ID1000 Injectors maxing out at 550 engine hp

Hi guys,

I'm currently tuning another rb26. It runs a pretty similar setup to my own car.

Stock Engine with camshafts and Headgasket and HKS GTSS Turbos.

Now I only run 700cc Injectors on mine. The owner of the car I'm tuning went for ID1000s.

As soon as I run into more than 1.2bars of boost the ID1000s already max out and go above 100% duty cycle.

We deleted the resistors, the fuel pump is new (DW300), fuel pressure is set correctly, dead times ect. All done correctly.

Somebody had a similar issue with these injectors?

The mixture was alsways around 12.5 afr but the duty just goes crazy at a certain point.

I added a log file

You don't mention the fuel pressure being used -- is the pressure regulator correctly referenced to manifold pressure? What is the difference in fuel pressure on your car vs. the customer car?

Can the fuel pump keep up?

Have you checked for a clogged fuel filter?

From the symptoms described, I 100% concur with David!

Adding a fuel pressure sensor will help you visualize the drop in pressure that's likely occurring.

What fuel are you running?

What gauge wire are you using for power and ground to the pump? Have you checked voltage at the pump during operation?

Hi guys,

Thanks for the fast responses.

We used the oem wiring as it was a "on the dyno" change of the pump (a nismo was installed which should be sufficient also, but we wanted to be sure).

Yes the Fuel pressure was setup at 3.5bar without vacuum and 3 bar with vacuum hooked up. In my car I run the same.

Fuel is 98 octane pump fuel.

Clogged fuel filter is very unlikely as we i stalled the radium filter (whole radium fuel rail kit with filter and regulator).

I did not check the voltage during operation since I never ran into a problem like that as my car also runs the oem wiring and runs 640hp.

You think this is a possibility?

According to DW300 flow diagram at that level of fuel pressure and boost it would provide about 275 lph (at 13.5 V) which is way enough to cover your needs even if fuel pressure is 0.5 Bar higher than normal. I can see only two reasons for that ( since fuel filter is already ruled out) - huge voltage drop on fuel pump or clogged fuel injectors (came across those a couple of times -used ones after using ethanol in aluminium fuel tank).

You're maxing out around the power level I'd expect with that pump, on pump gas, without a rewire.

I'd upgrade the wiring to something suitable for 20 amps in case you upgrade the pump later, add a fuel pressure sensor so you can see what's going on and add safety measures to the tune, then either back the tune down to what the pump can reliably support, or upgrade the pump. Since you're on a stock engine with pump gas, I'd probably back it down to what this pump can support, but perhaps I'm being overly conservative.

Also, it should be clear the fuel pressure is dropping as you're tuning the main fuel table because the values required will be extremely unreasonable at full load, especially as the engine revs out. With that knowledge, next time you see that happening, you'll know to stop right away and check fuel pressure.

Problem was found:

Fuel pressure did in fact drop from 5000rpm gradually to 2.5 bars.

As the problem persists no matter the pump it must be a wiring issue.

But first time I ran into this problem. Never had this before.

Thanks for the help guys!

You're welcome.

Having a sensor is always best to save diagnostic time and implement engine safety measures on equipped ECUs, but now that you've seen what a drop in fuel pressure looks like in terms of unreasonable fuel/VE table values to try and hit targets, you'll be quicker to catch it next time whether you have a sensor or not.

When you do the rewire, make sure you have a really good ground location. Very often people pick a spot on the chassis that doesn't work out great despite upgrading wire gauge. Hopefully that helps make this a one time fix!