Fitech EFI

[Knebel]

After a little while now, i gotta say it appears to be some "finnicky contraption". I am constantly getting a rpm noise code. I have already split the harness and shielded the tach wire and its nowhere near any ignition wires. I also seem to have an issue tuning out a lean tip in situation, that causes the fuel trim to jump in and make it super rich after the initial lean spike. I have my accel and fast accel at 50 and the accel gain at 200. I dont know... Honestly i feel like i should have invested in a better carb.

 

[65sporty]

Does Fitech have tech support to help with your tuning issues?

 

[Jimmyse23]

What are you using for an RPM input again? I was super worried about noise after messing with a Mega Squirt setup on a water cooled VW. I went with a Street Fire ignition so I could have a clean square wave rpm signal. Just a thought.

 

[twostick]

After a little while now, i gotta say it appears to be some "finnicky contraption". I am constantly getting a rpm noise code. I have already split the harness and shielded the tach wire and its nowhere near any ignition wires. I also seem to have an issue tuning out a lean tip in situation, that causes the fuel trim to jump in and make it super rich after the initial lean spike. I have my accel and fast accel at 50 and the accel gain at 200. I dont know... Honestly i feel like i should have invested in a better carb.

If you are using the distributor pick up, you need to shield right from the pick up. The RFI noisiest place on the planet is inside a distributor cap. I had the same problem with my old Holley Commander 950. Shielding the pick up cable cleaned up the signal.

Kevin

 

[Knebel]

If you are using the distributor pick up, you need to shield right from the pick up. The RFI noisiest place on the planet is inside a distributor cap. I had the same problem with my old Holley Commander 950. Shielding the pick up cable cleaned up the signal.

Kevin

Using a small cap hei with external coil. Picking up the tach signal from coil (negative?). Fitech tech support...ha ha ha. They dont say much more than what is already written everywhere. If there is such a sensitivity issue with the noise, why did they not create a better wiring harness?

 

[Jimmyse23]

Yea it would make total sense to run a better harness and provide a shielded cable to use. I don’t know what the fitech cables look like, but the sniper cables worried me a little.

 

[twostick]

Using a small cap hei with external coil. Picking up the tach signal from coil (negative?). Fitech tech support...ha ha ha. They dont say much more than what is already written everywhere. If there is such a sensitivity issue with the noise, why did they not create a better wiring harness?

I'm a little confused. Are you having the Fitech unit control the ignition or just the fuel? A tach signal when talking EFI usually refers to the signal the ECM needs to tell that the engine is turning and how fast. That needs to come directly from the ignition pick up or a crank trigger.

Kevin

 

[Knebel]

No timing control, just fuel. Okay, isn't the negative wire from the 2 wire distributor the pickup? Its connected to coil negative, and there the tach signal comes from!? Did i wire that up wrong????

 

[twostick]

No timing control, just fuel. Okay, isn't the negative wire from the 2 wire distributor the pickup? Its connected to coil negative, and there the tach signal comes from!? Did i wire that up wrong????

Depends. Did the instructions tell you to wire it to the coil or the pickup? If it said the pickup then you did it wrong.

Any of this high tech stuff needs to be configured EXACTLY as instructed. As an example, MSD 6AL instructions tell you to wire it DIRECTLY to the battery. I know someone that just wired it to a convenient 12v source because the battery was too far away. It didn't run so they blamed the box and got another one. Same result. When I told him to follow the instructions his response was 12v is 12v. I said then hook it to the battery and prove me wrong. Hooked it up and vroooom.

Kevin

 

[Knebel]

Instructions said to coil. However, I am going one problem at a time now. Changed my vacuum advance to ported and thats already made a difference.

 

[Jimmyse23]

Using the coil neg is a method to pull the tach signal for both of our setups. The problem is that it’s a very dirty signal and I wouldn’t doubt that your having issues with that. Can you pull a data log with fitech? I assume you can. Pull a log and then zoom in on a portion of it when you get the noise code. I bet you’ll see the tach signal all over the place.

 

[Knebel]

Using the coil neg is a method to pull the tach signal for both of our setups. The problem is that it’s a very dirty signal and I wouldn’t doubt that your having issues with that. Can you pull a data log with fitech? I assume you can. Pull a log and then zoom in on a portion of it when you get the noise code. I bet you’ll see the tach signal all over the place.

Ok i dont seem to understand this then. Isnt the two wire distributor pickup going to coil positive and negative? Where else would i get the tach signal from then???

 

[Jimmyse23]

Breezing through the fitech install diagrams and without one for an HEI setup with an external coil, I would assume it acts as a 2 wire ready to run distributor. I’m not at all smart on HEI ignition, but does the external coil have a tach out terminal?

How do you have the tach signal shielded if at all? When i ran MS, i used the shielded wire and then i added my own shielding around that. JThere really are no other options for a tach input out there unless you pick up a cdi box or possibly run a crank sensor wheel on the front of the motor.

 

[Knebel]

Breezing through the fitech install diagrams and without one for an HEI setup with an external coil, I would assume it acts as a 2 wire ready to run distributor. I’m not at all smart on HEI ignition, but does the external coil have a tach out terminal?

View attachment 178012

How do you have the tach signal shielded if at all? When i ran MS, i used the shielded wire and then i added my own shielding around that. JThere really are no other options for a tach input out there unless you pick up a cdi box or possibly run a crank sensor wheel on the front of the motor.

Thats how mine is connected. I took my blue tach wire out of the harness, put a braided shielding over it which is then also connected to a ground. I dont run the blue wire through the connector anymore and kept it as short as possible and away from ignition wires.

 

[Jimmyse23]

Can you data log and see how noisy the tach signal is?

 

[Knebel]

Can you data log and see how noisy the tach signal is?

Oh I am trying to get rid of the Noise. I am constantly havin the RPM noise code. I see in my logs that RPMs are not clean, as in have a 50 - 70rpm varicance always. And of course it throws the code. I dont know what else to do about that!?

 

[Deleted member 220]

My holley terminator set was easy plug and play

 

[Knebel]

i am finally fault code free. had to move the coil and plugwires further from the ecu. now I am finally able to start tuning this thing right. however,i would still not buy it again.

 

[commando1]

however,i would still not buy it again.

What I've been sayin....

 

[Knebel]

What I've been sayin....

its running great and all but there are some things which are not plug and play. Some tuning issues would definately be easier tuned out with a carb. for example, i am fighting a lean tip in which wont change with any kind of accelerator pump change. My idle wont go to my commanded rpm and stays lower than that, which seemed to have happened after a software update.