Hello everyone,

So some quick notes.
I just got my car back from the shop for some upgrades. After said upgrades, I noticed the car is having some problems. Also I am not the most experienced mechanic, so try and bear with me.

What was upgraded:

Fuel Injectors: 2x 1000cc and 2x 850cc
Fuel Rail
Fuel Pump
Fuel Lines
Spark Plugs and wires
Exhaust - catless, downpipe and midpipe
Fuel Cut Defender

Engine was rebuilt before upgrades, no porting done.

Now around the 6k rpm area, the engine just gives up, like there's a rev limiter. It happens every gear under load, neutral it's fine.

Any clues as to where I should start looking for problems? Coils perhaps?

I can provide pictures and additional info if needed as well.

 

have u checked fuel pressure?

 

Should probably give details about your ecu/tune. Saying you’re using a fuel cut defender leads to the conclusion you’re on a stock ecu….? With 1000 primaries and 850 secondaries compared to stock 550’s all around.

should verify leading coil and leading plugs are firing correctly… I’ve sadly made the mistake of not plugging in leading coil and had a similar situation of falling on its face at a certain rpm.

 

Stock ECU, no tune.

From what I can see, the coils are all plugged in. I don't really have a way of testing the resistance on them at the moment.

​​​​​​​Fuel pressure is at 35 psi at idle.

 

Do you have a wideband sensor and are monitoring air fuel ratios?

Not trying to be rude, but I think you’re not grasping the concept of how fuel stoichiometry and engine managements work.

if you’re running 1000cc primaries, that’s dumping 81% more fuel in. Add the multiple from the secondaries.

Unless we’re both missing something but I’m working with the information you provided: fuel injector sizes and stock ecu, no tune…

I understand you may be building for more power down the road, but certain items are necessary for parts to work together.

might want to get a stand-alone ecu in there or at least a programmable rtek.

good luck.

 

There is no wideband sensor installed.


No, you're right. Which is why I took it to a shop to get the fuel system done. I was under the impression that with what they did the car should run and drive normally.


I'm working on getting a haltech at the moment.

Also, from what I'm gathering I don't even really need the FCD once I have an ECU and a decent tune. Am I correct on that?

 

Ok cool then we’re on the same page. I was just hoping you weren’t going down the wrong path blindly.

yes you are correct the haltech will remove the need for the fuel cut defender.

stock ecu is mapped to run 550cc primaries and 550cc secondaries so you’re running wayyyyyyyyyy too much fuel in that thing, I’m actually surprised it’ll start and run.

I would assume the engine falling flat on its face is due to the large amounts of fuel it’s throwing in, and not really worth diagnosing more if you’ve already covered the basics, besides ensuring all injectors are firing.

Probably should pull the plugs every once in a while to see if they’re flooded with fuel and maybe try a new set of plugs.

I highly recommend running a wideband just to see what’s going on inside the engine or the fuel system and it’s an inexpensive investment.

I’ve only ran older haltech models (e6x and e6x), but I follow up on some of the newer haltech elite specs. You’ll be able to set target air fuel ratios in the haltech, and use the voltage output from the wideband along with the wideband’s voltage vs air fuel ratio polynomial equation. Then you’ll be able to just drive the car and it will begin to tune itself, which will reduce time the tuner needs to take, also reducing money spent at the dyno.

I do recommend getting the haltech sooner than later as running that rich has its negative effects too (carbon lock, etc).

out of curiosity, what turbo are you going with?

for reference, I’m running a BNR hybrid stage 3 on s5 t2 block with 850 primaries and 720 secondaries with walbro 255lph at 15 psi on an apexi PFC. Need to check my injector duty cycle to check how much headroom but that can give you an idea of how much higher you’re set up would let you go.

 

Definitely doing that. Like you said, it's going to help a ton when I throw in an ecu.


I'm not too sure on what turbo I want to go with yet, but I was trying to get the car to around 500hp. A garrett 35r maybe? However I am going to wait on the turbo for a bit. Still need to get a better intercooler and do some porting and whatnot.


I don't plan on driving it around anymore until I know it's not going to get messed up, haha.


I plan on getting a 20b, but that's still pretty far in the future for now.