How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Chris Your Own Question
Chris
Chris, Shop Foreman
Category: Dodge
Satisfied Customers: 13041
Experience:  Dodge/Cummins and Chrysler Certified Master Tech
12365498
Type Your Dodge Question Here...
Chris is online now
A new question is answered every 9 seconds

96 Ram 2500, engine swap, no spark

Customer Question

96 Ram 2500, engine swap, no spark
Submitted: 1 year ago.
Category: Dodge
Expert:  Chris replied 1 year ago.

Hello and welcome to just answer. Was this engine swap done with the same year and same engine?

Chris

Customer: replied 1 year ago.
The engine was just a long block, all items like distributor, coil, sensors, intake etc. were the same ones.
Expert:  Chris replied 1 year ago.

Gotcha. Do you have a scan tool so you can check cam and crank sensor sync status? ..

Chris

Customer: replied 1 year ago.
It was a crate motor, long block. After first start attempt failed, we started checking the usual culprits, and found a broken and defective crank shaft posistioning sensor. We've tested as many of the procedures as we could find online for various no spark conditions. We checked two grounds and two powers to the ecm, but never got the 5V output to send power. We had been told that everything pointed to a dead ecm, so that was replaced as well. Still the same problems. I can hear the fuel pumps kick on, and it cranks over strongly, but still no spark. I have an obd II code reader, but do not have access to a true scan tool for diagnostics. However, the obd code reader keeps coming up with a link error.
Expert:  Chris replied 1 year ago.

Ok. You may have a shorted 5 volt sensor. Disconnect all sensors incuding the transmission connector. See if the code reader will link up. Let me know.

Chris

Customer: replied 1 year ago.
Are you referring to all the canon plugs on the engine, or the three connectors at the ecm? or both? Just wanted to know exactly what connenctions I should be disconnecting. I wont be able to do this until tomorrow morning, but if this allows the obd reader to connect, what will that mean, diagnostically?
Expert:  Chris replied 1 year ago.

Well not the ECM connectors, leave them plugged in. Disconnect the distribuor (cam sensor) , crank shaft position sensor , Throttle Position Sensor, Map sendor, coolant sensor and transmission connector on the side of the transmission. Check to see if the code reader will link up after disconnecting the sensors one st a time. If it will, then thst means thst the last sendor you disconnected may be shorted and should be replaced. I hope that mskes sense.

Chris

Customer: replied 1 year ago.
We will go through that tomorrow morning, and get a hold of you asap when we complete that. So, will a bad sender result in a crank no start situation? or is this just attempting to establish connection with the obd system
Expert:  Chris replied 1 year ago.

A shorted sensor will cause both. A no start and a no communication with the scan tool. Let me know how it goes tomorrow. I will look for your reply. Have a good evening!

Chris

Expert:  Chris replied 1 year ago.

Hello, just checking back to see if you received my last reply, and if so do you still need help with your problem? Please remember, the website will not automatically credit me from your deposit or subscription without your Rating! Please, use the Rating System Box and Rate our Q&A session today or. If you need to ask more questions, please feel free to ask!

Thank you!

Chris

Customer: replied 1 year ago.
we have had trouble getting back into the shop, we intend to hit it tomorrow evening and will let you know.
Expert:  Chris replied 1 year ago.

Sounds good! I will look for your reply tomorrow.

Chris

Customer: replied 1 year ago.
Hey Chris sorry for the delay in getting back to you. We pulled every plug and sensor we could find, and never got the 5 volt power to read 5 volts. Each sensor we unplugged would raise it slightly, but it was at most by 0.1 volts. We have looked all around the bell housing, and the engine mounts, looking for a potential pinched wire, and again found nothing. Hoping you have another direction, because at this point its starting to look like a really expensive anchor.
Expert:  Chris replied 1 year ago.

Hmmm, did you disconnect the connector at the transmission also?

Chris

Customer: replied 1 year ago.
Was just thinking about that, and I honestly dont remeber a connector on the transmission. Although it is a manual transmission, so I dont know if it would have a connector there.
Expert:  Chris replied 1 year ago.

Oh, well speed sensor maybe?

Chris

Customer: replied 1 year ago.
where would the speed sensor be on an older truck? I know the newer stuff has speed sensors back behind the tires.
Expert:  Chris replied 1 year ago.

Well if it has one on the trans, then it should be on the rear left side of it.

Chris

Customer: replied 1 year ago.
OK, we'll be heading back down to the shop in about an hour, and we'll look for that, but I dont actually remember anything being plugged to the trans on this truck.
Customer: replied 1 year ago.
Found the speed sensor yesterday, unplugged it, still no change to the voltage on the 5V circuit.
Customer: replied 1 year ago.
How can we verify that the ECM is actually OK? We bought a used one off ebay that is supposed to be known to be good but it acts just like the old one. We need to have a true start point here because we are just chasing our tail around. Can you provide a diagnostic tree or a flow chart?
Expert:  Chris replied 1 year ago.

Let me see what I can find. Am at a memorial service, but when I get home I will get some information to you.

Chris

Customer: replied 1 year ago.
I understand that things got busy for you, especially with a memorial service over the weekend. Just needed to know if you had come up with any new ideas? I've been assuming that it will be a pinched/stressed wire somewhere, but was hoping to find a direction to go, rather than blindly tracing every wire in the harness.
Expert:  Chris replied 1 year ago.

Ok, well at this point, find the 5 volt reference wire coming out of the PCM connector. Cut the wire at a point to where you can splice it back together. Now turn on the key and see if you actually have 5 volts on that wire. If you do, then we must have a harness problem. If not, then it must be a voltage regulator in the PCM. Let me know if you need the PCM pinout connector info.

Chris

Customer: replied 1 year ago.
We cut A22 and A2
those are the 5v power out wires according to the pin chart we have. This should have eliminated all downstream issues in wires or sensors and have no output voltage at all. We tried it with both of the ECMs that we have on hand, one being the original that was running on the truck and one being a "GOOD" unit bought off ebay.
Now what?
Expert:  Chris replied 1 year ago.

Wow. Very strange. Check continuity between the wire coming out of the PCM and the terminal in the connector. Maybe a bad crimp on the terminal.

Chris

Related Dodge Questions