Hello all, swapped motor in daughters dodge and have a wierd issue. The truck is a 1999 dodge 1500 5.9, gas 2nd automatic transmission. The only code is the temp sensor voltage too high… trading them out tomorrow. The motor will run if I give it gas and stall when I let off the gas…. I’m not used to Dodge…. I’m a Ford man…. Don’t hate me… lol…. With the key in the off position and I run a jumper wire to spin the motor over, it spins with no problem. Turn the key to the on position and connect the jumper wire turn it over it spins a couple of things and drags like bad battery or starter… had both test and it is fine. Tested fuel pressure with key in the on position 10 psi, start the motor and hold it to stay running pressure is 49 psi. Replaced all vacuum lines, air control valve, map or mass air flow and throttle position sensor. Clean the throttle plate all those items hook into. New crankshaft sensor, new distributor cap, rotor and cam shaft plate on the distributor. When the engine bogs down (cranks like weak battery) when I’m trying to start it will make a pop noise I thought might be a back fire so I thought I might. Red to hook a timing light to see if the distributor needs to be turn A little like you would do on a ford, Chevy and every other vehicle I’ve worked on… but the Dodge 1500 does not work that way… the ECM sets the timing and I understand turning the distributor adjust the cam and crankshaft sink from what I’ve read. So, I’m confused why it does not idle, and why it bogs down and drags trying to start….. anyone have any thoughts? Sorry for the lengthy post but want to put to rest vacuum leak, ACV, etc….. last thing changed between three pcm and have the same results with all….

 

Did you set the fuel sync when installing the new engine? This gets the injectors and the engine timing set properly with the PCM and if not set may be causing your popping/starter drag issue you mentioned.

You can find the fuel sync process for 5.9/5.2 Dodge magnum engines by doing a quick search of YouTube...

 

Step 1 is to set the "fuel sync" correctly. The name is a bit misleading because it merely tells the engine which set of injectors need to be fired in the next revolution. It is also not very critical, the PCM can deal with +- 14 degrees (IIRC). Again, the injector timing comes from the crankshaft position sensor. Basic procedure is cylinder 1 on TDC on the compression stroke, then line up the distributor so the mark on the housing and the rotor align. That should be good enough to get it going.

If that checks out the crankshaft position sensor might be the culprit, most aftermarket sensor especially from Amazon or eBay are just junk.
FSM is here: https://dodgeforum.com/forum/2nd-gen...e-manuals.html

 

Thanks for the advice.. my buddy came and the snap on reader shows the sync is within parameters. Two issue I forgot to mention instrument gauge says no bus, will start and run as long as I hold the throttle open. Other issue is I can’t find a engine temp sensor connector… it’s the only error code I get

 

Sensor is probably down behind the a/c compressor, very near the thermostat housing. I can be difficult to see.....

 

Thanks, I found it and replaced it already. The issue is it is telling me the voltage is to high… the clip is broken and won’t stay down on the sensor… I’ve search the internet and I can’t find a replacement except for $65. I can’t believe a clip will cost that much…. I’m new to Dodge so my question based on my previous post……. If the temp sensor is reading to high…. Could that be part of the reason it won’t ideal?

 

FYI, the pigtail and connector are available here for less than $65 - https://www.rockauto.com/en/moreinfo...t=2564&jsn=547

Also, available here -

 

Need to check the voltage then, and see what you are getting. That sensor is on the 5 volt bus......

 

Yes, if the temp sensor circuit is open/disconnected the PCM reads -40F and will add way too much fuel. "no bus" indicates the cluster does not receive messages from the PCM, that can be related to the other issue if a wiring problem in the engine harness drags 5V reference down.

 

Yeah the Standard S-2120 is ~$38 at Amazon which is still ridiculous for what it is. It looks like these were used on many Dodge trucks and vans beginning circa '92. I'd try to hit a JY. Don't overlook Dakotas, Durangos and RamVans

A comparable connector for a SBC is more like $8 on Amazon. Crazy.