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Boost issue- need confirmation of my diagnosis
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Topic: Boost issue- need confirmation of my diagnosis (Read 4702 times)
Bugman100
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Boost issue- need confirmation of my diagnosis
« on: May 27, 2019, 12:35:20 PM »
I have a BJX 150BHP engine that i have transferred to a MK1 Caddy. The ecu tune has had SAI and Rear 02 deleted (along with a cat removed).
LDRXN has been tweaked slightly upping the boost by 1 PSI and holding onto boost further up the rev range.
The engine runs and drives well but is not reaching the desired boost with wastegate duty pegged at 85-95%
log file and chart attached.
i think its one or more of the below is at fault
Boost leak.
Failing wastegate actuator.
Failing boost valve.
Is there anything else I have missed or nuggets of wisdom before i go down the proverbial rabbit hole looking for mechanical faults?
Nigel
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nyet
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Re: Boost issue- need confirmation of my diagnosis
« Reply #1 on: May 27, 2019, 12:43:41 PM »
That's literally wg pressure.
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Bugman100
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Re: Boost issue- need confirmation of my diagnosis
« Reply #2 on: May 27, 2019, 12:57:52 PM »
Im relatively new to this please could you explain. Am i looking at the wrong thing?
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aef
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Re: Boost issue- need confirmation of my diagnosis
« Reply #3 on: May 28, 2019, 05:53:24 AM »
It means your car does not use the N75. Your turbo will create only base boost by using the spring rate in your waste gate actuator.
pressure test your system after a swap is never a bad idea. check n75, wiring to n75 and piping of n75.
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Bugman100
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Re: Boost issue- need confirmation of my diagnosis
« Reply #4 on: May 29, 2019, 02:59:23 AM »
Thanks, that's what I needed.
Sort of got to that point last night, unplugged the n75 and got the same results as before.
I tested for boost leaks last night, that all turned out good. I do have a small concern about the diverter valve leaking at higher pressures.
something to watch as I creep the boost levels up.
I reviewed my notes on my wiring conversion this morning so will check wiring tonight, along with the other things you have mentioned.
Thanks for the response, I will post my findings later.
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Bugman100
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Re: Boost issue- need confirmation of my diagnosis
« Reply #5 on: June 03, 2019, 12:42:32 PM »
Ok my boost issue is fixed.
The N75 valve was incorrectly fitted. Boost now following LDRXN
Thanks all
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nyet
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Re: Boost issue- need confirmation of my diagnosis
« Reply #6 on: June 03, 2019, 03:09:23 PM »
NP, thanks for the update. Always appreciate it when people come back to add info, it is always helpful for everyone.
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ME7.1 tuning guide
ECUx Plot
ME7Sum checksum
Trim heatmap tool
Please do not ask me for tunes. I'm here to help people make their own.
Do not PM me technical questions! Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your ex
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