Once again being a nice guy and the "dodge guy" in the neighborhood inherits me a headache. My buddy just finished replacing the 5.2 in his 2000 1500 4x4 and cant get it to run. The replacement engine is a 98 5.2 that had 80,000 miles. He says he heard the engine run before they pulled it. Now that its in his truck it starts ok but will only rev to 3,000 rpm. Sounds just like its hitting the rev limiter. Seems to idle fine for a minute or so untill the idle drops off and it dies. Always starts right back up. I've already checked the plug wires for correct firing order( all ok), Checked for a clooged cat(ok). Even went so far as to have him pull all the sensors off his old engine and install them on the new one( old motor ran ok was just developing a nasty knock.)......Now on to the troubling part.....The truck had a ken bell supercharger on the old engine that he decided to remove when he swapped the engines. Along with the charger it had a ken bell optimizer add on ignition box. Im wondering if this could be part of his problem. He just unplugged the connectors and removed the box.........Any suggestions?

I take it you have had it on the road and it still won't go over 3000rpm because it is rev limited in neutral and park.

I did try to drive it yesterday. It runs the same in gear as in park or neutral. As soon as the needle on the tach hits 3000 rpm it starts cutting in and out just like a rev limiter. I did call the local napa this morning and check on the flex plate. I thought perhaps there was a differnce between the two model years. Napa says both use the same part number so I guess thats a no go.

are you sure there's not a rev limiter in the kb setup? using your old computer, and the new engine without the kb charger? if the computer was set to run a blown motor, it's not seeing the signals it saw before. remove all the kb stuff, and return to the stock settings on the computer.

have you checked fuel pressure??

Crank sensor issue.Should be the same sensor 96 or 97 up to end of run.

Sometimes the cat. converter will get broken and cause an exhaust restriction and you'll lose power.I had it happen to me and had a friend that had same problem.I cut a flap in the converter and cleared honeycomb out and welded it back up.Good as new

Check with Kenny Bell if by default if disconnected the timing would limit the rev's to 3000.

Cheers Don.

You swapped JUST the engine? Who's truck had the KB? Your buddies or the truck your buddy got the motor from?

Anyone mess with the cam?

I once accidentally mistook a dot for a circle on a 3 way timing set that was used and faded. I ended up with the cam about 30 degrees advanced and it would not rev past 3k rpm. Found, and fixed my mistake, and all was well.

Took me a while to figure this one out. I'll get to the nitty gritty of it. I finally messed with this thing long enough to get it to throw a check engine light for the map sensor. I pulled the sensor off the throttle body to replace it and wedged inside the rubber elbow on the back of the map sensor I found a steel ball bearing. No idea how this thing got in there but I put the map sensor and elbow back on and she runs like a champ....Thanks for the help....