2000 suzuki 225 efi fuel issues

[ThereSheGlows]

I have a 2000 Suzuki dt225 efi 24" shaft

I will pump up the fuel ball until its hard, motor will fire right up, idle for 10 seconds, then taper off and die. It takes several pumps to get the ball hard again after it stalls. If you hit the throttle right away, as soon as you start it, it will run at high rpm all day. If you hesitate a few seconds after it starts, then give it throttle it just stalls out. Same results with a water test. Boat hauled ass but wouldn't idle, and didn't quite achieve full throttle either. Sometimes during the water test it would sit and idle in neutral fine, but then if you gave it power it would stall, even after 15 minutes of idling in neutral.

compression is 128 on all 6 cylinders


All 12 plugs are clean

It has brand new electric high pressure fuel pump

both low pressure mechanical pumps were also replaced completely with new suzuki pumps

lower end was just flushed, and fresh impeller kit installed, pees great

using a portable fuel cell with good gas and a brand new fuel line/ball( we also tried another fuel line/ball)

motor is still oil injected

tps was swapped with another good condition used one with no change

will only run with tps adjusted all the way forward

It has two filters under the hood, a cartridge style and a bigger denso filter, we have disassembled and cleaned the cartridge filter, and even ran it without the cartridge filter in the loop, still no change. Flow seems fine on the denso.


Can anyone tell me how to calibrate the tps? I am mechanically inclined and have a nice Matco multimeter.

Any suggestions or experiences would be greatly appreciated.

Thanks for any help

[ThereSheGlows]

No input from anyone!? I just took apart and totally cleaned the efi evaporator with no change. Didn't find anything noticeably clogged broken or obstructed.
So now it has both new low pressure pumps, a new high pressure pump, evaporator totally cleaned and inspected, mostly new fuel lines, still idles for 5-8 seconds then stalls. If i gun it as soon as it starts I can usually get it running at high rpm all day, as soon as I let it down, it stalls again. If i wait a few seconds after starting, then hit the throttle, it bogs and stalls. Any new ideas or suggestions? I'm cleaning the injectors next, if that doesnt help, I'm considering bringing it in to the suzuki guy to have the tps calibrated.

[CaptDjob]

EDIT. SORRY, this was fuel injection engine, my answer was carburator models. Of course the thermostat part is valid. Sorry again.

Hello,

I am amateur on this, but I had a bit similar case with my DT200 -87. There was external fuel pump installed by previous user (he thought he had fuel supply problems, but he didn't) and that pump was of course constantly on. When starting, it was convinient (no hand pumping with bulb) and in running it was just there, but in idle it ruined the system.
It seems that the needles are so "worn" on these old engines that the fuel pump was flooding the engine in idle rpms. With slightly higher rpms it worked fine. First thought the engine's own fuel pumps had broken element, but that was not the case.

So I have now power switch to the external pump and I use it only for starting, then I switch it off. Don't even use it in high rpms because it seems that engine is fine without it. Now everything runs nice and smooth.

So, you could take power off from the external pump and try the idle without it.
One thing that could cause problems with idle is cold engine, have you checked that you have both thermostats in place? Because it seems to be habit (at least here in Finland) people to run suzukis cold as those thermostats costs over $100/pcs here.

Regards
Capt.

[seaox230c]

If you are fairly mechanical you can verify proper fuel flow ...you need to tee off of the output side of the fuel press regulator...the line that runs to the injector rail...2 sides of the t continue the path to the rail..the 3rd side runs a 10 or 15 foot length of 1/4 or 5/16 tubing to a 0-60 psi gauge..shorter if you have a helper to read during operation...If all your fuel supply systems operate normal you should read 35-38 psi on that gauge at all times the key is on to run. Do a search for username seaox230c and the post title was dt225 missing at speed..I had a 2 year ordeal with my 2003 225 missing above 3500..I spent months tearing into that motor...the dealer mechanics were useless and the Suzuki manuals suck...there are 2 extremely fine cone shaped filter screens in line at the input and output of the high pressure fuel pump I don't think they are in the manuals..but you need to verify if you have a fuel problem first..do that search and read the entire post ..I will check back frequently if you need help-good luck

[mustangpete]

dt 225

seaox I was your neighbor at the marina in seaford...had starting issues resolved the starting issues now have the same problem bogging down above 3000 rpms....starting issue was the result of broken boot on spark plugs. now fires right up but bigs down above 3000 rpms....thinking it is the stator!

can you email me two894v@aol.com

Thanks Pete

[seaox230c]

Hi, I need to know if you break up at EXACTLY 3000 or if you get a little higher before it misses...exactly 3000 is a computer controlled misfire...to verify a bad stator you need 2 people and a timing light... if one entire bank...right or left misfires at 3000+ its a stator...if only one or 2 coils misfire its something else... not easy to diagnose...the good side sparks quickly and constantly on the timing light...the bad side skips and misses on all plugs on the same side...that's a stator...if less than 3 misfire its not a stator problem. You cannot have the timing light clamped over plastic it must be on a plain wire... its awkward and you need 2 poeple

[Solarman]

breaks down above 3k

Pete on your motor there are 3 timing coils, the wiring schematic should identify which coil is for which cylinders, if missing on 2 cylinders the timing coil may be your problem, if missing on 4, maybe 2 coils. If all 6 cylinders are breaking down above 3k, then you have a problem with the high speed condenser charging coil on the stator.

There she glows, those cone screens are important for fuel flow, but if running good at higher RPMs? You might inspect the gear counting coil, if in good shape and gives a good reading make sure it's adjusted from the flywheel properly.

On both these motors it wouldn't hurt to inspect under the flywheel for rust, loose magnets, or anything that might interfere with the motor getting good magnetic signals from all the coils and stator.

Just trying to help if possible. Good luck.