Falling on It's Face - VP501 DPA

[alldodge]

When I approached WOT it bogged. This time it did not die like it had the other times. I was able to back off slightly, and keep pretty high rpm's.

I still se a fuel issue, and while you said there was no anti-siphon valve (which there should be) there is a restriction somewhere which is leaning the fuel out. It could also be the tank pickup being a big clogged. In any case, installing a pressure gauge should clear up this issue

 

[Hook'd]

Tomorrow I'll add the fuel pressure gauge, tighten hose fittings, and switch out the alarm. Any comment on the wiring I observed? I don't know what function the manifold sensor serves because the temp sender is on a tee in the San Juan system.

While working on the boat yesterday I noticed the following wiring. The purple wire from the harness is spliced into 4 wires; the coil, the alternator (with resistor), oil pressure safety, and another wire. This wire hits the choke, and manifold sender. It then returns to an alarm in the dash, which does not work. This just does not seem right, and does not jive with the wiring diagram for the original boat. However, the Delco est is aftermarket, along with the electric fuel pump.

Could this wiring be at fault?

This all started when I installed a closed loop cooling system and second racor. Could the manifold sensor be overheating while the coolant temp sender stays at 160, causing the engine to die or bog.

Thanks,

 

[alldodge]

The purple wire is the ignition feed circuit. The Alt and Coil need it to run, and the oil pressure switch to keep the fuel pump running.

If the manifold senor should not be feed with 12V, as the temp increases the resistance values will reduce. Now if it is a water temp switch and it reaches high enough temp to close, it will ground the wire and blow the 20 amp fuse.

The alarm circuit should have the purple wire attached, but in most cases it is feed from the helm gauges purple wire. On the other side of the alarm there should be a Tan/Blue wire which goes to the water temp switch, oil pressure switch and the lube oil bottle switch

 

[Hook'd]

Thanks Dodge!

Update...

I put in the fuel pressure gauge, and it read 5 psi, then 5.5, then dropped over a ten minute period down to 2.75. I ran out of light, but will try bypassing the 10 micron filter for the stock 20 micron. Could the 10 micron be causing this? I assume it will fire right up at the correct 5 psi, then fade again.

Assuming this doesnt do it, then I'll open the hatch and look for an antisiphon. If that's not there, then I'll pull the pickup and look for an obstruction. Make sense?

With regard to the wiring, can you elaborate? I believe the device is a temperature switch. It is mounted on the starboard side of the tstat/coolant input. it seems aftermarket with two rabbit ears. I believe it is a temp switch.

The alarm may be wired incorrectly. I put a new one in today and tried disconnecting the temperature switch, and no alarm, and no effect on the engine. Maybe that is correct if it is a temp switch. But I need to verify where the other end of the alarm goes; to the gauge for example.

The choke is also fed from the same wire. Will this allow enough voltage to work the choke properly? Would it be better to run it from elsewhere?

It seems the temp switch and choke should be removed from the same circuit as the oil pressure safety switch controlling the fuel pump. Could this wiring preclude the fuel pump from having proper voltage, affecting the pressure?

Thanks again,

 

[alldodge]

Changing from 10 to 20 micron should have no effect on your pressure unless the filter is old and dirty. I think you should double check for the anti-siphon valve.

The temp and oil switches create a ground when activated. Temp goes to ground when temp gets around 200 or so, and the oil pressure switch grounds when the motor is OFF or when pressure drops below 3 psi or so. The temp switch does sound after market but should work correctly when wired correctly. To test the alarm, it should sound when the key is first turned to ON prior to starting. The alarm should stop once the motor starts. It should also sound if the lead going to the temp switch from the alarm is grounded

The alarm needs power run to it when the ignition is turned ON, this is the purple wire from the key switch. For the alarm to sound it just needs the other sided grounded. So the temp, oil and lube bottle are just switches to make a ground connection. All of these items need one side going to the alarm and the other going to a ground.

Running choke off the purple wire is not an issue. Running the temp switch direct to a 12V source is, it needs to go to the alarm not the 12V purple wire

 

[Hook'd]

First time I fired it up this am the gauge read 5-6#. Within 15 minutes, about the same time it got to temp, it decreased and fluttered between 2.5-3.5#. I opened the hatch, verified no check valve, and pulled the sender. I blew it out, and a nickel size thin, clear piece of plastic came flying out. That must be part of what's going on.

I put it back together and started it up, 3#, and again after a few minutes it settled in fluttering between 2.5-3.5#. I found a couple more bad connections I had made putting in the new pump and thought I had it again....no luck.

So for the first start of the day it seems to like 5-6# and after that 2.5-3.5# fluttering. I'll see if it's the same story tomorrow with the stuff I did today.

What should the pressure read, and should it be consistent. Maybe it's behaving correct now? When I see 5# and then it drop feels wrong.

I checked every part of the fuel system from carb filter to pickup, isolated filters, tightened connections, no anit siphon. Ideas?

 

[alldodge]

Your pump should be a minimum of 3# and a bit of fluctuation is not that much of an issue. You should see at least 5# at idle and it would reduce a bit as it gets to WOT. Are the rubber fuel lines new, if not new what does it look like inside, any collapsing?

Is the fuel pressure between the pump and carb?
Can you take a pic of fuel pump and filter locations?

 

[Hook'd]

Sounds like it might be operating correctly. I will take photos of the pump, lines and filters tomorrow am. All of the line is new and not collapsed. I blew out the line from the tank to the racor. The pressure is between the pump and carb.

Hoping the plastic in the pickup was the issue...can't be good. After the holiday I'll take for a trial and start with WOT and see if it can go the distance.

 

[Hook'd]

Delco Marine Voyager EST

In a separate thread I posted about my boat falling on its face. I've been digging through the fuel system and found a few things.

My setup is a indmar 5.7 vortex with roller cam, Rochester quadrajet, and Delco est.

My mechanic believes the distributor is not advancing. He was unaware of the Delco module and built-in advance. So today he is checking and setting the timing per the instructions.

Is there a difference in the curve from the auto versus marine version? I have a new module but it's the auto version. Will it provide the right curve?

If somehow the distributor is bad, what is a good recommendation for new?

Would the timing cause the boat to fall on its face? See my previous thread for more irritating details.

Thanks,

 

[GA_Boater]

Moved your latest post into the original thread. Fuel or spark advance can cause the same "fall on it's face" symptom. It's best to keep the problem and guesses in one thread to eliminate confusion.

 

[proshadetree]

The automotive and the marine modules do have diffrent advance rates. However automotive ones are in many marine distribitors just jack initial timing up a tad.

 

[alldodge]

The reasons why I don't see it as an electrical. You statements does not mention the engine just quits or starts misfiring and continues. I'm reading the engine gets to higher rpm and starts loosing power, then if the throttle is backed off, it catches up and continues to run. Your fuel pressure is low and drops to 2.5 lb and fluctuates.

If your timing was not fully advancing it would reach a given rpm and then have no more power. If this happened then it could also start getting to much fuel and plugs would start to blacken.

BTW I forgot to ask, have you checked the filter at the carb? This filter can starve to carb some fuel but still will not answer the question behind low fuel pressure

 

[Hook'd]

Dodge, When it first started it would completely die, then start right up; did that two weekends in a row. The next couple weekends it didn't fall quite as abruptly. Two weeks ago it did a hybrid and then didn't want to start back up. Last weekend I only did about 30 miles and opened it up toward WOT at the end. That's when it bogged, but didn't die.

The filters (including carb) and tank are all clean, except the nickel sized plastic I blew from the pickup line.

So today I took it to my mechanic to change the raw water pump, and had him accurately reset the timing. He set it at 8 with the timing plug, which resulted in 14 at idle without the plug, and 24 WOT.

We checked voltage at the coil, fuel pump, and oil safety; all 11-12v. I also jumped directly to the pump from battery; 3.5#. So now I suspect I have the wrong pump or the gauge is bad. I only suspect the gauge because I can't get consistant results. Seems the next thing to do is just take it out, and if it happens again, immediately check to see if it's getting fuel and spark.

With regard to the pump, the Volvo manuals say 4.5-6psi. I'll check Indmar, but the answer is probably based upon the Rochester quadrajet. so assuming the gauge is correct a new pump would be in order. In the interest of time I think I'll have all of the parts on hand for the next run. Can someone recommend a pump and regulator? I was thinking something capable of 6-9#, and regulating it to around 5.

Thoughts on the timing noted above are appreciated. Anything is appreciated. Gotta feel safe getting holiday crab!

 

[alldodge]

Agree you have had different symptoms but the last postings was my understanding.

The 11-12V reading could be an issue. With the motor running you should see 13-14.5V coming from the alternator. If your not getting full voltage the spark can be reduced, and can also be a sign of a bad connection. As with your fuel pump it could be the meter.

 

[Hook'd]

I'll take a multimeter with me too. Hope to get out and try it soon. The dash gauge does read 13.5-14.

 

[QBhoy]

Presumably you have checked the obvious ?
That being the pick up at the fuel tank ? Symptoms of this would be
Runs fine on first start up and at low speeds and calm seas
As soon as you open it up or rough water, loses power and probably stops.
Perhaps people have already mentioned. Just read the first and last page and perhaps you have already checked.

 

[Hook'd]

Qbhoy, Yeah, found a plastic film cap actually in the sender tube! Like the type which comes off an additive container, but clear. Hoping it is the cause of the exact symptoms you mention.

See trial Monday.

 

[QBhoy]

Sounds like it. Hopefully that will be it.
Good luck and keen to know how you get on !

 

[QBhoy]

Also jealous that you can take your boat out ! Mine is all tucked up for the Scottish winter

 

[Hook'd]

Update...

Ran the boat about 60 miles today. It died about 10 miles out, and again at the end of the day on the way in. After it died the second time I kept below 2600 rpm, and no repeat. Once close to harbor I opened it up to WOT, and ran over 4000 rpm' s a bunch of times; a few times at WOT for 20+ seconds. Ran so strong I though the issue had disappeared...the it died again.

This trip when it died there was no bogging, just like someone pulled a kill switch. Then it would start right back up. We monitored the fuel pressure and it was between 2.75 and 5.5. Highest toward WOT. And consistently high when we opened it up.

I'm pretty sure the plastic I found in the tank caused the bogging and slow starting because that is gone.

Before going out I switched out the corroded rotor and cap. I had an extra ignition module in the boat, but no timing light so didn't want to swap out on the water.

Because it started right back up I'd didn't see any need to check fuel or spark.

Back to thinking its now electrical. Today we noticed the windlass breaker was tripped, and it hadn't been used. This is the second time I've noticed this since the issue started.

I plan to trace that circuit and redo all the connections.

The current fuel pressure is not to spec so I ordered a 6-8# carter. The other thing I'll do is swap the module and reset timing.

The previous owners had loaded up accessories at the helm, and I'm going to install a Bluesea fuse block and start moving accessories over.

Could a lack of juice at the helm cause this somehow? I've started redoing connections at the battery.

Thoughts?