Hard start 97 12v

[Josh....................]

Hey guys I'm new to this forum. But I was wondering if any of you guys had an idea why my truck starts hard. If I barely touch the pedal while its cranking it'll fire right up or I can just crank on it and itll fire. It idles at high 700s. I've heard heating grid, fuel needs to be adjusted and a throttle position sensor. I'd love some help on this before I go needlessly replacing parts.

 

[Cummins12V98]

Turn up idle to 750 in drive.

 

[HPSimpson]

Welcome to TDR very knowledge people who are very good at helping people keep there Cummins Ram truck running!

 

[DonFitzwater]

As mentioned, set your idle to 750, hot. There can also be enough combined wear in the linkages inside the pump that you may need to lightly depress the pedal for a quick start. Even with my 94 adjusted properly I still have to lightly depress the pedal.

 

[GAmes]

You use the idle screw to adjust idle, not the linkage. According to the factory service manual the spec is 750-800 rpm, engine at operating temp, in drive, AC on. You can get a fsm, and a lot of other things, from Genos. I recommend you get one, it will be the most used tool in your garage. I prefer the print version. https://www.genosgarage.com/

 

[Cummins12V98]

As mentioned, set your idle to 750, hot. There can also be enough combined wear in the linkages inside the pump that you may need to lightly depress the pedal for a quick start. Even with my 94 adjusted properly I still have to lightly depress the pedal.

My 98 12V even with set at 750 in drive HOT needed a light touch to instantly fire.

 

[GrantP]

I'll throw in another vote for idle adjustment. Bonus, it's free. I had to do it on my 97.

 

[BigPapa]

I’ll make another suggestion for idle adjustment. Mine is at 750 in drive with the AC on. I still have to give it a bit of pedal for an instant start. The p-pumps don’t light off instantly like the VE’s and the 24 valves. Just the facts of life.

 

[GAmes]

I have my idle set at 900 in neutral. It starts on the first revolution without pedal input. I have it set a bit high because the AC work better with the higher RPM while I'm in traffic.

 

[Josh....................]

Update: I replaced the throttle position sensor(it was burnt) and the air temp sensor. And it fires up a little faster, I hooked an obd scanner and it said my coolant was -40 right after running so I'm thinking that's the next step

 

[DonFitzwater]

You need to take a step back and understand how your engine works. None of those items you’ve replaced or are thinking of replacing have anything to do with how quickly this mechanically controlled engine starts up. This is purely a mechanical engine. The electrical components are for shifting, charging and intake heater grid control.

 

[Josh....................]

I'll try to adjust the idle and go from there but any ideas on why the obd would say -40 though?

 

[DonFitzwater]

I'll try to adjust the idle and go from there but any ideas on why the obd would say -40 though?

What type of scanner are you using?

 

[BigPapa]

Does your ‘97 have the standard trapezoid OBD connector? I don’t know what year they started using them in the Rams. I know my ‘95 didn’t have one. Even if it does, I question the PCM and the very early OBD’s ability to report coolant temp.

 

[GAmes]

You don't have a factory service manual do you? Here is the note in mine;

NOTE: The DRB scan tool cannot be used to monitor
engine coolant temperature on the diesel
engine.

Now, have you adjusted the idle speed or not?

 

[GrantP]

Update: I replaced the throttle position sensor(it was burnt) and the air temp sensor. And it fires up a little faster, I hooked an obd scanner and it said my coolant was -40 right after running so I'm thinking that's the next step

An OBD scanner is near worthless on a 97. There's no reason to even hook it up.

 

[Josh....................]

Update: I adjusted the idle screw starts up and I shouldn't worry about the coolant temp then?

 

[GAmes]

........... I shouldn't worry about the coolant temp then?

I don't know. What does the gauge in the dash show? Do you have an IR temp gun to double check the temp at the rear of the engine?