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2003 DT225 runs good until 3200-3500 then cycles 200-300 rpm give or take. cant push it past 3500 when it misses but If I back off to about 3000 it smoothes out. it doesnt make any funny noise or runs rough, it just instantly drops rpm's like a cylinder is cutting in and out out I have verified constant and steady fuel pressure at 36 psi during the problem. New plugs and all new filters. Any way to isolate or have the computer read..it only does it under load..at Idle I can push to the redline
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You will need to take to a dealer for the computer read out, which is recommended. Could have a faulty sensor. -
Have been to the dealer several times.he has always done something to the fuel system with no good fix. I have since verified good fuel deliverey. I hung a timing light on the coil wires..4 of the 6 coil packs appear to go intermittent when the engine starts to miss. All coil packs appear clean and undamaged.might this be a bad CDI unit or ignition control unit...both expensive just to throw in for a testComment
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Replaced the CDI yesterday with a NEW unit..no help.I have to go back and check the coil outputs again inder a load .I found out yesterday that if the timing light pickup is over the black plastic sheathing on the spark plug wire it gets an intermittent signal..will have to verify the integrity of the coils againComment
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I haven't retested the coil packs yet..hopefully today. I did a compression test yesterday on a barely warm engine..1-120 2-120 3-125 4-120 5-125 6-115...don't see too much of an issueComment
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Well did a good coil pack check today...nbr 2-4-6 all miss above 3200 rpm..nbr 1-3-5 are all perfectly steady no matter what the engine does but the other bank blinks and missed everytime the engine stumbles. I have already changed the cdi for a NEW factory part so am I down to an ignition control unit or is there some other SINGLE part that drives plugs 2-4-6. I am assuming this is not a computer shutdown protection function because I have no lights or buzzers..and why would the computer only shutdown one bank of cylinders for protectionComment
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I know this is a totally different animal but I have a 03 150 EFI merc that was doing the exact same thing Wound up being a low 2 stroke oil sensor that had went bad and the man that had it before me must have jumped the sensor wires but the computer still picked up there was no 2 stroke oil and put the engine in reduction mode it wouldn't go over about 3500 rpmComment
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Yea, I will check the oil and temp sensors..I don't think its them because I have no warning lights or buzzers but you never know.Comment
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Well I purchased a used Ignition Control Unit...of course no help. I started reading all my sensors and I come to difficulty right away. On the top of each bank is a temp sensor. On the left bank(looking from behind the motor)--cyls 2-4-6 the temp sensor has 4 wires ..2 black/white joined at a single ground connector and a violet/white and a light green/white. I am pretty sure this is the cylinder wall temp sensor. The book says to check the resistance of the sensor at certain temperatures and make sure it is in the range. This sensor has 2 sensors in it...one is within the range at 1350 ohm at around 90 deg thats the green wire...the purple wire is 40,000 ohm. I'm pretty sure thats bad but the manual doesn't specify that there are 2 sensors or if they should be similar. If anyone can measure theirs for me it would be appreciated. The connections are in the big rubber boot right on top of the 1-3-5 bank and I measured from each pin connector to the dual black ground connector. thanksComment
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Well..went out today with a Fluke digital multimeter and an old Decade box ..found out that the 2nd half of the Cylinder wall temp sensor is my overheat sensor and it DOES run a totally different temp/resistance profile than the side that feeds the smartgauge fault code check engine light. .. funny that the Suzuki factory manual makes no reference to it. Starts off at around 40K ohm but as the engine warms up it drops and stays around 6000-7000 ohm. I jumpered around the sensor with my decade box and if I drop below 6000 I get the temp buzzer and light. If I dial up the resistance back up to 7000 and up I still have my engine problem at 3200-3500. If I dial in below 6000 and make the temp alarm go off I cannot get the rpm 1 hair above 3000. The engine also shudders and feels much different than my normal problem at 3200-3500, It appears not to be a protective shutdown issue. I then started checking the temp sensor in the other bank...It has a green wire with a red stripe and it goes to a connector with 2 green wires and a red stripe...the black wire was not connected. I cannot find this sensor anywhere in my wiring diagram..this is getting exteremely frustrating..any help is appreciatedComment
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----------------------------------------------------Originally posted by seaox230c View Post
Here is a link to another topic concerning intermittent Cylinder loss.
The hope is that cross-referencing will improve the odds of
better diagnostic outcomes/solutions.
DT150SS Intermittent loss of power/cyl's - Suzuki Outboard Forum
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Well, it gets more and more cloudy...went out today with the thermostats removed and I had the side of the cylinder wall temp sensor that reads approx 1500 ohm-400 ohm and appears to trigger the check engine code if disconnected. I had the sensor hooked up to a fluke meter and the computer wiring hooked up to my trusty decade box. The sensor drops to around 350-400 ohm when under full power and I had my decade box feeding the computer a steady 450 ohm...still sputters at 3500 rpm....no faults or check engine light. I again tested the coils and had all right bank 2-4-6 working normal when the engine stumbles. It was odd at first number 2 would misfire exactly in sequence with the engine dropping rpm then I checked number 4 which was perfect and number 6 would skip then I checked the left bank number 3 which was a used coil and it was perfect...then went back to 6 and it was perfect even when the engine was loosing rpm and I went back to 2 and it too was now firing perfect even when stumbling badly so I don't have a whole bank bad at one time. I will now pull out the injectors and have them checked and cleaned .I am still pretty certain that my fuel delivery to the rail is ok because I still have 36 psi measured between the fuel rail and the regulator at all times even when engine running bad. I never seem to have the same problem even though I can't get over 3500. The left bank 1-3-5 allways appear to fire perfectly..this sucks assComment
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Well, I got the injector report and it good which makes it bad...all injectors performing at 90% or better. I haven't put them back in yet but I assume my problem will still be there . More to follow ...foreverComment
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