Hoping someone can help. So Ive been all over this engine lately trying to figure out why it wouldn't start, Found bad trigger wires coming from trigger assembly and replaced it. The moment I tried to start it, it fired right up. Think I probably cranked it 4 or five times in a couple hours time, all good. Well, a few hours later I came out and tried to crank it and wouldn't crank. So I started checking everything, I've got good spark on all cdm's, fuel pressure is good, def getting fuel because its leaking down from EFI module on front of engine. So of course I start looking there. So I pull the ECU and the fuel injection on the front of the motor and leave it all connected. Had my wife turn the key on to let fuel pump turn on and bam... I see injector 1 and 2 spraying wide open flooding the crap out of the engine, they will spray as long as I let them if I leave the key on. So I told her to try to crank it and all 6 spray what appears as wide open also. So I take fuel injection off motor and swap injectors 1 and 2 with 3 and 4. Install back on motor and watched it again and this time, as soon as she turned the key on, injector 1 and 2 would just shoot a small squirt of fuel in and stop, that seemed normal to me, thinking it was like a prime or choke for a start. I believe this proved the injectors to be ok. So I installed everything back and of course the boat fired right up several times. Well here it is a few days later and wont start and if I keep trying then I get fuel leaking again down the EFI module. So I pull it back off and sure as shit, injectors 1 and 2 are firing full force and don't stop until you turn the key off. The first thing im trying to find out is, Is there any reason to think that the ECU would be telling those injectors to fire like that when the key is just in the on position, not cranking? I know they are gonna fire when cranking, but when cranking, all 6 are gonna fire. Im worried I have a bad ECU and its telling 1 and 2 to fire to start the motor and its not shutting them off after a second or so. I know the injectors fire in pairs and the ECU controls them, but im just wondering if there is possibly a sensor making 1 and 2 only fire when key is set to on. , seems unlikely to me but again, I think im just hoping it could be something other than the ECU. Its weird that it worked a few times and now it is doing the same thing. Ive been told about the injector drivers in the ECU burning up or going out, but I need to know what to do now. I have to figure out how to permenantly fix injector 1 and 2 to stop them from flooding my engine. Im wondering if a Mercury dealer can plug into ECU and see this problem or if im gonna have to send it out for repair. Ive got the little 2 wire plug hanging out of the ECU I think its for a dealer test and diagnostic port. Any help is appreciated, thanks in advance.
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Seadoo Challenger 2000 Mercury 240 EFI Injectors 1 and 2 spraying wide open with key on, not cranking
- Thread starter olekwj
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Dr Honda
Well-Known Member
Yes... the 2 pin connector is a data port. A real Merc dealer should have the software, and the DDT unit to talk to the ECU. But... I'm not sure the ECU is smart enough to know if it has a burnt up part or not.
I haven't heard about the ECU burning out injector drivers... but there are a few performance Mercury shops that can rebuild the ECU if it has issues. (like Simons motorsports) I would be more inclined to think that the injector itself is the issue. (unless you didn't swap them back after the test)
I haven't heard about the ECU burning out injector drivers... but there are a few performance Mercury shops that can rebuild the ECU if it has issues. (like Simons motorsports) I would be more inclined to think that the injector itself is the issue. (unless you didn't swap them back after the test)
Thanks for the input, I did not swap the injectors back, so its def not the injectors. The ECU is telling injector 1&2 to pulse the moment the key is turned on. I found an old post on here of the same exact situation from 2012. I’m trying to contact him to see if he ever found a solution, but no luck yet. It’s either a bad ECU or there’s a sensor telling the ECU to pulse 1&2.
Dr Honda
Well-Known Member
Yep... I saw you pull that up. I forgot about it. But, it was almost a 6 year old thread... and that was the only time this issue came up. So... OK... I guess it happens, but not a common thing. But it's strange that it's the same 2 injector drivers showing the failure.
Unfortunatly... That member hasn't been here since Aug 30 2012. So I doubt you will get an answer on if he got the ECU sorted out or not.
Over the years, I've seen the old style 240EFI ECU's come up on ebay. I should have bought one so I could dig into the board. I'm assuming that the FET or SCR driver has burnt out. Simons will fix it... but it's expensive. I'm guessing the actual part is only a few $$$.
Unfortunatly... That member hasn't been here since Aug 30 2012. So I doubt you will get an answer on if he got the ECU sorted out or not.
Over the years, I've seen the old style 240EFI ECU's come up on ebay. I should have bought one so I could dig into the board. I'm assuming that the FET or SCR driver has burnt out. Simons will fix it... but it's expensive. I'm guessing the actual part is only a few $$$.
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Update, sent the ECU to Simon, they said ECU was all good. Went ahead and had it rebuilt anyway. Re installed it and the injectors are not firing now. But it also did this before I ever shipped out the ECU. It seems like it just does it when it’s really hot outside. I’m torn on whether to replace ignition controller or maybe the stator. The trigger is brand new. Already replaced air temp sensor, and both head temp sensors, in process of testing TPS sensor, waiting on test harness. As far as status of boat running, it goes like this. The boat will crank and start pretty much every time in the driveway, I took the boat out to lake and it fired right up, idled for 15 minutes and got out on lake and it runs perfect at all throttle range. Rode it for about 20 min and parked at beach, and turned it off, tried to start it about an hour later and it wouldnt start, cranks all day just won’t start. Waited a couple more hours and it finally fired after about 3 minutes of cranking, could tell it was flooded when it started. Rode back to boat ramp fine, idled about 10 min then loaded boat and turned it off. Just for testing purposes, cranked it up again fine, turned off, cranked again, turned off and so on. Finally took it home, been messing with it in driveway for days. Seems like it will start every time in driveway. Just don’t trust it will start after running for a while at lake. Feel like there is still something out of sync. Just never seen a fuel injected machine just not start when the engine runs so good. I don’t know for sure, but I don’t believe I’m losing spark when it won’t start, I feel like it’s a fuel issue, like injectors overloading or something, or maybe even just the settings of idle and the butterfly’s open position at start. Really annoyed. No Mercury boat people in town will touch it. I want to figure this out. Thinking about just replacing all electronics such as stator, ignition controller box, and TPS, but can’t bare the thought of all that still not solving the hot start. I’ve read at least 100 of other posts of issues with hard hot start and still can’t figure out what it’s most likely to be. Compression is 115 on all cylinders. Fuel pressure is 35psi, spark looks good to me. Any ideas?
Dr Honda
Well-Known Member
The compression is a little low. I would like to see it above 125 psi. 135 is better.
The comment on "No Mercury people will touch it"... well... that's because it's mid summer. They are all busy, and don't have time. Trust me... if this was January... they would take it in.
Replacing the trigger or ignition control doesn't control the injectors. But on that thought... is the #1/2 injectors still spraying after you had the ECU serviced? With all this work being done... did you send the injectors out to have them rebuilt? It seems to be a big issue with these engines as they age.
And finally... you really don't need a test harness for the TPS. You can just check it across the plug, and read resistance. (make sure it's smooth, and no dead spots) If you want to check the voltage... just push a pin though the wires, and do the test as outlined in the manual.
The comment on "No Mercury people will touch it"... well... that's because it's mid summer. They are all busy, and don't have time. Trust me... if this was January... they would take it in.
Replacing the trigger or ignition control doesn't control the injectors. But on that thought... is the #1/2 injectors still spraying after you had the ECU serviced? With all this work being done... did you send the injectors out to have them rebuilt? It seems to be a big issue with these engines as they age.
And finally... you really don't need a test harness for the TPS. You can just check it across the plug, and read resistance. (make sure it's smooth, and no dead spots) If you want to check the voltage... just push a pin though the wires, and do the test as outlined in the manual.
The problem is the only way to find out if the injectors are still spraying, is to pull the ECU and the EFI off the front of the motor and its a pain. When I installed everything back after receiving the ECU back, 1 and 2 were not spraying when I turned the key to on position. Like I said, it’s done that before the ECU rebuild. When It won’t start I have to wonder are 1 and 2 spraying... no way for me to know unless I pull EFI off again. But I will say, before I sent ECU out, I had EFI off motor but still connected and 1 and 2 were not spraying with key on, so I installed everything and of course it fired right up several times, then later It wouldn’t start, so I pulled EFI back off and sure as shit, 1 and 2 were spraying which is why I would say it wasn’t starting. When I talked to guy at Simon about all this, he said his money is on the ignition controller, he says the ignition controller gets its signal from trigger and converts it and sends to ECU to fire injectors in pairs. He Says the electronics are 18 years old and when they warm up they do weird stuff. I’d give anything to know if there is ever a reason for 2 injectors to fire when the key is only in the on position and no one knows about it because there boat is still starting and they don’t have a reason to pull EFI off and look. I almost think it may be normal that it does that at times under different conditions, and that if other things were adjusted or synced better, like timing, or butterfly position on throttle maybe it would still start ok. I just don’t know. As far as injectors, they all fire and spray perfectly while cranking, none are leaking so I just don’t think they are a problem.
So I tested my TPS with harness and voltmeter. I don’t have access to an analog meter for the ohms test. But I tested on it for at least 20 minutes and I think it’s bad. I’m getting 2.4 volts to 4.5 volts from all the clockwise to all the way the other way with it on boat and connected and key on. Tried everything back and forth and pretty consistently it was always about 2.4 to 3 volts with it all the way clockwise with Throttle closed. Went ahead and pulled it off and left it connected and rotated it with my fingers and it does from 0 volts jumps straight to like 2 or 3 volts then smooth from 3 to like 7.5. But it’s very finicky, it will do some erratic up and down volts as I turn it. When mounted to boat it will say 0 volts. Then I touch it and it may say 2.8 2.9 3.0 or anything else it feels like. If I take hand off it will go back to 0, if I tighten it with it all the way clockwise, it seems to always be about 3 volts. And from my understanding it’s supposed to be about .24 to .29 volts, so it seems my voltages are really high and maybe that’s causing a rich start. Help me out and tell me what y’all think. Do I order the $500 tps sensor?
LesPaul
Member
Would you please explain in detail how you tested the TPS? That is my next test to do. I read the manual, but it wasn't really clear to me me how to do it with a digital multimeter (Fluke). I disconnected the harness today but found it hard to put the test leads on the connectors and gave up.
LesPaul, I ordered a test harness to make it easier. You unplug the tps connectors and it plugs in between the male and female tps connectors, and then it plugs directly in to voltmeter. Then I just disconnected the 2 striped wires on the port side head temp sensor and turned the key on and referred to voltmeter etc. I am curious if I was supposed to have boat running to test it though, I’m hoping Dr Honda chime in and tell me.
Dr Honda
Well-Known Member
Sorry... I was gone yesterday......... OK.....
It sounds like you were doing the TPS test correctly. It should be on the engine, and moving the throttle lever from "Idle" to "Full" with the key on "Run"... you should see a smooth sweep of voltage. If you see a spot in the movment that jumps
You should see 0.2v to 0.3v in the idle position... and 7.3v at full throttle. (and smooth transition in the middle)
I know you said you disconnected the stripped wires from the temp sender... but was it the Tan/blue wires? (just want to verify)
With all that said... with your description... it sounds like the contacts have burnt out, and simply puting pressure on the shaft will change the value.
As far as the ignition controller triggering the injectors... I'll have to double check that. The ECU does get injector signals from the ignition... but I was thinking it was from the trigger plate. I'll verify, and get back to you on that. But regardless of that... the injectors shouldn't stay open. If the ECU sees the signal, it would pulse the injector for what the conditions are. (RPM and the sensors)
It sounds like you were doing the TPS test correctly. It should be on the engine, and moving the throttle lever from "Idle" to "Full" with the key on "Run"... you should see a smooth sweep of voltage. If you see a spot in the movment that jumps
You should see 0.2v to 0.3v in the idle position... and 7.3v at full throttle. (and smooth transition in the middle)
I know you said you disconnected the stripped wires from the temp sender... but was it the Tan/blue wires? (just want to verify)
With all that said... with your description... it sounds like the contacts have burnt out, and simply puting pressure on the shaft will change the value.
As far as the ignition controller triggering the injectors... I'll have to double check that. The ECU does get injector signals from the ignition... but I was thinking it was from the trigger plate. I'll verify, and get back to you on that. But regardless of that... the injectors shouldn't stay open. If the ECU sees the signal, it would pulse the injector for what the conditions are. (RPM and the sensors)
Dr Honda
Well-Known Member
OK... learn something new every day. I looked over the diagram... and yes... the 240 trigger sends its signals to the "Control Module" and that, in turn, sends the signals to the ECU. Looks like on the green, green/white, and green/red wires.
But, as above... that doesn't control the ECU, and the ECU should still be just sending a pulse to the injector. BUT... if the control module is causing the issue... then it can be checked. If you can verify that the injectors are spraying... disconnect the 3 green wires, and see if it stops. Then hook them back up, and see if they spray again.
If they do... you will be the first person I've ever heard of with a bad control module on the 240 engine.
But, as above... that doesn't control the ECU, and the ECU should still be just sending a pulse to the injector. BUT... if the control module is causing the issue... then it can be checked. If you can verify that the injectors are spraying... disconnect the 3 green wires, and see if it stops. Then hook them back up, and see if they spray again.
If they do... you will be the first person I've ever heard of with a bad control module on the 240 engine.
LesPaul, do you have a green with white stripe wire that is not connected to anything on the starboard side like in the picture I posted above?
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