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cam vs howell fuel injection |
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Posimoto
AMC Apprentice Joined: Jan/11/2013 Location: Ma Status: Offline Points: 71 |
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Installed the new TPS, still code 34 790rpm @ 14" vac. The old one had a
problem with the signal at 3/4 open, went from 3.9 to .4, full open was
.45 The plates were closed at .68
I have .5v and a good ground at the map. checked all the wires from the map to the ecm. I tested the map with a vac pump as well and have all the correct readings at 5" 10" and 20". The map sensor holds vac, hose is less then 11" in good shape. The tests tell me the map is good along with the wiring yet it keeps pointing back to the map sensor. I started with an intermittent code 33 I fixed the intake leak, still had an intermittent code 33 . I unplugged the map then had a steady light for code 34. It has me wondering, although the map checks out good, it could be bad? I'm having a hard time justifying buying a new map sensor when I already tested the one I have to be good. |
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tufcj
Supporter of TheAMCForum Supporter of TheAMCForum Joined: Jul/10/2007 Location: Watkins, CO Status: Offline Points: 4065 |
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Have you tried resetting the ECU by disconnecting the battery for a minute minimum. Your check engine light may be residual. The light generally won't clear buy itself unless you complete 3 full warmup/drive cycles and the error doesn't recur.
Bob tufcj |
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69 AMX
74 Javelin AMX 67 Rogue If you need a tool and don't buy it... you'll eventually pay for it... and not have it. Henry Ford |
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Posimoto
AMC Apprentice Joined: Jan/11/2013 Location: Ma Status: Offline Points: 71 |
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Yes, disconnected the battery before installing the TPS.
My local AA said I could return the map sensor if it didn't solve my problem. |
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Posimoto
AMC Apprentice Joined: Jan/11/2013 Location: Ma Status: Offline Points: 71 |
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No change after installing the new map sensor. My tests on the original was correct, it works as it should. I returned the new sensor to AA.
By the process of elimination it has to be the o2 sensor. |
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tsanchez
AMC Addicted Joined: Jul/09/2007 Location: Arizona Status: Offline Points: 4302 |
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Without scan data I would stop guessing at it.
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tsanchez
AMC Addicted Joined: Jul/09/2007 Location: Arizona Status: Offline Points: 4302 |
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Posimoto
AMC Apprentice Joined: Jan/11/2013 Location: Ma Status: Offline Points: 71 |
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I wouldn't say I'm guessing, rather troubleshooting. I pulled the o2 sensor and bench tested it. The numbers were off as expected. Heading out now to pick one up at AA.
Thanks for the link! |
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Posimoto
AMC Apprentice Joined: Jan/11/2013 Location: Ma Status: Offline Points: 71 |
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The O2 sensor's bench test numbers indicated it was sluggish, it probably just needed to be cleaned after the PO ran it with an intake vac leak but for the $15 I bought and installed a new one. Still code 34, 14" vac
When I installed the new TPS it corrected the throttle dead spot. I checked the setting on the TSP and found .88v ( should be .5v-.7v). My TB came with a fixed TPS ( non-adjustable) so I tried to adjust the voltage by moving the throttle plates. I ran out of adjustment (fully closed) and still had .84v and the plates in this position would not allow the engine to start without opening the throttle plates. I decided to elongate the holes in the TPS to gain movement and after a few tries, plus grinding down one of the screw's washers I was able to get it down to 7.38. Prior to elongating the holes I reset the throttle plates to gain some adjustment room I was now able to set the TPS to 6.9v and have the plates in a position so that I could start the engine. Still code 34 and 14” vac. If you've been reading my thread you know the map sensor, plug, and wires were tested good. I decided to go back to the map sensor wiring to see if I missed something. I checked continuity on the three wires going from the plug to the ecm, as before, they were good. I also wiggled the wires with no change. I then decided to check each of the three wires from the map plug (voltage, signal, and ground) for continuity with all other pins in the ecm. I found continuity between ground at the plug (A, purple wire) to (C-9 pin purple/white at the ecm). This is a problem, the schematic doesn't show a connection between the two wires, C-9 is also the crank signal which should get 12v only in crank mode. It appears there is a short between the two wires or the po spliced the purple and purple with white tracer wires together at some point. If this is the case it may be sending the wrong voltage to the map sensor. If it ever stops snowing (47" with another 2' coming this weekend) I plan to run a wire from the A11 pin to the map ground. This should bypass the short and hopefully correct the code 34 and 14" vac. Edited by Posimoto - Feb/11/2015 at 5:44pm |
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Posimoto
AMC Apprentice Joined: Jan/11/2013 Location: Ma Status: Offline Points: 71 |
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Before I spliced in the new wire from A11 to map ground I wanted to check the crank sensor wire at the starter solenoid to the C-9 pin on the ecm. I found continuity so I checked the engine bay wiring by wiggling and moving them around but no change in the meter. I then rechecked the map ground to A-11 and C-9, last I checked I had continuity at both pins, tonight only at A-11.
I went ahead an spliced a new wire from A-11 to map ground, started the engine still code code 34 14" vac. About two weeks ago while the engine was running I moved some engine bay wiring to get at something and the engine rpms dropped, I moved it again and idle dropped again. I had to leave so I shut down the engine and planned to dig into the next day. The next day while the engine was running I moved and wiggled all the engine bay wiring and couldn't get the idle to drop or stumble. Looks like I have short to find so I'll post when I solved the problem. |
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Posimoto
AMC Apprentice Joined: Jan/11/2013 Location: Ma Status: Offline Points: 71 |
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For those who replied here are the results
Faulty map plug caused the code 34 Repaired the plug still ran rich with high idle Turned out the chip wasn't properly tuned for the engine All is good now. Thanks |
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