It fires without the fuel pump on.... Dies when you kick the pump on.

[Sinister]

We solved on issue and of course I now have another. I got the engine to fire up last night about 2am. If I turned the ignition on and the fuel pump on for about 3 seconds and then off, the car would fire up and run like everything was normal. It idled and revved no problem. However, as soon I turn the fuel pump on the car would flood out and die. I know that it has something to do with the big injectors but just not sure what. We tried several different ways adjusting the injector timing, trim, pulse, etc.. nothing worked. I have 160lb injectors and I run resistors since they are low impedence. Don't tell me it won't work because this set up runs fine on my pcm that is tuned using Hptuners. It revs fine and idles fine.

Any ideas? I am going to post on LS1tech also.

[joecar]

Hi Sinister,

is your FPR located at the fuel rails (MAP-referenced) or at the tank (non-referenced)...?

what is rail pressure with engine running (with reference hose removed from FPR if applicable)...?

for those injectors (160 lb/hr @ 3 bar), was IFR table calculated for your measured rail pressure (in your EFILive tune file)...?

[Sinister]

My FPR is located at the rails. I have a -10 fuel lines from the tank to a "Y" fitting. A single -10 off the Y to another Y fitting before the fuel rails. I then have the FPR at the front of the engine off the fuel rails. It is set at 50psi and stays there when running. When the car was running on HP tuners it would jump up to 65psi when the second pump would kick on at 4psi via a hobbs switch. I have never checked it with the hose off but I believe when it was tuned on the dyno they mentioned it would drop 5lbs of pressure if you removed the reference.

The IRR table was calculated for 50psi for 160lb injectors and a 2 bar, not 3 bar. My GM Map and the HPtune was 2 bar. I believe this tune on EFI live is also 2 bar.

[Sinister]

Here is a shot of my fuel regulator location.

http://i1009.photobucket.com/albums/af213/splitmastertiming/AirFilter3.jpg

Here is a picture of my control panel. Ignition switch, Push button start, Toggle switch (Fuel pump) Toggle switch (fans) LM1

http://i1009.photobucket.com/albums/af213/splitmastertiming/ControlCenter.jpg

[joecar]

I see the reference hose is removed from your FPR (do I see it right...?)... so the rail pressure should stay steady at what you set it at 50 psi;

If the manifold reference hose is on, then the FPR regulated rail pressure should go up/down as manifold pressure (MAP) goes up/down.

I don't follow by the FPR would allow pressure to jump to 65 psi with the second pump running... shouldn't the FPR regulate the pressure to 50 psi...? (unless the return line was too small or otherwise obstructed) (when the pressure jumps to 65 psi, then the IFR would be incorrect, this would need the VE table to be different).


Ok, understood, 160 lb/hr @ 43.5 psi rescaled to 50 psi, this is what IFR was calculated for ( i.e. at 50 psi they flow 172 lb/hr )[ at 65 psi they flow 196 lb/hr ].



[ or, is the IFR in your EFILive tune file the same as the IFR in your HPTuners tune file...? ]

[minytrker]

It honestly just sounds like you need it tuned. You just cant copy a 2 bar HPT tune over to a 2 bar EFI live tune.

[joecar]

Very good point... EFILive and HPT use un-used memory in different manners to implement their COS's.

[Sinister]

The picture is when we were building everything. Ie, not complete. I do have the reference hose hooked up. The fuel pressure is steady while trying to start it. It seems to initially jump up when the second pump kicks on but that was when it was running at WOT. As far as copying a tune. This is not the first tune. I have had it tuned and it did not start or run at all. So.......I copied the HPtune into a new EFI live tune and I can get it to run without the fuel pump on. The previous tunes is from those who have done several tunes and had no issues. Something must be going on with the injectors and the resistor numbers to make it run.

[joecar]

Hmmm... I see, the key point here is that it runs with the fuel pump off and not with it on...

can you draw a diagram showing how the resistors are connected between the injectors and the harness.

[Sinister]

I tried to take some pictures from under my dash. Not the best but I think you can see how we did it. We wired in a inline resistor to the power side. Basically cut the wire before the injector wire goes into the pcm and then wired the resistor between the two wires. We put one resistor for each injector. We also staggered the resistors so they would never touch each other or be against any other metal or wires due to them getting hot.

I am not sure if this would make a difference but since I am running my Fuel pump with a toggle switch I assumed we would disable the fuel pump on the tune but maybe that still needs to be enabled. Again, not sure just trying to figure out what is different from the EFI live from my HPtune. Thanks again for trying to help.

http://i1009.photobucket.com/albums/af213/splitmastertiming/Inj4.jpg

http://i1009.photobucket.com/albums/af213/splitmastertiming/Inj3.jpg

http://i1009.photobucket.com/albums/af213/splitmastertiming/Inj2.jpg

http://i1009.photobucket.com/albums/af213/splitmastertiming/Inj1.jpg

[slows10]

The fuel pump and the injectors have to be working at the same time. Are you sure that the injectors are working when the pump is running? Injector dynamics sells some quality injectors that include all the proper data that you can plug right into all the injector tables. And they are high impedence so you wont need those funky resistors to mess with. Sell them bosch injectors to somebody else.

[DrkPhx]

Hmmm... I see, the key point here is that it runs with the fuel pump off and not with it on...

can you draw a diagram showing how the resistors are connected between the injectors and the harness.


I agree with Joe. At first thought it sounds like something is up with the wiring or resistors (double check), until I read this...


I tried to take some pictures from under my dash. Not the best but I think you can see how we did it. We wired in a inline resistor to the power side. Basically cut the wire before the injector wire goes into the pcm and then wired the resistor between the two wires. We put one resistor for each injector. We also staggered the resistors so they would never touch each other or be against any other metal or wires due to them getting hot.

I am not sure if this would make a difference but since I am running my Fuel pump with a toggle switch I assumed we would disable the fuel pump on the tune but maybe that still needs to be enabled. Again, not sure just trying to figure out what is different from the EFI live from my HPtune. Thanks again for trying to help.

Good point. I would check the fuel pressure at the rail as soon as the second fuel pump is switched on and also check the voltage as well.


The fuel pump and the injectors have to be working at the same time. Are you sure that the injectors are working when the pump is running? Injector dynamics sells some quality injectors that include all the proper data that you can plug right into all the injector tables. And they are high impedence so you wont need those funky resistors to mess with. Sell them bosch injectors to somebody else.

[Sinister]

What would be the best way to check. They work fine with the pcm that has the HPtune. I would get some other injectors but I don't have a grand to lay down on some injectors when the car works with the resistors just fine with the HPtune. Surely, EFI live can be tuned with the resistors.

[Sinister]

I just wanted to post some updated info. First I have to thank my cousin Jeff who drove 7 hrs from Chicago to personally come down and find out what was going on with my tune. I greatly appreciate it. We got the car starting instantly and idling like a stock 5.3 right at 950rpms. He also fixed it so my car wouldn't die when we kicked the fans on with a toggle switch. I am going to post what we changed. He said that this isn't the way on paper that it should be done but it is what we had to do to get the car to run. I don't care. I am glad to have a starting point to start makeing some logs. Keep in mind that I have just started with EFI live, Gen III's, Turbos. I have been a big block NA guy for years.

First. The car would just not run with the IFR set at 160lbs or so. He adjusted it to about 69-80 or so along with adding about 30% more fuel to my main VE table. He also lowered the fuel pressure from 52 psi to 45psi on the money. To fix the problem I had even on the HPtune (the car would die when you kicked the fans on) he fixed all the cells in the table that adjusts when the volts drop. I had all those cells on zero. That was wrong.

At least now the car will fire up, doesn't run you out of the garage from the smell of E85, and purrrrs like a kitten. I am looking forward to making some data logs. Still have some mechanical issues to take care of with the trans but I wanted to update the thread for future reference to others trying to use huge injectors, resistors instead of an expensive driver box, and E85.

I am sure someone will want the tune posted. I need to wait and see if it okay with him to post it. Once he gives the okay I will post. I am sure people will try and tear the tune apart but it works perfect on my set up. Remember, just wanted a place to start so I can make some logs and then really start tuning.

[minytrker]

Glad you made some progress.

If your IFR tables are wrong then you will just have to cheat your VE tables to make it run. It just starts a chain of fuel related tables not being correct.

[Sinister]

That is how we get 160lb low impedence injectors to idle like stock. I would rather do that and blow my engine up that only costs $500 to replace then spend $1600 on a set of high impedence injectors. I have to start somewhere and right now this works. Hopefully, as I learn to tune I can eventually get it done the correct way but I have no problem manipulating the software to get the car to work.