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Thread: Used Pro-Jection Trouble

  1. #1
    mustangtoby Guest

    Default Used Pro-Jection Trouble

    I bought a used 1st gen system a couple of years ago, have had it setting on the shelf for awhile waiting for the "right project". So about 2 months ago I installed it, and it worked great, no problems. I've put about 500 miles on it and no complaints, everything has been fine so far.
    So today while driving it, it started sputtering, trying to die. If you give it full throttle it will run fine, soon as you let off it dies. I nursed it home, and watching it in the driveway you can see the injectors give plenty of fuel at WOT, but very little (not even enough to idle) unless it's at WOT. My guess is the throttle position sensor is bad. Any suggestions? Any help would be great. This is a 390 Ford in a 71 SWB 2WD truck. I love driving it at full throttle, but it's not as much fun when you HAVE to!

  2. #2
    noss1z28 Guest

    Default

    Check the actual fuel pressure. Low fuel pressure will cause some of the symptoms you have described.

  3. #3
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    Quote Originally Posted by mustangtoby View Post
    I bought a used 1st gen system...
    What's a "1st gen system"?
    The Projection 2D, 4D, 4Di, etc.? Commander 950, 950 Pro?
    Are we talking about a TBI system?
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: Dominator MPFI & DIS, 100HP progressive dry direct-port NOS, A/C, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, 160A 3G alternator, Optima Red battery, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, M4602G aluminum driveshaft, FRPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 tires.

  4. #4
    mustangtoby Guest

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    When I say 1st gen, it's a throttle body before the 2D. My brother in law bought a 2D system, and comparing them the computer is different. The throttle body looks the same, but the computer is about 4" wide, 2" tall, and maybe 8" long. No heat sink fins on the housing. The tuning knobs are the same. I actually have two of these systems that I've bought used over the years, but the wiring harness is shot on the other one I have, and the throttle body is filthy. I've tried the computer from it and get the same results, not a CPU problem. Other than age, it is almost identical to the 2D system, must be it's predecessor?

    For what it's worth, the instruction manual that came with it is dated 1993 (copyright). The manual just says "Holley Pro-Jection installation manual", While my brother in laws manual says "Pro-Jection 2D".

    I'll check the fuel pressure before anything else, gonna be a couple of days before I can get to it. Just seems kinda strange for the fuel pressure to change all of the sudden, went from running fine to crap all of the sudden. Could be a plugged filter, old truck could have a bunch of crap in the fuel tank. Thanks for the replies.
    Last edited by mustangtoby; 09-13-2010 at 09:59 PM.

  5. #5
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    Quote Originally Posted by mustangtoby View Post
    Just seems kinda strange for the fuel pressure to change all of the sudden, went from running fine to crap all of the sudden.
    Actually, that's not strange for a fuel pressure regulator failure:
    http://www.holley.com/512-1.asp (Fuel Pressure Regulator Service Kit)

    Aside from a fuel delivery problem, the TPS voltage at idle (on those early systems) has to be set at .63-.65 volts. This is imperative for proper operation. If you adjust the idle speed, you must also reset the TPS sensor voltage at idle.
    http://www.holley.com/data/Products/...99R9975rev.pdf (Pro-Jection 2D Manual)
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: Dominator MPFI & DIS, 100HP progressive dry direct-port NOS, A/C, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, 160A 3G alternator, Optima Red battery, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, M4602G aluminum driveshaft, FRPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 tires.

  6. #6
    mustangtoby Guest

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    Thanks for the info. I've not messed with the idle speed, but will keep that in mind. I still haven't had time to work on it, hopfully soon... Thank god it's a toy and not a daily driver. I think I'll check fuel pressure first and go from there. Thanks again for the link.

  7. #7
    mustangtoby Guest

    Default

    So finally got around to checking it out. After reading the instruction manual, it was really easy to check throttle posistion sensor, and it read .07 Volts. Losening the screws and adjusting it didn't change the voltage reading at all. I have another system identical to this one (except the wiring harness is shot), so I set the throttle body on the engine, plugged it in, and it read .7 volts. So I swapped them out (the throttle posistion sensor), adjusted the "new" sensor to .63 volts, and it started right up and ran great! So now when I get around to installing the other system, I've got to buy a new harness and a new sensor, but at least I know whats wrong with it. I've got a 69 Bronco I was gonna go with Ford fuel injection, but am toying with putting the other Pro-Jection on it.

  8. #8
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    Quote Originally Posted by mustangtoby View Post
    So I swapped them out (throttle position sensor), adjusted the "new" sensor to .63 volts, and it started right up and ran great!
    I'm glad to hear your success.
    Last edited by Danny Cabral; 09-11-2012 at 02:18 AM.
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: Dominator MPFI & DIS, 100HP progressive dry direct-port NOS, A/C, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, 160A 3G alternator, Optima Red battery, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, M4602G aluminum driveshaft, FRPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 tires.

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