Josh42 Posted July 28, 2019 Share Posted July 28, 2019 Apologies for the long back story... The car is an NA-T, running AEM V2, Greddy OLED and Whifbitz turbo kit. Running BKR7EIX plugs. Car was previously mapped to 510hp at 21PSI of boost, using a Walbro 255lph pump around 2 years ago. I’ve recently installed a Walbro 400lph and took it back for the map to be adjusted. The car maps up just fine on low boost (450hp @13.9PSI) l but as soon as we try and run high boost we encounter an issue. The car will build boost up to 4500-5000RPM but then immediately shut down all 6 cylinders. The ECU still thinks that the car is running and is still sending signals to the injectors to pulse. Injectors are still pulsing (verified with scope and on ECU). I’ve tried replacing the coil with another, but the issue is exactly the same. Any ideas welcome. Quote Link to comment Share on other sites More sharing options...
Mike2JZ Posted July 28, 2019 Share Posted July 28, 2019 What kind of map sensor are you running? Are you still running the dizzy? Quote Link to comment Share on other sites More sharing options...
Josh42 Posted July 28, 2019 Author Share Posted July 28, 2019 Hi Mike, It’s an AEM 3.5 bar map sensor and still running the distributor, yes Quote Link to comment Share on other sites More sharing options...
Mike2JZ Posted July 28, 2019 Share Posted July 28, 2019 And when you say its shutting down. Do you mean misfiring? Or is the engine turning off Quote Link to comment Share on other sites More sharing options...
Josh42 Posted July 28, 2019 Author Share Posted July 28, 2019 There’s no sign of a miss at all, it begins to make boost then immediately shuts down all 6 cylinders and won’t allow you to restart the car immediately (assuming because it’s flooded). Quote Link to comment Share on other sites More sharing options...
Mike2JZ Posted July 28, 2019 Share Posted July 28, 2019 Presumably your air fuel ratio is going rich as this is occurring? Have you got a copy of your map file. Feel free to send my way and I'll check if there is anything obvious map related causing that. Normally above 20psi in have issues with dizzy misfiring, but never had those symptoms. Assuming you havent got any mechanical or tune related issues could be the injector drivers on ECU on the fritz. Quote Link to comment Share on other sites More sharing options...
Noz Posted July 28, 2019 Share Posted July 28, 2019 Can you check the pulse from the ignition output on the ignitor for the dizzy coil. Surely that'll have a voltage output signal at the least. I'd also try and swap the old pump back. Only because you know that's one thing that has definitely changed. Quote Link to comment Share on other sites More sharing options...
Josh42 Posted July 28, 2019 Author Share Posted July 28, 2019 Presumably your air fuel ratio is going rich as this is occurring? Have you got a copy of your map file. Feel free to send my way and I'll check if there is anything obvious map related causing that. Normally above 20psi in have issues with dizzy misfiring, but never had those symptoms. Assuming you havent got any mechanical or tune related issues could be the injector drivers on ECU on the fritz. Yes, AFR’s down into the 10/11 region and then an almighty pop from the exhaust when restarting. I can pull it and send it over to you later Mike, if you wouldn’t mind. Nothing at all, other than the symptoms presented. It maps up absolutely fine on low boost, achieving perfect AFR’s and making strong power all the way up. We did suspect the injector drivers, however, the oscilloscope was showing the injectors opening and closing as they should, even after the shutdown Quote Link to comment Share on other sites More sharing options...
Josh42 Posted July 28, 2019 Author Share Posted July 28, 2019 Can you check the pulse from the ignition output on the ignitor for the dizzy coil. Surely that'll have a voltage output signal at the least. I'd also try and swap the old pump back. Only because you know that's one thing that has definitely changed. I don’t have the scope mate, unfortunately. I can see the voltage is at the coil, using a continuity test, but that’s all. Agree, the fault didn’t exist on the old pump Quote Link to comment Share on other sites More sharing options...
Noz Posted July 28, 2019 Share Posted July 28, 2019 Sounds like new fuel pump can't keep up. Need to check the logs to see what fuel pressure does. I'd be testing with the old pump. See if problem goes away. Quote Link to comment Share on other sites More sharing options...
Mike2JZ Posted July 28, 2019 Share Posted July 28, 2019 What kind of injectors & FPR setup are you running? Did your tuner mention anything about cam/crank sync issues when the issue was occuring? If either of these signals is failing to sync through dizzy then it can cause engine to turn off. Quote Link to comment Share on other sites More sharing options...
Josh42 Posted July 28, 2019 Author Share Posted July 28, 2019 Video here: Quote Link to comment Share on other sites More sharing options...
Josh42 Posted July 28, 2019 Author Share Posted July 28, 2019 What kind of injectors & FPR setup are you running? Did your tuner mention anything about cam/crank sync issues when the issue was occuring? If either of these signals is failing to sync through dizzy then it can cause engine to turn off. Siemens DEKA 650cc top feed and stock FPR mate. No mention of cam sensor issues (don’t think the GE runs a Crank angle sensor?) Quote Link to comment Share on other sites More sharing options...
Mike2JZ Posted July 28, 2019 Share Posted July 28, 2019 Siemens DEKA 650cc top feed and stock FPR mate. No mention of cam sensor issues (don’t think the GE runs a Crank angle sensor?) They don't, the equivalent crank & cam sensor signals run through the distributor, but can still fall out of sync if dizzy has problem. Do you have a log of your fuel pressure? Would rule out fuel pump issues etc Quote Link to comment Share on other sites More sharing options...
Noz Posted July 29, 2019 Share Posted July 29, 2019 I thought about this on the weekend. Why did you remap for a new pump. Was it purely for more horsepower or tuning the pump in. I ask because in my head. The pump would only change the flow rate returning to the tank. The pressure should be regulated meaning no fuel pressure to the injectors should change. Whatever pump you used. So the only reason you'd map it is for more power. Assuming the old one held you back? On 510hp I'm surprised you'd want to be mapping for more power. Have you put the old pump back in yet to see what happens? Quote Link to comment Share on other sites More sharing options...
Josh42 Posted May 6, 2021 Author Share Posted May 6, 2021 On 7/29/2019 at 11:16 AM, Noz said: I thought about this on the weekend. Why did you remap for a new pump. Was it purely for more horsepower or tuning the pump in. I ask because in my head. The pump would only change the flow rate returning to the tank. The pressure should be regulated meaning no fuel pressure to the injectors should change. Whatever pump you used. So the only reason you'd map it is for more power. Assuming the old one held you back? On 510hp I'm surprised you'd want to be mapping for more power. Have you put the old pump back in yet to see what happens? I think I may have finally got to the bottom of this (thanks to a random post from a member on here!). The Walbro 450lph pulls too much power for the stock wiring and therefore the wiring needs to be upgraded. I also need to install an inline relay. Once i've done this, i'll load the 450lph map back onto the car and try again, fingers crossed! Quote Link to comment Share on other sites More sharing options...
Noz Posted May 6, 2021 Share Posted May 6, 2021 6 minutes ago, Josh42 said: I think I may have finally got to the bottom of this (thanks to a random post from a member on here!). The Walbro 450lph pulls too much power for the stock wiring and therefore the wiring needs to be upgraded. I also need to install an inline relay. Once i've done this, i'll load the 450lph map back onto the car and try again, fingers crossed! Good shout. Glad you have got to the bottom of it man. Quote Link to comment Share on other sites More sharing options...
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