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Worst Dyno Results Ever ?

djvoodoo

By djvoodoo,
in Engines & Forced Induction

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djvoodoo Experienced

djvoodoo

Posted
Posted

Yo yo.

R34 GTsT. 3" turbo back exh- Walbro 500 hp pump- JustJap Turnflow FMIC- Mushroom filter in box- Standard ECU, Injectors and AFM- Greddy profec B- Greddy RS BOV plumbed back into intake.

I've been having some real headaches with how my car puts down the power. In a nutshell, anything over 7psi (my Hi boost is set to 9,5) turns my car into a pig rich fuel guzzling, retardation machine. At first I thought it was R&R, and changed my plugs, AFM, and got hold of another standard ECU. Coilpacks are fine, and no boost leaks as boost comes on consistent and strong.

So I took it to Pulse Racing to see how it looked on the dyno. Check out the pics attached. Their Dyno reads at it's lowest A/F point of 10:1. My cars AFR flatlines at 10:1 or possibly lower right from the beggining of the run. Check out the crazy power dips to and a max of 126 rwkw.

I need some help in getting some ideas what the problem could be. Replacement standard ECU made no difference, and simply "chucking in" an aftermarket item isn't going to fix the problem either...

Tuner recons it's not the 02 sensor, coils, plugs, boost control, but pretty much tried to "sell" me the idea of an aftermarket ECU, which really, is a bandaid fix to the actual issue. I want to diagnose the cause of the issue. Any help is appreciated

Cheers

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JonnoHR31 Grand Master

JonnoHR31

Posted
Posted
First thing I saw was Walbro fuel pump, did you use the stock wiring (6v / 12v depending on load) or did you give it alternator voltage like A/M pumps such as Walbros need?

i hardly think theres any problems with lack of fuel flow looking at the graph....

scotty nm35 Grand Master

scotty nm35

Posted
Posted
Yo yo.

R34 GTsT. 3" turbo back exh- Walbro 500 hp pump- JustJap Turnflow FMIC- Mushroom filter in box- Standard ECU, Injectors and AFM- Greddy profec B- Greddy RS BOV plumbed back into intake.

I've been having some real headaches with how my car puts down the power. In a nutshell, anything over 7psi (my Hi boost is set to 9,5) turns my car into a pig rich fuel guzzling, retardation machine. At first I thought it was R&R, and changed my plugs, AFM, and got hold of another standard ECU. Coilpacks are fine, and no boost leaks as boost comes on consistent and strong.

So I took it to Pulse Racing to see how it looked on the dyno. Check out the pics attached. Their Dyno reads at it's lowest A/F point of 10:1. My cars AFR flatlines at 10:1 or possibly lower right from the beggining of the run. Check out the crazy power dips to and a max of 126 rwkw.

I need some help in getting some ideas what the problem could be. Replacement standard ECU made no difference, and simply "chucking in" an aftermarket item isn't going to fix the problem either...

Tuner recons it's not the 02 sensor, coils, plugs, boost control, but pretty much tried to "sell" me the idea of an aftermarket ECU, which really, is a bandaid fix to the actual issue. I want to diagnose the cause of the issue. Any help is appreciated

Cheers

Are you sure the injectors are stock? Something doesn't add up... Checked fuel pressure?

He suggested an aftermarket ecu because he cant adjust anything without it.

djvoodoo Experienced

djvoodoo

Posted
  • Author
Posted
Are you sure the injectors are stock? Something doesn't add up... Checked fuel pressure?

He suggested an aftermarket ecu because he cant adjust anything without it.

To Moodles2, It was happening prior to the Walbro pump install, and if anything, it's getting too much fuel rather than not enough. the Pump was installed by Autosport engineering, who I dare say know what their doin. It wasn't a backyard job.

To Scotty, I haven't checked if the Injectors are standard. I would assume so as but will check that out for sure.

My thoughts are it's not necessarily the ECU at fault here. yes i kno that their is a safe map for knock etc with the Nissan standard unit, but there is no way that the map is "lets drop AFR to 10:1 through the entire rev range"

KiwiRS4T Grand Master

KiwiRS4T

Posted
Posted

Get an ecutalk or other consult reader and get some idea of what is going on - injector duty, afm readings (can you swap out the afm with someone?) And get a Nistune chip so that you can actually try to tune it. It will also help to identify problems.

DVS JEZ Grand Master

DVS JEZ

Posted
Posted
How has no one mentioned the fact he thinks he owns a R34 GTST? :D

Haha yeh i noticed that.

So is that run on stock boost?

Did u try running a higher boost setting. Like 12 ?

Check coolant temp sensor too. Its like its on cold start enrichment

STATUS Grand Master

STATUS

Posted
Posted

check the boost sensor is hooked up, and secondly that the boost source for the BOV is connected. If either are missing it will do that... as will a split hose (cooler)

Second dip is normal as the std ecu has a big timing drop in i, run std boost and dip goes away... or a quick remap removes it straight away.

paulr33 Grand Master

paulr33

Posted
Posted

yes

ECR33 has excess airflow protection

ER34 has excess airflow protection

ER34 also has excess boost protection via the 2nd map sensor that runs to the ECU

its likely you are just tripping that out, youll need a remap, a map sensor cut device, run it no where and crimp the vac line or get a stand alone

djvoodoo Experienced

djvoodoo

Posted
  • Author
Posted
Haha yeh i noticed that.

So is that run on stock boost?

Did u try running a higher boost setting. Like 12 ?

Check coolant temp sensor too. Its like its on cold start enrichment

Lo boost on Greddy - gain 28% set gain 13% Start gain .46 gives me about 7.3 peak boost

Hi boost on Greddy - gain 38% set gain 18% start gain .55 gives me about 9.3 peak boost

Running "lo" boost is fine

Running "hi" = what you see on the dyno charts

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