Conversion to DS2, Now it will not start
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From: Versailles, Mo
Conversion to DS2, Now it will not start
1986 F150 4.9l engine. Hi I am converting to a Dura Spark 2 system, I replaced the Distributor, Ignition Coil, Module, plugs, wires---all new. Found a used wiring harness off a 1980, checked the wiring and replaced 2 plugs. Hooked everything up. No start but it cranked. Finally found that the new Motorcraft module was defective and got a new one. I now have spark to all plugs ( Orange spark). Cranks but no start.
Voltage to the coil is 12 Volts with ignition on and 9 Volts when cranking---this seems backward. I reset the distributor 3 times to ensure TDC at the compression stroke. I tried moving the distributor a little in both directions and that made no difference. I tried using Starter fluid, still no start. Sparks but engine not firing.
There was a little mess with the wires when I picked up the truck but outside of the potential reversal in the start / run wires the resistance etc. all seem good.
Suggestions please I have read and studied for hours and have no more ideas. Thank you, Hank
Voltage to the coil is 12 Volts with ignition on and 9 Volts when cranking---this seems backward. I reset the distributor 3 times to ensure TDC at the compression stroke. I tried moving the distributor a little in both directions and that made no difference. I tried using Starter fluid, still no start. Sparks but engine not firing.
There was a little mess with the wires when I picked up the truck but outside of the potential reversal in the start / run wires the resistance etc. all seem good.
Suggestions please I have read and studied for hours and have no more ideas. Thank you, Hank
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From: Virginia
Pull the sparkplugs. If they are wet with fuel, they are fouled and will not fire. This can easily happen when trying to get an engine to start after working on the ignition. If they are wet, you can try to dry them out, but new ones are best. If you are close on the timing but not good enough to run, it still should spit and sputter a little bit.
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From: Versailles, Mo
Hi, I checked the plugs and they are dry. I still have the old feedback carb on the engine. I will check the fuel line in the morning. I still have a small tank hanging up on the hood from which the line goes through two filters then the mechanical pump and to the carb. Before the wiring change the truck started but ran very poor and shut off whenever you let off the gas.
As long as it has a reasonable spark on all cylinders and I get fuel direct from the small tank to the carb should it fire? I purchased an in line spark tester to get a better view of the sparks. I am sure I have the timing set right but at this point if I did overlook something would the timing being completely off keep it from at least sputtering? I'm grasping at straws here. Compression was decent at 125 to 140 on all cylinders (I am still cleaning valves to improve the numbers since it sat for several years ). Would the possible wire reversal to the coil, which gives the coil 9 volts in start, cause some of this problem? Could the feedback carb be part of the problem.? Thank you, Hank
As long as it has a reasonable spark on all cylinders and I get fuel direct from the small tank to the carb should it fire? I purchased an in line spark tester to get a better view of the sparks. I am sure I have the timing set right but at this point if I did overlook something would the timing being completely off keep it from at least sputtering? I'm grasping at straws here. Compression was decent at 125 to 140 on all cylinders (I am still cleaning valves to improve the numbers since it sat for several years ). Would the possible wire reversal to the coil, which gives the coil 9 volts in start, cause some of this problem? Could the feedback carb be part of the problem.? Thank you, Hank
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Joined: Jun 2013
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From: Somewhere n North America
If you have the wires reversed, you will have less than battery voltage Cranking, depending on the value of the voltage dropping resistor in the Run circuit.
Here is a link to a 1981 drawing;
Start, Ignition, & Carb Circuits - Gary's Garagemahal (the Bullnose bible)
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From: Virginia
You will not necessarily have 12v at the coil when starting if the starter is dropping the voltage to the battery when cranking. In other words, if you put your meter on the battery and crank it over and you are only getting 9-10v when cranking, you are only going to get 9-10v on the coil when cranking. Just sitting there you can get 12v on the coil in run because there is no current flow through the coil. As long as you are getting good spark, you should be ok. If you really want to eliminate this as a problem for now, just take a short scrap piece of wire and hook it to the coil + and hook the other end to the battery + post temporarily and then try it.
When you are cranking it over, is it a very even cranking speed or does the cranking speed slow down and then suddenly speed up and then slow down again?
When you are cranking it over, is it a very even cranking speed or does the cranking speed slow down and then suddenly speed up and then slow down again?
Cargo Master
Joined: Oct 2016
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From: Northern VA
You will not necessarily have 12v at the coil when starting if the starter is dropping the voltage to the battery when cranking. In other words, if you put your meter on the battery and crank it over and you are only getting 9-10v when cranking, you are only going to get 9-10v on the coil when cranking. Just sitting there you can get 12v on the coil in run because there is no current flow through the coil. As long as you are getting good spark, you should be ok. If you really want to eliminate this as a problem for now, just take a short scrap piece of wire and hook it to the coil + and hook the other end to the battery + post temporarily and then try it.
When you are cranking it over, is it a very even cranking speed or does the cranking speed slow down and then suddenly speed up and then slow down again?
When you are cranking it over, is it a very even cranking speed or does the cranking speed slow down and then suddenly speed up and then slow down again?
Nvm, just re-read, the feedback carb was designed to vary mixture in response to engine conditions (start, run, acell, etc). Maybe your mixture is stuck in the "lean" position? I would trade this carb in for regular carter YFA.
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From: Versailles, Mo
vjsimone, Franklin2,jakietreehorn-----This morning my wife had other priorities. Just got back. I will try the suggestions re: a jumper to the coil from the battery. I will also try gas into the carb direct since the feedback carb is not functioning and fuse 18 keeps blowing for unknown reason, I already tried to disconnect all items on the fuse except the computer.. As soon as it fires off I will get a new carb.
I set the timing a total of 4 times. I have the mark on the pulley side and the advance % markings are all in place and clean. I will get back to all this afternoon.
I set the timing a total of 4 times. I have the mark on the pulley side and the advance % markings are all in place and clean. I will get back to all this afternoon.
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From: Versailles, Mo
VJ ---I used the direct battery voltage on the coil. Unfortunately that did not change anything. I did what you suggested in my earlier post and screwed in the fast idle screw and placed the mixture screw back at 1 1/2 turns out. I then added about 3 tablespoons of gas and it tried to start. I did it again with the pedal and it tried to start again. Now I will need to reset my timing again but I have lots of practice.
Looks like a fuel issue. I need to replace that carb. It has been a challenge along with several new items that were bad. Once I get the carb installed I will contact everyone with the status. I believe I am almost there. Hank
Looks like a fuel issue. I need to replace that carb. It has been a challenge along with several new items that were bad. Once I get the carb installed I will contact everyone with the status. I believe I am almost there. Hank
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From: Versailles, Mo
Franklin, I jumped from the battery to the coil. No difference. I used fuel directly into the carb and screwed in the fast idle screw all the way. It started to fire off. I will get a new YFA carb. I will let everyone know what happens next. Hank
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From: Versailles, Mo
Jackie, I jumped direct from Battery to coil and no change. I shut the fast idle screw and added a little fuel. It tried to fire. I repeated with the pedal and it tried to fire again. I will install a new YFA carb. I will let you know what happens. Hank
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From: Angier, NC
If you look down the carb with the choke open move the throttle do you see fuel squirt?
If not the carb is not getting fuel, is the hose in liquid in that fuel can?
Some times the motor has to run to pull fuel but how do you do that if it will not pull fuel? (see below)
I had an issue doing the same you are, fuel from a can, and the pump would not pull fuel.
I found the hose was the wrong size 3/8" and should of been 5/16", think it was sucking air, once the right size hose was used the pump pulls fuel.
Now if your carb is not squirting and will not pull fuel till running you can fill the carb with fuel.
Get a squirt bottle fill it with fuel and use it to fill the carb bowl thru the vent.
Just thinking that may not work on the 300 six carb so this one may work.
You can also add a little more fuel to the carb than the 3 spoons
Dave ----
If not the carb is not getting fuel, is the hose in liquid in that fuel can?
Some times the motor has to run to pull fuel but how do you do that if it will not pull fuel? (see below)
I had an issue doing the same you are, fuel from a can, and the pump would not pull fuel.
I found the hose was the wrong size 3/8" and should of been 5/16", think it was sucking air, once the right size hose was used the pump pulls fuel.
Now if your carb is not squirting and will not pull fuel till running you can fill the carb with fuel.
Get a squirt bottle fill it with fuel and use it to fill the carb bowl thru the vent.
Just thinking that may not work on the 300 six carb so this one may work.
You can also add a little more fuel to the carb than the 3 spoons
Dave ----
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From: Versailles, Mo
Hi, thank you for the ideas. I agree and have checked further. I need a new carb and I need to reset my timing to TDC since I moved the cap to try to start it. Now it's a case of what to get. Option #1 is the JY and then rebuild it, cost approx. $80 total if I find one and if I don't mess it up or if it is all there and the shaft holes aren't totally worn out. #2 is to buy a Carter rebuild from one of 2 large companies $160, after returning the core and only a 90 day warrantee. #3 is to buy a new aftermarket one for $115 from EBAy or Amazon with a 3 to 5 year warrantee . #4 Almost forgot brand new Carter/ other co. for $400+.
What would you do? Hank
What would you do? Hank
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From: Somewhere n North America
The "Orange spark" actually prompted my comment.
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From: Versailles, Mo
I agree with your comment and suggestion. My first thought was about the poor spark not starting the truck. I still need to find out why the spark is orange. I will continue looking for an answer while I look for another carb.
I respect your comments and suggestions. Hank
I respect your comments and suggestions. Hank
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From: Versailles, Mo
1986 F150 4.9l conversion to Duraspark 2. Well I am back looking for help. I replaced the carb with a new r YFA style ,with electric choke. All of the Duraspark 2 system is wired, the coil, module, plugs, wires and distributor are new.
I base adjusted the carb and tested all moving components before installation, reset the timing to TDC on the compression stroke, checked again for spark, checked for fuel into the carb etc.
Cranks but does not fire. Compression tested good earlier at 125#+ on all cylinders.
I know that at my age , 77, that my compression isn't that great either
but I am obviously not as good as I used to be. Based on my earlier comments the spark is orange / yellow and not blue. Would changing from 0TDC to 10 Degrees help? My gas can is hanging off the top edge of the hood and is feeding into a new fuel pump. Would low fuel pressure possibly create this issue? I just tried a small amount of starter fluid and it seemed to want to fire but did not.
I don't want to give up. Thank you, Hank
I base adjusted the carb and tested all moving components before installation, reset the timing to TDC on the compression stroke, checked again for spark, checked for fuel into the carb etc.
Cranks but does not fire. Compression tested good earlier at 125#+ on all cylinders.
I know that at my age , 77, that my compression isn't that great either
but I am obviously not as good as I used to be. Based on my earlier comments the spark is orange / yellow and not blue. Would changing from 0TDC to 10 Degrees help? My gas can is hanging off the top edge of the hood and is feeding into a new fuel pump. Would low fuel pressure possibly create this issue? I just tried a small amount of starter fluid and it seemed to want to fire but did not. I don't want to give up. Thank you, Hank