92 Limp, Nav Lights, Voltmeter Problems

For sure, the SN's do have inadequate wiring to the dash. The voltmeter will drop alot when the blower and lights are on. Running feed lines is a good idea to reduce the voltage drop!!

I too have the problems Jeff mentioned! I'll fix it this winter. While troubleshooting last summer I found several connectors with corroded pins, white powder. I cleaned them up and coated them with Dow Corning #4. It's a special tube of grease (similar to vaseline) exclusively for connectors and contacts to retard corrosion and keep out moisture. We use it on aircraft all the time and it works great. Don't even think of trying vaseline. It's not the same.

Dow Corning #4? Where do you get it?

Isn't a Skyhawk the kind of plane Sky King flew around in (with Will and Penny)?

jbear, I remember the name of his plane but I don't remember the name of his ranch. Flying R?

A skyhawk is a Cessna 172. A single engine prop! You should be able to find DC4 anyplace that carries other Dow Corning products, they have a lot of differnt high and low temp grease's.

If you can mooch some off of somebody at your local airport that would work good. About 1/2 a 35mm film canister will last you for several years!

Hey DesertSkier,
Have you been able to run since you addressed the problem listed below? I will be using your advice to attempt repair of my 1991 PCM/ProTec Nautique Excel later today.
Tom

DesertSkier wrote: The other problem I have had is the engine will go to limp mode once in awhile. When the failure occurs all the sensors are OK. I have been able to temporarily cure the problem by remating the connectors on the ignition module and the main connector from the dash to the engine. I suspect that the voltage drop becomes excessive through the connectors and causes a less than required voltage to be presented to the ignition module. To try and cure this problem I ran a #10 wire from the 50 amp breaker on the engine to the ignition breaker in the dash and another #10 wire for ground from the ignition module ground point to the main ground connection in the dash. This fix has also been mentioned in another posting but I think it was for a different problem. Hopefully I don't see the problem again.

DesertSkier posted: <<I just got back from a week at Lake Powell. The boat ran great and the guages were all reading correctly>>

Congrats! I also hope have no more trouble, and I'll be attempting to duplicate your "patch" this week with my 1991 5.8PCM ProTec engine in a 1991 Nautique Excel. Interesting statement at the end of the thread listed below; someone told me the ProTec "limp mode" is activated only by two things, low oil pressure OR overtemperature.

I wonder if low system voltage can be confused with a wrong sensor reading on either of those sensors... In any case, I will be trying to fix my limp mode problem this week also.

http://www.correctcraftfan.com/forum/forum_posts.asp?TID=1934&PN=1
(see last post about two conditions to set limp mode)

I have the same problem with my 1994 nautique running on Lpg.
Have had problems with back fire only on accelerating from 800 rpm.
Changed the wires and the problem was over.

At this moment the problem is back a little bit. Sometimes it's running ok and sometimes at snuggles when we are trying to accelerate. When I put direclty power on the ignition unit, the problem is directly gone.

Now finding out which cable it is or... in the winter change all.

OK: It's been a few weeks, but I fixed the low voltage problem in my dashboard guages. Per the instructions provided in the previous message(s), I installed a 10ga. red jumper wire from the switched side of the ignition breaker directly to the battery (red) wire connection on the ignition switch. About a 2ft piece of wire, and my gauges no longer bounce to an offset, dim, and show low voltage when I turn on the Navigation lights.

Next is to tackle suggested wiring repair to the limp mode problem I'm having.

Tom

Tom:

First off, no, the Pro-Tec interupter does not have mechanical advance. The control module takes care of that task electrically.

Again, if everything is working properly, only two things cause limp mode: Low/zero oil pressure and engine over temp. You can easily check the sensors and wiring as follows:
1) The oil and temp sensors are wired in series, so you must disconnect the oil pressure switch wire to check either.
2) Using a multimeter, check for continuity between the electrical terminal and switch base. The oil pressure switch is normally "closed" and the temp switch normally "open" when the engine is not running. This is why you have to disconnect one to test either.
3) Test the wiring for shorts. disconnect the wire from the sensors to the tattle tale light. The wire splits to go to the light and the ECU. Disconnect the main plug at the ECU. My engine has a single GM weatherproof connector on the light green wire just before the wire heads for the main harness to the dash (light). Now check the wire for shorts to ground (you should still have the oil pressure switch disconnected).

If the sensors and wiring are fine, then you should be able to eliminate this as the root cause. Although, I suppose it is possible that maybe the oil pressure switch behaves badly at high rpms thus pressures. Disconnecting the wire at the oil switch will eliminate it from the circuit to test while running.

Now, I would check all grounds again. There are probably more than one. One may be under the mounting plate of the ECU and one may be at one of the bellhousing bolts. Look for all and make sure they are clean (corrosion free) and tight).

What worries me a bit is that you have to remove power to the system (ECU) in order to clear the ECU from limp mode. This sort of suggests that maybe the problem lies within the ECU and you are in essence hard booting the ECU. Maybe you should talk to Mark at PCM, (803) 345-1337 for advice on troubleshooting. He may have heard of this problem before and knows exactly the cause. However, I have a hunce that if your ECU is faulty, you are out of luck. Although I believe that PCM has a few Pro-Tec parts on hand, including the ECU, they are saving them for people that have EFI, like me. The EFI engines rely heavily on Pro-Tec as a system, so PCM is hoarding the parts to keep the EFI boats running, as converting to carb and conventional ignition would not be a popular option that makes owners happy.

I have heard that the Pro-Tec coils are prone to failure, but your scenario does not suggest this as a problem per se. Good luck.

Definately put the sensor in the correct location. If you want the heater, the sensor can be relocated to the circulation pump (not the raw water pump) if it has a plug just under the thermostat housing. You may have to remove the thermostat housing to install the sensor in this location as clearance is tight. FWIW, this is where mine is located since the standard location is used for the water temp sensor serving the EFI. I have three water sensors: Pro-Tec over temp switch, sending unit for guage, and sensor for EFI.

One last thing: Teflon tape can interfer with grounding of the sensor, but the over temp switch is normally open, so this may not be the problem.

The Pro-tec ignition system has a function called "cruise mode". This mode automatically advances the ignition timing after 30 seconds of steady throttle. The timing returns to base once the throttle is moved. This mode can be disabled by disconnecting the knock sensor located at the rear of the left cylinder head. May I suggest that you disconnect the knock sensor then check base timing and then run test the engine with the sensor disconnected. The knock sensor and "cruise mode" are the only "items" that have any direct control on ignition timing.

When you pull the plugs, read them. Look for two to four plugs being black or sooty. If so, trace the wires back to the coil pack. This may lead you to a faulty coil.

let us know.

I have a 93 SN and had a similar problem. The wire not sure of the name but the ones that plug into the firing Mod. (where the dist used to be) were not making a good connect. I trimmed some of the rubber back 1/16 of an inch or so and it fixed the problem. I was at the last moment before converting my eng. when I was shacking wires and as soon as I hit that plug the eng. picked back up. I had spoken to Mark and was on my second coil pack when I found this...Also I have the same problem with the gauges jumping when I hit the light etc. going home tonight and try the juup wire. My only worry is that when i put my volt meter on the neg. bat. term. and touch the neg. wires on the back of my dash pod it shows a .5 volt on the neg side. Shouldn.t neg be 0 all the time?

I found someone who upgraded their 1991 Nautique Excel to the SkiDIM distributor kit and I'm buying their old parts to try and salvage my system... Otherwise, I'm tired of "test drives" for this year and I'm gonna upgrade mine as well.

Tom

You made a very good observation and point. You are correct that I know about cruise mode based on my fuel injected (TBI) engine.

With that said, the Cruise mode lies wihtin Pro-Tec, not the fuel injection module. So, maybe the mode senses a change in RPM via the interupter. Maybe you are correct and Cruise Mode does not exist with carbureted engines.

I will try to do some research to answer this question definatively.