Engine cranks but will not start, no spark to the spark plugs?

JOETRACYJOETRACY

MEMBER
1999 DODGE RAM
8.0L
V10
4WD
AUTOMATIC
126,342 MILES

I just replaced the passenger side valve cover on my truck. Kind of a tough job for me. Had to remove upper intake to get to valve cover bolts as well as coil packs. After all put back together and complete. Truck spins over but will not start. No spark-to-spark plugs. Check all fuses to see they are good. Coil pack electrical connections were all good. Truck ran perfectly before replaced valve cover gasket. I've obviously missed something but can't find it. This is my only way to ride. Please, I'm desperate if anyone can help, I would greatly appreciate it. I even thought maybe cam sensor or crank sensor but don't understand because ran so well before I did this job.

5 Replies

JACOBANDNICKOLAS

MECHANIC
109,755 POSTS

Hi,

Does it do anything other than crank? For example, does it try to start or do anything other than turn over. Is it possible for you to record what it's doing and upload it for me to hear?

Also, check to make sure no fuses in the under-hood fuse box have failed. Something may have shorted when you had it apart.

Also, just as a test, see if it starts if you use starting fluid and then stalls. If that happens, we are dealing with a fuel related issue. If there is no change, then I need you to check if the spark plugs have spark.

Here is a link that explains how to check:

https://www.2carpros.com/articles/how-to-check-for-ignition-spark

Let me know.

Take care,

Joe

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Wednesday, September 11th, 2024 AT 6:38 PM

JOETRACYJOETRACY

MEMBER
25 POSTS

It does nothing but spin over. I removed a spark plug. Played it on exhaust manifold had wife spin engine over. Absolutely no spark on plug. All fuses inside truck and under hood I checked with test light. All good. Power on both sides of the fuses. It's simply lost all fire. At a loss. Thank you for helping me. I pray you can help me figure it out.

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Thursday, September 12th, 2024 AT 10:37 AM

JACOBANDNICKOLAS

MECHANIC
109,755 POSTS

Hi,

I have a feeling it is related to the crankshaft position sensor. It is located on the right side of the engine (the side you worked on). I attached a pic below of its location. Check the connector and wiring to make sure nothing was disconnected. Also, confirm the wires from it aren't damaged or pinched.

Next, if you have a live data scan tool, connect it and check if there is an RPM signal when cranking the engine. If you don't have one, pay close attention to the tachometer when cranking. You should see it move when cranking. If it doesn't, that reinforces the idea that the sensor is the issue.

Chances are the sensor is fine, but I think it is a wiring or connector issue. There isn't a lot of room to work and it's easy to damage something other when you do work on them. LOL

One other thought, I believe there is a ground at the front right of the engine block. It will be black in color. Make sure it is not damaged as well.

Let me know.

Joe

See pic below.

Image (Click to make bigger)

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Thursday, September 12th, 2024 AT 8:06 PM

JOETRACYJOETRACY

MEMBER
25 POSTS

With your help I was able to find it. I followed wiring from crank sensor and cam sensor, I found a black ground wire on top of intake manifold that was left disconnected when I replaced gasket. I hooked it up, and it fired right up just like always and ran smooth as ever. I want to thank you very much for your help. I was at a loss.

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Friday, September 13th, 2024 AT 7:29 AM

JACOBANDNICKOLAS

MECHANIC
109,755 POSTS

Hi,

You are very welcome. I'm glad you were able to resolve the issue.

It is so easy to miss something like that. Believe me, I've done it a thousand times. LOL

Regardless, take care of yourself, and feel free to come back anytime in the future. You are always welcome here.

Joe