DodgeDad needs help with trying to get a truck to run

I have a 1999 Dodge 1500 Pickup 5.2L that cranks but doesn't start, and the coil has an intermittent spark.

I could use some help in fixing this problem.

Any ideas?

-DodgeGuy

Do you need a wiring diagram?
Do you have cam and crank signal?

check is if the fuel pump is turning on. Can you hear it?
Possible PDC failure? Try a bypass test?

Is this a 4 pin COP?

Have you checked for 5V ref?

I’ve included an attachment. Which one is yours?

I spent several days troubleshooting my intermittent spark. Everything from ICM signal wire, grounds, voltages, ohm reading on the coil, you name it. One day I was using my test light to check for the spark signal from the ICM while cranking the engine, and the vehicle abruptly started and scared the hell out me (thought I was getting electrocuted!). Turns out it was the harness connector to the ICM that was making intermittent contact with the connector pins on the ICM at the crank signal wire. Sure enough I pulled the harness off and examined the connector openings, and they were too wide. I went ahead and spliced in a new and the vehicle has not had cranking issues ever since. I learned an important lesson that day, don't over look the simple things! Good luck.

Does the coil have power and control during the no spark condition? Knowing which you're missing will help point you in the right direction.

My experience with these trucks is that the coil housing cracks and leaks secondary voltage to ground. An easy check for this is to get the truck running, then mist the coil with a spray bottle. If the truck dies, you're on the right track.

Hi - old guy here. I have an Dodge Laramie 1500. Could I get a copy of the wiring diagram. The truck hasn't been licensed since 2013 and not sure when it ran last as I just picked it up at a deal. I was going to use it for parts but now think it's better than the car I have. I can follow a wiring diagram but vague on how to test it. Any thoughts?

DodgeDad wrote: Hi - old guy here. I have an Dodge Laramie 1500. Could I get a copy of the wiring diagram. The truck hasn't been licensed since 2013 and not sure when it ran last as I just picked it up at a deal. I was going to use it for parts but now think it's better than the car I have. I can follow a wiring diagram but vague on how to test it. Any thoughts?

Gotcha right here:



An incandescent test light would be preferable, but we can make a DMM work, too. Test light connected to B-, the dark green/orange wire should light the bulb during cranking. If that's there, move to the black/grey wire and change the test light to B+. Crank it again and look for rapid pulsing of the bulb.

This SD video demonstrates pretty well what to look for:

excellent rundown of no start possiblitys

Hi - DodgeDad here

I did the test, and this is what I found.

When testing the green/orange wire, the light stays on only when the fuel pump is on. There is no light on cranking.
I tested the black wire and there was no light at all.

Where do I go from here?

Thanks,

-DodgeDad

this is same thing I have my 98 1500 5.9 did they give a next step?

need same thing please

Doge dad/ have not got an answer yet

The pcm provides a ground on connector C3, pin 3 (dark blu/yellow) when ignition is turn to RUN position FOR 1 SECOND.

So for 1 second, in the run or start position, you should have power at the coil. Do you?

If PCM does not receive a CMP and CKP sensor signal within one second of engine cranking (start-up), it will turn this ground off.

If you don't have this power for 1 second at the coil, check for a ground at the PCM, connector 3. Pcm should provide ground for 1 second when ignition switch is turned to run position. Now if this ground doesn't stay put, now go chase the cam and crank sensors.

What DTC codes do you have? I'm going to guess it's related to cam and crank. Did you test those sensors?

Since my last post I've done all the checks, replaced the crankshaft positioning sensor (because the old one was all rusty), and then it tried to run, but only if I poured gas down it. So then I took the gas tank out and replaced the fuel pump and cleaned the fuel tank. Now I don't hear the fuel pump (maybe the new one is bad?) so I installed an in-line fuel pump to bring more pressure, but it's still not running. Injectors?? How to test? And how could all of them be bad?

Previous Post - www.scannerdanner.com/forum/post-your-re...tent-coil-spark.html

I am making a new topic so that hopefully I can have some questions answered. Since my last post I have replaced the crank shaft positioning sensor, the cam shaft positioning sensor or "coil pickup", and it still won't start. It won't run unless I pour gas down it.

All I have is a test light and a volt meter, where to I go from here?

-DodgeDad

Hey Dodge Dad,
Just read your previous thread. So is it safe to say that the intermittent spark issue is resolved since you can start the engine with an external fuel source?
Looks to me like it's time to investigate the fuel system a little more closely. I see you've changed the pump and added an in line pump. Do you have a way to check fuel pressure? There should be a Schrader valve on the fuel rail that you can tap a fuel gauge into. If you do not have a gauge many parts stores will loan them out with a deposit.
As a quick and dirty, (and kind of dangerous) check you can press the pin in the Schrader valve with a pocket screwdriver and fuel should spray out. Obviously take precaution to not get injured or start a fire.
Injectors control is also suspect, in this video Paul shows how to check for injector control using only a test light.
It's about 14:25 where he shows how to identify the control wire and check for computer control.
That's where I'd start any way: verify fuel pressure and injector pulse.

Thank you for responding so quickly.

I have tested the fuel pressure and it's about 50+ psi

I tested the injectors and on the Green/Orange striped wire the light will come on when the pump is on for about 3 seconds.

On the yellow wire the light doesn't come on at all even while cranking.

What should I do next?

Thanks,

DodgeDad

When you checked the yellow wire is your test light on ground or positive?

So, I just want to clarify a couple of points before going off into the weeds. Forgive me if it seems redundant, but I don't want to make any assumptions moving forward.

Have you corrected the no spark/intermittent spark condition, or is that still a symptom?

I made the assumption that you regained spark based on the statement you made about being able to start the engine by feeding it fuel, and you never confirmed or corrected my assumption.

I also assumed you had no engine codes only because you never mentioned any. Do you have a check engine light when it does fire up? Does it illuminate with the key on engine off? Can you scan the truck for codes?
I think if you cycle the key 5 or 8 times it will display trouble codes in the odometer screen. Any codes could be greatly helpful!

If I was there helping you I would do a long cranking spark test.
This will greatly effect the direction of the diagnosis.
If you have spark the entire time, this will verify the sensor inputs and the secondary ignition system.
Like Tyler mentioned, the ignition coils are a high failure component on these.

If you are losing spark and I was there helping you, my next step would be to plug a tail light bulb into the coil connector and give the engine an extended crank.

If the light flashes the entire time the engine is cranking but you still are losing spark, then the coil is need of replacement.

If the light does not flash the entire time the engine is cranking, then we need to revisit the control test.

Your reply to Tyler about testing coil control:
"When testing the green/orange wire, the light stays on only when the fuel pump is on. There is no light on cranking.
I tested the black wire and there was no light at all."

Is very similar to the results of the test you did on the injectors.

I would expect power at the coil only while the fuel pump is energized because of the Chrysler ASD relay setup.

This is one of many videos that explains how the ASD relay works and it's function:


You observed no light during cranking.
Even if you were on the coil control wire instead of the power wire by mistake, I would expect the test light to flicker or light dimly

While cranking, the coil and injectors should have steady power and pulsing ground.
I am interpreting your test results as though you might be losing the power at the ignition coil and the injectors during cranking.

But we can investigate that further if need be based on where we ever up from here.



Hope this helps you out

...And I merged your threads into one
It's better for anyone trying to help (or anyone researching in the future) if all the suggestions, tests and results are in the same thread.

I know that it's easy for a question to get swept up onto the next page, and out of sight out of mind from there.

But if you make another reply you'll get bumped back to the top of page one.

Even if you just post "bump".

Thanks for getting back to me

I'll try doing all of my tests again, I figured since pouring gas down it kept it running that my coil was ok.

DodgeDad