Installed new injectors, now it won't stay running

[speedjunkie]

Last week I put in Injector Dynamics 725cc primaries and 2000cc secondaries, replacing 1000cc and 1680cc injectors. I changed almost all the settings on the "settings 5" tab and I've tried with the injector map I had and I've tried tinkering with it, but no matter what else I do, the car will die if I don't keep revving the engine. I can't just hold it to a certain RPM because it will still putter out, so I have to keep blipping the throttle.

Not sure how many of these mods matter, but here they are:
-Power FC
-Large streetport 13B-REW
-A-Spec 500R
-725cc primary and 2000cc secondary Injector Dynamics fuel injectors
-CJ Motorsports fuel rails/kit
-MSD 8.5mm plug wires
-HKS Twin Power ignition
-Aeromotive fuel pressure regulator
-Supra fuel pump
-Kenne Bell BAP
-equal length lower intake manifold
-FJO water/methanol injection
-fast reacting air temp sensor

Can anyone see if there is something else wrong with my settings? Attached is a pic of my settings 5 tab.

[scotty305]

Blipping the throttle usually adds extra fuel for acceleration enrichment, if this is helping the engine stay running I would suspect the main fuel map is far too lean.


Assuming the old 1000cc/min injectors had resistors installed, did you remove the resistors when changing to the new injectors? Running high-impedance injectors with ballast resistors would screw with their opening times and could account for this sort of behavior.


Also, the fuel map should need about 30% fuel added, assuming the injector latency/deadtime/battery offset compensation was correct for the old injectors and has been adjusted correctly for the new injectors. Sorry I haven't used a PFC so I won't know the exact option names or values to use.


For what it's worth, my car (stock engine, stock ports) ends up at 2-3ms of fuel injector pulsewidth at idle using ID1000 primary injectors. If you're below that with your 725's, you should definitely add some fuel.

[speedjunkie]

I had an FJO injector driver installed and I did remove it. I've tried adding fuel and that didn't work either, but it was only in a small area around where I thought it was idling, not across the map as a whole.

What computer do you use?

Oh also, the AFRs looked to be around 12s but it's hard to say.

[scotty305]

If you had an FJO peak/hold injector driver, that means you will probably need to increase the injector offsets for the new injectors. It's my understanding that most peak/hold injectors will snap open more quickly (when using a peak/hold driver) than high-impedance injectors. If you haven't accounted for this, you'll probably need to increase the fuel map even more (although the correct thing IMHO would be to increase the injector offset values instead). Again, there may be some PFC-specific tricks or hoops you need to jump through here.

I have an AEM EMS. I've done quite a bit of tinkering with my car's fuel map, and found that the engine will still idle (albeit poorly) when the mixture is pretty rich (9's-11's AFRs) but does tend to stall pretty easily if too lean (14-15 AFR will stall more easily than 10-11 AFR). Something else that has worked for me is to flatten out the fuel map near idle (same exact pulsewidth from about 500-1500RPM, 0-50kPa), change all cells equally to get things roughed-in, then eventually make small adjustments to each cell to ensure the AFR doesn't go lean when turning on the fans / headlights or when slowly letting out the clutch to creep forward.

[speedjunkie]

I had a friend look at the map and he adjusted some things and now it's running at least. He changed a few of the things I had originally changed on settings 5. The only problem now is there is a chattering coming from the turbo side of the engine, it sounds kinda like when the water injection pump kicks on. There is also a squealing noise and I thought it was the compressor housing on the turbo since I had it off getting an elbow welded on, but when I spin the wheel I don't hear anything, so maybe it's just the pulleys or something. Got some work to do tomorrow. Gonna look at the map quite a bit more too and maybe take it for a drive to check out the rest of the map. He also told me to cut the secondary transition in half and see if that gets rid of the strange noise.

Thanks for your help Scotty! Here is the new settings my buddy gave me...

[cewrx7r1]

I could not read your very low resolution attachment even when magnified.
Thus I have to assume!
These injectors should come with their "lag vs voltage" tables.
If not they are on their site.
Did you set that up in Settings 5?

[speedjunkie]

Sorry. Yeah I set all that up according to the flow rates on their website. The things my friend changed were other settings. It's running and I fixed the noise problem...it was an air leak at the LIM gasket. I took it back off, put red RTV on both sides and tightened the bolts back down using a torque pattern starting from the middle and working out. No noise now. Now I just need to get it out on the road and see what my AFRs are, to see if they're safe enough to drive it to get tuned again.

Thanks Chuck!

[RICE RACING]

On my own car ....

I eliminated the POS FJO Injector driver, can give link to it if needed.

For the ID1000's I run they do need specific injector lag times to be tweaked in your ECU to enable good running at idle. Also for whatever reason *real AFR* as measured right out the back of the turbo you will find the engine is most stable at high 11 AFR to mid 12 AFR, much north of this leaves little margin and the engine can become unstable and want to stall.

Any revs higher than 1200rpm and with some load applies you can run stoich mixtures (14.5:1) no problem at all.

Most of its in the mapping and correct injector set up *lag times* in the ECU, these do vary with fuel pressure also which is listed on your ID injector sheet. I run 55psi static pressure @ 0 gauge pressure.

I'm sure you will sort it out