Perplexing 5.7GSI PEFS Fuel Problem Wont start - good fuel pressure & clean injectors
Hello all. I have a very perplexing problem, and hopefully somebody has some insight as to what I should check next, since I am out of options.
I have a 2000 248 Vista with a 5.7 GSI PEFS & DP-SM 195 drive. The boat ran great last year, but the oil pan rotted out so I ended the season early, and pulled the engine. While I had the engine out I did a mild overhaul, but didn't tear past the short block. I also sent out my injectors to be rebuilt, and when they returned I rebuilt my TBI.
Two weeks ago I dropped the engine in, aligned it, and bolted everything back up. Unfortunately it would not start. I went through the normal diagnostic procedure. I saw fuel spraying from both injectors, so I assumed it was an ignition problem. I double checked my firing order, and verified spark at each plug. This checked out, so I moved on to a compression test. I have 175 PSI at each cylinder, so the problem is not mechanical. Next I decided I would prime the engine with some fuel in the intake. I dumped a table spoon of fuel past the butterfly, and the engine fired up the second I turned the key. It continued to run until it ran out of the fuel I supplied it with.
At this point, I determined it was fuel related (the injectors either not flowing enough fuel per pulse, or not pulsing fast enough). First I checked fuel pressure, which is good @ 8 psi low & 30 psi high. I checked for vapor lock by bleeding the system multiple times, even though this should not exist. Then I decided to rebuild the TBI again just to be safe. New o-rings, diaphragm, gaskets, etc. This still provided the same result, that the engine will run if fuel is supplied, but not on its own fuel supply. At this point I do not think the problem lies in the fuel pump, as I have correct pressure, and it will fill up a coffee cup in 2 seconds if disconnected.
I tried disconnecting the TPS and MAP, with no change. separate fuel supply from a known clean source, no change. New water separator, no change.
The injectors appear to be firing rapidly, but that is a subjective observation. No leaks are present.
I am at the point where I am considering buying new injectors from Rock Auto just to rule them out.
https://www.rockauto.com/catalog/raframecatalog.php?ck[ID]=0&ck[idlist]=0&ck[viewcurrency]=USD&ck[PHP_SESSION_ID]=qbffopi7t2tsns21f0idk5k070
What am I missing here? I had a running engine in the fall, and still have a running engine (if you supply it fuel manually). The TBI itself is not leaking, and holds pressure. The last two things I can think of is the injectors themselves, or a computer problem.
For whats its worth, I have one wiring harness not plugged in to anything, but I have no idea where it goes. All the sensors are hooked up appropriately, and there are no other missing connections. I will take a picture later today, but I will describe it. There is a 32 pin connector which comes off the ECM, but it only has one pin in the whole connector, with a black wire leading into it. I then have a male 32 pin connector which plugs into it, and branches off into two separate two pin connectors (one male one female) with black wires. This connector has no power, and no apparent home. They are the exact same connector style as the fuel pump. Other than this, every single ground wire, connection, etc. is all spoken for. I also have an MEFI scan tool (basic style), and I can communicate with the ECM. Initially when I scanned it, I had many different codes, but I attribute this to all the times I tried disconnecting sensors and running the engine, and low voltage after cranking one afternoon. I cleared the codes to start fresh, and none have returned. I just have code 12 flashing in a loop.
I am at a loss. What should I do next? Buy a new set of injectors to rule it out? Then if that doesn't solve it, is there any input to the ECM that could case this to happen, or is the ECM itself bad? I have only had this boat for a year, but I am aware the ECM has been replaced before due to a failure three years ago. That is all the information I can dig up.
I will be forever in debt to anyone who can point me in the right direction.
Hello all. I have a very perplexing problem, and hopefully somebody has some insight as to what I should check next, since I am out of options.
I have a 2000 248 Vista with a 5.7 GSI PEFS & DP-SM 195 drive. The boat ran great last year, but the oil pan rotted out so I ended the season early, and pulled the engine. While I had the engine out I did a mild overhaul, but didn't tear past the short block. I also sent out my injectors to be rebuilt, and when they returned I rebuilt my TBI.
Two weeks ago I dropped the engine in, aligned it, and bolted everything back up. Unfortunately it would not start. I went through the normal diagnostic procedure. I saw fuel spraying from both injectors, so I assumed it was an ignition problem. I double checked my firing order, and verified spark at each plug. This checked out, so I moved on to a compression test. I have 175 PSI at each cylinder, so the problem is not mechanical. Next I decided I would prime the engine with some fuel in the intake. I dumped a table spoon of fuel past the butterfly, and the engine fired up the second I turned the key. It continued to run until it ran out of the fuel I supplied it with.
At this point, I determined it was fuel related (the injectors either not flowing enough fuel per pulse, or not pulsing fast enough). First I checked fuel pressure, which is good @ 8 psi low & 30 psi high. I checked for vapor lock by bleeding the system multiple times, even though this should not exist. Then I decided to rebuild the TBI again just to be safe. New o-rings, diaphragm, gaskets, etc. This still provided the same result, that the engine will run if fuel is supplied, but not on its own fuel supply. At this point I do not think the problem lies in the fuel pump, as I have correct pressure, and it will fill up a coffee cup in 2 seconds if disconnected.
I tried disconnecting the TPS and MAP, with no change. separate fuel supply from a known clean source, no change. New water separator, no change.
The injectors appear to be firing rapidly, but that is a subjective observation. No leaks are present.
I am at the point where I am considering buying new injectors from Rock Auto just to rule them out.
https://www.rockauto.com/catalog/raframecatalog.php?ck[ID]=0&ck[idlist]=0&ck[viewcurrency]=USD&ck[PHP_SESSION_ID]=qbffopi7t2tsns21f0idk5k070
What am I missing here? I had a running engine in the fall, and still have a running engine (if you supply it fuel manually). The TBI itself is not leaking, and holds pressure. The last two things I can think of is the injectors themselves, or a computer problem.
For whats its worth, I have one wiring harness not plugged in to anything, but I have no idea where it goes. All the sensors are hooked up appropriately, and there are no other missing connections. I will take a picture later today, but I will describe it. There is a 32 pin connector which comes off the ECM, but it only has one pin in the whole connector, with a black wire leading into it. I then have a male 32 pin connector which plugs into it, and branches off into two separate two pin connectors (one male one female) with black wires. This connector has no power, and no apparent home. They are the exact same connector style as the fuel pump. Other than this, every single ground wire, connection, etc. is all spoken for. I also have an MEFI scan tool (basic style), and I can communicate with the ECM. Initially when I scanned it, I had many different codes, but I attribute this to all the times I tried disconnecting sensors and running the engine, and low voltage after cranking one afternoon. I cleared the codes to start fresh, and none have returned. I just have code 12 flashing in a loop.
I am at a loss. What should I do next? Buy a new set of injectors to rule it out? Then if that doesn't solve it, is there any input to the ECM that could case this to happen, or is the ECM itself bad? I have only had this boat for a year, but I am aware the ECM has been replaced before due to a failure three years ago. That is all the information I can dig up.
I will be forever in debt to anyone who can point me in the right direction.
