Hello everyone,

I would like to share something I'm seeing on the Aeromotive FPR gauge. My current system is a 1992 JDM 13B rebuilt single turbo with Aeromotive Fuel pump, Stock primary rail with 550cc Denso and KGParts Secondary with 1680cc managed by PowerFC.

Does this FPR behaviour means is broken? Video of turning the key 3 times: https://filebin.net/kptshrhnzrritf5e...mp4?t=9rbfv4ox

The car is cranking but not starting after I remove the primary KGParts rail with 850cc injectors and resitor. (Was starting before with bad Idle). I also removed the OMP, put the block off plates and inj screws. Using a SHELL 2T premix.

What I tried already:
- Check for leak on the primary injectors. They were on the shelf for a while after cleaning and testing them. The first time I installed them they were stuck, so I tap them lightly and applied 12v until they fully open and close. I took the rail out and I saw them spraying what it seem fine.
- I have what it seems to be a good spark on the 4 x BUR9EQ T.
- Bypass the Fuel Pump resitor.
-Tried different maps with different IGL / IGL /Fuel values and still not making it to fully start.
-When I crank the PowerFC reads around 9V so I connected an extra 72ah battery to the PC680 , both fully charged and stil getting 9.5v max while cranking (you can see that in the log)
-VTA1 and VTA2 values are within specs.
-New oil, oil filter, fuel filter.

I'm not sure what to do next.. other than getting a new FPR and send the injectors back for testing.

Attached the latest log capture during cranking.

Any help appreciated.

 

I'm not going to download the video. Post it as an unlisted video on YouTube and post the link here

So without seeing the video I'm going to suggest the following...

Verify that your injector settings are correct. If you could post screen shots of each of the settings tabs then we can verify your settings.

Based on what you did, it's more likely a mechanical issue with something you have set up. The primaries don't even do anything until the proper load settings have been reached. So I would say also verify that you hooked up your fuel lines correctly.

Your low voltage situation is odd. Make sure you have adequate grounds of a proper gauge on your battery and motor. Also verify your alternator is good.

Everything else you posted sounds and looks right.

 

cr-rex thanks for the comment. Please look at the FRP video in youtube: . Also I attach the pfc settings. I tried a lot of settings and a lot of different maps. I just want to at least have a rought idle.

 

All of your idle values are set at 0 rpm.... might be an issue there. Idle-IG should also be enabled.

 

well step 1 lol

you have a fuel leak. its likely AT your fuel pump. when you replaced the pump, if you reused the the factory hat thing with the oring in it then you need to replace that o-ring. when you prime the fuel pump, pressure is supposed to remain on the gauge. its not supposed to bleed off like that. also, same as what k-tune said, set your idle values all to 1000. theyre not supposed to be at 0. also turn your fan temps down to fan 1 no ac 85 and the other 2 to 90 in settings 3.

start with that and let us know what happens but a combination of those 2 things will likely fix your problem

 

yeah, the 0 rpm is because on one of the test I put all the settings to 0rpm and disable the idle-ig control to see if it did make any difference.
I'm not sure what o-ring you mean, but I will take the fuel pump out and figure it out. Thanks guys!

 

Oh yea, that's right. I forgot about being able to do that. It's something that's detailed in chuck westbrooks notes.

On the fuel pump hanger at the top of the fuel pump there is a hat type peice that attaches The pump to the hanger. Inside of that is an oring. If that oring doesn't seal properly then it's basically a straw with a hole in it. Depending on the severity it can be anything from what you have now to excessive injector duty at low load due to the crazy low fuel pressure.

You can either replace this oring or eliminate the hat entirely and use a peice of SUMBERSIBLE fuel hose with the proper NON PREFORATRED clamps. Once you pull the hanger back out, you'll see what I'm talking about

 

So I removed the pump, cr-rex is this the o-ring you mean? I clean it and oil it as it didn't look that bad. I put everything back together and now before crank looks like 46psi stable.

I'm looking for a fuel preassure sensor sender so I can read the pressure all the time it with the data logger, any recommedations?

 

That already has an aftermarket pump so won't have the o-ring he mentioned. Looks like non-fuel safe hose tho, all swelled up and soft with hose clamps digging in.

 

Correct. You don't have the factory oring set up. The one you have the arrows pointed to is basically a vapor/fume seal. It wouldn't hurt to replace it but if you never smell gas randomly then I wouldn't worry about it. The hose you have on there absolutely needs to be SUMBERSIBLE fuel hose. There is a very serious difference. A 3in section is 12-15$. It's a special hose that won't break down from being submerged in fuel like how yours is doing now.

If you checked your fuel pressure with the gauge and it holds 46psi with no problem then your fuel system is sealed correctly. Did you make the changes recommended to your tune?

You don't really need to log fuel pressure or watch it. A gauge will be more than sufficient. You really only need to monitor fuel pressure if you have some wild fuel set up where that information is actually relevant. For the sake of troubleshooting, any inline test gauge will be more than enough.

 

Thanks for the quality response guys, I will replace that hose for a sumergible one. I applied the recommended changes and for the moment I'm double checking the rest of the fuel system, frp, injectors, cabling, etc. Once I have that done I will try to start it again.

 

Hello guys, I finally started the car

What I did:

1. Did the 2kw starter conversion. As it was reading 140rpm during crank. Cranking speed went up to 210rpm Still the engine didn't started.
2. Replaced the battery from a PC680 to a PC950 (odyssey) as when cranking the powerfc was reading 8v.Cranking speed is steady on 250rpm and 10-11v. Still the engine didn't start.it looked like it was going to to.. but no..
3. Replaced all 4 spark plugs for new NGK BUR9EQP. and... STARTED right away!

Now.. I will try to do a safe tune....

I have several maps.. and the IGL and IGT values are very different to each other. What are the guidelines? I guess the best would be to test the best torque peak on dyno for several readings.

 

Sounds like you may have had fouled plugs, usually comes from flooding the engine. Glad you got it started!

There's a LOT out there on timing, that's a big topic. Basically you have your leading map and the split for trailing - trailing always fires a certain amount of degrees after leading. You can fire trailing before leading, that's called negative split and is generally a bad idea, especially under power.

Dale

 

2 months late, most aftermarket FPRs will bleed off pressure after initial prime.

 

Can anyone confirm this?

 

Yup, my Aeromotive one does.

 

Mine does not. It holds pressure for a very long time. A few hours or so. Also an automotive. The big one with the 3 ports on it.

 

I'm going to chime in on the Aeromotive bleed down. The one I bought was brand new in box never installed - as soon as you trigger the fuel pump by key, diagnostic jumper or other means and then shut it off, it would bleed down about as quick as in the video, and down to zero in under 5 minutes. Triggering the fuel pump with the diag connector and slowly adjusting the diaphragm preload screw could bring the fuel pressure up to about 55psi and then the needle would begin to flutter, with no additional pressure gained with more preload added. This was all seen on a new pressure gauge fitted to the 1/8th npt port on the front. Checking the entire fuel system front to back showed no signs of leaks. I opened up the FPR and fairly poorly machined seat for the check valve, it seems Aeromotive does not finish the seat beyond what ever tool was chucked up in their CNC. Ideally, I'd like to see a replaceable seat made out of brass so it leaks do occur, it can be replaced if the hardened steel ball in the diaphragm is in good shape.

I ended up milling a new seat profile with a (IIRC) 60° countersink, going just barely passed the stock depth of the seat. Now after switching off the key it holds between 35 and 38PSI (set for 38 base) for over an hour. Testing it again with the preload screw will have it hold the needle dead steady over 65PSI. The timer I setup to plot bleed down every 5 minutes got shut off by the time I went inside and was still holding around 10 psi the next morning.

 

So I got lucky with mine then. What you're describing that yours does after you fixed it, is what mine does now. It just holds the pressure. It doesn't bleed off like in that video. I was unaware that there is a flaw in the design causing that to happen. I will keep this is mind next time I see it.