Fuching DJet issues *SOLVED*, Running out of things to try |
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Fuching DJet issues *SOLVED*, Running out of things to try |
rjames |
Jun 12 2019, 12:19 AM
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#1
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I'm made of metal Group: Members Posts: 3,914 Joined: 24-July 05 From: Shoreline, WA Member No.: 4,467 Region Association: Pacific Northwest |
Last summer all of a sudden my car wouldn’t stay running. If I could get it started the idle would hunt and the car would die unless I kept on the gas. Lack of power at times. All somewhat erratic.
Found that the MPS wouldn’t hold vacuum. Replaced the bad mps with a known good one. Car idles high when cold (higher than I think it should ~1600 rpm) so AAR is good, then when it warms up idle hunts from ~900rpm to the point where it almost dies unless I open the throttle body bleed screw quite a bit and turn the ECU knob just a few clicks away from full clockwise. So I did the following hoping to fix the issue: Replaced all vac hoses including intake runner to plenum hoses. New intakecrunner gaskets Verified plenum isn’t leaking New throttle body gasket Installed NOS throttle body Rebuilt the distributor New condenser Rebuilt injectors and flow tested New fuel lines Fuel pump is less than 2 years old Set timing and dwell with advance disconnected New CHT (resistance reads 1.7 w/engine off @70 degrees in the garage) Calibrated the TPS, even unplugged it to take it out of the equation, didn’t change anything. ECU matches the MPS (both correct part #s for a ‘75 2.0) Tried a known good ECU from a ‘74, no change. Feels like the MPS needs to be calibrated...but then again, these are all the same symptoms I had with the old bad mps. Replacement mps is from a Jeff B and was tested, but I haven’t retested it to see if it’s holding vacuum. (Don’t have the necessary tool, but maybe that’s the next step) Help! What am I missing? |
76-914 |
Aug 18 2019, 08:55 AM
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#2
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Repeat Offender & Resident Subaru Antagonist Group: Members Posts: 13,490 Joined: 23-January 09 From: Temecula, CA Member No.: 9,964 Region Association: Southern California |
Issues fixed. Had multiple things going on. Distributor vacuum canister leaked. Replaced with the 123 distributor. Tiny vacuum leak ended up being a worn throttle body linkage shaft (at least that’s what I’m calling it). Was a very minor leak, but a leak just the same. It didn’t show up on the smoke test I did, but it did show up when I tried pressurizing the system. Replaced with a NOS throtyle body I found on ebay (got lucky there, price was reasonable, too). It doesn’t have the safety spring like the later models, but I doubled up on the TB return spring for piece of mind. Engidlebidles at a perfect 950rpm. Next step was to tune the air fuel mixture. The rebuilt MPS I got from Jeff had been reset to factory default settings, but was way too lean for my car as I had originally thought. I adjusted the MPS using Chris/Tangerine Racing MPS adjustment tools in conjunction with the Plex wideband sensor I installed last year. My AFR is now 13.5 at partial load, and 12.5 at WOT. Idle is at 12.2. I may try bringing the idle mixture up a bit with the ECU knob. The car drives fantastic. Having a steady idle after 12+ years of ownership is a thing of beauty. And just in time to enter the car into the Edmonds car show in Sept 8th! What a journey! Although extremely frustrating at times, I sure learned a lot through the process. Thanks for all the input/help from everyone! A huge congratulations to you. I like your approach; check everything and repair it. Newbies take note: these are 50 year old cars. You cannot rely upon any 50 year old part. Looks like your good for another 50 now! (IMG:style_emoticons/default/beerchug.gif) |
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