manolomanza

Hi friends. I'm new to this forum and I have a question about an issue I have in my truck.


I have a 1995 Dodge Ram Cummins 12 valves with a 141 thousand miles. This truck was bought in an action and it runs and drives. The truck is hard to start. The only way for it to start is to press the pedal and I have to hold the switch on. If I just let it go, the car just starts and dies after a second. If I hold the switch and I push the pedal, the car starts. Does anyone have any idea what the problem is?

maybe368

Welcome to the forum, now get out of here , just kidding. This is the 1st gen forum and you probably should post this in the second gen forum. Anyway check for suction side air leaks...Mark

manolomanza

thanks maybe368, I was think it to replace the fuel filter.
Do anyone else have any other sugestions

2mtrucks

I own both 1st and 2nd gen 12 valves and I can tell you that the 2nd gen p7100 pump motor requires that you depress the throttle to start it in cold weather...the instructions on the visor also state this....and you need to stay in the throttle a little bit for a few seconds to keep it running. Every 1st gen VE pump motor I have ever owned has started instantly. There are lots of tech articles dealing with hard start 2nd gen 12v. There is a reason 2nd gens have two batteries.

patdaly

Ok, let's see if we can't help out.

When you say hard to start, we have to clarify a few things.

How cold out is it?
How fast does it roll over ( RPMS while trying to start ), nothing technical, but is it a ruh-ruh-ruh or a ring-ring-ring?

A slight bit ( say 1/4 or under ) bit of pedal is normal for a P7100 pump truck to start, but any more, or not starting rigth away with a bit of pedal is not.

What RPM does it idle at warmed up, in gear? If it isn't 750-800, then you need to get the idle set.

Before all that though, since it is an auction vehicle, and you have no idea of maintenance, get yourself a good fuel filter, and pre-filter screen it and start there. This thread shows a 97, but yours is similar except the fuel filter just screws off for you.

https://www.dieseltruckresource.com/...-320795/page3/

Let's start there and see where you are.

patdaly

Yea, they got smart.......... My P7100 starts instantly with a little pedal, just like a VE truck.

manolomanza

Hi patdaly, when I try to start normaly, the truck start and die, the only way I can run the truck, I have to roll over the swich around 8 seconds and pumping the gas pedal to the end. After the 8 seconds, the truck stay running. The engine sound good, the idle is normal. is not shaking the engine. I don't know if is a air lines problem

The weather is not so cool is in LA around 60 F

tdiot

Could be many causes but one I recently bought was hard starting and white-ish smoke on start up. New overflow valve on the injector pump and starts easy with a puff of black smoke now.

manolomanza

yes, when I start the truck take out white smoke

tdiot

I bought one from Larryb fostertruck.com for about $28. He may be out of stock, he was last time I checked. Easy five minute job that could be worth a try. Good luck!

manolomanza

in my truck after start to running the idle is good, no shake, or die, and this is one of the symtoms when need to replace the overflow valve

tdiot

Yes it is. Mine ran like a top once it started but was hard to start and blew white smoke at start. There are other problems that can cause these symptoms like leaks in the fuel lines, fuel filter problems etc etc. I could find no leaks or diesel smell from the engine on mine so went ahead and changed the OF valve and that did the job. Easy and inexpensive to change out and eliminate as a possible cause of your start issues but by no means the only possible cause. Worked for me though.

patdaly

Ok, now we are going to try something.

On the drivers side of the engine is the lift pump, and at the top of it will be a plunger, black rubber boot if it is still there, white plastic tube if not. What you will do is before your next start, take an implement of destruction such as a shovel or garden hoe, and use the end of the handle to depress that plunger until you hear a sound from up front what roughly sounds like the hissing made when you force air thru your front teeth.

If it does so almost immediately ( first or second stroke ) then you don't have a prime issue, if it does, and the truck now starts right away, it is time to find the air leak....... Anyway, try that and let's see where3 it leads us.

manolomanza

Patdaly sorry I don't answer because out of the town and I can't test the truck.
But I have a question; my batteries are die and when try to started, I use 2 booster's, do you think, the batteries can cause this problem

patdaly

Yes, Diesels start on compression, so the RPMs at which the engine turns over while starting makes a HUGE difference in how they start.

These Cummins are not an engine you want to get cheap with either batteries, cables, or a starter on. If she doesn't whip over like she means it, get it to where it does.

The worst thing is as you have less amperage from the batteries or cables, the starter will try and suck more juice, and you can ruin your starter.........