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Discussion Starter #1
Hi guys. In my '85 I'm running a 6M with a CT-26 Turbo. What fuel pressure should I be running if I'm using stock injectors? I have a Cartech RRFPR and according to their documentation, you need a minimum of 95 psi fuel pressure for 7 to 8 psi of boost. Well, according to my fuel pressure gauge my max pressure is about 80 psi. What happens is I can boost up to about 4 psi with half throttle. That's it. If it press the pedal down anymore, my boost stays the same and my a/f gauge jumps to the lean side. Should I be upgrading the fuel pump with a high flow unit? Or should I be looking at larger injectors? Any info would be greatly appreciated.
 

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Talk to Phil Dupler. He's running a 6M-GTE, and can offer you advice. You can locate him on the MkII list.

I'd also suggest talking to Aaron Garney, as he's using the same setup I believe in his 5M-GTE. You can reach him at [email protected]

HTH.
 

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Discussion Starter #3
Yeah, I know both of them. They were a big help in getting the project completed. They seem to be confused also as to what it could be. I was just hoping to get as many opinions as possible as to what it might be. I know that both of their cars run great and do not run lean. Phil has the larger injectors in his 6M plus a high flow fuel pump. Aaron is using stock injectors but is running a 5M turbo. This is strange.
 

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Obocecha said:
Yeah, I know both of them. They were a big help in getting the project completed. They seem to be confused also as to what it could be. I was just hoping to get as many opinions as possible as to what it might be. I know that both of their cars run great and do not run lean. Phil has the larger injectors in his 6M plus a high flow fuel pump. Aaron is using stock injectors but is running a 5M turbo. This is strange.
I guess I'll throw my thoughts in then:

Ok. It sounds to me like you just aren't flowing enough fuel for the application. Several things come to mind:
1) Is your fuel pressure gauge hooked-up right?
2) Are your injectors clogged?
3) Are all of your injectors working?
4) Is your fuel pump working correctly?
5) Are your fuel lines clean? No potential clogs?
6) Is your filter on the fuel pump clogged, reducing flow?

Aaron is running 7psi of boost in his car I believe. He tried to increase the boost at Zupan's and had problems, so we turned it back down ...

Hope that helps... you might also ask Jim King...
 

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Discussion Starter #5
I replaced the fuel pump and the little strainer on the end of it. The fuel filter is new. My car idles very smoothly so the injectors should be fine. These are the same injectors I had been running on my 5M with no problems. The injectors and lines should be clean, I always run super unleaded and occasionally run fuel injector cleaner. I'm guessing that I just don't have enough fuel pressure and/or my fuel injectors need to be upgraded.
 

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Obocecha said:
I replaced the fuel pump and the little strainer on the end of it. The fuel filter is new. My car idles very smoothly so the injectors should be fine. These are the same injectors I had been running on my 5M with no problems. The injectors and lines should be clean, I always run super unleaded and occasionally run fuel injector cleaner. I'm guessing that I just don't have enough fuel pressure and/or my fuel injectors need to be upgraded.
...despite the fact that the car idles fine, couldn't the injectors be reaching their max duty cycle incorrectly (like an ECU problem)? ...or just have a slight clog such that they flow fine until they hit higher duty cycles?

Have you ever run injector cleaner in them?

When you say these are the same as you ran in your 5M... did you swap the 5M injectors into your 6M? Why?

Someone on the MkII list had a set of 6M injectors for sale...
 

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Discussion Starter #7
The injectors from the 5M are the same as the 6M. I knew my 5M injectors worked so I just used them. I have run injector cleaner through them but not since completing the 6M swap. I'll run some through and see what happens.
 

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Obocecha said:
The injectors from the 5M are the same as the 6M. I knew my 5M injectors worked so I just used them. I have run injector cleaner through them but not since completing the 6M swap. I'll run some through and see what happens.
Interesting. Here's hoping everything works out.

Otherwise it'll be time to get some of those 4A-GE injectors I guess.

Are you hearing detonation when you go lean?
 

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Discussion Starter #9
No, I'm not getting any detonation. I guess what I'll do is step up to the larger injectors and swap out fuel pump for a high flow unit. That should take care of it.
 
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