OK, so I have made 2 attempts to get my car tuned and both times run into the same issue of breaking up. What happens is when revving it is fine but underload it runs lean on my LC-1. Runs up to 15ish-1 . We have replaced everything on the ignition side,added grounds, replaced plugs and gaps, switched from p72 Neptune to a P28 on S300, OE distributor that was used later to tune another setup perfectly, the car is on ID1000s. We pulled the injectors and physically look fine. We have attempted to add and pull fuel when on dyno and it breaks up but that had 0 effect to the issue. Ideas?

 

You need to monitor your fuel pressure during a pass on the dyno to determine if you have a fuel supply issue.

 

^ we were actually supposed to do that. My tuner stated that as a whole we were getting sufficient fuel. We pulled the Walbro 400 and checked all connections. I run a -6 from the tank to the Fuel Labs regulator and to the Golden Eagle rail and filter.

 

The first attempt at tuning a few weeks back we were able to get a good dyno pass and pull numbers but it would mainly start breaking up from 8-9k rpms.

 

The fuel pressure is steady at 45 psi with a increase at WOT

 

Did you try using another wideband controller & sensor to make sure your wideband is properly functioning?

I have seen people have similar issues and it ended up being the wideband.

 

We did try using both the dyno wideband and my LC-1 and on 2 different dyno Jet Dynos. This was second attempt to tune, and on a different dyno. First time tuner was convinced it was a bad distributor/ignition issue. So we removed the MSD setup and went with different Distributors and same outcome as original.

 

Also he did try adjusting fuel up and down while on dyno when issue was occurring. Is it possible that a clogged intercooler could cause such a symptom?

 

You need to focus on the fact that the air fuel ratios are lean before you do anything else.

You don't happen to have a resistor box or injector resistors installed do you?
ID1000cc injectors are high impedance and cannot properly function with a resistor box.

 

I figured. Thought I'd throw it out there. So fuel is my issue, I will trace back from injectors to tank and see if there is a restriction. Maybe send the injectors to be flowed and cleaned. What are possibility of it being wiring related?

 

If you are seeing steady fuel pressure at the fuel rail which is rising with boost during a dyno pull then the fuel system maybe working the way it is supposed to.

Check your wiring harness to make sure no one has added resistors for low impedance injectors in the past etc.

 

^ John , there were resistors on the car prior to the turbo setup, but they were removed and all wires routed to one single power wire. The issue seems to be getting progressively worse as I just went into the garage and revved it while watching the pressure gauge. Seems now it is dropping fuel pressure when revving but only by about 5 lbs. but it does break up. I have no way of actually putting a load on it and checking at the same time.

 

you can get a braided line for fuel and put the mechanical fuel pressure gauge inside the car, you can also get an electronic fuel pressure gauge and wire it up inside the car...

i recently tuned a b16 turbo it was stock sleeve but everything else built, bottom end, head had springs cams ported, it held power to 9400 rpms and had no problems of braking up

actually only problem i was having was heat soak doing a dyno pull within a few minutes of the last to verify power i noticed it got richer and lost power (of course with the map i have it set to get richer as iat temps go up so that explained that)

but i didnt have any lean problems car has 660cc and 255lph

i would definitely check your fuel line... do you have a fuel filter anywhere in that line? you could have gotten debris in the injectors could have gotten debris in the fuel line itself and holding up fuel pressure as rpms increase, maybe your line is messed up and can only flow up to a certain cfm for fuel pressure...

i would definitely check out fuel pressure another thing as the tuner is tuning the car, you can watch fuel pressure your regulator could be bad as well, ive seen that happen

good luck post up if you figure out what the problem was

oh yea another thing, if your running a big fuel pump, you might want to use a relay and use 8 gauge wire from the battery to the relay and from the relay to the pump and 8 gauge wire as well for the fuel pump ground, you could be having a voltage issue as rpms increase and load increases on the fuel pump

 

^ I did hear about the relay to the fuel pump and I am looking into it right now. It is a Walbro 400 and I've heard this issue occur before. Also I have new -6 Braided line. From the tank to a inline filter then -6 to the rail. Also the FPR is a new Fuel Labs regulator. I plan on adding that relay and then sending out my injectors to Boost Lab for flow test and service .

 

Besides fuel pressure/pump for your leaning issues you may want to make sure that if the tuner disabled ignition adjustments in parameters the rpm based dwell timing was added back into the ignition map appropriately. This will make the output at the distributor significantly retarded if not done properly.

 

Well, I wired in the relay for the pump, to get a constant voltage. Also bought a new battery with no result. Tomorrow I will bypass the fuel filter to see if that helps. If not that I will perform a smoke test and check for vaccum leaks.

 

Misfires from ignition breakup will cause a wideband to also read lean since the oxygen isnt being burned during the combustion event.

just something to think about.

 

^ how so if all parts of the ignition were replaced to no results? All parts tried went back on the original car then tuned to 400whp.

 

Well, tonight I replaced the harness with no result to my issue. Monday I will send the injectors out for service. Also the fuel pressure does not drop when power breaking it to the misfire.

 

What are your plugs gapped at? They may simply be too wide, which is something you should have already tried.

 

Plug gap was played with from 26-18 to no change. Also fuel pressure does not drop when power braking to the miss. Only thing I can think of is Clogged Injectors, they will be shipped to Boost Labs Monday.

 

^Btw I'm moving back to AZ in January from Florida and you will be my new tuning solution. Kenny Samson is my tuner now.

 

I don't know if you can Log Battery Voltage with Smanager, as I've never played with that system. But, I know if your Voltage Dips it can affect the Fuel System more so the Injectors.
I know in AEMPro there is actually a Battery Offset Wizard and Table that needs to be adjusted to tell the Injectors how to work at differant Voltages?
Again I don't know if you have this feature with Hondata. Another thing to think about. GL

 

Just got the injectors back and the pulse on 2/4 were 124 & 176 the other two were 218/226. After service all 4 were at 240. Sounds like my issue MAY be resolved. I will test tonight and post results.

 

Well.....Injectors were clogged! My issue is fixed. Now to get back on The Dyno. Kenny was right!