350Magmpi

[Masinc]

Got the Rhinda gadget working…..more questions.

 

[Masinc]

IAC solenoid is toasty. Idle is too low (560). Out of water (trimmed in most of the way) RPM advanced to 4000 just to check console tach and see if I could get oil pressure to fall off at idle. Second run got a long tone beep (possible rpm exceedance sensor not working IDK). Oil Px still okay but down from 50’s to 22. Check out the fuel Px attached.

 

[Scott Danforth]

Your fuel should not drop below 43psi

 

[Masinc]

Your fuel should not drop below 43psi

Books made today so I can start a more focused approach. Still dont see how the vacuum source from intake brings fuel pressure down…what part is failing…which regulator or pump. No data on why the IAC solenoid is so hot so quick. Why does a plug removed from fuel injector not show some fault. I can squeeze off the IAC hose and bog the engine down and that doesnt code either. Got a lot to learn

 

[Scott Danforth]

Without the engine load reference signal (vacuum) the pump should be pushing about 50psi

I would be looking at inlet restrictions

 

[Masinc]

Without the engine load reference signal (vacuum) the pump should be pushing about 50psi

I would be looking at inlet restrictions

I did remove the water seperator filter and carefully poured out what I could. Bout a 1/2 teaspoon of untrapped water is all I could capture but yeah I pretty sure this rig has suffered a water intrusion event. And contaminated fuel. I managed to pull my little Optimax out of the grave so I figure I can clean this one up too. Just gonna take a lot more effort this time.

 

[Scott Danforth]

You didn't reuse the filter, did you?

 

[alldodge]

Fuel pressure should maintain 43 psi give or take no matter what the manifold vacuum is.

Dropping below this is an issue

Lets start with a engine serial number so we know what your working on. There are a lot of 350 mag MPI's but many of them have different inputs causing different faults/outputs

 

[Masinc]

You didn't reuse the filter, did you?

Well only for testing purposes. I aint about to launch it till all this irractic idle and on plane hesitation and intermttent growling issues are handled. Once I get into the manuals tomorrow I plan to perform a full yearly service event so I can start a record book. All my piddling to this point is more familiarization and experimenting with activities that do or do not yield any changes. I hope to get a few extra filters ordered next pay cycle. My first trip to the boat shop has left a bad taste. They just went nuts on my engine and out drive oil and filter order…and $$$$ wow. I hope the shop guys get some of the loot.

 

[Scott Danforth]

Once you pull the fuel filter, you contaminated the clean side

 

[alldodge]

Suggest give it a rest

 

[Masinc]

Once you pull the fuel filter, you contaminated the clean side

 

[Masinc]

Well one way of looking at that is maybe if i break it bad enough the computer will report something or engine will quit bad enough to finally find something to fix. So far any thing I have tinkered with has had no continuous effect (good or bad). I figure the cool fuel pump is screwed anyway and no telling what kind of paint chips are hanging out in the injector rail. A little water aint gonna hurt it now. Any idea on what the ohms reading is on the IAC coil? Cant imagine it getting that hot that quick. A little warm yeah but up to 161*f pretty quick dont feel right.

 

[Masinc]

Finally got the boat shed roof on. Recieved and studying manual 36. Gathering test t-pins and fluke multimeter. Neighbour’s v-6 boat acted up and cost him a starter and oil pressure sending unit. I think I will give his technician a try when we start planning the gimble update. I do want to try to give the boat tech’s some work but the last two shall not be represenative of the whole vocation.

 

[QBhoy]

Well one way of looking at that is maybe if i break it bad enough the computer will report something or engine will quit bad enough to finally find something to fix. So far any thing I have tinkered with has had no continuous effect (good or bad). I figure the cool fuel pump is screwed anyway and no telling what kind of paint chips are hanging out in the injector rail. A little water aint gonna hurt it now. Any idea on what the ohms reading is on the IAC coil? Cant imagine it getting that hot that quick. A little warm yeah but up to 161*f pretty quick dont feel right.

161 is about exactly the temperature your engine block and coolant water temp will be…no doubt having a conductive heat transfer to anything close by or attached to. 160 t stat spec might just about back up my thinking perhaps.

 

[Masinc]

Fabricated oil change extraction rig today with some scraps from around shop (old weed spray tank) and used the A/C vac pump. Oil was decent; not really burnt or stinking of gas or frothed with water but pumped 8-1/2 quarts out. Looked in parts book and engine manual and looks like it has the wrong stick in it. About 2” too short so it has way too much oil in it. Best I can tell it should have 4-1/2 quarts. I suspect the oil gets foamed up from the crank/rods splashing too much and probably negatively affecting oil pressure. So new oil filter installed, new IAC muff and upon futher confirmation of quantity I will put some of the Merc oil in it. Removed low pressure fuel pump and it’s screen had trash in it. Looked to be organic instead of my suspected rubber fragments. Installed new pump, spin-on fuel filter and relieved the nearly kinked rubber fuel line but no change in peak fuel pressure. So now its on to the fun pump. Hopefully the new regulator and high px pump will bring the pressure to spec.

 

[Masinc]

So while I wait for the new fuel pump regulator I polked around some more. Access to the port side pump will be a fine chore. I carefully removed the vac line from the regulator and sure enough it is breached and rusty inside the damaged portion of hose and definately loosing vac. Hopefully this pump and regulator update will lead to an improvement.

 

[Masinc]

So I finally got the fuel cooler rig out. Found two orings on the elbow were shaved so I am glad to discover and get that resolved. The little regulator had thread tape around the threads but way too much of it ended up inside the regulator. Dought that was helping anything. The tiny screen seemed to be clear but there were some bits in the pump screen. Drained the out drive system and found the resevoir had about a third of the lower portion contaminated with some kind of sludge. Removed and washed out the tank and cleaned the the two wire connectors so hopefully the float is not ruined. Oil the came out of lower end was black. Its a shame that equipment like this gets neglected and then lied about just to sell it. I havent checked hours on the Optimax for last season but when I changed gear oil it was still blue. The used stuff makes great chainsaw bar oil. Greased the coupling and fingers crossed I can get a few more outings while we save $$$ for the gimble update. Removed shift cable from upper bracket and applied the new rigging tool and sure enough it is going to need adjustment. Got my Uniden comm radio operational but missing the gps side so I cant set up the emegancy address yet but at least we can call for help and get weather updates.

 

[alldodge]

The used stuff makes great chainsaw bar oil

Never thought of that, thanks
I just dump it in with old oil and recycle it

 

[Masinc]

So I convinced the fuel cooler to get back into its nest with some extra thermal paste. Starts and runs. Warmed up to same 165ish water temp as during our last lake trip and 50ish oil pressure prevails with 42ish fuel pressure and 16-17”in MAP. Ran it for about 15 minutes beyond that at around 2500rpm and oil pressure finally came down to about 40 so I made a rapid deceleration to neutral and oil pressure stays just slightly above 20 now instead of barely 10. Not a timed study but it takes a pretty long time for fuel pressure to drop below 35 after shut down so MAYBE I have gained some high ground on this beast. I imagine everybody else has similar tricks but some extra telescope magnets and those long rubber hose picks help parts retreival from the pit.