Engine idle / dying at temp
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=43296
Printed Date: October-06-2024 at 12:26pm
Topic: Engine idle / dying at temp
Posted By: wdg8769
Subject: Engine idle / dying at temp
Date Posted: August-01-2018 at 12:08am
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Greetings - I have a 95 SN with the PCM GT-40. I was having some problems at the beginning of the season with the idle failing after the boat warned up and the engine would sputter and die. I usually do my own work but thinking this may be a multitude of problems with sensors, etc., decided to finally bite the bullet and take to a local boat mechanic. He got back to me that the fuel pressure was about 27 PSI (below 39 PSI Spec) and had him install FCC Retrofit kit with new pumps, etc from NautiqueParts.com (as can't get old HP fuel pump for the 95 GT-40 any more). He is getting 39 PSI now at fuel rail when running, but the engine is still failing at idle / dying when gets up to 160 degree temp. He has swapped out the MAP Sensor and Water Temp Sensor, scanned the computer and not coming up with any errors or fault codes. Also checked all the grounds to see if that is an issue. He thinks it may be something wrong with the distributor (which I have read can lead to idle problems). Checking if anyone has had this problem or known fixes / recommendations. Thanks! Wilson |
Replies:
Posted By: gt40KS
Date Posted: August-01-2018 at 12:29am
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Yep, GT40's aren't too easy to troubleshoot and all the electronics seem to be the cause about half the time. Sputtering could be the distributor but I'd think it would sputter all the time not just when the temp rises. The only problem I've heard of with the distributor (aside from normal cap & rotor) is the PIP sensor inside - known issue as they are prone to loosen over time and cause timing/ idle issues. Bad cases have been known to keep the engine from starting or cause it to die easily, especially at idle speeds. They can be replaced, but it's difficult unless you have the right equipment because it requires R&R of the press-on gear. It's best to just replace the entire distributor. How was the temp checked - with the dash gauge? Those are sort of a good guess most of the time, not super accurate like you need for diagnostics. Check the true temp with a good IR gun to be sure you're not overheating. ------------- JCCI 1995 Ski Nautique GT40 |
Posted By: wdg8769
Date Posted: August-01-2018 at 3:52pm
| Thanks for the feedback - the temp gauge was also one of the initial problems and the mechanic took temps all over the engine and was not overheating. He replaced the temp gauge and now holding pretty steady 160 until idle problem kicks in and engine sputters. |
Posted By: gt40KS
Date Posted: August-01-2018 at 4:28pm
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Another thought was to check the TFI - Thick Film Ignition module. I don't recall reading anythi g about failures and in all honesty not really sure what it is or how it works, but being part of the ignition system it might be worth checking out. ------------- JCCI 1995 Ski Nautique GT40 |
Posted By: gun-driver
Date Posted: August-03-2018 at 1:48pm
| Wow an $800 fuel cell conversion that did nothing was there some $ kicked back. |
Posted By: Jmattison
Date Posted: August-04-2018 at 1:07am
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Yes I'm having similar problems with my 95 SN not running over 36 mph. Could this be the hpfp? Thinking about doing the fcc conversion but can't find any help on how its done. Does anybody have any idea how to do it yourself? Not really feeling paying for it to be done since the kit is so expensive. I really need help with this. |
Posted By: TSchroeder
Date Posted: August-04-2018 at 10:14am
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Jmattison, I just got done installing the FCC Retrofit Kit on my '95 Ski Nautique. I was frustrated when I received the kit and it contained no instruction. Where I bought the kit from, will not mention, and other places were not helpful at all. I found great resources on this site and took a photo of the finished product. I removed the entire old fuel pumps system LPP and HPP and return from the fuel rail line. Everything removed except the LPP is pictured here:  Image from TrevorB's post. The new low pressure pump and FCC mount on the front of the engine. I had to remove one of the engine lifting eyes and use the threaded hole to mount the FCC. You can interchange the fittings around the perimeter of the FCC so you have clearance to mount it and not hit the alternator. Low pressure pump mounting point:  This image came from tnplicky's post.  This image came from tnplicky's post. I moved the 90 degree barbed fitting to position 2 for my return to tank line. I saved 90 degree elbow that came off the old low pressure fuel pump. cleaned it up and reused it in order to make the hose routing clean by putting it in position 3. In order to make Point A (Feed to the Fuel Rail) and B (Return from Fuel Rail) work I had to swap out one of the top fittings with another supplied fitting in order to make the connection to the supplied fuel line. I actually opened up the FCC to see which line was coming off of the pump versus a return to make sure I had them connected correctly. You will need to buy about 10 ft of marine 3/8" fuel line and a hose mendor in order to get lines run from your current fuel filter to the new low presure pump and from the FCC back to your return to tank line. Finished product:  I cut and soldered into the old 12V power supply to the original pumps for the new wiring harness. I also shorted the 12V supply harness to the low pressure pump as it was so long I would have had two loops of extra wire. I also needed to buy about 18" of 1" Marine Coolant line and cut it to length as the FCC bracket interferes with the coolant line. I turned the fitting going into the manifold up a bit and used a longer coolant line to make the connection. Once everything was connected and tight, I reconnected the battery. You need to cycle the fuel pumps a few times (turn key on and off without starting) and prime the fuel rail before the boat will start. There is a Schrader valve on the front of the fuel rail. Use a rag and screwdriver to push in the valve a bit, Air and then fuel will shoot out so use a rag. Once the rail is primed the boat should start. I really appreciate the other posts and pictures. I would not have gotten this done without them. I hope this helps. |