Whenever you venture into the world of custom components, you have to anticipate there will be issues. This is very familiar to me, as my old race car was a Saturn station wagon. Not very many racing parts are available for that platform. For me, it isn’t as exciting or satisfying to buy parts off a shelf and bolt them on. Before you get to the satisfaction, you most often have to go through some frustration. But, overall, it’s still fun.
After the trials and tribulations of installing the big turbo, I had the misfire issue arise, putting a damper on tuning the new turbo. The misfires were on cylinders 3 & 4, and since I hadn’t changed anything with the injectors or coils, I suspected it had something to do with the wiring.
When I suspected the wiring was the issue, I went back through all my data logs, specifically looking at the misfire count. I made a chart so I could easily compare the logs, and I found that the misfires were all over the place, jumping from cylinder to cylinder. That pretty much confirmed my suspicion.
Digging through a wiring harness is time-consuming, so the first thing I did was swap a couple of the coils and then plug wires to rule out that possibility. The next thing I looked at was the injector connectors. When I purchased the flex-fuel upgrade, it came with new injectors. The new injectors required a different connector but came with the adapters.
As with most connectors, even OEM connectors, they have a life expectancy. They can only be connected and disconnected so many times before they start to loosen, and the connection begins to deteriorate. I had disconnected those adapters quite a lot when performing various upgrades and the engine rebuild, so I decided to order a new set and see if that might be the issue since it would be easy to do.
Once I got the new adapters, I switched them out and logged a couple of runs. The car ran nice and smooth, and after checking the log, it confirmed the adapters were the issue. No more misfires! Now we could start tuning.
The tuning process is remote and slow. It requires data logging full throttle runs with a handheld logger, then downloading and emailing the logs to the tuner. He looks over the logs, makes adjustments, and then sends me an update. I upload the update to the handheld, flash the ECM with the update, and then start the process all over again until the engine is optimally tuned.
After quite a few rounds of the tuning process, we came to our next set of issues. The first was the mass airflow sensor. I was hitting the limit of the sensor, which meant the intake tube was too small. I had the K&N intake adapted to the new turbo, which was 2.75″ in diameter, which was too small. I needed to have a new intake fabricated that was all 3″ tubing.
Piper Motorsport undertook the project and fabricated a new intake tube for me. Once they completed the intake, the tuner updated the sensor’s calibrations, and another issue was resolved.
The second issue was the fuel injectors were going static, which means they were going to 100% duty cycle, and I believe they are supposed to be no more than 80 – 85%. That indicated the fuel pump was too small for the fuel I was using.
I use straight E85, and it apparently demands a lot from the fuel system. If I ran a mix of 60% E85 and 40% regular 93 octane, it would reduce the demand on the fuel system and the fuel pump might be sufficient, but I really would like to run straight E85.
I’m going to have to give this one some thought and see what upgrading the fuel pump would entail. If it isn’t too difficult, I’ll probably go ahead and do it. We’ll see.
DS
