No Spark (kind of urgent help req'd)

[JimmieD]

The other guys may be correct in their analysis, especially with the truck having the TBI and much more complicated electronic engine control.

But....just maybe it isn't the electronic stuff. My experience based on an 86 W250 360 gave the same symptoms. But I can start the truck by holding the auto shift lever just a hint into the "drive" position and wiggling it towards "neutral" while cranking. It will pick up "the message" and start pretty quickly. Now I assume this is a misalignment of the neutral safety switch due to under cab rust which has lowered the cab closer to the frame, thus the linkage is outta wack. Otherwise you can crank till the batt dies and the engine is badly flooded. The wierd thing about this sequence is that the truck needs this special starting technique for first start in the morning, but will usually start in normal "park" the rest of the day! That part I really don't have a clue about. The good part is that nobody is going to steal my truck first thing in the morning.

Good luck in getting yours going, I hope the solution is as cheap as mine was.

Paul in MN

Paul, that is such a classic example, just marvelous, of KISS! Can't count the times that I've had 2-3-4 service manuals opened and every tool I own scattered for a half acre doing mortal combat with monstrous mechanical demons and whole legions from the fiery pit and all of a sudden: "Ya gotta be kiddin' me....."

For me it's often been one tiny piece of wire or a few flakes of rust defeating a simple ground somewhere, enough to block the entire electrical system!

[pieter]

Well, the simple gear selector trick didn't work. I replaced the pick-up module in the distributor. Guess that leaves the computer. I'm heading to my junkyard to pick on up. New it is $201.00 plus $60 core. Can't spend that much on an uncertain thing.

Also - The automatic shutdown relay, parts store doesn't show it. IN the testing, it says to check post 87A. There is no 87A. There is an 87, 86, 85 and 30....

[JimmieD]

If you're still there, I have a computer I can lend you. It would take me a couple of days to get a box & prepare it for shipping, maybe by tomorrow. I do need to get it back, but you could try it as a test mule. I keep it as a spare for my '90 W350 and it's a used Dodge box.

Also if you're not in a hurry I can check my truck against those instructions & see what's up on that ASD relay. I do know you can purchase relay sockets, so hard telling what someone has installed in the past.

Just don't know what your situation is, how quick you need to be running. But on the computer, if it got you running, use it for awhile and then send it back when it's convenient for you to buy another?

[JimmieD]

On relays 30 is normally source voltage as incoming power, 86 is the load being energized, 85 & 87 are grounds. Depending on how it's wired that sufficient. On the ASD Relay it is switching ground, and of course that requires a clean bare metal ground connection unless it grounds through computer circuit. I can look it, but again don't know your time frame.

[JimmieD]

From what I see on the electrical diagrams you should have 4 colors of wire. DB/BK as dark blue with black stripe goes to ground loom, another DB/BK connects to A/C Wide Open Throttle Relay [not used on yours, possibly that's the missing wire on yours], Dark Blue with Yellow stripe goes to pin 51 on computer, Red wire goes to charging system, Dark Blue with no stripe goes to hot 12v loom connection from Ignition Switch.

.

[Paul in MN]

JimmieD

Thanks for the "pat on the back". As we run a farm with 12 tractors and about a half dozen working trucks, I have to remind my son (a high tech guy) about starting with the basics. Don't assume anything worse until you have checked out the easy and cheap stuff. Tee Hee....we bought an older tandem axle 50,000 gvw grain truck last fall for about the price of the used box and hoist and it ran awful, backfiring through the carb and exhaust system. The owner had taken it to 2 different shops and had spent a lot of $$ on parts and diagnostics, and decided it had to get parted out unless a new engine (478 cu in IH) could be found. When we drove it off, the guy asked if I had another engine, told him "no, but I plan to work with this one". He waved goodbye. We got it to my son's house, compression tested it (all OK, so it wasn't valves) and then I began with the cap and wires. I had the basic tuneup data in front of me. I found 2 interchanged spark plug wires that were for cylinders sequential in the firing order (one firing with intake valve open, next one firing with the exhaust valve open). Problem solved in 20 minutes!! Changed the wires around and we had a good running truck that did heavy duty work on our grain harvest. My son thought I was a god. A real example of the KISS principle.

Paul in MN

[pieter]

Hey JimmieD,

Thanks for the offer to ship your computer, but I don't want to take the risk that it gets damaged in shipping or plugging it into my vehicle. I did manage to find one at the junkyard. The truck that I wanted to pull it from, was no longer where it sat just a few weeks ago. I finally found it and unfortunately someone just took out the computer. I mean the connector was still superbly clean. I found another truck with a computer and as I removed it, I realized this computer had two sets of plugs. Mine, only had the one large 50 or 66 pin plug. At least, I'm hoping I remembered that correctly.

After walking close to 2 hrs, I finally found a 1990 Ramcharger. Computer was there. I took that, the module behind the glovebox (anyone know what this is). I also picked up a couple ASD relays from the first two trucks I looked at. $50, I can hope this solves the issue.

Just to have more knowledge, I stopped by my Normal auto parts store (one that still has books and knows how to use them and will even let someone like me browse through them if needed). They don't show a Automatic shutdown relay. They did show an ignition relay and ignition start relay. Both same part number and $15/piece. I asked about the MAP sensor as that was one error I've had from time to time. $69.00 for that. I then inquired on the SMEC module. $300 plus $75 core. The interesting thing that he said to me is that he needs the code off of my existing box. Stated there are 14 different modules for my truck. That is an interesting tidbit. If this Ramcharge module does work, it may and probably has some different programming within it...

JimmieD, I will check my colors for the ASD relay. I want to say that 2 of the wires going into the relay were showing 12v. I'm not 100% positive, but I think I made a mental note this morning as that did not seem correct or at least a little odd.

My plan in the morning is to disconnect the battery, pull my old computer at the fender and put my junkyard replacement in. I will also swap out the module behind the glovebox. Then doublecheck the coil, distributor and all the other plugs under the hood for good connectivity. The put battery back in and hope for the best. I re-test the wires going into the ASD relay and probably throw one of the three I picked up today in it's place. I'll double-check all my grounds as well.

As far as urgency, I'm 65 miles from home. Borrowing a friends car and staying at their place. So, I'd like to get this running as soon as I can.

Well - Thanks for your help so far!

Pieter

[JimmieD]

Hoping the best for you, Pieter! Glad you have a friend there to offer shelter. Can't remember for sure but off the top of my head the unit behind glovebox may be the Anti-Lock Brake controller? Not sure....

Holler if I can help.

[pieter]

The phrase of the day is "Still no spark!"

Change out the computer in the fenderwell, behind the glove box. Checked all the fuses (someone suggested there might be an ignition fuse). Put in a new rotor & cap. Already put in a new halo ring in the distributor. Double-checked and cleaned all my grounds and connector plugs.

Reading over the troubleshooting info, the idea of a crank position sensor came up. Either near the harmonic balancer or some say it is behind the head sort of embeded into the bellhousing of the trans. I can't find one anywhere. I don't have an wires that disappear into no where. I went to the auto parts store and had them pull the crank sensor that is called for on my truck and it is huge. I see nothing on this engine that even comes close. JimmieD, does your 90 have a crank position sensor? I removed the bolts from the dust shield to access the torque converter and I see no reluctor lugs on the torque converter that would suggest there is a sensor to pick up rotation. Unless it is on the backside(curved side) or the torque converter.

Auto parts guy also said that the halo in the distributor, MAP sensor, idle air circuit and stuff are wired in series. Meaning that if one device fails, it could fail the whole system and cause an issue much like mine. Since I have been getting a MAP sensor code, I figured to try it. I tested mine and it seems ok, but I might not be understanding the test procedures 100%. One will be delivered in the am and I will try that.

The other thing that I have not replaced was the coil. The resistance tests within specification. Problem is, my coil says right on the side to be used with electronic ignition. The one the parts guy gave me earlier in the day said to be used with an external ballast resistor. This truck does not have the ceramic balance resistor. Does anyone know if there really is a different in the two types of coils?

At this point, short of tracing each and every wire in the system for continuity or a short, I don't know what else to do.

If anyone has any thoughts on a crank position sensor or on the coil, I'm all for thoughts or suggestions.

pieter

[Paul in MN]

Pieter,

I've got to give you credit for being the most persistant person in trying to beat this beastly problem. I'm sure my patience would have been waaayyy shorter!

Just to get back to trying to tame this beast, I am reminded again of a very vexing wiring problem I had some years ago (Ford van). My Fluke VOM measured OK voltage where it was supposed to be (tail light circuit) but I could not make the lights work. It finally turned out to be a bad factory splice in the original wiring harness totally unaccessable until I scrapped the van. It was corrosion that let just enough current pass to show up on the meter as OK, but would not carry enough current to light a tail light. Now to get specific to your Dodge problem, I wonder about the current carrying capability of your ignition key switch. I am not familiar with the computer circuit on the Dodges (mine is pre-computer), but I would think that there needs to be a measurable number of amps available to the ignition coil. I think you measured the voltage there and found 9? volts with the key on. On older vehicles, the voltage to the coil came on with the key and then followed to the distributor making and breaking the connection to ground. How about disconnecting the feed wire(+) to the coil (full time hot w/key "ON") and connecting that wire through a tail light bulb (bright filament) to ground. The bulb should pass about 1 amp if it is fed 12 volts. If you connect 2 bulbs in parallel (not series!) they should pass 2 amps. I do not know what the expected amps through the coil should be (and it is being switched on/off very quickly by the points/electronic ignition circuit), but I'll bet that it has to be more than one amp available. If your bulb lights up, that is proof that you have sufficient voltage and current for ignition. If the bulb lights up, reconnect the hot ignition wire to the coil, and the problem has got to be downstream from there (like the distributor or computer). Please, if someone really knows this, help us out here.

I am thinking basics again, and have a lot of experience with older tractors and trucks, but (thankfully!!) no such experience with the computer controlled vehicles. Remember when we used to "hot wire" a non-running vehicle?? In this case you could hot wire from the + on the battery directly to the same +terminal on the ignition coil. I know my truck has a ceramic resistor in that circuit, so I would buy another $2 resistor and put it in line from the battery + to the coil+. The truck should start and run with the key switch being activated. If it runs, you have bypassed everything before the coil, such as ignition switch and neutral safety switch and possible ignition relays. Will this hurt your computer?? Danged if I know, but you have tried darn near everything else.

I am pulling for you!! (a "Red-Green" line).

Paul in MN

[pieter]

Thanks Paul!!

I guess since this is my only vehicle, I have to try everything that I can. It may be as simple as a loose or broken wire someplace. I've pretty much given up. I am going to talk to a mechanic a mile down the road and he said he would go through everything I did and think of anything I may have overlooked.

Today, I got a second coil as that is the only thing I did not swap out. I picked up the new MAP sensor as well. No change.

As far as error codes, I get the disconnected battery, a/c clutch error, I get a new error code 36 I believe for a air something, but that solenoid is not on my vehicle, so I figure it is programmed in the computer from the Ram Charger. One other, but it's not on this vehicle either.

Last thing I'm going to check in the morning is to see if the timing chain has slipped. I find doubtful, but I guess it could happen. I know the distributor turns. The reluctor ring in the distributor was a little corroded, so I may try and sand that. Again, The pick-up coil only detects the metal, then air gap so I don't see how a little corrosion would make a difference. Short of that, I would have to start tracing each wire and circuit for continuity and such. I don't think I can do that w/o a factory service manual, which I don't have. At that point, I don't think it would be worth my time or effort.

I have another mechanic that is willing to work on it for very little money, but I have to get it to his house which is about 20 miles away. Supposedly, he has a buddy who is a Repo man with a Sleeper Tow Truck, but I don't know that they realize it's a 1-ton dually with a service body. If he will haul it for next to nothing, then that's probably the route I will go. There's nothing left that I can do.

There could be the chance that maybe the new pick-up coil I bought is defective. I may try and do some of the testing again as well....

I've already spent more then I wanted picking up duplicate parts. If I have towing and mechanic look at it now, I'll probably spend the same amount I've spent already (doubling my costs) which is money I really don't have because of the economy. A few hundred more dollars I could have picked up some cheap beater vehicle that ran :(

So, it's hard to know when to just call it quit and walk away. To be honest, this truck has been a headache since the day I got it. Maybe it just has a gremlin buried deep within that keeps showing his ugly head every so often.

[Paul in MN]

Pieter,

As you've put much more time, effort, and $$ into this than it deserved, why not try the hot wiring I mentioned? I'm just hoping that one of the Mopar Gurus here will sign in and either approve my idea, or tell us why it won't work.

Really, I know why you are hesitant, and I would be too if it was my truck. But this is like a "Hail Mary Pass" and one last try before giving up.

I wish I could help you more.

Paul in MN

[712edf]

Pieter, when you are checking for spark are you using something metal (screwdriver) sticking out of the plug wire end, or due you have a sparkplug on the end of the plug wire but touching a ground and not installed? Once when I was a teen my roadrunner would not fire, checked everything over & over, nothing, finally I took an Ohmmeter and checked my virtually new autolite plugs for continuity and guess what. They were bad & the source of my problem all along. You've tried everything else so while your studying about the situation take an Ohmmeter & check those plugs (wires too). It can't hurt!

[712edf]

Yeah either run a hotwire to the coil, or do you have an smallblock electronic distributor/ECM/ballast that you could throw in to get it home? You'd have to leave the SMEC thing hot to run the TBI though, and that might not even work!

[pieter]

Paul - I tried the connecting "+" of the coil directly to the "+" of the battery on Sunday. Trying to put voltage right there and that did not do a thing.

712 - I've checked for spark at plugs and the coil (to distributor cap). I didn't check resistance of wires or plugs. If i have failure rate of all 8 plugs and wires going at once, then maybe I should never leave my house with that kind of luck. :( :))

Anyways, I'm going to pick the brain of this mechanic and see what he suggests then I'll go back and start testing things. I'm thinking the timing chain jumped or at least it could be a culprit. Since I've been thinking about how it's been running lately, it would not accelerate worth beans. Coughing and sputtering. Once it got up to speed, it would run ok. If I accelerated like a bat out of ****, then it would be ok. I could see that with greater engine speed, the timing chain would tighten up and work somewhat properly...
I guess people do get hit by lightning... lol

laters