1998 7.4 MPI Stalls While Running on Step
04-02-2016, 02:22 PM
#22
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I am sure many would like to get an update and some more detailed info - including myself.
Thinking logic after getting more detailed scripts from you thru out the thread - would point to these problems areas first especially shifting back in N gear.
Kill switch
and or N safety switch
and or Key switch
and at all times proper voltage and constant voltage and solid connections with no out of spec resistance
If all of this has been 100 % detailed checked and good to go - I do have some other ideas
This thread is interesting most likely to many including myself. So what updates do you have ???
Thinking logic after getting more detailed scripts from you thru out the thread - would point to these problems areas first especially shifting back in N gear.
Kill switch
and or N safety switch
and or Key switch
and at all times proper voltage and constant voltage and solid connections with no out of spec resistance
If all of this has been 100 % detailed checked and good to go - I do have some other ideas
This thread is interesting most likely to many including myself. So what updates do you have ???
Last edited by BUP; 04-02-2016 at 03:50 PM.
04-02-2016, 02:56 PM
#23
Registered
iTrader: (1)
In regards to the engine saving spark plugs, Does your mechanic smoke pure weed or is something mixed in with it ?
04-02-2016, 03:55 PM
#24
Banned
iTrader: (9)
Said he tested with a remote fuel tank afterwards and still did the same thing. I can understand a fuel pick up and or its screen getting clogged from crap in the gas tank or the anti siphon valve sticking or restricted but the phrase the spark plugs are fail safe designed to protect the pistons ??? huh ?
I missed that post completely.
I missed that post completely.
04-02-2016, 05:35 PM
#25
Registered
Said he tested with a remote fuel tank afterwards and still did the same thing. I can understand a fuel pick up and or its screen getting clogged from crap in the gas tank or the anti siphon valve sticking or restricted but the phrase the spark plugs are fail safe designed to protect the pistons ??? huh ?
I missed that post completely.
I missed that post completely.
04-04-2016, 01:24 PM
#26
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I have tried to reply with all the facts a couple times and the site will not let me. It ask me to refresh the page and sign in again when I try to post. Then half of what I wrote was not saved. Main thing is now it looks like the fuel pump has failed. The next move is to sell it as is for which I may have a buyer or take it to the shop. I am tired fooling with it. Again thanks for all the input and interest, I have used much of the advice during all the trouble shooting.
04-04-2016, 04:16 PM
#27
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I have tried to reply with all the facts a couple times and the site will not let me. It ask me to refresh the page and sign in again when I try to post. Then half of what I wrote was not saved. Main thing is now it looks like the fuel pump has failed. The next move is to sell it as is for which I may have a buyer or take it to the shop. I am tired fooling with it. Again thanks for all the input and interest, I have used much of the advice during all the trouble shooting.
04-04-2016, 05:26 PM
#28
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If was something like a bad voltage reg , causing the ecm to see too much once the rpms come up at cruise, could or would that do this, or is the recovery too quick? Just thinking out loud..
04-04-2016, 08:46 PM
#29
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This is history of problems.
1. Boat running fine at WOT when it acted as if it was running out of fuel. Found the pick up tube in the fuel tank plugged. Tried to remove it but aluminum tank and aluminum fitting galled and will not back out. So replace pick up tube in another fitting on tank, changed fuel hose and new fuel filter.
2. Ran again and it had developed a miss and would not tach out, only 4,000 RPMs. Discussed this with local mechanic and he suggested " check the spark plugs, when pick up tube was plugging up fuel pressure went down and caused the engine to lean out creating heat in the cylinders and possibly damaging a spark plug".
3 Pulled the plugs and found 2 with cracked ceramic on the electrode. Put another set in and the miss was gone.
4 Took boat out for a test run and it jumped on top normally and ran great for about 2 minutes then just died, no sputter or warning. It started right back up and did the same thing 2 more times. Idled it home.
5. Changed the fuel filter and went out again and stall problem was gone but would not go past 4,000 RPMs. Ran it for about 2 hours with the Test Tool hooked up. No codes, Gallons per hour about 30 and volts 14.
6. Put fuel pressure gauge on it. When started it held 32 PSI. When RPMs increased pressure dropped below 30 PSI. This is MEFI 2 so pressure should be 32 to 38 PSI. Did not take it out and run it with pressure gauge only tested in lift.
7. Took it out a few days later. Had to idle about 30 min. to get past no wake zone. It only idled about 10 min. and acted like it ran out of gas. Pulled the filter had a little trash and some water.
8. Had to tie up. Went home returned with portable tank and fresh gas. Did not have another filter so filled old one with fresh gas and hooked portable tank with primer bulb to engine. Pumped bulb to make sure. Engine started for only a few seconds and died. Would not start again. Towed it home.
9. During all of this the neutral switch and kill switch have been bypassed and all electrical connection are clean and tight. Think fuel pump finally went out. Debating whether I will keep working on it or bring it to the shop.
1. Boat running fine at WOT when it acted as if it was running out of fuel. Found the pick up tube in the fuel tank plugged. Tried to remove it but aluminum tank and aluminum fitting galled and will not back out. So replace pick up tube in another fitting on tank, changed fuel hose and new fuel filter.
2. Ran again and it had developed a miss and would not tach out, only 4,000 RPMs. Discussed this with local mechanic and he suggested " check the spark plugs, when pick up tube was plugging up fuel pressure went down and caused the engine to lean out creating heat in the cylinders and possibly damaging a spark plug".
3 Pulled the plugs and found 2 with cracked ceramic on the electrode. Put another set in and the miss was gone.
4 Took boat out for a test run and it jumped on top normally and ran great for about 2 minutes then just died, no sputter or warning. It started right back up and did the same thing 2 more times. Idled it home.
5. Changed the fuel filter and went out again and stall problem was gone but would not go past 4,000 RPMs. Ran it for about 2 hours with the Test Tool hooked up. No codes, Gallons per hour about 30 and volts 14.
6. Put fuel pressure gauge on it. When started it held 32 PSI. When RPMs increased pressure dropped below 30 PSI. This is MEFI 2 so pressure should be 32 to 38 PSI. Did not take it out and run it with pressure gauge only tested in lift.
7. Took it out a few days later. Had to idle about 30 min. to get past no wake zone. It only idled about 10 min. and acted like it ran out of gas. Pulled the filter had a little trash and some water.
8. Had to tie up. Went home returned with portable tank and fresh gas. Did not have another filter so filled old one with fresh gas and hooked portable tank with primer bulb to engine. Pumped bulb to make sure. Engine started for only a few seconds and died. Would not start again. Towed it home.
9. During all of this the neutral switch and kill switch have been bypassed and all electrical connection are clean and tight. Think fuel pump finally went out. Debating whether I will keep working on it or bring it to the shop.
