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B200FT turbo swap now cuts out after throttle?

105Charlie

New member
Joined
Jan 21, 2018
Hi

I've just swapped from the 13g to a 15g on my b200ft (in a 343). Running LH2.4, standard chips and injectors but a 012MAF and 2.5in DP/1BAR actuator. Idles and revs perfect throughout the rev range but dies after any sort of boost or hard throttle usage under load. Seems to bog quite a bit and obviously can only be driven gently at the moment.

Are there any obvious reasons for this before I start checking the loom for damage? I have the original MAF but it won't fit easily with the new pipe setup (a lot less space in a 343). I also have a set of 470cc injectors that I could try if it could be fuel starvation?

Was running perfectly fine running 14psi before I did the swap and tidied up the loom. Any obvious ideas?

Cheers
 
Boost leak? Once upon a time I forgot to check the tightness of a clamp on the hose from the turbo to the intercooler on my 88 765. First time I pulled out to pass a car the car fell flat on it's face. Idled fine. That wouldn't be this cars first boost leak.
 
Install the 470 cc/min injectors before you kill your engine! With the stock injectors and a large AMM you are running way too lean.

012 AMM, LH2.4 and 470cc/min injectors should work fine.
 
Install the 470 cc/min injectors before you kill your engine! With the stock injectors and a large AMM you are running way too lean.

012 AMM, LH2.4 and 470cc/min injectors should work fine.

I fitted them and everything was a little better - still stalling when coming off throttle though!

I'm currently running the flametrap through to a catch can with a filter out... could not running this back into the intake be causing this? I'm putting the same amount of vacuum as before though.
 
I fitted them and everything was a little better - still stalling when coming off throttle though!


still under boost as well?

I'm currently running the flametrap through to a catch can with a filter out... could not running this back into the intake be causing this? I'm putting the same amount of vacuum as before though.

could be TPS related...
and is idle valve working like it should?

but i'm only guessing
 
still under boost as well?



could be TPS related...
and is idle valve working like it should?

but i'm only guessing

I cleaned out the idle valve recently, seems fine and opens and closes quick. It still has a slight hesitation sometimes under boost but that might be something to do with my boost controller's boost cut. I will test that.

Main issue is still that when I come off throttle it stalls. If I come off the throttle slowly it seems fine, just when I come off quick to say change gear.
 
Sorry, mobile phone spellcheck hates English. Could be something over there, maybe wastegaten isn't doing it's job and/or for some reason you are getting a lot of backpressure. Have you tried without it?
 
This usually happens when the throttle idle switch is not adjusted properly and/or there is a bad connection.
 
Have you checked the rubber hose between turbo and air filter? They go soft with age and oil contamination and then get sucked flat under load.
 
Sorry, mobile phone spellcheck hates English. Could be something over there, maybe wastegaten isn't doing it's job and/or for some reason you are getting a lot of backpressure. Have you tried without it?

New 1BAR actuator on, all tested and worked fine when I put it on. Would be surprised if this is it but something to try.

This usually happens when the throttle idle switch is not adjusted properly and/or there is a bad connection.

I will check this, was adjusted correctly but connection could be bad as I did rewire.

Have you checked the rubber hose between turbo and air filter? They go soft with age and oil contamination and then get sucked flat under load.

Brand new silicone hose on there and is fine under boost, it's once I let off it dies.
 
Probably torn compressor bypass valve.

I was thinking this, I did have it off recently and it appeared fine though. Also sounds as if it's working pretty strong.

I will pull it off and take a look, I suspect a stronger one would be better anyway considering I'm running more boost.
 
So just to be clear, the stalling appeared right after swapping the turbo or was it with the old turbo on as well? Also, was the turbo swap the only thing you changed before the stalling appeared or did you do anything else along with it?

Probably torn compressor bypass valve.
I was thinking this, I did have it off recently and it appeared fine though. Also sounds as if it's working pretty strong.

I will pull it off and take a look, I suspect a stronger one would be better anyway considering I'm running more boost.

That sounds very reasonable, the diaphragm could have a tiny pinhole in it which would be hard to spot. Have a look at it again and inspect thoroughly, as it's off very quickly.
 
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