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I recently bought a pair of 2004 hpdi 300's for my boat, I have them running pretty decent accept one motor spins 500 rpm less than the other.port runs 5800 starboard 5300, I have gone through the fuel system 100% and had the injectors cleaned and flowed, and I have 1,000 psi on the high side at 5,300. the engine idles well and power is smooth all the way through. there are no codes on yds, compression is good, 110 to 120 all across, I am looking at the timming, I saved the engine monitor report @ 4900 and timming was only 6 btdc. my manual says it should be 14 btdc wide open, what information does the ecu look at to adjust the timming? Thank's for any imput,
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tps and map -
So are you refering to the mapping in the ecu or manifold preasure? - atmospheric pressure sensor?Comment
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Manifold Ablolute pressure, and TPS, tells the ECM that the throttle is opening and that there is a load or not on the enigne,, there are other things that happen as well, with without throttle angle and load the ecm does not know what to do..Comment
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main determinates for ign timing are TPS and pulser coil signal with the coolant temp sensor giving a trim for various block temps.
the CPS gives an indication of engine speed for ign trim timeing as well.
air temp,air pressure and fuel pressure sensor are only used for fuel correction.
shift position is only used to kill 2 cyls in N and allow 6 cylinder operation in gear.
did the data show all 6 cylinders firing?
what did the atmospheric pressure sensor read at key on power without the engine running?
what was TPS voltage at 4900?
what was TPS voltage after properly syncing the shutters?
normal ign timeing if a sensor has failed,in range or out of range, is 7*BTDC.
some failures will lock base timeing but allow it to advance, other failures lock base timeing at &*BTDC for the entire RPM range.Comment
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Hello rodbolt, I have read many of your post and just want to thank you on behalf of the entire yamaha owner group for your help,tps voltage was 3.09 at 4900 rpm, my max tps voltage is 4.09 wide open on both engines, the atmosphe was 30 inhg,fuel pressure 1008.2 ignition timming 6 btdc, I have done the link and sinc, and at idle tps is .62 volts. today I actually brought a timming light with me and checked each plug wire while running wide open to make sure I had spark, I'm at a loss, I have compression, spark, and fuel, my last thought is could the timming not be advancing, the engine runs smooth just low on power. I plan to check the timming again on the water with yds hooked up tomorrow, I allready switched all coils from one engine to the other to rule out a coil dropping out and the problem did not change, I'm getting close to taking it in to a dealer, but I still want to learn my way around this engine. Thank's again.Comment
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alot of info there Rod, but even you know that with out throttle angle and baro/map, the ecm has no where to go, even with coolant temp or knock, or pulser coil,, this is why I hesitate to answer some of these questions,, I stated there are other things going on as well,, but what do I know, apparently Im not as good as you,Comment
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I am more than greatfull to take in all of the info that I can get, and also I have read every thread I can on these engines before wasting your time, it seem's 99% of the problems with these things are fuel related or the shift switches, and I happen to have the oddball problem that may need a proffesional tech, which is hard to find anymore.Comment
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on a 4 stroke EFI the map sensor is a duel function unit.
on a 4 stroke it locks a baro pressure into the ECU map for that key on cycle.
then at engine start it monitors manifold absolute pressure.
however we cannot do this on a two stroke due to the reed design and the low intake vacuum, it would bounce to bad.
on the yamaha two stroke EFI the manifold absolute pressure is NOT monitored, it is locked in at every key cycle and remains that way for the cycle.
at sea level if you toss the map sensor in the creek your only symptom would be .
nothing.
however if it was failing due to corrosion or bad harness and locked in say 19"Hg the would react by leaning out the A/F mix.
the F250 will actually try to run at this reading however at sea
level it runs very lean and wont turn past about 2800 RPM.
yes Virginia some of the ECU maps actually think a 22,000 ft lake exists.
but no the MAP sensor on a Yamaha two stroke does not affect ign tining.
main timing determinates are pulser coils, CPS and TPS and below 113* F the CPS.
fuel injection is based on TPS and CPS with corrections from the map and airtemp and fuel pressure sensors.
when in gear does the shift position read on or off, then when started in N does it read on or off?
the pulser coil assy is mechanically mounted at 7* BTDC.
that's how the default thingy works.
if all is normal the ECU can modify the pulser coil timing.
have you indexed your flywheel to see if the TDC mark for #1 actually coincides with 1 TDC mechanically??Comment
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just thinking on your posted numbers, cant happen.
If the throttles are correctly syncned,TPS at .5 with shutters fully closed and the stop screw NOT touching.
then screw down the stop screw until it reads .62 AND the timing was actually 6*BTDC you will idle between 1100 and 1300 RPM.
it just will.
does the timing lamp and the ECU agree on timing at all RPM's?
wont be the first braindead ECU I have monitored.
had several 2.6L Z motors that wont communicate with the YDS and one that only displayed part of its information.
none of it affected running though.Comment
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Over the years on the HPDI 250's and 300's I have run into several hundred rpm losses that cannot be explained. Everything else seems to test out OK. Even though they look good and may have less than 50 hours on them, installing brand new sparkplugs would bring back the missing rpms.Comment
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a Kv tester will find a bad plug rapidly.
and a bad plug especially on cyl 2 or 3 may not be noticed much at low speeds yet the ECU would react to the lowered engine speed by increasing timing and fuel.
the CPS and the TPS and the pulser coil inputs don't know a plug failed but the ECU map will see the drop in engine speed and try to make it correct.
if you really want to see this effect.
get to an 8.1L Volvo,merc or crusader.
pull a plug wire at idle.
try to see the engine speed react.
if your quick you can "feel" the momentary RPM drop then the engine will instantly smooth out at about 650 RPM.Comment
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I have set the tps on both engines the same, idle screw backed off not touching the seat, and shutters closed, set the tps at .52, then turn the idle screw in until you have .62 on the tps, and my idle is 700 rpm on both engines. the timming at idle would be 7*atdc not before, I was running 6*btdc at 4900 rpmOriginally posted by rodbolt17 View PostComment
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Ok guys, this is not a timming issue, just ran it with the yds hooked up and I am getting the full 14* advance at wide open, sorry for the misdirect of my problem, I even swapped ecm's and injector drivers, same result, I am almost wondering if someone may have put a 250 lower unit on this motor which would be a 1.81 ratio instead of the 1.75. anyone know if there is a part# stamped on the lower or do I have to drop it and count the revolution's?Comment
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Well I found the problem, my port motor has a 250 lower unit which is 1.81 and my starboard is the correct 300 lower unit at 1.75. so there is nothing wrong with my engine it is just working harder than the lower geared one. I am happy the problem is solved, but not so happy with the guy that sold me the motors. Thank you guys for all your help,Comment
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