View Full Version : 03 prostar 197 wont start/need manual/wiring diagram

08-28-2007, 08:16 AM
Hello to all,
This is my first post. History time: several weeks ago the motor (LQ9) would not turn over while using the key. We, my neighbor and I, just got the standard clicking, symptom of a starter solenoid gone bad. Battery had a good charge but we tried boosting it with no different results. BTW the boat (2003) only has 40 hours total on it. Its pretty sweet. So the starter Solenoid was replaced and now the motor turns over just like its suppose to but...... no ignition. We had ignition before the starter /solenoid problem.
Heres what I do know:
1. when the key is turned on the fuel pump spins up and pressurizes the fuel system. The shrader valve on the fuel rail has pressure, I did not use a gauge, just a rag to keep the fuel from spraying too far.
2. The dash gauges power up and the check engine light comes on. The cel turns off during start attempts.
3. The 3 relays at the back of the motor(fuel pump, ignition,and ecm) all click when the key is turned on.
4. If we attempt to start we get no ignition but we do smell fuel , not a leak, just from turning key off and on during several start attempts. Just confirms that fuel is present, but not the psi.
5. If we remove the kill safety lanyard the fuel pump does not pressurize when the key is turned on. I'm assuming the kill switch is fuctioning properly.
6. The 3 fuses down near the big red engine breaker visually apear to be good.
7. The big red engine circuit breaker is firm with no play. It sticks out about 1/4 inch and does not appear to be popped. According to other post one would definitely know if it was popped visually.
8. All breakers under the dash are in.
I have not had a chance to test the relays, but my other neighbor has an 02 prostar, different engine but same cadillac northstar ignition system, and I may swap a relay if they have the same part number.
I have not tested to see if the plugs spark during start. I'll do that today time permitting. My gut feeling is no spark signal is getting to the system. Is there a crank shaft or speed/rotation sensor on the motor that signals the fuel system or ignition and if so where is it located?
I guess I also need to check the grounds on the fuel pump and the motor.
I've looked for inline fuses (info from other threads) from the ignition switch under the dash but did not see them.
I dont know if the injectors are functioning
Does anyone have a wiring diagram they can send me.
Can anyone recommend a good service manual for this boat, a book that walks you thru the diagnostic steps needed to narrow down the cause of this problem.
I'm hopng its not the ECM but is there a DIY test for this? Hopefully the ecm didnt get fried when we tried to jumpstart the boat.
The nearest dealer is 60 plus mile away in Richmond VA. I'm not ready to throw in the towel yet.
But I need a good diagnostic resorce or some help from my MC friends/family.
I spent most of yesterday trying to analyse the problem and I caught my wifes cold, didnt sleep well so I may not get to far today. Summer colds suck..
I do plan to go back and check the wiring/connections at the starter and batterry terminals. Those are the 2 things that changed since the motor was last running. Correct me if I'm wrong here but there isnt a wire at the starter that has anything to do with ignition spark is there? Thanks

08-28-2007, 09:46 AM
Are ALL wires connected to the battery? Black to negative, red to positive? Is the red wire that is covered in black loom on the positive terminal?

If you have wire connected improperly the boat will not start.

east tx skier
08-28-2007, 10:21 AM
Does it turn over, start, then immediately die? I had a friend who had this symptom and it ended up being a loose wire to the ignition. But as you hear the fuel pump priming, you may have a different issue (or a different loose wire). Good luck.

08-28-2007, 10:59 AM
I have 4 wires or cables coming into my battery box. 2 solid black cables going to the 2 separate negative battery terminals. 2 Red cables/wires going to the 2 positve trminals on the battery. One of the cables is red with white stripe and goes thru a 40 amp fuse. All connections are clean and tight.

08-28-2007, 11:00 AM
It turns over fine but never starts

08-28-2007, 11:06 AM
Use a gauge to check fuel pressure. Check for spark with a timing light.

What is the service history and what happened the last times out before the problem appeared? Any overheat, run out of gas, stumble, surging, cutting out?

For checking the injectors and their harnesses, there's a thing called a Noid Light, which may be available fro rent/borrow at some of the chain auto parts stores, like Ckecker/Kragen/Shuck's and AutoZone. If they're firing, you'll see it light up. If not, you won't.

08-28-2007, 11:50 AM
i had the simalar symptoms on my 04ps197. after some time at the dealer, they finally found the problem. they identified it as the main wiring harness. what ever that is.

08-28-2007, 04:50 PM
Just checked for spark during cranking and there was no spark. Sounds like the ecm or ecm relay, ignition relay, or ? Anyone have any ideas. Is there a crank/rpm sensor this engine and if yes, where is it on the engine?

08-28-2007, 04:53 PM
To the best of my knowledge, the engine has run fine. It only has 35-40 hours on it. I dontknow much about service history. Lets say it hasnt been in the shop recently( this summer)

08-28-2007, 05:00 PM
Does an '03 have an OBDII port? Can you read out the DTC's? If so, that should tell you what component is bad...maybe.

08-28-2007, 05:09 PM
I dont know if it has OBDII. I havent seen a port but that doesnt mean its not there.

08-30-2007, 10:48 AM

08-30-2007, 10:52 AM
Looks like were taking it to the repair shop for some computer diagnostics. Were definetly not getting any spark, the relays all check good, fuel pump is pressurising, fuses are ok.... hope its not too painfull

08-30-2007, 11:07 AM
There is a DLC at the rear of the motor and codes can be found with a scan tool, but not OBDII. OBDII is post '96 cars and trucks, and boats aren't that current because they don't need to be, although CARB and the EPA are making newer technology necessary (O2 and cat).

AFAIK, they don't use a cam sensor on the newer motors. I'll look in my manual, or maybe one of the dealers will add something.

08-30-2007, 02:08 PM
Thanks JimN,
I need to take it to someone that has Diacom marine specific software for diagnostics.
Do you know of a particular scan tool that works for the DIY guy?

08-30-2007, 06:09 PM
You can make your own tester with an led and paper clip. I made one from a post on this site. It blinks out the codes. 3 times #12 will flash(one blink a pause then 2 blinks)followed by the error code.

08-30-2007, 08:57 PM
f16- as far as I know, the dealers buy a specific cable and connect it to a PC now. It's not quite as portable as the Tech 1 but it shows a lot more data and does a lot more.

09-06-2007, 07:20 AM
Update time,
I used the paperclip method to pull codes but their were no bad codes, just the normal good ones.
I opened up the kick plate area under the steering wheel to check for loose wires but found none.
I had 2 no 3 guys who were familiar with mastercraft boats look at my boat in my driveway.
I also finally tested the fuel pressure which turned out to be good, but still no spark.
So, having zero luck at starting the engine, I drove it 24 miles to the factory authorized INDMAR repair facility..
Turaround time was actually pretty good. The boat was dropped off at 9 am and they were able to look at it the next morning. Heres the really weird part. They turned the key and it started. Thats all they did.
To be safe they did the Diacom diagnosis and eventually decided the fuel pressure regulator was not doing its job consistently. In testing the engine would not rev much past 1500 rpm. So I told them to go ahead and change the fuel pressure regulator. And they told me I'd have to take it to a Mastercraft repair facility because the pressure regulator is part of the fuel pump which is located in the fuel tank and its a Mastercraft part.
What a racket!!!
Since the nearest Mastercraft repair facility is way far away I just trailered the boat home to my driveway, attached the waterline so that I could run the engine in my driverway and started her up. She ran fine and had no problem getting good RPM's.
So I'll do a little more clean up on the boat and maybe put my new amp in, but its going in the water for a test drive today.
Who knows what caused this but driving it down the road on the trailer made something shake and now it starts.

09-06-2007, 07:26 AM
If you have the problem again try taking a wrench and tapping on the side of the starter. If it then turns over your starter is going bad. I had a similar problem on my 97 190 and when it wouldn't start I would hit the starter and it would fire right up. That got me through until my new starter showed up.

09-06-2007, 10:29 AM
f-16- have you looked for a cam sensor? Make sure the plug is secure. Also, since you now know the problem can be affected by vibration, start it on the trailer and go around the motor, wiggling wires, harnesses and plugs. If you still don't replicate the problem, move to the safety switch, ignition switch and the plug that connects the motor to the boat.

I can't think of a reason for the regulator to be in the tank and not on the motor. Call MC to verify this and see if they can shed more light on the problem.

09-06-2007, 09:46 PM
Took the boat out for a test drive today. It was difficult to start but eventually got it running. It revs up but seems to miss a little at the lower rpms and more so near 4000 rpm. It doesnt feel like an engine that has 385 horsies. Maybe it is fuel related, INDMAR suppects fuel pressure regulator. I think I'm going to take the fuel pump apart tommorrow and clean it along with the pressure regulator and filter. Maybe they're clogged from too much inactivity.
I need to locate the cam sensor but the indmar guys checked all the sensors with the diagnostic software and didnt come up with anything on the engine.
I like your idea about wiggling wires while the engine is running.

09-06-2007, 10:17 PM
The first things we were taught to do were:

1) Verify the complaint
2) Visual inspection
3) Wiggle Test
4) Diagnostics with tools, manuals and notes

Look for Engine Nut here, or send him a PM- he knows that motor a lot better than I do.

09-06-2007, 10:58 PM
You say your motor is 385 HP so you must have an LQ-9
Here are your 3 keys to fix the problem


a) Get NEW PLUGS...the correct ones (If idling rough)
b) Kill Switch
c) Fuel Pump

[email protected]

09-07-2007, 06:54 PM
Spoke with MC tech today and discovered fuel pressure was running a little low (50psi) at all power setting. Engine still wont go above 4 grand rpm without complaining (missing, going pop pop pop), until I back off on rpm.
Changed fuel filter and got 59 psi.
Engine runs a little better but still pops at higher rpms. The fuel psi stayed consistently high while travelling in a straight line.
One odd thing happened, 6 or 7 times,,,engine loss power during tight turns. I was monitoring fuel pressure and it dropped to 20 psi in the turns. Once we ended the turn and reduced throttle setting engine returned to normal. The engine never died. This occurred with a half tank of gas.
So off to the gas station we went to fill the tank with 93 octane. A small amount of 87 octane had been used previously.
She runs better, can get to 4400 rpm before popping starts and bat turns did not cause a power loss.
I also put 2 cans of fuel system cleaner in the tank.
Not sure what we'll do next, possibly try a neighbors spare fuel pump.

09-07-2007, 06:58 PM
[email protected]
What are the correct plugs? Mine doesnt idle rough though.
I'm pretty sure the kill switch is ok.
Fuel pump is part of our suspect list.

09-11-2007, 06:05 AM
I am having the same problem but at a more intermitant level on my 03 197 LQ9. Have you disonnected the battery and allowed the ECM to "reset" from lack of voltage. That seems to let it start right back up. Like you I am 80+ miles from dealer so looking for the answer here locally atleast untill ski season is over and I can get it down to dealer.

09-11-2007, 06:09 AM
If engien is popping on an LQ9 Definetly change the plugs, fixed mine twice now.

09-11-2007, 12:09 PM
The boat is starting fine now but the engine pops/ looses power above 4000 rpm. I dont know if I'm asking too much from the engine cause this boat ownership is new to me. But the INDMAR web page for LQ-9 says max rpm 5250 and I'm coming up short by 1 grand. Now I dont plan to run the boat at that rpm often, but if it starts popping at 3800-4200 I'm wondering is it me, are my expectations to high or the boat?
BTW when you say change the plugs do you mean get a different plug or just new ones cause my boat is an o3 but it only has 45 hours total on the original plugs.

09-13-2007, 08:40 PM
Today I pulled all the plugs for several reason. I read a service bulliten from Cadillac regarding the LQ-9 and recommending a different spark plug. The bulliten was dated Dec 2003, 6 months after my boat came off the show room floor. So I was curious which plugs I have installed and what the gap was set at. I actually have AC Delco 12567759 ngk pztr5a. They were gapped @ .055. The service bulliten calls for ac delco 41-985 12571164 plugs. My owners manual say AC41-952 with a gap setting of .050. So for grins I set the gap at .050, put a little dielectric grease in the wire boots struggled getting the plug wires to make that good connection sound when their on properly. These wires are tought to get on.
So off I went on a test run, warming up to 160 before going WOT. On the first run it went strong right up to 4500 rpm with no hint of popping or power loss. Second attempt I got a similar run. The next couple of tries I got some popping and power loss near 4000rpm. So go Figure. Speculation on my part...spark plug wires dont make firm connection and maybe get loose after a few runs at high power causing power loss and popping. Anybody care to comment on my speculation?

09-14-2007, 09:37 PM

What prop are you running 14 x 20 Stainless or which

Did you replace the FUEL FILTER at the base of the pump?

[email protected]

09-15-2007, 09:36 AM
I'm checking to find out what prop I have. Its a 4 bladed johnson but I dont know the pitch. I'm pretty sure Its stainless steel.
Yes I did change the filter at the bottom of the pump and realized an improvement in fuel pressure.

09-15-2007, 12:30 PM
Out of curiosity,did you ever eliminate your 20 PSI Fuel Pressure drop during sharp turns? By your description on problems, your issue may be completly fuel related. My boat would lose power at high RPM's under load due to a fuel line restriction (specifically my fuel pump intake screen). I ended up correcting my problem by meticulously going thru my fuel line starting at the intake screen in the tank. I'm not as familiar with the FP regulator, however, I'd assume by its design that the pressure valve could possibly "stick" open, much like a thermostat? I'd guess that would allow a pressure drop. Not sure on that though. JimN, Stormtriple and Enginenut seem to know that stuff inside and out.

09-15-2007, 12:30 PM
Sorry. Double Post...

09-27-2007, 08:01 AM
Update time. (short version) In the beginning my 03 PS with LQ-9 engine had a starter problem. I replaced the starter solenoid and the motor would turn over but would not run. We were not getting spark at the plugs. After a road trip to the shop for computer diagnostics it started right up. (no service performed-it just started right up)The diagnostics showed a possible fuel pressurre problem. I brought the boat home 3 weeks ago and yesterday put in a new fuel pump. Interestingly both old and new pump are putting out the same 50 psi according to my guage. The boat ran well on the old pump until getting above 4000rpm. Then it would pop and cough and miss till I throttled back.(sounded like it was running lean) I also changed the plugs because a tech bulliten recommended AC41-985 iridium plugs for the LQ-9 engine. In the process of changing the plugs one of my plug wires end broke off. I had previously suspected a problem with this one wire. I repaired the wire, its now about 2 inches shorter but works. So new pump, new plugs, 1 plug wire making a better connection. Boat starts quicker and after proper warm up time, accellerates to 5000 rpm with no problem. Its runs smoother and a touch quieter. I'm not sure if it was the pump the plugs or the wire but my boat sure runs nice. Thanks to all for your input. I'll try and post some pictures of the pump change soon.

03 Prostar 197

10-08-2007, 06:41 PM
Out of curiosity,did you ever eliminate your 20 PSI Fuel Pressure drop during sharp turns? By your description on problems, your issue may be completly fuel related. My boat would lose power at high RPM's under load due to a fuel line restriction (specifically my fuel pump intake screen). I ended up correcting my problem by meticulously going thru my fuel line starting at the intake screen in the tank. I'm not as familiar with the FP regulator, however, I'd assume by its design that the pressure valve could possibly "stick" open, much like a thermostat? I'd guess that would allow a pressure drop. Not sure on that though. JimN, Stormtriple and Enginenut seem to know that stuff inside and out.

In answer to your question......When I dismantled the original fuel pump assembly, I found the pump itself was not held securely in the bracket that keeps the pump stationary. I speculate that the fuel pump was able to move around inside the pump assembly and during hard turns the pump may have moved to a position that restricted fuel thru the screen or maybe the wiring stretched and made a poor connection. Thats just speculationon my part. It didnt do it anymore after securing the pump in the proper location.

11-14-2007, 08:11 PM
My 2007 X-Star with a LY6 400HP started having the same popping, slowing down above 3800 etc. as yours has done. It wasn’t consistent. You’d be running down the lake just fine and then all of a sudden the engine would start slowing down, sometime pop, and then if I would go to an idle everything would be just fine for a short period and then it would start acting up again. The engine barely had 10 hours on it when this all started to happen. I took the boat to the MasterCraft shop but they could not find anything wrong while monitoring it on the computer even though it would act up when it was connected to the computer. I finally forced them to change out the fuel pump and everything has been great since then. It was interesting that as I was leaving the shop, the mechanic mentioned that MasterCraft seems to be having a lot of problems with their new fuel pumps.