Intermittent engine stall

[dmanderson]

My 1998 Supra Comp with the HO EFI PCM engine started stalling
intermittently and won't restart. I can feel the engine hesitate and sputter before stalling. After sitting for an hour or more, the engine will restart and run fine. I had the fuel filter and spark plugs replaced last week and the dealer indicated this will fix the problem. They ran the engine to operating temperature with no problems. The same problem happened again today and I have not been able to get the engine restarted. However, when gas is poured into the butterfly valves in the intake the engine will start and run briefly. Temperature seems fine.

When I turn the key to the on position, I am not hearing any fuel pump activity. Any suggestions?

[Ed Obermeier]

Do you get the sputter and stall after a fairly tight turn-around with the tank below a third or so full, or just out of the clear blue for no apparent reason?

I have a 2000 Legacy (MP-EFI) and a ski buddy has a 2000 Moomba Outback LS, same engine in both (330 HP Indmar Assault) that will sputter like they're running out of gas after a tight turn-around with the tank getting low (below maybe a third or quarter full), although we've never actually had the engine die and not restart. We only get the sputtering. Funny thing though is that it only happens if you turn around one direction (counter-clock-wise I think), not the other. It will sputter like it's run out of gas but after jacking the throttle lever a few times (with the boat back on level) it will pick back up and go. Leaves us screaming into the entry of the course sometimes but we've learned how to deal with it.

Our assumption is that the position of the fuel pickup in the tank has something to do with it but we've never looked into it too hard. Seems as if in a tight turn-around the "wrong" direction the fuel shifts enough that the pickup in the tank is left sucking air for a moment. We just don't make our turn-arounds that direction and it's not a problem, just a pain in the ass.

Sound like anything you're dealing with or is yours different from this?

Ed

[neardana]

I have been having this problem for two years. At first, once warm, it would not restart again for 30 minutes. Now it just stalls and won't restart for 30 minutes. All other times it runs fine. I am still in the process of solving the problem and have discovered that it is very common and no one has a solution. The suspected problems are: ignition module, ignition switch, coil, condenser, gear shift switch, fuse box connector, safety switch, auto shutdown switch relay, tank vent, fule control cell, vapor lock, engine coolant temperature sensor, water separator, fuel filter, water in gas, and, the generic, a wire shorting out.

My Supra does not even have some of these parts, but I have tested/replaced most and eliminated them as the cause. I suspect that it is a vapor lock, but I cannot determine a cause. Once I figure it out, I will post my findings.

[selle92]

neardana,

What year/model do you have?

I have the same problems you describe.. Had em since I got the boat at the beginning of last season.

I have a 91 Mariah.

On the lift, under the canopy.. I can cranker her down, fire up the blowers, and she fires up like a champ... never a problem.

I can go out and ski/board/cruise the lake no problem. But, once I run her for awhile and dock or anchor out in the lake, the boat won't turn over again if it sits for any period longer than 10 mins shut "Off".

Solution (last yr).. Every time I docked or shut down:
1) could keep engine running with blowers on. (not what I want to do)
2) open up the dog house and let it cool down (plus get rid of any vapor lock- if there was any)
or
3) Wait 30min+ until she cooled off.- However, if on the end of the dock and it's getting beat on in the sun (say a 90 and humid day).. that wait could take forever!

On thing that did help the time go quicker if I shut off. Open up the dog house, pull off the air box and expose the carb. I had a big piece of cardboard that I used as a fan- just waving over the top/air intake while I turned it over.. and that usually did the trick.. least it did last year.

Now, this year... it seemed to get worse. For one, when I was docking and going at idle speed sometimes she just completely killed on me, and then wouldn't restart...

I've been going round and round with this, and it just happened again last night. Not to mention my new solenoid stuck on again and I beat on it to get the engine to die (to the point where I cracked the black housing)..

So, now, I need to go get a new solenoid (think this one was faulty anways).$26.. no biggie.
while I'm at it, going to replace the plugs at the same time and check the gaps. Not sure if this would cause it or not, but could be one minor peice to the puzzle.

Only other thing I can think of would be: Clogged carb possibly... might be a good idea to rebuild anyways..as this boat I have is older and probably hasn't had the carb redone at all- least I don't think it has been. Or possibly something along the fuel line- or maybe a short???

I think I may have 2 separate issues going on... but for the life of me, can't seem to figure it out.

Really sucks when you are looking forward to going out to watch fireworks on the lake, and then you have to walk your damn boat up onto the lift and go out with a neighbor.

My wife wants it on ebay... to me, I just can't do it. I know its something that can be fixed, I'm just not the mechincally minded or talented one who knows enough on how to fix the problem.. But going to try what I can and do the process of elimination.

let me know what solutions for fixes you come up with.. I'll post here as well with anything I find out or what works for me

[neardana]

92,

I have a 92 Supra ts6m with PCM engine. I spent several hours today talking with PCM mechanics. No one wanted to deal with my problem because it can't be replicated in the shop (and my boat is too old for them to care -- "they have some new boats if I'm interested"). After all this time, the collective suggestions were "replace the nox sensor" and "clean the spark plug wire connections with alcohol".

The spark plug wires are new and I'm not replacing the nox sensor unless someone can test it and determine that it is bad.

Since the problem only occurs in the lake and is a function of time rather than when it is always running, the only constant is the lake water. Three years ago the exhaust manifold risers clogged causing the engine to overheat and blow out the "mufflers". We were warned to be careful when cleaning out the risers because "there is only a thin wall between the water and air chambers". We were not told what the resulting performenace problems would be if the risers were leaking water back into the engine. It would explain why the problem is geting progressively worse as the leaking increased. We are contacting the guy who designed the Supra boat and now works for Tige. The maunal does warn about this condition, but does not explain the consequences other than "severe engine damage".

My wife and kids are down with my "broke-down" boat too. I guess it does get boring after the fourth 30 minute "break".

[selle92]

Sounds good.

I went out to the MC dealer and talked "Shop" with them for awhile, while I picked up another new solenoid.

I got alot of good info, however, it was more of.. bring her in for a diagonistic check. I just can't bring myself to do that, as like you say.. it's hard to replicate the problem unless you are out on the water and can spend some real time with it.. maybe a 1/2 day or more to really see it going on.

their suggestions (after just hearing my description of what was going on).
1) could be the intake/outake of the gas.
2) could be the carb
3) Fuel filter- if any water was in there
4) vapor lock.. said some boats get it more than others.. depends on boat/yr and luck.

I've been working on figure out the problem with my neighbor who has an 87 comp.

I replaced the solenoid and think that was my "MAIN" troubles. The old-old one I had that died.. I think was caused by the Key'd ignition. I put in a new solenoid a few weeks ago, and think I messed that one up (or it was faulty) and THEN I replaced the ignition switch.

now that the switch is new, I put in the 2nd replaced solenoid and have had no problems whatso ever on that end.

I did also add 2 bottles of seafoam to the gas, and it has been running great.. Hasn't stalled like it had- after a full day on/off use.. and had been starting well.. even after she sits for a bit.

We checked the fuel filter, and that looked good. Checked the plugs- again good.

So we were out this past sunday skiing and cruising.

I was leary to shut down after skiing for a hour, but we parked just out front of our place with our neighbors. Figured, if it didn't start, I was close to home.

Killed the boat and ran the blowers. After swimming for a bit, I noticed as I came up on the platform-that I think one blower had been mounted backwards.. one side had air blowing out... one side appears nothing was going on.. BUT, when I stuck my hand on it, it appeared it was sucking in.

Not sure if that is really an issue or not.. just flowing the wrong way. However, it might not be helping the cause (if vapor lock is happening). Just sitting- it probably doesn't matter, but when cruising- regular flow should go from the front to rear.

Need to swap that around and see what the differnce is- if any.

So, my neighbor with the comp swam out and we opened up the engine box to take a look.

His thought, was that maybe the heat was expanding the carb to the point where the needle(s) might be dripping gass & flooding it a bit , causing it not to fire.

We turned it, and it didn't fire-- just as before if shut off after out for awhile. We took off the flame arrestor, and checked it.. didn't appear to be dripping any fuel. After sitting for 20 mins while we were swimming, it only took only about 5 mins of the cover off, and then she fired up. NO black smoke out the rear- so it didn't appear as if it was flooded.. just fired up and idled great...

He's almost thinking its something electrical causing it now. Not sure what, but seems like something is just a bit off.

Good news I guess, is that its back to where it was before (last year) and don't think its a carb problem- though, rebuilding the carb might be cheaper than any electrical issue going on. I guess I just baby it and know that after running it for awhile, just open it up and let her cool down... TLC may just be whats in store.

[selle92]

PS.

NOX sensor? Hrmm. not sure what exactly that is.. However, if there is vapor build up (not necessarily lock).. maybe that could be causing my issues as well.

Seems if you open up my engine box for 10-15 mins, then I don't have problems.- after it cools (or so I thought).. but maybe this sensor is picking up something causing it not to fire?

Where is that sensor located- if you know? I would like to check that.

any ideas if you can adjust it?

Thanks.

I finally determined my problem. From 1991 through 1994 PCM used an electronic ignition module made by Pro-Tec. The ignition module has been known to be faulty since 1994. The problem is hard to diagnose because the failure slowly increases in frequency. The electronic ignitiion module is not properly shielded so it receives other electronic signals from the engine which shuts it down. The problem increases when the unit gets hot. Eventually it resets itself. The fauilure is a function of usage over time.

The module is not manufactured anymore nor is a replacement. PCM has a few left, but only sells those to owners with fuel injection because the two are interrelated. For others (carbs), the solution is a Pro-Tec Ignition Conversion Kit (part no. RK107025A). The kit replaces the electronic ignition module with a distributor and coil (still electronic ignition). Skidim sells the kit for $455. I installed it in about an hour and have had no problems the past 2 weeks (12 hours on the water).

I finally determined my problem. From 1991 through 1994 PCM used an electronic ignition module made by Pro-Tec. The ignition module has been known to be faulty since 1994. The problem is hard to diagnose because the failure slowly increases in frequency. The electronic ignitiion module is not properly shielded so it receives other electronic signals from the engine which shuts it down. The problem increases when the unit gets hot. Eventually it resets itself. The fauilure is a function of usage over time.

The module is not manufactured anymore nor is a replacement. PCM has a few left, but only sells those to owners with fuel injection because the two are interrelated. For others (carbs), the solution is a Pro-Tec Ignition Conversion Kit (part no. RK107025A). The kit replaces the electronic ignition module with a distributor and coil (still electronic ignition). Skidim sells the kit for $455. I installed it in about an hour and have had no problems the past 2 weeks (12 hours on the water).

[selle92]

neardana ,

I posted an update to my vapor lock/stalling issue.. check it out in General Chat. Maybe you need a new T-Stat like me?

[neardana]

I finally determined my problem. From 1991 through 1994 PCM used an electronic ignition module made by Pro-Tec. The ignition module has been known to be faulty since 1994. The problem is hard to diagnose because the failure slowly increases in frequency. The electronic ignitiion module is not properly shielded so it receives other electronic signals from the engine which shuts it down. The problem increases when the unit gets hot. Eventually it resets itself. The fauilure is a function of usage over time.

The module is not manufactured anymore nor is a replacement. PCM has a few left, but only sells those to owners with fuel injection because the two are interrelated. For others (carbs), the solution is a Pro-Tec Ignition Conversion Kit (part no. RK107025A). The kit replaces the electronic ignition module with a distributor and coil (still electronic ignition). Skidim sells the kit for $455. I installed it in about an hour and have had no problems the past 2 weeks (12 hours on the water).

[OUI]

Partsman.com sells the entire kit including, wires, cap and rotor for $249.00 includes shipping. It's a great deal and works perfect.

[selle92]

partsman.com

Sure that is correct?

Edit.. never mind.. PARTMAN.com

[selle92]

http://marineengineparts.com/shopsite_sc/store/html/page82.html#716


Says Chevy... assume this will work with the 351 as well?

[neardana]

A Chevy conversion kit will not work on a Ford engine. In addition, Partman's conversion kit does not inclue the wiring harness. This is necsessary to convert to the distributor system. Skidem works directly with PCM. I reccomend dealing with Skidem and getting the parts in the kit as designed by PCM.

[selle92]

Anyone ever go down this route?

http://www.jegs.com/webapp/wcs/stores/servlet/CategoryDisplay?storeId=10001&catalogId=10002&catalogIdentifier=Jegs_Direct&categoryId=99308&parentCategoryId=10299

I'm still having problems, and considering this option.

[riveredge]

This is rare, and I don't know if the Supras even have them, to be honest (my '89 certainly does not). BUT I have seen those stupid safety lanyard thingys become loose or otherwise faulty causing this: you hit a wave, it moves a TINY bit to the spot it doesn't like, the boat turns off. Won't restart until, by some miracle, it moves just enough to re-engage the switch and Vroom off you go. I give Supra boats a lot of credit, and I have only seen this problem on an '05 Ski Supreme and an '04 Chris Craft. You'll never see someone feel so stupid as when you show them that if they had just fiddled with the switch a little they would have been fine, rather than calling a marina and having someone come out there to check their engine, fuel system, ignition, etc.
Most likely not the problem 99% of the time, but it's kind of amusing when it happens, especially when the best solution is cutting both wires going to the switch and connecting them permanently.