ccarlisi

Ted, can we narrow down this list by taking into conisderation the fact that mike only has this problem at 13.5psi+ We did a bunch of pulls at less than 13.5 without incident, but as soon as we hit 13.5 it starting losing vac with each pull.







I think it's important to note that Steve said the variance between the front and rear rotor would normally be considered insignificant, but he decided to correct for it only because we asked him to be extremely careful with every aspect of the car's tuning since mike had already gone through a couple motors. I was the one pulling the burning hot plugs after every run :-p. The front plugs were less damp than the rears, but the variance was minor.



Also, Steve's fuel comment is slightly misleading. His point was that the car ran ok with an extremely rich AFR on the wideband, not that it ran ok with extremely high duty cycle settings. Just to clarify, high duty cycle settings were not needed to get normal/conservative afrs.

Badog

The variable list to date in no particular order (culled from the messages):



1-secondary injectors

2-primary injectors

3-front to rear rotor lean condition and being corrected in PFC (usually the REAR needs the extra fuel!)

4-crank wire trigger wires being reversed

5-caca map (at one point in time too much timing)

6-secondary injector harness

7-OMP / pre-mix issue





Could somebody add what I missed? Just trying to get a clear picture.



Questions:

Oil pressure behavior at 13.5psi versus other times? What is it reading?

Oil temperature behavior, too?

Judge Ito

The apex seal to rotor groove clearance is .002 of an inch. .002 is ideal for rotor tip to apex seal clearance. 002 is nice and tight in the groove for good sealing compression but enough room incase the metal on the rotor tips tries to expand(grow from heat) and not jam the apex seal in the rotor groove.

j9fd3s

cas wires and sensors? is this the original engine harness?



has anyone verified tdc on the engine vs the crank pulley?



send the injectors to be flow tested?

ccarlisi

We put a brand new factory main wiring harness in the car before the last motor got tuned. As I believe Mike said before the timing is accurate (or at least consistent) from idle to redline. Not sure about the TDC thing, maybe Ito can confirm that.

93FDGT3540

1-secondary injectors



Secondary injectors as well as primary inj were sent to RC engineering to be flow tested. The pri were dirty and were cleaned. The sec inj were odd ***** and suggested we replace them with equal units.

I in fact bought 2 new 1680cc inj and ITO installed them.



3-front to rear rotor lean condition and being corrected in PFC (usually the REAR needs the extra fuel!)



Well this was a marginal change in fuel but was noted as there is no aspect of this tuning i want to omit. The Break -in plugs were white but the car was carefully broken in with only vac driving and the car rolled up onto the dyno with great idle VAC. As soon as Steve adjusted the map the idle vac went to -15 inches. Best i've seen on this motor. It also sounded fabulous. Pulls were made on the wastegate spring at 10 psi and the map was set up for very rich air fuels. There wasn't a dry eye in the house. It def wasnt burning it all. Everyones skin and eyes were covered with Fuel. Very nasty. Oh the burn and tears. It was so rich it was spitting out fuel and flames were showing out the pipe. Fuel pressure was steady and Air fuels held on wide band in the 10's and Duty cycle on the inj low to mid 80% max.

Im skeptical the car needs more fuel but i am willing to entertain any ideas toward progress. The fact the car is running lean with this fuel set-up doesn't make alot of sense to me. The car could run on stock fuel sys at 13 psi yet I have alot of upgrades that all my friends use with even up to 500 RWHP with no issues. I put down 350rwhp 13.5 psi and the motor was failing. Fuel issues usually show up on pressure gauges, if not pressure then elevated duty cycle on Inj due to volume loss. The one issue is the resistors and im temped to yank them just to eliminate the possible problem. Just want to make sure it wont fry the PFC.



4-crank wire trigger wires being reversed



This happened on the very first motor. the car had very high coolant temps 106degrees on the PFC. I got to ITO's and he found the problem and fixed it. He could hear the car running rough and put a light on the crank and sure enough the wired had been crossed. he fixed the issue. The motor had about 50 miles driven on it with the crank angle sensor wires reversed. The harness was replaced before the 3rd motor was tuned and the timing verified at idle on the dyno before tuning.



5-caca map (at one point in time too much timing)



This was also something ITO fixed when he fixed the Crank angle sensor. John Dewer (sp?) fixed the negative split and made sure the map was safe to drive till tuned. Ito was there supervising.



6-secondary injector harness



This had seemed to be a problem with motor # 1 but with # 2 Ito had fixed it # 3 Chris and I replaced the entire engine harness with a Brand new OEM harness and I soldered the Resistors myself. I have done soldering before and i did these fine. I took extra care.





7-OMP / pre-mix issue



Well The OMP seems to be working ok, i have also added premix and the car is stumbling all over itself at idle. Smokes alot due to premix and OMP combined. Also so far this issue isnt consistent with OMP failure. Also the Oil temps don't seem like a problem because there is no Apex seal spring flattening, no bearing wear. No elevated coolant temps to indicated higher oil temps. No chatter marks on the housings from Apex seal springs loosing tension.



Oil pressure is very high. I see higher pressure due to ITO installing Racing beat Plug. doesn't seem out of the ordinary except for crankcase being pressurized by Combustion

j9fd3s

it might do that. i know of one pfc that popped due to no resistors.

83turbo

So has anyone actually measured the resistance of the injectors?



Some injectors are sort of "medium impedance" - I've measured ~5.2 ohms for some large injectors. Adding a resistor to those might be a problem.



If the PFC has requirements for injector impedance, be sure to heed them. Don't put low impedance (~2 ohm) injectors on a saturated driver - either the driver or the injectors will die quickly.

j9fd3s

thats right the 1600's are like 5ohms. i think its right on the edge as far as keeping the pfc alive. i believe the pfc has a 1 watt chip



ah its 3w https://www.nopistons.com/forums/index.php?...&hl=6+injectors

83turbo

Okay so that's 3 watts total rating for all 4 drivers. I wonder if Apexi has ever heard of a "heat sink". sheesh. So if your 1680 cc injectors are 5 ohms (measure this!), this would be ~3 amps, with 0.25 ohm FET "on" resistance is 1.25 watts per secondary injector. You sort of have to work the duty cycle in there, but this is the

upper bound. Primaries (high impedance) would come to about 0.25 watts each.



Total is then 3 watts @ 100% duty cycle for 2 "medium impedance) 5 ohm secondaries (no resistors) and 2 high impedance primaries. This looks to be within spec, but remember to check the resistance of your injectors to verify.



Also it's a good idea to make sure your fuel pump is getting enough voltage.

You need to check the voltage between pump+ and pump- as close to the pump

as possible. Checking pump+ to chassis ground is not valid as it does not

consider voltage drop across the ground wire.



Finally, I know this is silly, but check the fuel filter.