mdrouillard1983

Hey everyone!

I'm new to the community but have been running into some issues with my turbo build. Some background, it's a '90 CRX Si, with a ZC SOHC swap, in the process of putting in a T3 turbo.

Over the winter did a bunch of upgrades including a SKUNK 2 intake manifold, ALPHA throttle body, BoSCH 320CC injectors, high flow fuel rail, etc to support the turbo along with a fuel pressure regulator with guage.

Running at 43PSI fuel pressure, I have an MSD Blaster Coil External Coil ignition setup as well. Car fired up fine prior to the following changes:

1) Skunk 2 Intake Manifold & Throttle Body (FITV DELETE **)
2) Bosch 320CC Injectors with new Fuel Rail and FPR
3) Turbo w/Intercooler Piping, etc. (But turbo doesn't spool just in the starting stages haven't tested with boost)
4) Basemapped OBD0 ZIF Chipped ECU (I want to remain OBD0 for simplicity) (Will tune once I get the idling/starting under control)


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Problem:
Car fires up, but sometimes takes a bit more cranking - starter is fine, battery is fine, it will almost sporadically idle up and down and die. I have to repeat 2-3 times and give it gas up and down in order for it to jut stay on, it's rough but eventually it seems to even out and idle around 700-1000rpm.

I am noticing my air fuel ratio gauge (with a brand new O2 sensor, down pipe mounted on turbo DP now) is registering a very lean condition, checked for all vacuum leaks and cannot find any by ear (haven't tried the carb cleaner trick yet).

What could be causing this lean AF ratio and or the sputtering starts? It sounds like its about to die until it warms up dropping sometimes to like 500rpm or lower and recovering slowly (bouncing idle). Sound's like my car's going to explode. BTW, I replaced radiator and coolant and also burped the system.

I KNOW this could be related to the FITV I removed, but I had no where to put it on the Skunk2 manifold, could it be related to the larger injectors causing it to run lean? Fuel pressure not high enough? Or ECU?

I've also entertained the idea of it being the main fuel pump relay, tonight I think as an insurance policy I'm going to pull it and re-solder the joints just to cover my bases..

Anyway, being my first post hope someone can chime in; I've been searching all day long with this and have found bits and pieces but not an actual solution.

--Matt

Freemananana

iTrader: (3)

Stock fuel pressure is lower than what you are running iirc, so that isn't the lean issue. Larger injectors will not run lean, so that's not an issue. FITV will only increase your idle at cold start. Does this go away when it is warmed up? I haven't really heard of a lot of people having an issue with aftermarket/deleted FITVs before. Newer, 92+, civics don't even have FITV so I don't think that is your issue.

What does stick out to me is the MSD ignition system. Judging by your other mods, that is entirely overkill. Try the old distributor and plugs out again. I bet that is were your issue is stemming from. Distributors have dealt fine making much more power and at higher RPMs than you will probably run at.

mdrouillard1983

Thanks for the quick reply The car was running without these issues even with the MSD ignition installed last fall. So I'm not sure it is the ignition, brand new NGK blues wires and Bosche platinum plugs as well have been installed.

So this leads me to believe it has to be something after the MSD was installed, it is about -2 degree celcius here today; will that affect the startup without the FITV? (I know I keep going back to this - what test would confirm - leaving a vacuum line open while starting it to simulate the FITV?)

Thanks guys!

mdrouillard1983

Okay found the problem with the starting/sputtering. I made a few adjustments:

1) There was a small leak in the gas feed line to my adjustable fuel pressure regulator, I tightened it up and replaced the line with a new one, re-clamped on fuel rail and regulator.

2) The valve cover vent port wasn't connected, so I re-connected it to my oil catch can (possible vacuum leak?)

3) Adjusted throttle body

4) Removed main relay, soldered all the joints. THIS IS what I think was the real culprit because it starts up and idles like a dream now, fuel pressure is slightly higher running at 45 PSI up from around 42-43 before, but this could be somewhat related to the small fuel leak.

So in summary, I think main fuel pump relay was the main issue, I recommend everyone does this simple fix and/or replace the relay if they have the cash - Parts Source wanted $75 bucks for one but I was able to fix mine easily enough.

Thanks
Matt