I have a 1997 Dodge Ram 1500 with the 5.9l. It’s had the same issue for awhile now and everytime I think I have it fixed it comes back to haunt me. The issue is that when attempting to start the truck it runs really rich and doesn’t want to start like the engine is flooded. The only way I can get it to start is if I take the fuel relay out. That allows the truck to run for awhile until it burns up the gas. I tried putting it back in while it was running and it’s either 50/50 it will stay running or stall but when I apply the throttle it stalls. I’ve replaced the fuel pump, fuel injectors, throttle position sensor, spark plugs, wires, distributor cap and rotor, pick up coil and coil pack. I know it’s getting plenty of fuel and it’s getting plenty of spark. I was able to drive it after replacing the injectors the other day even everything was smooth and fine until I parked it and it sat overnight. Any ideas?

 

Do you have a scan tool that can show you what the PCM registers as the intake air and coolant temperature ? Seeing you are in NM I think temps are still fairly mild there, if the PCM "thinks" it's ice cold (bad sensor) it adds too much fuel.

 

I have a reader, the issue now is I’ll have to see if I can get it started again long enough to get the temps. I did have a code awhile ago for the coolant temp sensor but I cleared it and it hasn’t came back on yet. I figured that wasn’t the issue.

 

Do you have any codes now?

 

The engine doesn't need to be running to pull the data. Ignition just needs to be on.

 

I scanned the truck for codes I’m getting a p0118 code, I checked my reader and it’s showing -40c on the ECT. I replaced the temp sensor which the old one basically fell apart when I was taking it out. I cleared the codes and was able to start it but it was running very rich. The code came back on and I erased it again. Now the ECT dropped to -35C on the scanner. Do you think the PCM just needs to relearn itself? Or do you think there is another issue?

 

No the PCM should read the temperature correctly right away. The P0118 is a dead giveaway that it's not. 97 has two coolant sensors, one for the PCM and one for the instrument panel. Did the sensor you replaced have one or two wires ?

 

I replaced the small coolant temp sensor with a single wire right underneath the alternator and the coolant hose. Where is the other located and is it called something other than the coolant temp sensor?

 

That was the one for the gauge cluster. The other sensor is somewhat behind and to the right of the thermostat housing. See here: https://dodgeforum.com/how-tos/a/dod...-sensor-394089 Keep in mind it could also be that the wiring is broken.

 

okay so I ended up replacing both sensors. The sensor for the gauge was behind the alternator and when I took it off it fell apart. The coolant sensor that relays info to the ecm was behind the ac compressor. I replaced that one as well. I wasn’t aware that there was two sensors so it was throwing me for a loop when I was reading 200f on my cluster and -72 on the scan tool. After replacing the coolant sensor to my ecm the temp went up to 130f and my truck starts just fine now and isn’t running rich.
thanks for all the help guys.