boat electric fuel pump circuit at hot idle fluctuates on and off

Thread Starter

sdowney717

Joined Jul 18, 2012
711
It's a bust, I cant use these relays.:mad:
Due to a rev limiter built in. The engines cut out above 2300rpm.
My engines are V-8, these relays must be designed for 4 cylinder motors.

So my distributor pulses are running twice what the relay expects to see.
Anyone know if this relay can have the rev limiter disabled?

Any thoughts?
 

debe

Joined Sep 21, 2010
1,389
Just a thaught, The circuit i posted will work with about 8 turns of wire from the sensor wraped around one plug wire & taped there. You could try that with your relay sens wire, this will give you a lot less pulses. Just capacitance pickup might work.
 

Thread Starter

sdowney717

Joined Jul 18, 2012
711
Interesting idea it is worth a try.
So just take a small wire attach one end to the sense pin on relay and wrap other end around a spark plug wire
Leaving the other end free unattached?


I have looked into the kracker 24.1400.20 relay which some claim have no rev limits

Another site claims the 321 906 059F relay has a higher limit than stock but still a limit.
Not sure if I want to spend more money finding out. If the Kracker company has contact info I would ask them.

http://forums.vwvortex.com/showthread.php?1217606
]It's in the fuel pump relay.
A lot of people say "use a Fox FP relay". This is only half right, because some Foxes are Digifant and I think even some of the CIS ones have OEM relays which still have the rev limiter. However........SOME foxes (and maybe even some Mk2's, who knows) will have an aftermarket relay made by Kracker (seriously) which has NO REV LIMIT

How do I know? I just got one at the wrecker today and she works like a charm. It's white, has no big number on the end which you can see when it's plugged in, but the Kracker part # on the long side is 24.1400.20 and there's also a number PA66-GF30. I ran mine up to nearly 7k today with no issues.

I believe the part# 321 906 059F above will also work. ABAScirocco indicated that the 059E which came in his car has no limiter, and I know for a fact that the 059E supercedes to 059F (confirmed at the VW dealer yesterday).
more on the rev limit seems to be 8000 rpm so not unlimited
Also mentions digital vs analog controlled relays.
http://forums.subdriven.com/showthread.php?1473613-Knock-Sensor-Control-Unit-and-Rev-Limit
 
Last edited:

Ron H

Joined Apr 14, 2005
7,063
Many years ago, i had a car whose oil pressure did that. It was the result of a bad rod bearing. I could hear an accompanying knock. You might not hear that on an engine without a muffler.
If that is your underlying problem, the engine will eventually seize up and throw a rod if you continue to run it, probably destroying the engine in the process.
 

Thread Starter

sdowney717

Joined Jul 18, 2012
711
Yes, your right.
Ok some history on the motor.
Ran for a number of years, then noticed lower end main bearing noise.
Pulled motor and tore it apart, everything looked ok except crank had worn the mains down to the copper in places.
When I tried new bearing shells, the mains were from .003 to .0035 clearance which is at the max for this engine an IH 392.
So put together with new pistons, bearings, rings. And it is ok except when hot, idle oil pressure fluctuates a lot. According to the IH forum, this is fairly typical for the motor. Motor used to have mechanical pump so you would never notice.
IF I had to do over, would have turned crank for oversize and tighten up the clearances.

Any electric pump is better as
I can prime system without cranking. And easier to troubleshoot. It has been much more reliable with the electric pump as it gives me quick starts.

I may go back to the oil pressure switch and install an electronic timer which will keep power flowing adjustable from 0 to 60 seconds. Ebay has an Omron timer H3Y-2 for cheap with the mounting base. Idea is the timer will recieve an on signal from the oil switch and then run pump for x number of seconds.

Will the Omron timer keep resetting itself with a pulsed on signal from the oil switch? So it keeps the pump running for the tiny bit of time the oil pressure drops.
 

debe

Joined Sep 21, 2010
1,389
This is a LPG safety switch, it gives about 6sec ON for priming then OFF, then looks for IGN pulses to turn back ON & stay on unless engine stops, then it will switch off. The circuit i posted earlier is from one of these units. The IGN sens wire on these can be fitted as in the picture wraped around an IGN lead. Or conected directly to the IGN coil primary pulses.
 

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Thread Starter

sdowney717

Joined Jul 18, 2012
711
Tried the coil wire on spark plug idea and it does not function.
So will go with timer idea.

Anyone know if there is a V-8 version of this type relay?
 

gerty

Joined Aug 30, 2007
1,305
Do they make a high pressure/volume oil pump for this motor?
Sounds like you need the additional pressure/volume, and it'll cure your electrical problem as well.
 

cork_ie

Joined Oct 8, 2011
428
Interesting idea it is worth a try.
So just take a small wire attach one end to the sense pin on relay and wrap other end around a spark plug wire
Leaving the other end free unattached?


I have looked into the kracker 24.1400.20 relay which some claim have no rev limits

Another site claims the 321 906 059F relay has a higher limit than stock but still a limit.
Not sure if I want to spend more money finding out. If the Kracker company has contact info I would ask them.



more on the rev limit seems to be 8000 rpm so not unlimited
Also mentions digital vs analog controlled relays.
http://forums.subdriven.com/showthread.php?1473613-Knock-Sensor-Control-Unit-and-Rev-Limit
The rev limiter you refer to was only in some of the later relays. The Mk1 Golf GTI did not have it
I am not familiar with the aftermarket relay you bought but there is a good chance if the relay has discrete components that a very simple mod could sort that problem.
It is basically a pulse counter powering a relay. Can the relay be opened easily or is it fully sealed?
If you can open it, please post a clear large scale photo of both sides of the PCB and I will try and draw out the circuit and suggest how you can overcome the rev limiter issue.
 

Thread Starter

sdowney717

Joined Jul 18, 2012
711
Hi, thanks would appreciate that.
I have opened the relay to see how it was made. Boat is there and I am here so cant do it yet.
In a couple days I will post a picture. And perhaps you can tell me how to diasable the rev limit.

Meanwhile, I bought two of these Omron H3Y2 timers with bases.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=130742697598&ssPageName=ADME:L:OC:US:3160

spec sheet info
http://www.ia.omron.com/product/family/196/index_spc.html
My idea is it will keep the pump running at hot idle. Oil pressure momentarily drops about 1/3 of a second kicking off pump so wont this timer keep resetting continuously and pump will stay running?

Thinking of a 2 to 5 second timer setting. It will keep the pump running and also a few seconds on a starter crank event .

Plan was to have timer relay run the 40 amp rated pump relay. they say continuous duty rating 12 vdc plus or minus 10 percent. When motor runs, the volts are about 14.5v courtesy of alternator so wondering what will happen. Running the second relay will use very little current so thinking will work.
 

cork_ie

Joined Oct 8, 2011
428
3 pics of the circuit board
components on top relay
Great - they are reasonably clear. I will try and draw a schematic from it later on this evening and post it to verify it is correct.

It should be easy enough after that to see how the rev limit is controlled.

I suspect it is one half of the HCF4538BE and it is likely a change of cap or resistor will do the trick
 

cork_ie

Joined Oct 8, 2011
428
I am having some trouble with the pic of the underside of the board.

The lower and right sides are difficult to see exactly and the critical parts.There are tracks running under the components and they are difficult to see.
Please retake the pic at a higher resolution so that I can blow it up without it pixelating ,
Clean the specks of dust off the board first if possible .
Try and have the illumination face on.
 

Thread Starter

sdowney717

Joined Jul 18, 2012
711
Thanks, ok, will do soon.

This looks better and can try again. It is raining and it has to be done inside today.
I also uploaded the file in an attachment.

 

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cork_ie

Joined Oct 8, 2011
428
I am still having problems with the photos because of an apparent change of contrast between the tracks near pin1 & 2

Can you take another picture of the area inside the red circle paying particular attention that there is clear contrast and avoid casting shadows.

Face the camera straoight down on the board - not at an angle
What is the 33K resistor on the extreme left side connected to?
Can you confirm that pins 3, 6, 9 are not connected?

I have pretty well sorted out the rest of the circuit and am quite clear at this stage how the relay is triggered. Just not yet sure how the rev limit is set.
 

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cork_ie

Joined Oct 8, 2011
428
Thanks,
I look forward to hearing from you.

I have this nearly cracked and will post the schematic as soon as I can confirm the connections.

It would be nice if someone was prepared to build a simulation on LT Spice once I post the schematic. I am not that proficient with it just yet.

I have traced through the relay driver etc and it seems an easy circuit.
 
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