compression test and new plugs...... now it wont run or even start

[93xplorersport]

i did a compression test on my truck over the weekend when i put new plugs in, i figured since i was doin plugs i might as well do a compression test to see where the motor sits. compression was good cyl.1 175 cyl.2 165 cyl.3 170 cyl.4 180 cly.5 180 and cyl.6 180 i put new motorcraft platnuims in it put my fuel pump relay in and went to crank the truck and nothing tried starting it a few times and still nothing i forgot to plug in the coil pack. i plugged it back up and it cranked and idled perfect, so i went in the house to was up to go to town and when i got in the truck to leave it wouldnt start. it back fired a few times but when it finally started it would idle but as soon as you touch the gas the rpms would drop and come back up then the truck would die. it didnt stutter then die it flat out died like you turned the key off. the firing order i believe to be is correct the engine turns over but wont crank i am stumped and so is my dad and uncle which both are mechanics for at least 15 years

 

[Roadrunner777]

I'd swap the fuel relay to another location and see if it changes things. I'm thinking fuel pressure. Maybe check fuel pressure with gauge or right after it dies, pull a plug and see if it is wet.

 

[FIND]

Engine is laid out as

3 6
2 5
1 4

firing order is 1 4 2 5 3 6

coil pack

3 4
2 6
1 5

 

[Iron Weasel]

A picture is worth a thousand words.

 

[93xplorersport]

Ok got home from work and checked everything for the millionth time all my plugs are right everything is plugged in right I'm gettin fuel the tester said 35 pounds I have compression all my fuses are good but now I have no spark I took a coil from a know running motor and still no spark. Help me

 

[marragtop]

Check the vacuum lines, particularly at the vacuum tree located drivers side by firewall. If one of those lines is off, it will give you what you are describing.

 

[93xplorersport]

if your talkin about the tree that sticks out on the intake on the drivers side those hoses are good

 

[2000StreetRod]

no spark

If you're certain that you have no spark then with a voltmeter measure the voltage at the red/lt grn wire that connects to the ignition coil pack. It should be battery voltage when the ignition switch is in Run. Then measure the voltage at the red wire that connects to the ignition control module pin 8. It should be battery voltage when the ignition switch is in Run. With the ignition switch at Off measure the resistance to ground at the black wire that connects to pin 9 of the ignition control module. It should be almost zero ohms. If you have power to the coil pack and the ignition control module then check the connection to the crankshaft position sensor.

 

[93xplorersport]

ok my crank sensor is good the voltage to it is 1.5 volts and drops to 1.45 volts my book says if it fluctuates more than .1 volts then its good. im gettin voltage to my coil pack so my ignition control module is good as well, so replace my coil would be the thing to do. but heres the kicker i have tried 4 coils and 3 of them came off running trucks, whats the odds that 4 coil packs could go bad in a matter of hours? someone help please

 

[marragtop]

When you are checking for spark, are you checking at the plugs or the coil pack? Also, have you pulled the codes? If the CEL is out there still may be a code present that can help you trouble shoot. If it's a 93, you will need a Ford OBDI/EECIV reader, or you can jumper the connection and count the flashing CEL lights.

 

[93xplorersport]

Got a spark tester that you touch to the wire and the only code was a 543 secondary fuel pump. A friend of my dads that has done work for gm he has wrote dome manuals for them. Anyways he had us do some test and came up with a bad pcm or icm

 

[marragtop]

If you think it's PCM related, be aware that it could be as simple as the PCM relay located in the power distribution box. When you turn the key to the ON position, does the CEL come on?

Also here's a thread that should be helpful: http://www.explorerforum.com/forums//showthread.php?t=282241

Mike

 

[93xplorersport]

yea the cel does come on when you turn the key on

 

[Iron Weasel]

Here's my Google docs file on DTC 543.

Give it a whirl and see what you come up with.

 

[93xplorersport]

is the cel suppose to come on?

 

[DR_APLET]

i know this is a lame question but are you sure there is fuel in it. if your fuel sender is broken or you are low on fuel or on an angle then the truck will not turn on the coil pack sounds like you have been having fuel pump issues not so much to do with coils. just a lame sugestion.

 

[Iron Weasel]

is the cel suppose to come on?

When you turn the key on?

Yes. It turns on so that you know the bulb is working.

 

[93xplorersport]

yea it has a full tank i have been using the same gas and the fuel pump is only a year old and the truck is sittin level but i see where your goin aplet

 

[93xplorersport]

this may help or not but i was told my fuel trim is all the way open

 

[2000StreetRod]

What about the spark?

this may help or not but i was told my fuel trim is all the way open

I thought that you had no spark. Did you solve that problem or were you mistaken?