PRS Stand Alone Fuel Injection systems INSTALLATION TIPS
Sometimes the best time to install a Stand Alone system is before you do all those heavy modifications. Most people wait until last to do it. If you do it first you can save your self a lot of time. In this case we are looking to raise the RPM limit and replace the digital MAF meter with a 2.5 Bar MAP sensor. Here are a few tips.
Lets say we are doing a V6 engine like the one in this GMC 4.3 Jimmy. The trucks is running off the stock OEM ECM which is firing one coil and 6 injectors. We can use the PRS 2, 4, or 8 to run this truck. In this case we will show you how the PRS 2 ($642.00) will do the job. Our plan is to configure the PRS 2 to fire one coil. For fuel, we will pair two injectors, as per firing order, to 1 of 3 injector drivers. the first step is to take the fling leads from the PRS 2 and just tee them to the stock harness. We used www.Alldata.com to get the trucks OEM ECM pin out. We looked at the PRS wire diagram and marked the wires we will need to tee into on the GMC wire harness. We then teed in all the input wires we can, but did not cut any. Now we can start and run the truck, still running on the stock ECM, and monitor the PRS on our PC or lap top. We now set up the global setting as per the manual instructions. A good study of the manual before hand is recommended. Now that the RPM reading is accurate and the live data is being displayed we can now go on to wiring the coil. What I like to do is wire in a 2nd coil with a wire and spark plug hanging out of it, temporarily. Now I can still run the truck, which is still running on the OEM ECM, and compare the timing from #1 plug to the signal I am getting from the PRS coil. If all looks good just swap over the coil wire and we are now running on the PRS for timing. If your signals are not adding up you may have not configured the PRS correctly, so you will have to go back and see what you may have missed.
Ok, now we have control of the timing, now we will do the fuel next. We refer to the Alldata print again. We find, in this case, 6 injectors wires. Because the PRS2 has 3 injector drivers, we pair them up according to firing order. (If we use the PRS4 we could have one driver for each injector.) The first pair we cut and wire to our first injector driver. We start the engine, 2 injectors are being controlled by the PRS and the other 4 are being controlled by the OEM ECM. Tune the 2 injectors with the PRS analog map until the engine sounds normal again. This is going to give you a good idea what the fuel #'s need to look like. Now swap 2 more injectors over, 2 at a time. Now your car is running on the PRS, and you can take it from there. We will not be removing the OEM ECM on this vehicle because we need it to control the transmission, but if it were not, then it could be removed. As long as we are leaving it, we let it to continue running the Idle air motor.
global settings
function assignments modes
ignition
map
fuel map
This had excellent data logging playback that can easily me e-mailed for tuning or diagnoses.
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Just some of the vehicles running Perfect Power products!
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| BMW | Mitsubishi 3000GT Turbo |
Porsche Twin Turbo |
New Ford Products......Even with sealed ECM |
GM and Ford Truck |
Honda |
Viper
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Prowler |
| Customer Input
Bob, I spent a couple of hours this afternoon working with this Durango out on the road. We used an accelerometer to tell what kind of gains or losses we were making. We backed each run up with 2 more runs to be sure we were fairly consistent. By playing with the settings on my laptop I was able to make quarter mile gains of 10 mph and 1.3 seconds. We were thrilled. I'm sure the settings are not all perfect or maybe not where we can leave them, but it was neat to be able to see results. I'm having trouble with engine temp sensor. The screen says it is jumping all over. I haven't had time to recheck all of my wiring yet. Thanks again for your help. Kevin --------------------- Hughes Engines inc. 23334 Wiegand Lane Washington, IL 61571 Voice: (309) 745-9558 Fax: (309) 296-9990 www.hughesengines.com --------------------- |
Hi Bob & Silvia, I have a few pictures for you regarding my recently refurbished (inside and out) 1976 Triumph TR7 coupe. The 2.0L slant four with 4-speed was discarded and replaced with a stock 2000 Ford 3.8L V6 with 5-speed from a wrecked Mustang. The only mods I have done to the engine are a big dual exhaust, big intake, higher fuel pressure and a larger radiator. This car now weighs about 2500#. I have added up-rated front and rear sway bars, Koni shocks, lower stiffer springs, bigger rotors and calipers on the front and an up-rated 1980 TR7 3.45 rear tube axle with bigger drum brakes, and larger wheels and tires, plus many other little things. The PRS8 was wired into the existing Ford harness for wasted spark ignition (three outputs), injectors (three outputs), and crank sensor. I then wired the MAP sensor, GM water temp sensor, GM air temp sensor, O2 sensor, fan and pump relays, rev counter for digital tach, rev light for shift, and the ignition on light. Initially setting up the PRS8 was a little tricky in trying to get the outputs assigned to the correct ignition leads. Bob Ida (thanks Bob!) was a tremendous help. Initial fuel and ignition mapping was fairly easy from the many examples. I have since gone through one trial of street tuning with good results. The car starts as easy as any new car and idles at 800 rpm. I have not been using the IAC since I never could get it calibrated correctly, that’s on my to-do list. The tach output jumps around slightly above 3000 rpm. I need to change the dwell to see if the output signal will stabilize. Slow acceleration at low speeds with rpms below 2000 needs more tuning as it is slightly off. However, with more throttle there is no problem, and full throttle is impressive, now I’m looking for more traction. From 2500rpm in 3rd gear the acceleration is just awesome, seeing the front end lift and feeling the seat pressing harder for the first time was great, and still is, way faster than my SC400. Cruising at 40mph and beyond is smooth and enjoyable. I have not dyno’d it yet so the HP is not known. I will buy a G-tech sometime to see what the RWHP might be and to help with tuning. The car is totally fun to drive and could not have been done without the PRS8, which is a good and affordable engine management system, even for an amateur. Please feel free to share my comments and photos as you like. Sincerely, Mike Layman Corpus Christi, Texas
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