EASTER water test (502), updated

[Bryan Tuvell 33ZX]

Well, water test sucked, every sensor on the motor is in tolerance, we did find a few pins pushed back on the ECU connections, he took the plug apart and reset them in, we are now leaning toward the ECU, maybe it got damaged somehow.
We splash again in the morning with a new ECU and extra sensors and a merc dash unit that will plug into my dash harness to take my dash out of the loop, pretty neat.
Fuel pressure was 42 on top and strong, did not leak down when key was shut off either.
Timing was advancing correctly.
Compression remained good.
No codes.

What keyed us on the wiring harness was when we moved the merc comp to the other side of the engine bay the motor returned to normal.

My motor is NOT going into the safe/limp mode. She just runs like **** at 3500 rpm to 4000 and put the motor in some funky no power mode.

He said IAT normally has a number close to something, and when the condition arises IAC shoots sky high.

More tomorrow.
Nothing like a COLD 8am Easter Ride.
Bryan

[KMLFAMILY]

Good luck Bryan,I hope this Easter day turns out to be a good one for you.

[BUIZILLA]

Hmm, IAT is Intake Air Temperature and IAC is Intake Air Counts... two different deals entirely... IAC is dependent on throttle opening % and IAT is dependent on ambient temperature...

hmm...the mystery deepens..

I thought you took an ECM with you yesterday??

J

[Bryan Tuvell 33ZX]

We forgot the ECU at the shop.
IAC is new and working, fixed my starting problem.
On the technical side, when I have the symptom, timing is fine and all cylinders are firing.
I am waiting on my mech now.
Hoping for the best.

HAPPY EASTER!
Bryan

[MOP]

Hopefully its over with the new ECU those pins are probably the culprit that caused the crap out of the ECU. I've seen outboard packs die for the same reason. Hope Happy Easter is a Happy Day for you 502!

[Bryan Tuvell 33ZX]

Well, all bad.
What we did/swapped:
-MAP
-ECU
-Used Merc dash conrols
-IAC numbers shot up again, when were consistant yesterday, it is new.
-Dist is new, complete.
-IAT, odd thing was it had oil in it, odd. Swapped to a new one, did not help.
-New plugs
-New wires
-TPS sensor, swapper throttle bodies

Poodle to clarify my above, each of the 8 are recieving fire base on clipping the light to each wire.
Comp 150ish to 160 on all but #2, but within 10% and recovers when warm.

Still no codes.
So, it will now officially go into the the largest shop in the area with a full service department and Z-Care claim.

We are done.
Bryan

[BUIZILLA]

Okay, another stupid suggestion... :confused:

vacuum leak? re-torque intake manifold?

this IAC thingy is wierd...

I'm stumped..

J

[Bryan Tuvell 33ZX]

Good vac.
You are not the only one stumped.
Hopefully after my travels (3 weeks) I will come home and it will fixed and Z-Care will work as always for me.
I will keep you posted.

Bryan

Va Smoked ham a cook'n... :)

[MOP]

Boy this can get you real sour on the electrics related to the new fuelies. Question how much oil was up in the distributer or IAT, seems a bit odd. Is there a possibilty of you building crank case pressure. I have seen that happen when the crank case breathers were plugged up on automotive stuff. Don't make sense on boat stuff as they usualy have excellent crank case breathing. I know -0- about this new fuelie stuff but the oil thing got my attention.

[Bryan Tuvell 33ZX]

No oil in the dist.
The IAT is to the left underside of the plenum, almost the size of a spark plug.
Dist is fine, brand new.

Yep, electric sensor motors suck when they are broke but I would not trade it for an intake an carb any day.

Time heals all, even motors, my time has come.
Thanks
Bryan

[MOP]

God Bless! Glad I am off the wrenches these days, I only fool with my vintage stuff!

[Lil Grizz]

If the engine is running poor at higher RPMs I would seriously focus on your fuel pressre and injectors. It is possible that the FP regulator is failing or leaking. I know you say the pressure is holding at 42 but is it ramping up like it should be? What are the lower and upper limits on that pressure supposoed to be?

There is a pressure dampener on the fuel rail somewhere (looks like a mini blow off valve) and when they go bad sometimes they act like what you are describing. Its one of those parts that few people know what it is and fewer people ever think of checking.

Another thing that could be causing this issue is the hall effect ring inside the distributor. Its the pickup that tells your coil when to fire. They like to break loose and rotate back and forth making the timing erratic. This is easy to check, pop off the cap and rotor, see if the ring or the pickup is loose. If its loose replace it.

[Bryan Tuvell 33ZX]

Lil, Griz, book said 43 at the rail, or so that is what he told me, we were 42.

Distributor is brand new from merc.

She goes in the shop Thursday for a going over, ZCare was contacted today, I am going to let someone else deal with it.
Wish us luck and thanks for the info.

Bryan

[Air 22]

B..
What was the cause off all your problems..the beginning, 1st thing? 502's are usually ok to begin with but i'd missed when problems 1st began? Did you change something out etc then problems began? eek! hope I'm not in for issues as i changed out my manifolds and risers, plugs, wires, flame arrestor and impeller and(housing)etc but she runs fine so far. Any tips? wink

[Bryan Tuvell 33ZX]

Nope, started with a starting issue, needed gas to help her start, it was the IAC, instant fix in less than 10 minutes. I had some concerns over us prying the rotor off the distributor so I replaced the whole dist. assembly.

1st time out we lost power while on plane @ 4000 rpms.

No longer sweating it, ZCare is onboard, she goes in for a complete going over Thursday at 8am. Going to go ahead and do a few things extra while she is there.
ZCare requires boots and belows for 3rd season, so I will also have that done etc.

We are considering a new motor purchase to have to install this fall anyway, I wonder why people put things in the classified sections of these boards, I tried to buy an HP 500 EFI this morning, seller is reconsidering selling.
(that comment does NOT apply to this board :) )
Bryan

[Donzi Dreaming]

Bryan,

Does this seem to happen more when the motor is hot or cold?

Reason that I ask is I have seen FI fuel pumps that will show pressure at idle but can keep up with the volume at speed. They usually get worse the longer that they run, meaning they start out OK when the pump is cool and gradually loose pressure or volume as it heats up. Is there a dead head pressure test spec for the fuel pump in any of the manuals?

John

[Bryan Tuvell 33ZX]

John, it is at all temps. I do not own a service manual (do not know where to buy one),
wish I did. Most I have seen on the net are for the older 502's.

We are normally at temp when we leave the dock though.

MPoodle mentioned the volume/PSI when we spoke also. I hope you guys are correct, a fuel pump or regulator would be a pleasant ending to my saga.
Thanks.
Bryan

[Lil Grizz]

First rule of parts swapping - Just because it is new DOES NOT mean it is not broken. If you changed your distributor because of a hard start problem and shortly after picked up this upper RPM issue I would swap back to the old one and see if anything changes. Its sounding more like two unrelated problems, the hard start (which was the IAC) and the 4000rpm issue which could be a bad module inside the distributor or weak fuel pressure.

Did you actually replace the whole distributor or just the cap/rotor?

[BUIZILLA]

Bryan Tuvell 26ZX:
I had some concerns over us prying the rotor off the distributor so I replaced the whole dist. assembly.
1st time out we lost power while on plane @ 4000 rpms. Bryan BINGO Before you take it in for the proctology, put the OLD distributor back in, index it, and splash that mutha...

Get back to us...

J

[Air 22]

Bryan..

Hope ZCare fixes your problems :D If you go for a new eng this fall the HP575 might give you some "GO" and then some :D eek! good luck and remember even though its tough now..you are gaining valuable experience & knowledge...putting a spin of good on the bad wink
Keep us informed..
Dwight

[Bryan Tuvell 33ZX]

BUIZILLA, the dist story was after the cap replacement and rotor, we went to remove the screw (which had always worked tight and it snapped, drilling and tapping made the cap sit funny, so as a precaution we dropped a whole new dist in, we had no other option really.

She leaves in the morning.
Bryan

[BillR]

Since nothing electrical was found, I might assume it is mechanical.

At higher RPM's it begins to run like crap, and gets black soot all over the transom. Fuel presure was check and you said that was ok. The next thing I would suspect is a sticky valve(s).

Any thoughts anyone???? :confused: :confused:

[BUIZILLA]

Pepe' from Pantera Boats brought me 8 injectors from a 385 to flow yesterday.... black transom syndrome...all 8 injectors flowed within 2%...turns out the throttle body shaft was spinning on the lever when the throttle got to about 3/4 rotation...it almost closed back up because of the spring tension. Throttle at helm was at 75%, blade was almost closed. The computer saw % travel, but NO AIR. Engine was pig rich.

J

[MOP]

Boy I hope Mr. B has spoken the magic words, this has been killing you TOOOOO long!

[Bryan Tuvell 33ZX]

BILLR, not sure yet, who knows.
I dropped her off this morning, if it is internal ZCare will certainly cover it, I reread the warranty this morning, if not I will just have to suck up the expense.
Whatever it takes to get her right.
I needed 100 hour maitenance anyway and I will be gone the next two weeks on the ship so no big deal on the timeline.
See ya soon Bill.
Bryan

[Bryan Tuvell 33ZX]

Lil Griz, any more thoughts after my posts?

I need to catch up with big Griz soon.
Maybe I will ring him up tomorrow.

Boat is in the shop as of Thursday @ 8am, we plan to visit her in the afternoon.
More to follow.
Bryan

[Lil Grizz]

Without actually witnessing the problem in person I am still leaning on a faulty distributor. Wether you had to change it or not is irrelevant to the fact that right after you changed it your problems started.

You wouldnt believe how many times I installed brand new parts that turned out to be defective.