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[GMCnet] FiTech EFI looks like the real deal [message #291738]

Wed, 09 December 2015 10:04

glwgmc

Messages: 1014
Registered: June 2004

Karma: 10

Senior Member

The FiTech EFI system I ordered for the Clasco came yesterday. It is beautifully machined and comes with what appear to be high quality fittings, hoses and sensors. Everything is integrated into the throttle body - the mass air sensor, throttle position sensor, vacuum sensor stock off the shelf GM injectors and the electronic control unit so the only external sensors are the temp sending unit and the off the shelf Bosch two wire O2 sensor. They even include a band-in-place bung so you can use a simple step drill to position the O2 sensor bung and band it in place. Later you can drive to a muffler shop and have it welded if you wish. The four even sized throttle plates all open at the same time and the fuel is injected through very small holes that ring the top of each throttle plate. They claim this provides better and more even fuel atomization. They say they have now modified the base so it fits properly on our stock manifold without an adapter plate, also. The linkage looks to be the same as our stock Qjet set up without the need for external return springs. All the wiring is included with what appear to be OEM quality connectors. I will report more later but it looks like a really simple and fast install.

The surge tank (they call it “Command Center”) is especially nice looking. It is a single round module (with two different diameters, larger at the top and smaller at the bottom) which houses a high pressure, fully submerged fuel pump to supply the EFI fuel rail, a low pressure input with a float valve that mimics the Qjet float float and valve so you can fill it from your existing mechanical or electric fuel pump, high and low pressure gauges and a vent fitting. There is no return line to the fuel tanks required or suggested, just a vent line that I will T into the fill vent along side the fill tube. The whole thing is small enough that it mounted easily on a stock passenger side radiator bracket on my 77 using a piece of UHMW sheet for noise and vibration dampening. Took about an hour to fabricate the bracket, drill the holes and mount the unit. It sits in the air stream ahead of the radiator but off to the outlet side where it will do little to impede the air flow to either the radiator or to the external, fan assisted transmission oil cooler that I mounted on the outboard side of the radiator side air baffles. It is easy to confirm correct fuel pressure on both the high pressure EFI supply side and the low pressure surge tank fill side just by opening the passenger side hood.

Dick Patterson is off to an industry trade show where hopefully FiTech will have a booth. If so, he will talk to them about any recommended changes to the stock HEI advance system for those who want to let the distributor take care of spark control. The FiTech unit also appears to have spark control functions built in if you want to lock out the mechanical advance and let that unit control spark. I will initially have the stock HEI control spark and then see about moving to the FiTech unit controlling spark once it gets the fuel/air ratio and spark advance maps all filled in from the elevation-load and rpm data gathered during the initial drive-in period.

Dick also suggested adding a push button to let you spin the motor to pull oil up to pressure without starting before using the key to engage the EFI and start the motor after it has been sitting for a long time. He is concerned about oil drain down and bearing wear from the EFI instant start putting full compression load on the main bearings before the oil pump has a chance to bring everything up to full pressure. He characterizes the hard starting of the stock system (to pump fuel into the empty Qjet fuel bowl) as a blessing in disguise. That is easy to do by simply running 12vdc to a push button switch and from there directly to the engage post on the starter solenoid. Pressing the button will spin the starter without powering the HEI or the EFI. Once oil pressure is established then turn the key normally for an instant start with oil already in the bearings. That only would need to be done if the coach has been sitting for a long period of time (weeks or months). For normal daily use just turn the key and go.

It is raining cats and dogs outside today so not sure how eager I am to get out to the RV garage to do the install and initial drive in but will report progress. One last comment is that the packaging is really professionally done. Die cut foam to house everything inside a heavy presentation box which ships inside a shipping box filled with foam peanuts. Full color instructions for both the EFI and the Command Center. Nicely done. If it works as well as it looks it might be a good alternative for us, especially at around half the retail price of the other add-on EFI units available for our coaches. The EFI unit is $995, the Command Center is $395 and shipping was $55.

Jerry
Jerry & Sharon Work
Kerby, OR
glwork@mac.com
http://jerrywork.com

78 Royale with most everything done to modernize a GMC mechanically
77/94 Clasco bone stock (soon to have EFI) and looks like it just left the Clasco facility

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Jerry & Sharon Work
78 Royale
Kerby, OR