Brake Booster Vacuum from Intake Manifold.png;|||Closer Look at Injection Ports.png;|||High idle caused by open secondary butterfly valves.png;|||P4190014.JPG;|||P4190015.JPG;|||P4190016.JPG;This was a great purchase. I highly recommend this fuel sump to GMC'ers going to EFI|||P4190017.JPG;|||P4190019.JPG;|||P4190020.JPG;|||P4190021.JPG;|||P4190023.JPG;|||P4190024.JPG;|||P4190025.JPG;|||P4190026.JPG;|||P4190027.JPG;|||P4190028.JPG;|||P4190029.JPG;|||P4190030.JPG;|||P4190032.JPG;|||P4190033.JPG;|||P4190034.JPG;|||P4190039.JPG;|||P4190040.JPG;|||P4190041.JPG;|||P4190042.JPG;|||P4190043.JPG;|||P4190044.JPG;My daughter helped me with fabricating the fuel sump mounting bracket|||P4190048.JPG;|||P4190053.JPG;|||P4190054.JPG;|||P4190055.JPG;|||P4190056.JPG;|||P4190057.JPG;|||P4190058.JPG;|||P4190059.JPG;|||P4190060.JPG;|||P4190061.JPG;|||P4190062.JPG;|||P4190063.JPG;|||P4190064.JPG;|||P4190065.JPG;|||P4190066.JPG;|||P4190067.JPG;|||P4190068.JPG;|||P4190069.JPG;|||P4190070.JPG;|||P4190071.JPG;|||P4190073.JPG;|||P4190075.JPG;We won't need to use all the vacuum ports|||P4190076.JPG;|||P4190077.JPG;|||P4190078.JPG;|||P4190080.JPG;|||P4190081.JPG;|||P4190082.JPG;|||P4190083.JPG;|||P4190084.JPG;|||P4190085.JPG;|||P4190087.JPG;|||P4190088.JPG;|||P4190089.JPG;|||P4190090.JPG;|||P4190091.JPG;|||P4190092.JPG;|||P4190093.JPG;|||P4190094.JPG;|||P4190095.JPG;|||P4190096.JPG;|||P4190097.JPG;|||P4190099.JPG;|||P4190100.JPG;|||P4190102.JPG;Good spot for an engine battery fuse box|||P4190103.JPG;|||P4190105.JPG;|||P4190106.JPG;|||P4190108.JPG;|||P4190109.JPG;|||P4190110.JPG;My daughter suggested the blue powder coat and she was right, it looks great|||P4190112.JPG;|||P4190113.JPG;|||P4190114.JPG;|||P4260141.JPG;|||P4260142.JPG;|||P4260143.JPG;|||P4260144.JPG;That pink wire is IGN-1, the wire we need to switch on (through a relay) the EFI|||P4260145.JPG;I already added a house battery fuse box, just need to route a few new wires through the grommet|||P4260146.JPG;|||P4260147.JPG;IGN-1 is the pink wire on the back of the OEM fuse box|||P4260148.JPG;|||P4260150.JPG;Tapped into the pink IGN-1 wire|||P4260151.JPG;|||P4260152.JPG;|||P4260153.JPG;|||P4260154.JPG;|||P4260155.JPG;|||P4260156.JPG;|||P4260158.JPG;|||P4260159.JPG;|||P4260162.JPG;Low pressure fuel pump now has its own dedicated fuse and wiring|||P4260163.JPG;Used to run FP off the tank selector solenoid, but then the FP only worked when on AUX tank|||P4260164.JPG;|||P4260165.JPG;|||P4260167.JPG;|||P4260168.JPG;|||P4260169.JPG;|||P4260170.JPG;|||P4260171.JPG;|||P4260172.JPG;|||P4260173.JPG;|||P4260175.JPG;|||P4260177.JPG;|||P4260178.JPG;|||P4260179.JPG;Fuel sump overflow now goes into filler fuel vent line which drains into aux fuel tank|||P4260182.JPG;Fuel sump overflow is not a return, it really is just for emergencies where fuel is overflowing|||P4260186.JPG;|||P4260188.JPG;|||P4260190.JPG;|||P4260193.JPG;|||P4260194.JPG;|||P4260195.JPG;|||P4260196.JPG;|||P4260197.JPG;|||P4260198.JPG;|||P4270199.JPG;|||P4270200.JPG;|||P4270201.JPG;|||P4270202.JPG;|||P4270203.JPG;|||P4270204.JPG;|||P4270205.JPG;|||P4270210.JPG;|||P4270234.JPG;|||P4270236.JPG;|||P4270238.JPG;|||P4270239.JPG;|||P4270240.JPG;|||P4270241.JPG;|||P4270242.JPG;|||P4270243.JPG;|||P4270244.JPG;|||P4270245.JPG;|||P4270246.JPG;|||P4270247.JPG;|||P4270248.JPG;|||P4270249.JPG;|||P4270250.JPG;|||P5100261.JPG;|||P5100263.JPG;|||P5100264.JPG;|||P5100267.JPG;|||P5100268.JPG;|||P5100269.JPG;|||P5100270.JPG;|||P5100271.JPG;|||P5100272.JPG;|||P5100273.JPG;|||P5100274.JPG;|||P5100275.JPG;|||P5100276.JPG;|||P5100278.JPG;|||P5100279.JPG;|||P5100281.JPG;|||P5100282.JPG;|||P5100284.JPG;|||P5100285.JPG;|||P5100286.JPG;|||P5100287.JPG;|||P5100288.JPG;|||P5100289.JPG;|||P5100291.JPG;|||P5100298.JPG;|||P5100299.JPG;I don't like how shallow the sensor is but seems to still give accurate readings|||P5100300.JPG;|||P5100302.JPG;|||P5100304.JPG;|||P5100305.JPG;|||P5100306.JPG;|||P5100307.JPG;|||P5100308.JPG;|||P5100309.JPG;|||P5100311.JPG;|||P5100312.JPG;OEM gasket was cracked. That's not good. Hopefully I cracked it while removing the carb|||P5100313.JPG;|||P5100314.JPG;|||P5100315.JPG;|||P5100316.JPG;|||P5100317.JPG;|||P5100318.JPG;|||P5100319.JPG;|||P5100320.JPG;|||P5100321.JPG;|||P5100323.JPG;|||P5100325.JPG;|||P5100326.JPG;|||P5100327.JPG;|||P5100328.JPG;|||P5100329.JPG;|||P5100330.JPG;|||P5100331.JPG;|||P5100332.JPG;Cruise bracket in the way|||P5100333.JPG;Had to cut cruise control throttle bracket|||P5100334.JPG;|||P5100335.JPG;|||P5100336.JPG;|||P5100337.JPG;|||P5100338.JPG;|||P5100339.JPG;|||P5100340.JPG;|||P5100341.JPG;|||P5100342.JPG;I ended up not using silicon for brake booster (3/8 line)|||P5100343.JPG;|||P5100344.JPG;|||P5100345.JPG;|||P5100346.JPG;|||P5100347.JPG;|||P5100348.JPG;|||P5100349.JPG;|||P5100350.JPG;|||P5100351.JPG;|||P5100352.JPG;|||P5100353.JPG;|||P5100354.JPG;|||P5100355.JPG;|||P5100356.JPG;|||P5100357.JPG;|||P5100359.JPG;|||P5100362.JPG;|||P5100363.JPG;|||P5100364.JPG;|||P5100365.JPG;|||P5100368.JPG;|||P5100370.JPG;|||P5100371.JPG;|||P5100372.JPG;|||P5100373.JPG;|||P5100374.JPG;|||P5100375.JPG;|||P5100376.JPG;|||P5100377.JPG;|||P5100378.JPG;|||P5100379.JPG;|||P5100380.JPG;|||P5100381.JPG;|||P5100382.JPG;|||P5100383.JPG;|||P5100384.JPG;|||P5100385.JPG;Initial setup before trying to crank the engine with EFI for the first time|||P5100386.JPG;|||P5100387.JPG;|||P5100388.JPG;|||P5100389.JPG;|||P5100390.JPG;|||P5100391.JPG;|||P5100392.JPG;|||P5100393.JPG;|||P5100395.JPG;|||P5100396.JPG;|||P5100401.JPG;Need extension wire for EFI LCD screen to go up on dash|||P5100402.JPG;|||P5100403.JPG;|||P5100405.JPG;|||P5100406.JPG;|||P5100409.JPG;|||P5100410.JPG;|||P6080642.JPG;|||P6080643.JPG;I am very excited to finally block off this stupid noisy port|||P6080644.JPG;|||P6080645.JPG;|||P6080646.JPG;|||AlbumDescription;My 1977 GMC Palm Beach has the stock Oldsmobile 403 engine with the orignal quadrajet carb. The carb was causing me problems. The engine was extremely hard to cold start, sometimes taking a full minute of cold cranking. Installing an electronic fuel pump helped but not much. I think the choke was not working correctly. Second, and more importantly, I was getting terrible pinging when going up grades at sea level.
I decided to take the plunge and convert to fuel injection. This is neither cheap not quick but it is relatively easy these days and is not THAT expensive relative to the cost of a quality new carb. Here is the primary part list.
- Holley Sniper EFI, part # 550-869
- 12 foot extension for Holley Sniper display, part # 558-454
- Edelbrock EFI fuel sump, part # 36031
- Block off plate for choke heat pipe port on intake manifold
- 100 feet of 12 gauge wire
- 1/2 x 5/6 x 1/2 inch brass tee for fuel line
- A bunch of silicone vacuum line (good time to replace the old vacuum lines)
- 1/2 MIP to 3/8" FIP brass adapter. Needed for coolant temp sensor.
Everything else is typical consumables.
The install took me a a couple days of actual work. The parts that took the longest was:
- Figuring out how to mount the fuel sump and fabricating the bracket for it
- Figuring out what all the original vacuum lines went to, which I still needed, their size, and if the were ported or not
I would like to note why I am using that Eldelbrock fuel sump. It is a graceful way to submerge your high pressure pump in fuel for better cooling and it keeps fuel flowing even on grades or corners where a in-tank pump in such a shallow tank as ours on the RV would start spitting out air. The fuel sump eliminates the need for a small fuel reservoir or air/fuel separator later in the system. The fuel sump is also a returnless design. End result, the fuel sump is worth the price (at least to me).
There were a couple things about my RV that made this installation go faster. First, I already had an electronic low pressure fuel pump. This allowed me to quickly skip the mechcanical fuel pump and instead pump directly to the new fuel sump. Second, I already had done some electrical work installing a house battery fuse box up front, thus I already knew where to tap into the ignition line and how to route the lines through the firewall. Third, I had already installed Doug's headers which had an O2 sensor bung welded in.
I am very happy with the finished product. The RV starts very easily and runs well. I have done minimal tuning, just applied a self learned map. Having the LCD display for engine monitoring has been very helpful (I have a tachometer now!). There are a couple issues I still plan to work through at some point.
- While cruising at 70 MPH in Colorado, I have the throttle at about 60%. At that throttle the EFI system wants to achieve 13.2 AFR. That is too rich for just cruising is wasting fuel. It does smell like gas behind the RV. I would like to set the normal 14 AFR to be used up to 70% throttle.
- On a cold or warm start, if you give it lots of throttle then abrubtly let off the throttle, the engine may die. It seems like the IAC doesn't catch it on the way down and the engine dies. There is a narrow window where this is possible, usually only within the first couple minutes of starting the vehicle. It is worth letting it idle and warm up first. But there is likely a fuel setting to slow the RPM drop in the advanced settings.
I recently drove 1000 miles from Colorado to Utah and back, cresting 12,800 feet. On that trip I got about 9.5 MPG. I am happy with that. Eventually I will play with the cruisting AFR but even 9.5 MPG is pretty good for what and where I am driving.