Djet Injection on late cars, 75-76 |
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Djet Injection on late cars, 75-76 |
914work |
Dec 4 2011, 05:27 PM
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#1
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Member Group: Members Posts: 291 Joined: 9-November 11 Member No.: 13,762 Region Association: None |
On the latest cars (late 75 & 76 2.0L) the Brain/harness came with an additional logic circuit plugged in to a connector near the MPS.
What was this for? (IMG:style_emoticons/default/idea.gif) Would the car run w/o it? (IMG:style_emoticons/default/confused24.gif) |
type47 |
Dec 4 2011, 05:37 PM
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#2
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Viermeister Group: Members Posts: 4,254 Joined: 7-August 03 From: Vienna, VA Member No.: 994 Region Association: MidAtlantic Region |
any pix and do you know if it's as supplied by the factory? Only component I can think of that might be id'd as a logic circuit is the L-Jet relay mounted to the battery tray support. Decel valve on the same mount as the MPS is not connected electrically.
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914work |
Dec 4 2011, 05:42 PM
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#3
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Member Group: Members Posts: 291 Joined: 9-November 11 Member No.: 13,762 Region Association: None |
sorry I should have been more clear, yes this is a OE feature.
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TheCabinetmaker |
Dec 4 2011, 05:42 PM
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#4
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I drive my car everyday Group: Members Posts: 8,309 Joined: 8-May 03 From: Tulsa, Ok. Member No.: 666 |
Ive been driving a late djet car for many years. Ive never seen what you are talking about. We need a pic please.
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76-914 |
Dec 4 2011, 06:00 PM
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#5
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Repeat Offender & Resident Subaru Antagonist Group: Members Posts: 13,611 Joined: 23-January 09 From: Temecula, CA Member No.: 9,964 Region Association: Southern California |
Me 3. The only connection's in that area are the map & CHT, unless the CA model was different.
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JeffBowlsby |
Dec 4 2011, 06:21 PM
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#6
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914 Wiring Harnesses Group: Members Posts: 8,663 Joined: 7-January 03 From: San Ramon CA Member No.: 104 Region Association: None |
That's a CA-only speed limiter circuit...details on my harness webpage at the link in my signature block below.
Yes...it will run without it, just unplug it. |
914work |
Dec 4 2011, 07:23 PM
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#7
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Member Group: Members Posts: 291 Joined: 9-November 11 Member No.: 13,762 Region Association: None |
thanks Jeff (IMG:style_emoticons/default/smile.gif)
Speed limiter? what, how does it limit speed? Would cars not delivered for the CA market also have that same harness just no limiter? |
PancakePorsche |
Dec 4 2011, 08:16 PM
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#8
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Member Group: Members Posts: 236 Joined: 29-July 11 From: Southern California Member No.: 13,373 Region Association: None |
Speed control module limits rpm by shutting down injectors at a pre specified rpm. Car will run just fine without it, but you will not have over rev safety. My 76 California model has one. The cars with the additional cat and egr dash lights have the speed module.
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JeffBowlsby |
Dec 4 2011, 08:28 PM
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#9
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914 Wiring Harnesses Group: Members Posts: 8,663 Joined: 7-January 03 From: San Ramon CA Member No.: 104 Region Association: None |
thanks Jeff (IMG:style_emoticons/default/smile.gif) Speed limiter? what, how does it limit speed? Would cars not delivered for the CA market also have that same harness just no limiter? That's exactly correct. There is a CA version (with the branch/connection) and a 49-state version of that harness (without the branch/connection). |
914werke |
Dec 5 2011, 12:43 AM
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#10
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"I got blisters on me fingers" Group: Members Posts: 10,542 Joined: 22-March 03 From: USofA Member No.: 453 Region Association: Pacific Northwest |
I think he meant might you find that CA only harness on non CA cars, just w/o the limiter module?
So I have a question why was this necessary, and only in CA, since the cars already had a limiter..the rotor in the Distributor. |
jcd914 |
Dec 5 2011, 01:35 AM
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#11
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Advanced Member Group: Members Posts: 2,081 Joined: 7-February 08 From: Sacramento, CA Member No.: 8,684 Region Association: Northern California |
I think he meant might you find that CA only harness on non CA cars, just w/o the limiter module? So I have a question why was this necessary, and only in CA, since the cars already had a limiter..the rotor in the Distributor. Possibly: 49 state cars used rev limiting rotors which cut ignition but not fuel. And in CA they used the speed limiter to cut the fuel so they were not dumping Raw fuel into the cat. Jim |
PancakePorsche |
Dec 5 2011, 01:58 AM
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#12
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Member Group: Members Posts: 236 Joined: 29-July 11 From: Southern California Member No.: 13,373 Region Association: None |
I believe that to be the case. ECU on these cars had overrun fuel cut-off and and over-rev fuel cut-off (module) to prevent cat from overheating hence the thermocouple (cat temp module in rear trunk) and warning light on dash which flashes when a overheated cat is detected.
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blitZ |
Dec 5 2011, 06:56 AM
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#13
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Beer please... Group: Members Posts: 2,223 Joined: 31-August 05 From: Lawrenceville, GA Member No.: 4,719 Region Association: South East States |
I have a California 76 car and it had the silver box your extra connection probably plugged into. I removed it with the rest of the pollution control and never missed it.
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JeffBowlsby |
Dec 5 2011, 10:47 AM
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#14
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914 Wiring Harnesses Group: Members Posts: 8,663 Joined: 7-January 03 From: San Ramon CA Member No.: 104 Region Association: None |
This circuit was actually a 1975 & 1976 'feature'. See this from the 1975 S&T manual, no similar manual was published for the 1976 cars.
Attached image(s) |
914werke |
Dec 5 2011, 01:00 PM
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#15
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"I got blisters on me fingers" Group: Members Posts: 10,542 Joined: 22-March 03 From: USofA Member No.: 453 Region Association: Pacific Northwest |
S&T manual ?
maybe this is a good opportunity, we should add pics of all the concerned elements, and move this thread to the CW & originality forum? |
r_towle |
Dec 5 2011, 01:44 PM
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#16
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Custom Member Group: Members Posts: 24,624 Joined: 9-January 03 From: Taxachusetts Member No.: 124 Region Association: North East States |
What is the engine speed limit?
How does this work? Rich |
JeffBowlsby |
Dec 5 2011, 02:07 PM
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#17
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914 Wiring Harnesses Group: Members Posts: 8,663 Joined: 7-January 03 From: San Ramon CA Member No.: 104 Region Association: None |
What is the engine speed limit? How does this work? Rich I dunno how it works...its a circuit. I do know that its wiring is connected to the triggter points so it senses engine speed, I think there is circuit diagram somewhere, I'l post it if I can find it. Attached image(s) |
JeffBowlsby |
Dec 5 2011, 02:11 PM
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#18
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914 Wiring Harnesses Group: Members Posts: 8,663 Joined: 7-January 03 From: San Ramon CA Member No.: 104 Region Association: None |
S&T manual ? maybe this is a good opportunity, we should add pics of all the concerned elements, and move this thread to the CW & originality forum? Service and Training Manuals. Really good stuff, you should see all the info on the 914/6 and 73 2.0L. Here is a summary I wrote up a while ago...keep an eye out for them, they show up on ebay only rarely. USA 914 Service and Training Manual Highlights S&T manuals were supplied to dealerships presumably for tech and sales training purposes. They describe new model year features and upgrades and detailed information some of which is not found in other factory documentation. The manuals were published in several languages including English, German, Italian and French. In addition to subtle cosmetic and functional changes they describe: 1971 914/4 and 914/6 • 104 pages • Manual describes both the 1970 ad 1971 model years • General description of the 914s basic features • Selected 914 prototype features • Detailed engine specifications • Detailed D-Jetronic fuel injection description • Detailed Sportomatic transmission description • Transaxle driveshaft adjustment specifications • Limited slip differential • Detailed suspension specifications, maintenance and adjustment requirements • Detailed steering system specifications and maintenance and adjustment requirements • Detailed brake system specifications, maintenance and adjustment requirements including brake force limiter • A significant number of part numbers • Detailed section drawings of manual and Sportomatic transaxles, rear brake caliper and brake force limiter. • Cabin extractor duct system • Electrical system specifications and wiring diagrams for 914/4 and 914/6 • Detailed engine tune-up procedures 1972 1.7L only • 24 pages • 6-digit model numbers • Engine CO adjustment procedure with new adjustable ECU • Positive crankcase ventilation (PCV) system • Cabin heating and ventilation system • Overrun air supply system (decel valve) and evaluation • Engine intake air preheating system and evaluation • Crankcase oil baffle plate and installation • Revised engine intake vacuum hose routing • Revised lubrication and maintenance schedule • TPS evaluation and adjustment procedure 1973 1.7L and 2.0L • 49 pages • 6-digit model numbers • Dimensional specifications of major new engine parts – Crankshaft, connecting rods, pistons, valves, valve seats, heads, intake manifold • CO adjustment value for 2.0L engine • Fuel injector pulse width graph • 2.0L decel valve and auxiliary air valve function and hose drawing • 2.0L PCV system function and hose drawing • 2.0L engine distributor vacuum and centrifugal advance/retard curves • Sideshift transmission improvements • Sideshift transmission shift linkage adjustment procedure • 2.0L clutch pressure plate specification • Minor brake and suspension revision • Wheel centering specifications • Door window operator mechanism revision 1974 2.0L only • 15 pages • 6-digit model numbers • Standard and Appearance Group specifications • Seat belt warning system 1974 1.8L only • 26 pages • 6-digit model numbers • AFC (L-Jetronic) fuel injection system and evaluation 1975 1.8L and 2.0L • 21 pages • 6-digit model numbers • Modified exhaust system • Catalytic converter (CA vehicles only) • Exhaust gas recirculation (EGR) system (CA vehicles only) • Air injection system (2.0L engines only) • Fuel feed cutout system (2.0L engines only) • Fuel pump revisions • EGR/Catalytic converter service interval warning light system • 5 mph bumper system • Exhaust gas measuring procedure and values Attached thumbnail(s) |
Drums66 |
Dec 5 2011, 05:12 PM
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#19
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914 Rudiments Group: Members Posts: 5,321 Joined: 15-January 03 From: Coronado,Cali Member No.: 151 Region Association: Southwest Region |
Speed control module limits rpm by shutting down injectors at a pre specified rpm. Car will run just fine without it, but you will not have over rev safety. My 76 California model has one. The cars with the additional cat and egr dash lights have the speed module. (IMG:style_emoticons/default/stones.gif) (IMG:style_emoticons/default/tunez.gif) (IMG:style_emoticons/default/rock_band.gif) (IMG:style_emoticons/default/dead horse.gif) (the short & sweet of it!!) |
Dave_Darling |
Dec 5 2011, 06:57 PM
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#20
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914 Idiot Group: Members Posts: 15,048 Joined: 9-January 03 From: Silicon Valley / Kailua-Kona Member No.: 121 Region Association: Northern California |
Possibly: 49 state cars used rev limiting rotors which cut ignition but not fuel. And in CA they used the speed limiter to cut the fuel so they were not dumping Raw fuel into the cat. AFAIK, this is exactly the reason. I think that the box shorts out the trigger points signals (to ground), so you get no injection events. --DD |
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