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EZ EFI 2.0 Throttle Body System Vehicle #2 - An '81 GMC

Discussion in 'FAST Support Forum' started by A A, Jun 5, 2016.

  1. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    Hi Jens,

    15x8's aren't that hard to find here. Summit can also often get what it doesn't show. Bias ply rayon or nylon with a thin racing stripe were what originally came on your Vette. The bias ply tires drive better with the OEM suspension settings tune. But, with some suspension upgrades and different settings, belted radials can be used to greatly improve traction and handling. I buy a lot of radial Cooper tires reasonably through Summit using their "Best Price Guarantee". The '81 GMC sits on a set of Discoverer A/T3, 235 /75R15, Radial, T Speed Rating, 104 Load Range, Open White Letters on 7" rims - and rides, and handles good. My '85 TA sits on Cooper Zeon Radial 245x50 ZR16 on 8" rims - the TA handles the road like it is glued there - but it also has all of the UMI performance suspension upgrades they make.

    Your factory rims would have been 7x15, and a good tire would be the Cooper Cobra GT, P225/70R15, Radial, 1,753 lbs. Maximum Load, T Speed Rating, Solid White Letters with 7" wide rims.

    For 8x15 rims, you'll need to pay more attention to wheel offset, but Cobra GT, P255/60R15, Radial, 1,885 lbs. Maximum Load, T Speed Rating, Solid White Letters might be what you want - with the proper suspension settings for radials. I used to run Goodyear P255/60 HR15 on a '79 Vette with 8x15 rims. The '79 had zero interference problems and handled fairly well for a Vette with close ratio steering running the Goodyears. The Goodyears just weren't tires that wore well over time. About 20,000 miles was the life of them before a new set was needed. I can't be sure these tires won't scrub but, if your '71 Vette has the same wheel wells and rim offset my OEM '79 had, this size will work perfectly.
     
  2. Pfingstl

    Pfingstl Member

    Joined:
    May 30, 2016
    Location:
    Denmark
    I run 255/60 15 BF Goodrich Radial T/A - no interferance. For dry roads they are OK, but on wet roads they easily loose traction. Lockup on braking is also a problem on wet roads.

    It's a compromise between the 8 x 15 Rally Wheels with Chrome details and safety. Our oldest daughter are allowed to drive it. Note to self: Remember to adjust the FAST RPM Limiter when lending someone the Vette ;-)

    I was considering some American Racing Torq Thrust II Classic 17/8. They look Classic enough for the '71 and the tires available would be a lot better.

    For now I am waiting for Spring. Only minor work this winter, which is nice. Changing the Rack & Pinion to a Borgeson system - will pass inspection and have a smaller turning diameter. Not easy to get things approved here !!
     
  3. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    The new rims and steering sounds like a good plan. The BF Goodrich you currently have are speed rated S. The Coopers I suggested, and those I have, are rated T. The Cooper Zeon tires on my TA are speed rated Z Traction AA. Traction AA with a Z speed rating is what you should look for to use with the new rims. My Vette was also touchy on wet roads. I always avoided driving it in wet weather - not just because I didn't want it to get dirty from road spray.

    Daughter driving - I would include "Fun, Fun, Fun, 'till her Daddy takes the T-bird away" by the Beach boys as part of her listening experience. Hearing "Mustang Sally" might also help slow her down.;)

    When I was young and drag racing, Magic Carpet Ride and Born To Be Wild by Steppenwolf, turned up loud, was what I listened to while staging and leaving the lights. Every time I heard those two songs, my right hand itched for the feel of a four speed shifter - accompanied by the feeling of my right foot planted firmly planted into the accelerator. Avoid those two songs as a part of her music curriculum. That urge still strikes me when I hear those two songs.:D
     
  4. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    Back to my '81 GMC, the FAST 30272 filter had some dirt in it. There was also some white looking slime that could have only come from the FAST pump. I washed the filter in water and it felt greasy - so I used some Dawn dish soap to wash the bronze filter good. After that, I could see the flow was back to the filter and blew it dry.

    A FAST tech had told me an Aeromotive 12601 was the replacement paper filter for the bronze in my FAST 30272 filter. It most definitely isn't, being almost twice the size of the FAST 30272 housing. It arrived today from Summit. I didn't trust the FAST tech after he said I should not use a pre-filter for my FAST inline pump, and I was right not to. Dirt can and will quickly eat a pump up. So, I had also ordered a 40 micron pre-filter and installed it before the pump. I started the engine without the FAST 30272 filter installed after flushing the pump and resetting the regulator. I could hear some of my injectors clicking excessively, and knew this was due to some particles still getting through the pump. I then reinstalled the cleaned FAST 30272 filter at the FAST electronic pressure switch. With both filters now installed, my pressure remained constant at 43 with the engine off using the handheld. Pressure was normal again at 35-36 with the engine idling and at steady cruise - similar to my other EZ EFI 2.0 in my '85 TA. The injector clicking also immediately returned to the normally low level. A check of both the regulator gauge and the handheld showed them both in agreement with pressure.

    One thing I was glad about was not seeing any rust or magnetic material in my filter. That saved me the job of having to clean the old factory dual tanks on my GMC. I can just watch my filters and clean or replace them as needed. I will be checking that any tank vent filters are clean.
     
    Last edited: Dec 28, 2016
  5. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    The last set of NGK non-resistor heat range 8 race plugs (R5674-8) I installed to this iron head engine are still running perfectly using the last timing and fuel settings I related in post #18. Cold and warm/hot idle could not be better. I haven't done an actual fuel mileage test yet. But, I can already see this truck is getting much better fuel mileage than it ever got before in short trips using a 750 Holley carburetor - even better than the factory motor with its Rochester 4 bbl gave. The only way the original factory engine could ever spin a tire was on a wet road. Very pleased with this 400 horsepower engine using FAST EZ EFI 2.0 throttle body fuel injection.

    The engine is running perfectly on Standard Oil 86 octane fuel. Power at a 10 MPH roll in first can easily ignite both of the Cooper Discoverer A/T 3 235/75/15 factory size rear tires.

    I'll be doing a proper fuel mileage test on a 100 mile round trip soon. I expect better than the 17 mpg this truck used to average on the highway for the same trip using cruise control.
     
    Last edited: Jan 19, 2017
  6. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    At cold start, the engine was wetting the plugs some with gas and sooting the plugs a little until the engine warmed up. But, the engine was still starting great and running good to the 125 degree warm-up - when cold start enrichment turns off. The engine has always run great after the 125 degree warm up, and warm or hot starts are perfect.

    I filled the gas tank and put 30 miles of highway driving time (with 7-8 miles of city traffic driving) on the truck the day before yesterday, and it ran great - requiring much less pedal on hills than my new Silverado needs to pull the same hills. Had my 95 year old mother to ride with me, and the only complaint she had was the slight bump the new TCI Streetfighter transmission makes when shifting (even when going very slow) - a bump I like as I know it means there is less clutch slippage on shifts.

    After having to race the engine a little (during cold starts over several days earlier in the week and again today) to clear an occasional raw fuel miss, I decided to reset cold start enrichment from -2 to -4. I'm hoping that will be all it needs to stop the minor plug fouling on cold starts.

    I wrote down my mileage on the fill-up before the 30 mile drive, but want to get in at least 100 miles of driving before filling up again and figuring the mileage. One thing I noticed was the gas gauge hasn't moved from where it was after filling the tank. When the truck was carbureted, and before my engine changes, even a shorter drive would move the needle a little in the full range - and the gas needle is still working properly.
     
  7. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    This engine is providing some challenges the prior 470 horsepower engine didn't - or I just didn't drive the previous engine enough with the EZ EFI 2.0. I increased the cold start enrichment all the way to -8 and cold start was still causing wet plugs requiring a little racing of the cold engine to clear them. I spotted the warm idle A/F was now hovering at -9% O2 correction at 13.8:1 - so I changed the idle A/F to 14.0:1 after seeing 13.9:1 only corrected the O2 to -6% at warm idle. The engine responded well to the idle A/F change and now shows a +3% O2 state at a fully warmed idle.

    I also took a closer look at my NGK heat range 4 plugs and saw I mistook some splash deposits for pre-ignition/detonation deposits. So, I cleaned them to almost pristine condition using some cleanser and an old tooth brush, and re-installed them after a good flush with brake cleaner. They may still be too hot, but I'm going to watch them for some miles. Revving the engine under load doesn't seem to be showing any problem.

    Looking at my NGK heat range 8 sparkplugs, the engine still appeared to like the 14.3:1 cruise AF with WOT at 12.7. I also set the cold start enrichment back to -2.

    Speaking of cleaning plugs, I never use a wire brush on them as it contaminates the ceramic with metal to cause voltage loss - just the same as carbon tracking or carbon fouling. I also never use a torch to burn them clean as plugs are not designed to withstand over the temperatures seen while installed in a cylinder. Both of these methods are all over the Internet, along with using metal objects to scrape the insulator clean (leaves metal on the ceramic), but are foolish as they damage the plugs. If you can't clean a sparkplug properly with chemicals and/or brushing with a tooth brush using a household abrasive cleaner, you should replace them - or expect problems.

    I also installed a new Kenwood eXcelon KDC-X998 radio to the '81 - even without yet replacing the 36 year old speakers it sounds great!
     
    Last edited: Jan 26, 2017
  8. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    Set cold start enrichment to +3 to get a smoother cold idle and to stabilize the idle RPM on throttle release with cold engine. Engine no longer needs any added throttle to clear any of such as the previous slight raw fuel miss at cold start. Set WOT to 12.8. Raised cruise AF to 14.5. Engine still feels strong with no hesitation.
     
    Last edited: Jan 28, 2017
  9. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    When I put the parts together for this FAST EFI kit, I purchased a Summit brand regulator in an effort to keep the total cost down. Turns out the Summit regulator is garbage. The needle seat bypass consists of nothing more than a ball bearing on the diaphragm, and the mating seat was chrome over aluminum. This design allowed the running pressure to be set, but also allowed all residual pressure to bleed off instantly on fuel pump shutoff. I removed the chrome and re-machined the aluminum seat. But, this only partially restored residual pressure for a few seconds after pump shutdown. I'll be replacing this regulator as its residual pressure performance is far below that of the FAST regulator. While the FAST regulator on my '85 TA works fine, I'm going with an Aeromotive 13129 on the GMC.
     
  10. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    I'm replacing most of the front suspension with new parts this week - along with the regulator. Brand new upper and lower A-arms with ball joints and bushings, all drag links, and the idler arm. The steering has very little play, the tires are still wearing well, and the tracking alignment is good. But, I just don't trust the 36 year old factory original suspension - or the groaning I hear coming from it now and then. With 400 horsepower, I see no reason to take unnecessary chances. The new parts will restore the steering and suspension to brand new performance - and ease my mind.
     
  11. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    Since the engine liked the 14.3 Cruise ratio, I set the idle F/A to 14.3 and took cruise A/F to 14.7. These settings should be slightly lean for Standard regular with the slight amount of Ethanol it contains, but it doesn't look that way so far. I changed the cold idle enrichment to 0 and ran the engine for about fifteen minutes on city streets. The next day, the engine cranked perfectly, and drove perfectly well while still cold. I left the WOT at 12.8 with the other enrichment settings also left alone. The engine is running just perceptibly smoother, and warm idle vacuum has remained the same. Engine loading in gear with air conditioning and power steering has shown the 14.3 idle A/F to be no problem maintaining an even idle speed. A look at the sparkplugs shows normal looking white unblistered insulators with some light gray deeper into the plug shell - zero splash deposits. I'll take the truck for a short highway drive and re-check this before any decision to change WOT. I may also need to drop total timing to 30 degrees once I see the reactions to some hard acceleration. This engine has only gotten sweeter with each change. Once I get the new front suspension parts and install them this week, I'll look for some more fuel refinements, then I'll top off the tank and do a freeway speed mileage test at a steady 70 mph. So far, all indications are my cylinder temperatures are still looking good.

    Hey, I might be losing a little top end power, but I don't intend to drag race this truck. I only use it when I need its long bed to haul something - but I also just like driving it now and then. I once only used it as my car hauler to local circle tracks here, but I also quit racing and hauling car trailers a long time back.
     
    Last edited: Feb 1, 2017
  12. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    Received the new Aeromotive 13129 regulator today. It's a tiny thing compared to the same FAST part and the even larger Summit regulator I removed. I installed it immediately, and it cured the very rapid pressure drop I previously had on pump shutdown - working exactly like it should. Refined the enrichment settings to Accel +2, Crank 0, Cold Start 0.

    The new assembled upper and lower front A-frames also arrived, and I will install those tomorrow. I'm still waiting on the new drag link sleeves, but I also now have the new drag links.
     
  13. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    Received the drag link sleeves today. Finished the driver's side suspension and steering upgrades today. But, between rusted frozen parts and the weather, I still have the passenger side to do. Unfortunately, I have too much going on in my garages to pull inside one of them and get comfortable with the work. At least I'm getting there.
     
  14. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    Between dental visits (had to have a bridge after loosing a front tooth) and an overload of projects, I finally got around to finishing the front suspension. The truck steering now feels like it did brand new, and there are no more irritating squeaking, groaning, or creaking noises coming from the front end. While I was at it, I installed new drag link joints and new Energy Suspension polyurethane sway bar bushings to the factory front sway bar.

    For those wondering, I put the new lower controls arms aside and decided to fully rework the original lower control arms, as the new C2500 lower control arms would have required re-drilling the factory C1500 spindles for the larger C2500 ball joints - new replacement C1500 lower control arms are no longer available and carry a smaller ball joint. The rework in itself was no easy task - considering there was also some damage requiring re-shaping the original lower arms with my 30 ton shop press. Even removing the 36 year old bushing assembly was a huge pain. All repaired with new MOOG parts, and painted, the front suspension also now looks great.

    New fuel settings have the engine running again sweeter - Idle 14.4, Cruise 14.8, WOT 12.8. Have lowered total timing to 30 degrees - 24 mechanical with 6 vacuum.
     
  15. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    Latest settings for this engine - slope changed from all-in at 3400 to 3600. Total mechanical advance - 24 degrees. Vacuum advance at 6 degrees. F/A: idle - 14.4, cruise - 14.8, WOT - 12.8. Fuel - Standard Oil Regular 86 octane garbage with no octane booster additive. Factory plug heat range looks good, timing appears good at the side electrode, insulator staying white with no blistering. Also, no sign of any splash deposits.

    Initial timing: 20 degrees, 5 degrees idle trim
    Enrichment: +2 accel fuel, 0 cold start, 0 cranking fuel.
    Maximum Vacuum Threshold: 60 Load %
     
    Last edited: Feb 26, 2017
  16. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    Arrgh! I had been noticing my fuel pressure dropping a few points from what it had been during hot idle after a drive, from where it still was cold, and a louder whine coming from the pump only after a drive.. Checked my filters, which were clean, and replaced the FAST supplied WALBRO 392 pump with a new spare WALBRO 392 I had stored away. The pressure came back to normal and stayed where it should be warm after a drive - with a normal low whine from the pump. Then, I decided to switch tanks, and immediately got fuel pressure loss and pump shutdown with fault code... I'll be replacing the tank switching valve with a new one in the morning.

    That factory original valve had been working, but had acted up some in the past requiring me to repeatedly press the dash switch back and forth sometimes. The tipoff on these valves needing replacement is when the dash gauge reading goes higher than normal after switching tanks. Instead of playing with the dash switch to get my gauge reading right, I should have replaced the valve long ago.

    At least the removed WALBRO pump is still good, and the pre-filter and the filter before my injectors were both clean (which means my tanks may be clear of the previous road dirt I found before adding the pre-filter). If the newly installed pump drops any pressure later, I may just add a lower pressure pre-pump. I'll do a good free flow flush of this pump before storing it - just in case something did get stuck in it before I added the pre-filter.
     
  17. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    Bought a new BWD (lifetime FSV3) valve today, but the three port return line selector side has 5/16" ports instead of the original 1/4" line ports. At least the feed line selector valve ports are all correct 3/8". There are no "OEM" valves any more, only "universal". What fun - converting to universal to try staying original. Selectable new dual tank pumps with new selectable returns is still by far the best solution for these older OEM dual tank installs.

    For kicks, I'm going to try rebuilding the OEM selector.
     
  18. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    Wow! The valves inside of the old tank selector valve were really worn out OEM garbage - that were creating an unrealized restriction. With the new selector valve installed, my static fuel pressure went up 3 PSI. Reset the pressure back to 43 PSI. The fuel gauge, for each tank, also reads correctly for the first time in many years. It's just touch the tank switch once to select whichever tank I want to use now. Switching from one tank to the other while driving is no problem, and no longer causes fuel pressure errors and engine fuel pump shutdown.
     
    Last edited: Mar 2, 2017
  19. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    After my handheld began showing more fuel pressure today, I made sure to check actual pressure on my fuel lines. Pressure on the lines was correct. I'm hoping it's just a bad pressure sensor. Looks like Murphy's law is trying to haunt me.

    Also, let's thank FAST for supplying two different fuel pressure connector harnesses with the EZ EFI 2.0 main cable, and supplying two different sensors. This means you have to match up sensors. - the one stamped 0032K30 on the inside end only works with the one cable connector that has groove between two pins. The 0034A03 sensor is "universal", and will fit either cable style.
     
    Last edited: Mar 3, 2017
  20. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    I had just started a new blood pressure prescription and it brought my blood pressure down. Once down, I remembered why I install my 10 micron filters after the electronic sensor - to alert me to filter stoppage by showing increased pressure on the handheld. The supplied 10 micron FAST 30272 bronze filter didn't look dirty, but the water turned black as I washed it with Dawn detergent. The cleaning restored flow back to normal pressures. I will be replacing the supplied FAST 30272 filters with larger 10 micron Aeromotive filters, and already have one ready to install once I have some needed 90 degree AN fittings. The small FAST 30272 filters just plug too easily in real world applications.
     

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