# surging ,no codes , test fuel pressure regulator maybe ?



## no66mac (Jan 27, 2021)

At lower rpms it surges , whether its on cruise control or I try to gradually increase speed up slight incline . I have changed the air & fuel filters and on 2nd tank with cetane boost & fuel cleaner. (since filter was black /possible algae) ..When it surges it will fluctuate rapidly from from 0-29 lbs boost and if you step on it ; at 2800rpms it will take off. I asked about it where I got the tune from and he said it sounds like the fuel pressure regulator. I didn't ask more then, I didn't think muck about it . All the pressure sensors I seen were out of stock / unavailable , except for the fuel rail with sensors on it , a lot more expensive , so is there a way I can test the sensors to be certain if its bad ?


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## no66mac (Jan 27, 2021)

an update ,we checked fuel rail pressures etc. all were normal range. I took the fuel rail pressure sensor off and cleaned it with crc throttle & intake cleaner and it improved it , 2nd time more improvement. going to run more fuel cleaner/ algae killer through the tank . this is my wife's car , I don't know where she last got fuel at but it sat for over 2 months in warm weather perfect for it to grow . the fuel filter was black when I changed it with 38% life left.


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## revjpeterson (Oct 2, 2013)

Those boost numbers you mention make me think it would be a good idea to also check the vacuum system for leaks. There's a vacuum pump mounted at the driver-side end of the camshaft, which feeds a distribution block just below it. One hose from that block supplies vacuum to the EGR system, and the other supplies vacuum to the VGT actuator. If there is a leak in the vacuum system, it would impact the performance of the turbo, possibly causing it to fluctuate like you describe.


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## no66mac (Jan 27, 2021)

revjpeterson said:


> Those boost numbers you mention make me think it would be a good idea to also check the vacuum system for leaks. There's a vacuum pump mounted at the driver-side end of the camshaft, which feeds a distribution block just below it. One hose from that block supplies vacuum to the EGR system, and the other supplies vacuum to the VGT actuator. If there is a leak in the vacuum system, it would impact the performance of the turbo, possibly causing it to fluctuate like you describe.


thanks for your input , I lost the egr on this car , after cleaning fuel pressure sensor 2nd time I was able to step on it from a stop ,spin tires enough for the traction control light to come on , but it wasn't long before it to started to hesitate / surge again after that. It is not nearly as bad as before,it will pick up and go at a lot lower rpm than before . I think there is more junk that grew in the fuel lines after the filter that has been coming loose causing issues, at least that is what I hope  . also I did plug off the 2 lines up front that were no longer needed.


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## no66mac (Jan 27, 2021)

For anyone who was following this I finally figured it out, I took it to a local mechanic and everything was operating as it should until it came to the map sensor, said they needed to replace it to continue so I said I would (dealer wanted $118 for just the pigtail so I was going to get it from a wrecking yard. I decided to unplug the edge cts plug off the map sensor and just go straight to the map sensor with the stock plug in and everything was great , so something in the plug in or wiring from the edge insite was bad


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## Johnny123 (11 mo ago)

no66mac said:


> For anyone who was following this I finally figured it out, I took it to a local mechanic and everything was operating as it should until it came to the map sensor, said they needed to replace it to continue so I said I would (dealer wanted $118 for just the pigtail so I was going to get it from a wrecking yard. I decided to unplug the edge cts plug off the map sensor and just go straight to the map sensor with the stock plug in and everything was great , so something in the plug in or wiring from the edge insite was bad


Did you have any check engine light codes? Curious as mine can't start when sitting overnight and I need to crank it like 5-10 times until it finally starts


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## no66mac (Jan 27, 2021)

Johnny123 said:


> Did you have any check engine light codes? Curious as mine can't start when sitting overnight and I need to crank it like 5-10 times until it finally starts


no I didn't have any codes at all. Is it real cold right now where your at? if so could be fuel related like gelling or glow plugs, you could try cycling your glow plugs a couple times before trying to start. if you were losing fuel pressure somehow, turning the key on and not starting the motor you can hear the fuel pump pressurizing the system, you could do this 4-5 times first (same as you would do when you change the fuel filter) then try starting it , hope this will help narrow down what issue you may be having


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