boost, too lean, too much timing, too much fuel
faulty equipment- faulty maf/tps (that are the load basis of the ecu), ect (dictator of fuel and timing allowances)

We also have a very lean throttle tip in value, so it is not coincedental this happens right when you get on it
thanks for explaining the difference, I appreciate it. I do believe that "oil reducing octane may be partly to blame for this and I am going to do a catchcan setup asap to see how that does.
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Old 04-19-2012, 01:11 AM   #15
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I noticed a bit of icky getting into my G inlet system, but I am not using a fuel succeptable to any octane loss of significance
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Old 04-19-2012, 01:15 AM   #16
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^what fuel is that haha
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Old 04-19-2012, 01:17 AM   #17
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ethanol
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Old 04-19-2012, 01:19 AM   #18
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nice; shouldve noticed from yr vehicle info lol. yeah i notice the knock light mostly on throttle tip in i would say. how concerned should i be about this?
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Old 04-19-2012, 11:17 AM   #19
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filled the tank up halfway with gas from a diff station and turned the mbc down half a turn and no more knock light! does this just mean i was exceeding mechanical limits (i.e. fuel) by having the boost too high and maxing out the injectors?
-Alex
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Old 04-19-2012, 12:30 PM   #20
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You would have to try the gas with the boost up to know which one was the problem lol but id be afraid to turn up the boost if i was getting a significant knock. up to you haha i would stick w what works have fun get bigger injectors or get yours modded crank up that boost
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Old 04-19-2012, 01:14 PM   #21
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There are actually a couple of unasked obvious questions.

First:
What octane are you actually running. Where is the fuel from? Are you consistently running fuel from the same station?

Second:
Have you installed any actual gauges or are you trying to diagnose the issues only operating with information from Rob's knock lite and the Factory water temp gauge which really isn't actually a gauge as it is a needle that gives you a thumbs up/thumbs down on water temp with no useful data in between.

Third: The water temp sensor on my EJ20G was quite screwy. The idle and fan operation completely changed when I replaced mine. There are actually two water temp sensors; one for that useless gauge and one for the ECU. It cost me $18 to replace to water sensor that goes to the ecu. Totally worth it.

Fourth more useful gauges: oil temp, real water temp, A/F ratio(even if its a cheapo non wideband). Do you have any way to tell if you perhaps have a clogged injector causing one cylinder to run lean and therefore hot? What is your fuel pressure @ right now? Low fuel pressure can result in a lean condition in all cylinders.
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Old 04-19-2012, 08:36 PM   #22
carlck19
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Quote:
Originally Posted by TommyAtomic View Post
There are actually a couple of unasked obvious questions.

First:
What octane are you actually running. Where is the fuel from? Are you consistently running fuel from the same station?

Second:
Have you installed any actual gauges or are you trying to diagnose the issues only operating with information from Rob's knock lite and the Factory water temp gauge which really isn't actually a gauge as it is a needle that gives you a thumbs up/thumbs down on water temp with no useful data in between.

Third: The water temp sensor on my EJ20G was quite screwy. The idle and fan operation completely changed when I replaced mine. There are actually two water temp sensors; one for that useless gauge and one for the ECU. It cost me $18 to replace to water sensor that goes to the ecu. Totally worth it.

Fourth more useful gauges: oil temp, real water temp, A/F ratio(even if its a cheapo non wideband). Do you have any way to tell if you perhaps have a clogged injector causing one cylinder to run lean and therefore hot? What is your fuel pressure @ right now? Low fuel pressure can result in a lean condition in all cylinders.
thanks for the advice!
1. im running 93 octane, the bad appearing gas was from a mobil station, and i just filled up at a 7 11 and their gas is the one i get most and don't have any issues with generally.

2. I have not monitored with actual gauges but my next purchases will be catch cans and an aem wideband so i should be able to feel things out better.

3. Should I replace the ect temp sensor? Where is it located on the motor?

4. I do have a walbro in the car but how would i measure fuel pressure?

Since The knock light activity has gone away maybe it was just too much boost to handle on this injector setup, but I will continue to work towards fixing this issue anyway.
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Old 04-19-2012, 10:35 PM   #23
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Advanced auto sells a $40 fuel pressure test kit which doesnt really mate up to the car so i bought 2 5/16 hose barbs that mate up to the t block the kit came with cut ur fuel inlet line put it in line good to go give me ur email i can semd u a pic if ur not completly sure what i mean
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Old 04-21-2012, 07:43 AM   #24
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Can you send me a pic of it too? I'll pm you my email
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Old 04-21-2012, 04:26 PM   #25
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Quote:
Originally Posted by DonnIefnoker View Post
Advanced auto sells a $40 fuel pressure test kit which doesnt really mate up to the car so i bought 2 5/16 hose barbs that mate up to the t block the kit came with cut ur fuel inlet line put it in line good to go give me ur email i can semd u a pic if ur not completly sure what i mean
alherman@vassar.edu

thanks!
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