cold drivability

[Hagar1]

I have a 2012 Ram 1500 with an interesting problem, well for me anyway.
It starts normally and well cold or hot. But with cold start, and starting to drive, it has almost no power and there feels to be a slight miss. If it was a carburetted vehicle, I would think that the power valve was stuck closed. Once it warms up it appears to run fine. The other interesting part is that the fuel economy dropped from 21 -22 MPG on the highway down to 14 MPG highway.
The spark plugs were recently replaced with no improvement. Air filter is clean.
Any ideas much appreciated.

 

[Daw14]

How many miles ? Have you looked for codes ?u

 

[Hagar1]

About 218,000 Kilometers (136,000 miles) No codes, no check engine light. Both problems appeared at the same time.

 

[Hagar1]

On one occasion, it actually popped back through the throttle body. Sort of similar to a "back fire" in a carburetted engine.

 

[Riccochet]

Sounds like a timing issue. Bad cam phaser, maybe.

 

[Hagar1]

Sounds like a timing issue. Bad cam phaser, maybe.

I've been out of touch for a long time now, is this a fairly common failure? Is there any diagnostic other than replacement? Thank you

 

[Riccochet]

I've been out of touch for a long time now, is this a fairly common failure? Is there any diagnostic other than replacement? Thank you

Typically it's going to throw a cam position code. It throwing no codes is odd. But back firing through the intake is a timing issue.

It's also odd that it runs fine when warm.

Not really a common failure. But possible the cam chain tensioner is bad and the chain jumped a tooth. Phaser is trying to make up for it, as best it can. Still, it should throw some codes.

You need to get it to a shop that hook up scan tool. That's the only way to know what's going on.

 

[RamDiver]

About 218,000 Kilometers (136,000 miles) No codes, no check engine light. Both problems appeared at the same time.

What scan tool are you using that shows no codes?


If your truck runs poorly when cold and OK after warm, I would be inspecting the throttle body opening, especially around the butterfly valve.

If the TB is coated with crud, after 11 years and 218,000 KM it may well be, it might impact cold performance more noticeably than warm.

Check YouTube for inspection videos and search throttle body cleaning with the site search tool, in the upper right corner.

This link has good instructions for cleaning the TB.

Help! — Throttle Body, clean or repair? 2012 Ram 1500

Hi All, My check engine light came on yesterday. Had the codes checked. Main code was P0121.. Printout had the following recommendation, “replace throttle body and reprogram PCM”. I was going to clean the throttle body first (figured there was built up fuel and debri making the butterfly...

www.ramforum.com

If it were my truck, I'd remove the TB before cleaning. This link has instructions and a video of the cleaning process in the last post.

So Unclear-Throttle Body Cleaning

Hello, This is my first post, but I am hopeful using this forum. I have a 2012 Ram Sport with the 5.7 hemi. I have searched online for days and days, and I can't find a clear answer about cleaning the throttle body on a 4th gen ram Hemi throttle body. I would like to clean mine, and I've...

www.ramforum.com

PS: I'd keep metal tools away from the inside of the throttle body & butterfly valve for scraping gunk, plastic or wooden are much safer.

.

 

[Hagar1]

Typically it's going to throw a cam position code. It throwing no codes is odd. But back firing through the intake is a timing issue.

It's also odd that it runs fine when warm.

Not really a common failure. But possible the cam chain tensioner is bad and the chain jumped a tooth. Phaser is trying to make up for it, as best it can. Still, it should throw some codes.

You need to get it to a shop that hook up scan tool. That's the only way to know what's going on.

It is a strange problem indeed. No codes, no light. We had the front off the engine a couple of weeks ago to check chain, tensioner and guide, they were all ok. I even ordered a chain just in case. It is sitting in my parts supply waiting for me to build another 5.7. The problem started long before we took the front off. I was sort of hoping to find something wrong but unfortunately, all ok.
I've got an intermittent lifter tick. Cold start, it is quite pronounced. Once it warms up, it goes into "quiet mode" Might there be a relationship there? Maybe a valve not functioning properly when cold? There are new lifters in it, we inspected the cam and it was good. No failed rollers on the lifters.
Could the MDS solenoids play a part?

 

[Hagar1]

What scan tool are you using that shows no codes?


If your truck runs poorly when cold and OK after warm, I would be inspecting the throttle body opening, especially around the butterfly valve.

If the TB is coated with crud, after 11 years and 218,000 KM it may well be, it might impact cold performance more noticeably than warm.

Check YouTube for inspection videos and search throttle body cleaning with the site search tool, in the upper right corner.

This link has good instructions for cleaning the TB.

Help! — Throttle Body, clean or repair? 2012 Ram 1500

Hi All, My check engine light came on yesterday. Had the codes checked. Main code was P0121.. Printout had the following recommendation, “replace throttle body and reprogram PCM”. I was going to clean the throttle body first (figured there was built up fuel and debri making the butterfly...

www.ramforum.com

If it were my truck, I'd remove the TB before cleaning. This link has instructions and a video of the cleaning process in the last post.

So Unclear-Throttle Body Cleaning

Hello, This is my first post, but I am hopeful using this forum. I have a 2012 Ram Sport with the 5.7 hemi. I have searched online for days and days, and I can't find a clear answer about cleaning the throttle body on a 4th gen ram Hemi throttle body. I would like to clean mine, and I've...

www.ramforum.com

PS: I'd keep metal tools away from the inside of the throttle body & butterfly valve for scraping gunk, plastic or wooden are much safer.

.

I'm using the Ancel FX4000 off Amazon. I will pull the Throttle Body and definitely keep metal stiff away. I am thinking of buying another scanner that has the capability to do data recording.

 

[RamDiver]

I'm not familiar with that scanner.

Please post before and after pics of both ends of the TB, if possible. This could be very helpful for other users.

And do remember to use caution when torquing the mounting bolts.

.

 

[Hagar1]

It is a strange problem indeed. No codes, no light. We had the front off the engine a couple of weeks ago to check chain, tensioner and guide, they were all ok. I even ordered a chain just in case. It is sitting in my parts supply waiting for me to build another 5.7. The problem started long before we took the front off. I was sort of hoping to find something wrong but unfortunately, all ok.
I've got an intermittent lifter tick. Cold start, it is quite pronounced. Once it warms up, it goes into "quiet mode" Might there be a relationship there? Maybe a valve not functioning properly when cold? There are new lifters in it, we inspected the cam and it was good. No failed rollers on the lifters.
Could the MDS solenoids play a part?

I pulled the throttle body today, it had a bit of crud but nothing out of the ordinary. I cleaned it to bare, shiny aluminum with parts cleaner and just my fingers. I took a while and in the end, nothing changed.

 

[GTyankee]

Check the PCV
shake it & it should rattle pretty good

OMG, you cleaned it with WHAT ?
you must use Throttle Body Cleaner and make sure it is labeled as sensor safe. Some people try to use brake cleaner for this but it is super harsh and could damage sensors.

 

[Hagar1]

Check the PCV
shake it & it should rattle pretty good

OMG, you cleaned it with WHAT ?
you must use Throttle Body Cleaner and make sure it is labeled as sensor safe. Some people try to use brake cleaner for this but it is super harsh and could damage sensors.

I just cleaned the throttle body and throttle plate, did not touch the air temp sensor. I prefer to approach a problem step by step so air temp sensor will get cleaned by throttle body cleaner.

 

[RamDiver]

Check the PCV
shake it & it should rattle pretty good

OMG, you cleaned it with WHAT ?
you must use Throttle Body Cleaner and make sure it is labeled as sensor safe. Some people try to use brake cleaner for this but it is super harsh and could damage sensors.

I just cleaned the throttle body and throttle plate, did not touch the air temp sensor. I prefer to approach a problem step by step so air temp sensor will get cleaned by throttle body cleaner.

A failing PCV valve could contribute to rough idle and excess fuel consumption.

We're trying to eliminate the low cost items and probable root cause before the more costly potential issues.

The PCV valve is a great idea.

They usually throw a CEL notification but I wouldn't ignore it as a potential cause without the notification.

I'm sure that whatever you used to clean the TB isn't as important if you removed it first, however; cleaning it while connected is best using the specific cleaner to avoid creating more grief by potentially damaging sensors.

.

 

[Hagar1]

A failing PCV valve could contribute to rough idle and excess fuel consumption.

We're trying to eliminate the low cost items and probable root cause before the more costly potential issues.

The PCV valve is a great idea.

They usually throw a CEL notification but I wouldn't ignore it as a potential cause without the notification.

I'm sure that whatever you used to clean the TB isn't as important if you removed it first, however; cleaning it while connected is best using the specific cleaner to avoid creating more grief by potentially damaging sensors.

.

I hadn't given the PCV any thought, but I will be pulling it to check it out. I picked up a can of Throttle Body cleaner today (CRC brand) ... smells a lot like brake cleaner. I had the TB off to clean it.
I appreciate the help, it is amazing what one forgets over the years. I have been "out of the game" for 17 years now.

 

[RamDiver]

Yes, the PCV idea credit goes to @GTyankee. And also the choice of TB cleaning fluid should indicate, 'sensor safe'.

I still think it's not too important if you remove it entirely and wipe it clean before re-installing it, but, maybe he knows differently and will correct my thinking.

You're most welcome for the assist. There is so much experience and talent at Ram Forum, you can find almost endless assistance here.

I've been a home mechanic for years and still learning more stuff and about Ram trucks.

.

 

[Hagar1]

It is a strange problem indeed. No codes, no light. We had the front off the engine a couple of weeks ago to check chain, tensioner and guide, they were all ok. I even ordered a chain just in case. It is sitting in my parts supply waiting for me to build another 5.7. The problem started long before we took the front off. I was sort of hoping to find something wrong but unfortunately, all ok.
I've got an intermittent lifter tick. Cold start, it is quite pronounced. Once it warms up, it goes into "quiet mode" Might there be a relationship there? Maybe a valve not functioning properly when cold? There are new lifters in it, we inspected the cam and it was good. No failed rollers on the lifters.
Could the MDS solenoids play a part?

Sounds like a timing issue. Bad cam phaser, maybe.

"Back in the day" I have seen a "pop back" on carburetted vehicles, oftentimes because of an extremely lean fuel delivery. It has only popped back once but it sort of feels like a carburetted vehicle would if the power valve was stuck closed. I'm sort of leaning towards an excessively lean fuel delivery when cold. The coolant sensor seems to be working, the intake air sensor is working, throttle position sensor seems to be working. If I recall correctly, those would play the biggest part in fuel delivery.
Something that just struck me as I am writing, they used to use a "dual range" coolant sensor, is that still a "thing?"

 

[RamDiver]

I have a 2012 Ram 1500 with an interesting problem, well for me anyway.
It starts normally and well cold or hot. But with cold start, and starting to drive, it has almost no power and there feels to be a slight miss. If it was a carburetted vehicle, I would think that the power valve was stuck closed. Once it warms up it appears to run fine. The other interesting part is that the fuel economy dropped from 21 -22 MPG on the highway down to 14 MPG highway.
The spark plugs were recently replaced with no improvement. Air filter is clean.
Any ideas much appreciated.

Could you confirm that this fault was occurring before the plug replacement and that it definitely didn't start after?

Any update on the PCV valve check/replacement?

.

 

[Hagar1]

Could you confirm that this fault was occurring before the plug replacement and that it definitely didn't start after?

Any update on the PCV valve check/replacement?

.

I can confirm that the problem started a moth or so before the plug change.
The PCV valve was clean and rattled when I gave it a shake.
In regards to the plugs, I checked the gap on all of them prior to installation. I'm kind of old school that way.
I looked at the adaptives and they flip back and forth between about +2 and -4 on both sides. On a cold soak overnight, both the intake air temp and coolant temp read the same.