1999 454 Mag MPI just quits - videos

douglee25 said:
Verify part numbers, but this company sells the pump and the regulator (reuse the cooler). The genuine pump and cooler (no regulator) is about $830 from Mercruiser.

Free shipping and lifetime warranty. I used them before for ATV pumps. I couldn't tell the difference from OEM.

www.highflowfuel.com

QFS OEM High Pressure Fuel Pump w/ Regulator for Mercury Mercruiser, V6/V8 305/350/377/454/502 EFI, Replaces 861156A1, 807949A1, Sierra 18-35433

The Authority in OEM Quality and Affordable Powersports Replacement Parts. Shop with confidence. Guaranteed fit, backed by a lifetime warranty.
www.highflowfuel.com www.highflowfuel.com
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Great price!!!
 
370Dancer said:
I am not quite following the logic behind the FPR causing a loss of pressure at the rail, UNLESS the diaphragm was compromised, allowing fuel to run up the vacuum line into the intake plenum. And, if it's busted, wouldn't it stay busted instead of time (heat) related? Never the less, I'll check that first. Seems like I would have smelled or seen gas when I removed the plenum to check for injector o-ring leaks. There is no hint of gas anywhere around the engine. The FPR is in the Cool Fuel 2 enclosure, not on the rail like early models, so it's same level of effort as doing the HP pump. Finally, the hose from the FPR to the plenum is brand new.
This is the MEFI-3 version of the Cool Fuel 2 system. FPR is in the pump assembly, so same level of effort as changing the HP pump.
My tank gas is 3.5 years old. Even as rec fuel, I'm sure the combustion properties are gone, or severely reduced. Gonna have to throw away 200 gallons. So running off of known good tanks 6 gallons at a time. I don't want to be chasing ghosts that are bad fuel related, thinking it's something else.
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The FPR is on the return leg of the fuel system (after the injectors). If it fails open or sticks the rail pressure will drop and injectors will not properly spray the fuel. The pressure regulates based upon manifold pressure - that is what the little rubber hose going to it is for. Anyhow I've seen them act erratically due to sticking.
 
ttmott said:
The FPR is on the return leg of the fuel system (after the injectors). If it fails open or sticks the rail pressure will drop and injectors will not properly spray the fuel. The pressure regulates based upon manifold pressure - that is what the little rubber hose going to it is for. Anyhow I've seen them act erratically due to sticking.
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I have a new regulator in the bag, so while I'm in there.......
I did see the QFS pumps. I got something similar but already had a regulator. I'm gettin on it. Finally a few days of nice weather where I'm not stuck doing something else.
 
meh

milkshake 2.jpeg
milkshake-1.jpeg


No breaks on this side of the planet.......
I'll change it and see if it's rising. Good compression, and not losing closed cooling at all. WTF? Maybe leftover from when I had the stuck valve and bent pushrod, but don't remember seeing chocolate. PPPPFFFFFTTTT.
 
370Dancer said:
meh

View attachment 159708View attachment 159709

No breaks on this side of the planet.......
I'll change it and see if it's rising. Good compression, and not losing closed cooling at all. WTF? Maybe leftover from when I had the stuck valve and bent pushrod, but don't remember seeing chocolate. PPPPFFFFFTTTT.
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I vote for left over from all the work. If you doubt it .....throw a pressure tester on it and see what happens. My bet is that it is fine. A coolant leak sucks coolant out of the exchanger and reservoir.

My Slant pressure tester takes the guess out of situations like this.
 
I know some head bolts run into water jackets on big blocks
 
Scott215 said:
I know some head bolts run into water jackets on big blocks
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Yup.....but he doesn't think he is losing coolant.....so a pressure test proves it one way or another. If the pressure test is good then it could be one of the oil coolers.
 
Or maybe never getting it up to temp to "burn off" the moisture in the crankcase. Especially in humid weather, short trips and never running long enough to burn off moisture leads to the milk shake on the fill cap.
 
Bill Curtis said:
Or maybe never getting it up to temp to "burn off" the moisture in the crankcase. Especially in humid weather, short trips and never running long enough to burn off moisture leads to the milk shake on the fill cap.
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Right - it's not uncommon to see the white milkyness in the valve covers on a cold engine. If the crankcase oil doesn't show any signs then cool moist air is getting in through the crankcase vent in the valve cover. Get the temperature up then take an oil sample and get it analyzed. $35 and you'll know.
 
ttmott said:
Right - it's not uncommon to see the white milkyness in the valve covers on a cold engine. If the crankcase oil doesn't show any signs then cool moist air is getting in through the crankcase vent in the valve cover. Get the temperature up then take an oil sample and get it analyzed. $35 and you'll know.
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crankcase oil is milky. That's the brown tube extracting in the pic. It's not the coolant side, that hasn't moved. dipstick was 3-4 inches over full, so it's coming in from somewhere. Typically, I have seen an oil cooler fail, and allow water in. I'll remove and pressure test that to confirm or deny. Then, I'll switch to electric (or take up golf). I will also check the exhaust manifold for intrusion. I have a bad feeling that my new manifold has a casting failure, costing me this engine if true.
 
370Dancer said:
crankcase oil is milky. That's the brown tube extracting in the pic. It's not the coolant side, that hasn't moved. dipstick was 3-4 inches over full, so it's coming in from somewhere. Typically, I have seen an oil cooler fail, and allow water in. I'll remove and pressure test that to confirm or deny. Then, I'll switch to electric (or take up golf). I will also check the exhaust manifold for intrusion. I have a bad feeling that my new manifold has a casting failure, costing me this engine if true.
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O yea - if it wasn't for bad luck.....
 
changed the oil today. Let it settle, and made note of the dipstick level. Started and ran the engine for 10-15 minutes, well up to operating temp, 700 to 2500 rpms. shut down, and waited for 15 minutes for oil to drain back. and checked the dipstick. Oil did not change color, (still a bit milky from existing) or rise or fall in level. That tells me that the oil cooler is not leaking internally. overflow tank in closed cooling didn't move either.
So, maybe the encounter with the stuck valve and water intrusion into the exhaust manifold and intake plenum a few months ago was enough to cause what I saw. Will change again tomorrow, and move ahead changing the plugs, taking a peek in each cylinder with my borescope camera, and making sure timing is set right. Then, back out for sea trial again.
 
Hope everything works out
 
Did you check the lining of the exhaust hoses? I believe I mentioned it back in October. Just want to make sure the water is getting through the exhaust hoses.
 
@PlayDate My exhaust hoses are less than 24" long with water lift mufflers. All are intact, and visual inspection is pretty easy.
@douglee25 The latest:
Success on the oil change. It is clear, and not rising with running the engine. I have to assume that the water intrusion into the oil was from the previous exhaust leakage, and didn't get mixed up until I started running the motor a lot more.
What I am facing right now, that is happening on both engines, is that the idle is low at minimum throttle, and the engines can stall when shifting in and out of gear. If it doesn't stall, it will surge up and down for few cycles until it stabilizes. The Stbd is somewhat "worse" on this issue, requiring some throttle to keep the engine running, even after warmup. I am skeptical that I am not getting enough fuel, although I am running off of 6 gal portable tanks with 3/8" lines, and a ball valve (possibly reducing that diameter even more) at the tanks. The engines do act that way, though.
So, back to basics. I have ignition spark on all wires. I have new plugs, although the old ones weren't fouled. I will be recording more info about TPS % and voltage, along with MAP and vacuum. IAC's seem to be working just fine, and they are new as well.
At zero throttle (mechanical), the idle is 650 or a bit lower. Under load of shifting, it drops as expected, before recovering, but sometimes not fast enough to prevent a stall. If I add some throttle, and base them more like 750 rpm, things get more predictable. If I drop the throttles to zero, the engines will stall. Not good in general for docking......
I had put some pre-load on the throttle cables to ensure the butterflies were closed at zero throttle, and now I'm thinking perhaps I got too aggressive with that. I also want to recheck and reset idle timing in service mode before touching anything else, in case that has moved since setting it a couple of months ago and continuing to troubleshoot.
I am close enough to taste it, but schedule doesn't allow me the time to play mechanic for long stretches.
Comments on why dead idle is low, and why the engine wants to surge and fall when recovering from a load are appreciated.
I am about to qualify for my Masters in YouTube mechanics. That happens when you can't find vids on your issues, and have to make them yourself.
 
370Dancer said:
@PlayDate My exhaust hoses are less than 24" long with water lift mufflers. All are intact, and visual inspection is pretty easy.
@douglee25 The latest:
Success on the oil change. It is clear, and not rising with running the engine. I have to assume that the water intrusion into the oil was from the previous exhaust leakage, and didn't get mixed up until I started running the motor a lot more.
What I am facing right now, that is happening on both engines, is that the idle is low at minimum throttle, and the engines can stall when shifting in and out of gear. If it doesn't stall, it will surge up and down for few cycles until it stabilizes. The Stbd is somewhat "worse" on this issue, requiring some throttle to keep the engine running, even after warmup. I am skeptical that I am not getting enough fuel, although I am running off of 6 gal portable tanks with 3/8" lines, and a ball valve (possibly reducing that diameter even more) at the tanks. The engines do act that way, though.
So, back to basics. I have ignition spark on all wires. I have new plugs, although the old ones weren't fouled. I will be recording more info about TPS % and voltage, along with MAP and vacuum. IAC's seem to be working just fine, and they are new as well.
At zero throttle (mechanical), the idle is 650 or a bit lower. Under load of shifting, it drops as expected, before recovering, but sometimes not fast enough to prevent a stall. If I add some throttle, and base them more like 750 rpm, things get more predictable. If I drop the throttles to zero, the engines will stall. Not good in general for docking......
I had put some pre-load on the throttle cables to ensure the butterflies were closed at zero throttle, and now I'm thinking perhaps I got too aggressive with that. I also want to recheck and reset idle timing in service mode before touching anything else, in case that has moved since setting it a couple of months ago and continuing to troubleshoot.
I am close enough to taste it, but schedule doesn't allow me the time to play mechanic for long stretches.
Comments on why dead idle is low, and why the engine wants to surge and fall when recovering from a load are appreciated.
I am about to qualify for my Masters in YouTube mechanics. That happens when you can't find vids on your issues, and have to make them yourself.
Click to expand...
It's not a fuel issue. It's either air or ignition timing. Check to see if there is a microswitch on the shift selector mechanism (usually on the engine). This is used to signal the ECM to advance the timing when the engine drops into gear. Some configurations had it some not - I'm not sure. The second thing is to clean the Idle Air Control Valve- it may be sticking and not moving fast enough to add the needed air to increase the RPM. But didn't you replace the IAC - I seem to remember you did....
 
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