Stumble and Backfire during accel |
Post Reply | Page 123> |
Author | ||
ski_in6
Newbie Joined: March-11-2014 Location: Lafayette IN Status: Offline Points: 16 |
Post Options
Thanks(0)
Posted: May-15-2014 at 1:48am |
|
I have a 92 Ski Nautique with a carbureted 351. Last season, it started hesitating intermittently under hard acceleration. Finally it got to where it would not pull up a skier - hesitation, loss of power and backfires. IT does this warm or cold. If I give it less throttle and ease my way up, it runs wide open just fine, which makes me think it's not fuel filter. I have rebuilt the carburetor with help from a friend. No effect. I just changed the fuel filter anyway, and have not had a chance to run it yet (other than idle - it still idles fine). The engine still has the Pro Tec ignition, which I know is very problematic, but it does not seem to fit what people describe as typical failures for that system. Any thoughts would be appreciated.
|
||
KAI
|
||
Orlando76
Grand Poobah Joined: May-21-2013 Location: Mount Dora, FL Status: Offline Points: 3108 |
Post Options
Thanks(0)
|
|
Slipped timing?
|
||
levinmark
Senior Member Joined: November-11-2010 Location: illinois Status: Offline Points: 375 |
Post Options
Thanks(0)
|
|
I had the exact same issue with our 96' and it turned out to be that the secondaries were not opening due to corrosion. Maybe check those and see if you can move them?
|
||
levin
|
||
TX Foilhead
Grand Poobah Joined: February-01-2009 Location: Kingsland TX Status: Offline Points: 2076 |
Post Options
Thanks(0)
|
|
That's similar to the way my ProTec died. For years we used about half half throttle to ease everyone out of the water, then one summer it started taking more throttle and and by the end it was open it all the way and wait a little. Never had an issue with backfiring or hard starts. I had a brand new carb at the time so it was running absolutely flawless and the Perfect Pass was able to handle the driving duties. I'm sure without those things the problem would have been more noticeable much quicker.
|
||
Waterdog
Grand Poobah Joined: April-27-2006 Location: United States Status: Offline Points: 2020 |
Post Options
Thanks(0)
|
|
I don't think the timing is ajustable with a Pro-tec and they ARE problematic.
1) It could be a coil pack braking down. 2) Check the spark plugs and wires if there all firing tan in color thats good. 3) Check for a vacuum leak by spraying wd 40 or carb cleaner LIGHTLY around the base of the carb and at the intake/head gaskets. Easy to do and pretty much free. |
||
tahoegaper
Newbie Joined: May-19-2014 Location: Sacramento Status: Offline Points: 8 |
Post Options
Thanks(0)
|
|
OK I am in this same situation. I have a '92 SNOB has about 1200 hours. I have converted the protect to a standard distributor system, then rebuilt the carb, then installed a brand new carb. I have the same symtoms as above: starts right up pulls wells off the start then after about 10 minutes I can so from WOT to 20 MPH and then to stop and they the engine seems to load up and choke out. I have replaced spark plugs several times in this process, and the ignition work was done by the dealer. I am at a loss on our what to do next. I am ready to sell and be done with it, as my wife and I now have twin 1 year olds and we can not trust the boat we have loved for 13 years. Help
TG |
||
desertskier
Platinum Member Joined: December-19-2006 Location: Az Status: Offline Points: 1115 |
Post Options
Thanks(0)
|
|
tahoegaper:
Do you know what standard distributor system they installed and how they wired it? If they used the 12V wire coming from the dash it still may be a low voltage problem caused by the dash wiring issues associated with our boats ( I have a '92 also). |
||
tahoegaper
Newbie Joined: May-19-2014 Location: Sacramento Status: Offline Points: 8 |
Post Options
Thanks(1)
|
|
So it looks to me that they replaced the ignition with:
PROTEC RETRO KIT PCM FORD the same one that you can purchase from SkiDim I have not check sparked plugs after yesterdays trip on the river, but have got to think I have basically eliminated the large pieces of this puzzle. Thank you, TG |
||
tahoegaper
Newbie Joined: May-19-2014 Location: Sacramento Status: Offline Points: 8 |
Post Options
Thanks(0)
|
|
I forgot to mention that I have also replaced the water/fuel separator with a Racor system.
Like I said all of the major components that I can think of has been replaced. Thanks, TG |
||
desertskier
Platinum Member Joined: December-19-2006 Location: Az Status: Offline Points: 1115 |
Post Options
Thanks(0)
|
|
According to the skidim website the replacement system uses a Mallory distributor with an external coil and ballast resistor. I would make sure that there is 12V at the ballast resistor.
ski_in6: The symtoms you are experiencing are what mine did before I beefed up the wiring to the ProTec. |
||
Hooty222
Senior Member Joined: May-10-2009 Location: Flagstaff AZ Status: Offline Points: 141 |
Post Options
Thanks(0)
|
|
My first gut feeling is accelerator pump not working..
Disregard if too elementary. Good day. |
||
1986 Ski nautique 351
1988 Barefoot nautique 454 |
||
Tomski
Senior Member Joined: October-19-2006 Location: United Kingdom Status: Offline Points: 227 |
Post Options
Thanks(0)
|
|
x2 for accel pump. Look down the primaries and have someone open the throttle as you would to take off, there should be a good squirt of fuel going in to each of the primaries.
Failure of the pump is a classic for bogging an engine that runs OK otherwise. The pump jets often get overlooked on a rebuild. |
||
Easily Parted From Money
|
||
Bri892001
Grand Poobah Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4947 |
Post Options
Thanks(0)
|
|
I agree with the accelerator pump for the first poster.
Keith, the key is not only that the accelerator pump is working, but that it's coming in immediately. Make sure adjust out any slop by using the adjuster but on the pump linkage arm. If there's any free play, you'll get that bog. |
||
Bri892001
Grand Poobah Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4947 |
Post Options
Thanks(0)
|
|
Tahoegaper, yours sounds like a textbook overheating coil situation.
Another possibility is a fuel vent issue, you could try removing the fuel cap when it's acting up. Or maybe a clogged fuel screen problem. |
||
ski_in6
Newbie Joined: March-11-2014 Location: Lafayette IN Status: Offline Points: 16 |
Post Options
Thanks(0)
|
|
I have actuated the accelerator pump by hand, and watched the fuel streams into the primary venturis - seems ok, but I don't have much frame of reference. I'll check for slop. Will also look at the plugs. From everything I've read/seen on Youtube about Holleys, it seems more likely a problem with the secondaries. It picks up smoothly off idle, where the accelerator pump is supposed to add fuel. But when I try to open past say 60-70% throttle, that's when it sputters, backfires, etc.
Next steps: 1.) check plug condition; 2.) check accel pump linkage; 3.) check for vacuum leaks; 4.) check idle timing; 5.) try loosening fill cap. desertskier: could you elaborate on what wiring you beefed up to the Protec? Thanks for all your input, I hope to run the boat this week and get to the bottom of this. |
||
KAI
|
||
62 wood
Grand Poobah Joined: February-19-2005 Location: NW IL Status: Offline Points: 4527 |
Post Options
Thanks(0)
|
|
Not familiar with that dizzy, have you checked for sticking timing advance plate? Does it have springs and weights? Are they loose?
|
||
desertskier
Platinum Member Joined: December-19-2006 Location: Az Status: Offline Points: 1115 |
Post Options
Thanks(0)
|
|
A known problem with our boats is the dash wiring. CC wired the instruments in series (daisy chained) rather than using terminal blocks for power and ground and wiring in parallel. There are some very good posts that describe how to correct the dash wiring issues just search for dash wiring. The main symptom of the poor dash wiring is when you turn on your navigation lights the gauges jump or peg. But the daisy chains also affect the ProTec because it gets power from the key switch on the dash. The power (12Vdc Battery) starts at the 50 Amp breaker at the engine (point 22 on the schematic) it is then routed through the main connector back to the dash. It enters the dash at the ignition breaker switch on the right side of the dash. The output of the ignition breaker switch is then daisy chained through the dash wiring and ends up at the input to the key switch. From the key switch it is routed back to the engine 12.5 Amp breaker (point 41 on the schematic). Then the output of the 12.5 breaker is routed to the ProTec pin "P". The main problem is that because of IR voltage drops through the dash wiring the voltage is less than it should be by the time it gets back to the ProTec. I "beefed up" the dash wiring by adding a single wire that goes directly from the output of the ignition breaker to the input of the key switch. This increases the voltage at the key switch and ultimately the input to the ProTec. You can start by turning on the key and measuring the voltage at the 12.5 Amp breaker. It should be close to battery voltage. Mine reads about 11.5 volts after I fixed it. If it is low then there are several options depending on how comfortable you are with wiring. You can add the dash wire or a cleaner fix would be to install a relay at the input to the 12.5 breaker that is controlled by the key switch but gets battery voltage from the 50 Amp breaker and routes it to the ProTec. I guess the first question is do you have a voltmeter and know how to use it? If not they are pretty cheap to buy and easy to use. If you don't know how to use one there are posts with pictures that we can point to and help you through it. |
||
backfoot100
Platinum Member Joined: January-03-2007 Location: United States Status: Offline Points: 1897 |
Post Options
Thanks(0)
|
|
So is this the problem?
Or is this the problem? Two different issues with two different fixes. If it's an inconsistancy issue check the wiring as stated from others. FYI, my brother-in-law has a 92 with the Pro-Tec. He had a problem where the boat ran great until WOT. It would sometimes just die like turning the key off. Not all the time though but started to progressively get worse. When it happened you put it in nuetral and start it like nothing ever happened. Everything about it ran perfect except at WOT. He ended up finding a loose connection in the dash. He couldn't tell me where it was or what it did but he tightened it up and the boat has ran perfect for three years. Start there like others have suggested. |
||
When people run down to the lake to see what's making that noise, you've succeeded.
Eddie |
||
Bri892001
Grand Poobah Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4947 |
Post Options
Thanks(0)
|
|
Here's the thread where I added the dash ground and later added a new positive:
http://www.correctcraftfan.com/forum/forum_posts.asp?TID=21901&PN=1&title=added-new-dash-ground-to-93-with-pics That fixed my gauge and perfect pass issues, so I stopped there. It sounds like to get the Protec all the power it needs, you'd want to run a new ignition (Purple) along with the new ground and positive. Might not be a bad idea to just totally replace the Dash to Engine Harness: http://www.skidim.com/prodinfo.asp?number=R121014 |
||
desertskier
Platinum Member Joined: December-19-2006 Location: Az Status: Offline Points: 1115 |
Post Options
Thanks(0)
|
|
The ProTec gets a solid ground at the motor (point #40 on the schematic). Only the power wire needs to be addressed.
|
||
ski_in6
Newbie Joined: March-11-2014 Location: Lafayette IN Status: Offline Points: 16 |
Post Options
Thanks(0)
|
|
Eddie,
It is one problem, not described very well on my part. If there's a dramatic change in throttle setting, the engine misses and backfires. If the throttle change is gradual enough, I can get to full throttle and run full speed. I actuated the secondaries, they don't appear to be stuck. I looked at the spark plugs, cyl 7 was definitely darker and wet when I pulled it out. The rest were light tan or almost white (fairly new plugs). I checked compression, 145-155 psi on all cylinders. I was thinking of putting the timing light on the cylinder 7 wire and just see if it's getting current at all. Desertskier, thanks for the schematic, that really helps. I will check voltage at the 12.5 A breaker (good chance to use my new voltmeter!) |
||
KAI
|
||
ski_in6
Newbie Joined: March-11-2014 Location: Lafayette IN Status: Offline Points: 16 |
Post Options
Thanks(0)
|
|
desertskier, I checked voltage at the 12.5A breaker. With 12.5 volts battery voltage, I get 11.7 volts at the breaker. You mentioned 11.5 volts with the direct wire installed. Am I ok here? Or does something change when the engine is under high load?
|
||
KAI
|
||
desertskier
Platinum Member Joined: December-19-2006 Location: Az Status: Offline Points: 1115 |
Post Options
Thanks(0)
|
|
You could check it again with the engine running just to be sure but it looks good. If there is some resistance in the path it will drop more voltage as the current increases.
|
||
ski_in6
Newbie Joined: March-11-2014 Location: Lafayette IN Status: Offline Points: 16 |
Post Options
Thanks(0)
|
|
I fired the boat in the driveway this weekend, it ran worse than ever, popping and missing. It would stay running at 1500 RPM but was clearly not running on all cylinders. I put the timing light on, and just to see which cylinders were missing, clipped on to each wire in succession. The front 4 cylinders read the correct RPM, but the rear 4 read double (3200 RPM instead of the correct 1600 RPM). It seems to me that the coils are failing and putting multiple sparks, probably at the incorrect timing, to the rear four cylinders. It was running so poorly I am not sure I could verify timing on cylinder 1. This was the worst it's been. My thought is that another ProTec has bit the dust. If someone knows better, please let me know ASAP as I plan to order the distributor conversion kit in the morning. Thanks!
|
||
KAI
|
||
TX Foilhead
Grand Poobah Joined: February-01-2009 Location: Kingsland TX Status: Offline Points: 2076 |
Post Options
Thanks(0)
|
|
It's the front cylinders that are the problem. ProTec is a waste spark system, it fires 2 plugs at the same time, one is on the compression stroke and the othe is on the exhaust so it doesn't matter. There are plenty of coil packs around, Ford and Chrysler both used them, but there isn't any documentation that I've seen that explains the design enough to know what else might work.
|
||
ski_in6
Newbie Joined: March-11-2014 Location: Lafayette IN Status: Offline Points: 16 |
Post Options
Thanks(0)
|
|
With some help, I've managed to isolate it to a coil (as opposed to the ignition module). I can find 3 coil versions of this coil pack, but not a 2 coil. I assume they are not available anywhere?
|
||
KAI
|
||
Bri892001
Grand Poobah Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4947 |
Post Options
Thanks(0)
|
|
Is it two sets of two? Is the brain box integrated or is it separate?
Someone on her once claimed they replaced them with a Cadillac Northstar coil pack set, but no details where ever given. |
||
ski_in6
Newbie Joined: March-11-2014 Location: Lafayette IN Status: Offline Points: 16 |
Post Options
Thanks(0)
|
|
Interesting you should mention that... I work with a guy who worked on that system. It takes more than just coils, but it could be done. It's more than I am willing to bite off at this point.
To answer your question, it's 2 sets of 2 coils each. As TX Foilhead said, it's a wasted spark system. The coils can be unbolted from the brainbox (ignition module). By swapping the coils around I was able to isolate the problem (or at least the worst of the problem) to one coil. An easy test that pointed me in the right direction was simply checking resistance across the coils. I've been told they can all measure the same but still have a bad one, but in my case the resistance was 50% higher on one of the coils. |
||
KAI
|
||
ski_in6
Newbie Joined: March-11-2014 Location: Lafayette IN Status: Offline Points: 16 |
Post Options
Thanks(0)
|
|
Ok, I finally isolated the problem to the Protec. I bought the conversion kit and have it installed. I plan to run it this evening, but am confused about setting the distributor. There is an ignition pulse every 90 degrees (45 cam angle degrees). I understand any location can be cyl #1, but I don't know how to get the rotor oriented so the timing will be close enough for the engine to run. It could be as much as 45 deg early or 45 deg late. Is there a way to get closer? Also, the PCM instructions call for 5 deg timing. Is there a reason it's later than the 10 deg recommendation with the Protec?
|
||
KAI
|
||
SNobsessed
Grand Poobah Joined: October-21-2007 Location: IA Status: Offline Points: 7102 |
Post Options
Thanks(0)
|
|
Get #1 piston at TDC on firing stroke. Adjust the dizzy so that the rotor is centered over #1 terminal, then you will be close enough to start it.
PCM is being conservative on timing, I would be the same for liability reasons. |
||
“Beer is proof that God loves us and wants us to be happy.”
Ben Franklin |
||
Post Reply | Page 123> |
Tweet
|
Forum Jump | Forum Permissions You cannot post new topics in this forum You cannot reply to topics in this forum You cannot delete your posts in this forum You cannot edit your posts in this forum You cannot create polls in this forum You cannot vote in polls in this forum |