Hello all,
This is my first post here. I have an issue with one of my 95 2500 4x4 trucks, I have a v10 that will not start. I have swapped all the relays under the hood with known good ones, I hear the fuel pump engage, I have tested and replace crank sensor, cam sensor, and tried another computer. I have tested the coil pack and have battery voltage on supply wires, I do not show cylinder supply voltage when the motor spins over. Help Im out of ideas!!! Thank you in advance.

 

So are you not getting any spark at all to the plugs? Have you checked all the contacts for the Distributor cap. Some times they get really caked up with carbon build up and don't make good contact.

 

v10's use coil packs, not distributor's and stuff.

 

Ok, so where to go from there? First if you dont mind let me ask you a few questions that you've probably done but I just want to be sure! First I'm going to assume that the engine spins over just fine meaning that your starter is working, you said that the fuel pump is turning on... have you verified fuel pressure at the fuel rail on the engine with a fuel pressure tester? Hearing it click On won't mean a thing if there is a clog in the system not allowing fuel to reach the injector rails and thus the injectors and engine

You mentioned you've checked the coilpack but the way you described your method is that you verified that you have voltage at the pigtail that connects to the coil... while knowing that you have voltage going to the coil is good this will not tell you however that the coil itself is good. You can take the coil up to an autozone or some place like that and have them test it for you properly they have a bench tester for that job. Once you've had them tested pull your spark plugs and verify you are getting a good spark from each plug. Kaldir may have been wrong about the type of ignition sytem you have But, He was absolutely right to ask if you've verified spark At the Spark Plugs themselves. Which you did not answer rather your response concentrated on the fact that you have a different style of ignition. Coilpacks and Distrubutors bot have one sole purpose in life and that is to deliver a highly calculated amount of energy to each spark plug at a very specific point in the engines rotation and if it isn't happening then it really is irrelavent which style ignition you have. Because the only internal combustion engine style in an automobile that you'll get to crank without a spark is a diesel not a gasser!

The last thing you said was that you do not have supply voltage when the motor spins over... If I understand your post correctly You have supply voltage going to the coil with the key on but when you turn it to the cranking position you loose that voltage...which would mean no spark from the spark plugs... for that reason I would tend believe you'll find something either in your fuse block, relay block, wire harness, or computer that is out of order... Just out of curiousity how did you learn that you do not have supply voltage while cranking over the engine... were you back plugging the pigtail connector for the coil and using a volt meter to test this while trying to vrank the engine?

Not sure how much of this you've done. Check Each Individual Fuse With A VOM Meter(commonly known as a volt meter.) Check each fuse individually for continuity... they can some times appear to be good to the naked eye but they can never lie to the meter. Check your connections and the wires leading from the coil back to the computer verify that everything is properly grounded and that you do not have any shorted out wires... next check your harness going back from the computer to your fuse block/power distribution block/ relay block... I believe you'll find a block of fuses and relays both under the hood and under the steering wheel...


Sorry If I missed something between the lines but your post half way makes it sound like you checked for voltage going to the coil but not out of it...

Also on a side note just a little not so well known fact... most people will tell you that there is no way of checking a relay but that is utterly false if you can read the schematic on the relay its very easy to do... If you dont understand electronic schematics I'm sure you know some one that does and that can save you a ton of money because relays are not a cheap item usually. I say this because I was a parts guy for several years in my past and I found that it was not common knowledge and had to break many hearts due to a no return policy on electrical items.

Hope this helps I know it sounds basic but in order to give you more ideas I kinda need to know exactly where youre at in the troubleshooting process and the is a bit of vagueness to your post. Again please don't take this as patronizing but rather instead as me simply trying to catchup to what you have already looked at.

 

Broken roads, thanks for the reply
I have taken all the relays and tried them in my running 1995 5.9 2500 4x4. all work to spec.

I do not show voltage back probing the coil to cylinder spark wires aka no spark to each cylinder. this verified by spark tester between wire and plugs.

I have not put a gauge on the fuel rail, but do have pressure there when depressing the schrader valve.

Is there another ignition control module hiding in this rig? I am wondering if the key switch is defective, I install electronic in emergency vehicles and had a durango with a bad ignition override module (after market for police) go bad and after replacing found the key switch was the culprit for burning up the module.

Looks like i need to dig the magnifying glass out look at the wiring schematics in my haynes manual and locate the feed wire to the computer from battery and ground wires.

 

In the red part i quoted here and combining it with your original post then you have power coming from your battery all the way upto the the pigtail where the wiring harness connects to the coil pack but when you crank over the engine with a spark tester connected between the coil and spark plug you do not have any spark. If that is the correct interpretation of what you are saying then Personally I would pull off the coil pack take it up to autozone have it tested and see if it's still good. They were the ones that tested the coil pack itself for my friends 86 camaro when I was diagnosing a stalling situation his car was having plus they had a diagram that I snapped a copy of that showed exactly how to test the coil on the vehicle. If it's bad get the Good stuff at NAPA

Cool to know that you install electronics for the emergency system. Hope I wasn't coming acrossed as belittling you. That was not my intention. If I do apologize. Now that I know you have a good grasp on electronics we can really get this ball rolling!:icon _teeth:


In response to your question about another ignition control module. I have a scanned copy of the Echlin Ignition Parts Manual, from the local NAPA that I used to be the Store Manager at, and for the V-10 it doesn't list a seperate Ignition Control Module nor do they list one online. My understanding is that function has been controlled by the computer in these things for quite some time now.

If my interpretation of what you said in that red area is indeed correct I'd almost bet you got a bad coil pack NAPA p/n IC51 $124 or IC52 $119 depending on which style you have and of course what kind of a discount you can get due to being with the emergency system

Let me know if this helps or not! If it doesn't or if I'm misinterpreting what you're saying we'll look at some other things. Hang in there though It's a good truck she just needs some TLC!

Oh also did you try hooking your spark tester directly to the coil and the spark plug deleting the spark plug wire from the equation? I only ask in case you have plug wires that have gone bad internally with no outward tell tell signs... I know it may sound like a silly thing to say but I have seen such craziness. Yes It's Highly unusual but It does occur from time to time with cheap wires. p/n 700911 $51.99 for a new set and they're the good ones 8mm wire with a limited lifetime warranty.

Let me know what you find!

 

OK, yes i have power all the time even when cranking to the coil packs, sorry i dint keep it simple. tested spark from wire to plug with tester, i will ohm the wires out to see if they went bad, is there a way to see if the computer is telling the coil pack to fire each cylinder? thought i read in haynes that you can test the pigtail wires as the engine rotates and see voltage increase on each of the wire telkling that fire the individual cylinder coils.
I appreciate the replies, no you have not belittled me, i understand its hard to tell skill level of members if you do not know them, so its easier to make it simple.
your preaching to the choir, i trust belden / echlin more than anything else next to msd but everyone has issues now and then. I do get master installer at napa, lol
thanks again!!!

 

Show's how much I know about the v10's.

 

Ok so again if I'm understanding you correctly you have checked and made sure that you have power coming into the coilpack and you have checked and found that nothing is coming out of them. That usually indicates an internal problem and the only thing you can do if that is your situation is take and test the coilpack itself. Autozone and I'm sure some other stores have a way of testing it for you. But it sounds like you need a new one to me get it tested and you'll probably find out that it's faulty.

The function of the coil pack is to take the 12Volts that are supplied to it from the battery and then to amplify it in to the 10's of thousands of volts range and then pass it on down the line through your spark plug wires.

If juice is being sent to the coil but nothing comes out the exit hole in other words the plug wire then you got a bad coil usually so get it tested at autozone or some body like that. I'm trying to remember but it seems like the last time I needed to test a coil they opened their book that shows the process on how to test the coil and let me snap pics with my phone.

Think of it this way lets say its raining and the rain is falling on the roof of your house. You dont like having water drip over the edge of the roof at your front door because it splashes into your house everytime you open up the door so you install a gutter and downspout to re-route the water to some place you dont mind letting it splash. If all of the sudden one day it rains and even though you have a gutter and downspout to divert the water you open the door to water that is just pouring right over the edges of the gutter and splashing inside your door again.

Well the rain falling on the roof isn't the problem and it's not going to be the down spout either (at least not in this scenario) It's the clogged gutter that has too many leaves in it clogging it up and stopping the water from ever making it to the down spout and thus causing the water to over flow and splash inside the door when you start to go outside!

The rain is basically the power coming from your battery. the down spout is like the spark plug wires and the spark plugs! Of course that means the clogged gutter is like the coil pack not allowing electricity to flow to the (downspout) Plug wires/Plugs!

As far as testing to see if the computer is telling the coil to fire the only way I've ever heard of doing that is with a very expensive OBDII scannerDodge calls it a DRB if I remember correctly.

From what you keep saying though I'm suspicious of the coil!

 

Kaldir,

At least you were using the right logic! And trying to be helpful instead of just trying to point out some one had made a mistake. Kudo's to you for trying to be helpful. Your point about making sure he's getting spark at the plugs was right on target! So no matter how much or little you know about the V-10 specifically the principles still remain the same. Without all three 1) fuel, 2) air, 3) and spark a gas engine will not run!

Again Kaldir Bravo for making the effort to help!