Problem Resolved [was I'm Stumped], Runs briefly, then dies & won't restart |
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Problem Resolved [was I'm Stumped], Runs briefly, then dies & won't restart |
ThinAir |
Aug 2 2008, 04:04 PM
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#1
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Best friends Group: Members Posts: 2,543 Joined: 4-February 03 From: Flagstaff, AZ Member No.: 231 Region Association: Southwest Region |
Background: In preparation for last year's RRC I fixed the mounting on the MPS of my son's stock 1971 914-4. All seemed well until we went out for the Saturday morning run - we turned a corner and the engine suddenly died and was clearly flooded. It restarted quickly, but we had the same problem several times on that trip after that.
I assumed that I had disturbed something electrical on the passenger side of the engine and in digging around I discovered that the wire connecting the Cylinder Head Temp Sensor was corroded at its base (in fact it fell off in my hands). Ok, this is simple I said - so I bought and installed a new CHT. Current Problem: The engine will start, but runs for only about 30 seconds before it dies. At that point it will not restart, but it smells of fuel as if it is flooded. I've checked for spark and I have spark. I've disconnected, cleaned and reconnected every electrical connection on the engine & relay board that I can find - including every relay on the board. The only connections that I have not checked are the connector where the FI harness connects to the brain. Does anyone have any ideas on what could cause this and where to look next? |
ThinAir |
Aug 2 2008, 05:08 PM
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#2
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Best friends Group: Members Posts: 2,543 Joined: 4-February 03 From: Flagstaff, AZ Member No.: 231 Region Association: Southwest Region |
A check of Pelican Parts has this description of the MPS:
"The pressure sensor is the key component of the MPC (Manifold Pressure Control) D-Jetronic fuel injection system. Its function is to measure the amount of vacuum being drawn into the engine. Based on the amount of vacuum being drawn, it sends a electrical signal to the fuel injection computer. Based on this signal, as well as the two temperature sensors mounted in the system, it controls the fuel-air mixture. When these sensors fail, they typically cause the engine to run rich at all times and lose power under acceleration." That sounds like it fits pretty well with what I'm experiencing. Of course PP also says it's NLA. Does anyone know of a source? |
justdrive914 |
Aug 2 2008, 07:30 PM
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#3
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Member Group: Members Posts: 88 Joined: 31-July 08 From: Asheville, NC Member No.: 9,374 Region Association: South East States |
A check of Pelican Parts has this description of the MPS: "The pressure sensor is the key component of the MPC (Manifold Pressure Control) D-Jetronic fuel injection system. Its function is to measure the amount of vacuum being drawn into the engine. Based on the amount of vacuum being drawn, it sends a electrical signal to the fuel injection computer. Based on this signal, as well as the two temperature sensors mounted in the system, it controls the fuel-air mixture. When these sensors fail, they typically cause the engine to run rich at all times and lose power under acceleration." That sounds like it fits pretty well with what I'm experiencing. Of course PP also says it's NLA. Does anyone know of a source? Of course there are places to get them, Auto atlanta for around 240.00 plus and performance products for around 190.00, lots of used parts people to, German auto dismantlers and many others |
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