Hard cold start after header install

[Jjrich04]

Hello,

Any advice or ideas on this is greatly appreciated.

Problem: Truck is hard to start on the first start of the day. This started occurring directly after installing my headers so I’m wondering if I did something during the install to cause this issue. It runs fine and starts up great the for rest of the day after the initial cold start. Even after letting it sit for four hours, it starts fine (seems it has to sit at least 8 hours to replicate the issue). It turns over okay but chugs for the first 5 seconds or so then goes to normal idle.

Checked with Sean at HemiFever and confirmed it has nothing to do with the tune. I later verified this by restoring the factory tune which did not help. Tuning is ruled out as far as I can tell.

I’ve attempted the fuel priming procedure (turning ignition to start several time before starting) which did not seem to help at all so I don’t think I’m losing pressure overnight.

Will continue to attempt to diagnose this over the weekend but I will have to take it into a mechanic if not resolved by then. Either way, I’ll post the resolution here in case anyone runs into this in the future.

Thanks guys!

 

[BowDown]

Sounds like a leaking injector

 

[Jjrich04]

Sounds like a leaking injector

I can’t imagine there is a simple way to check for that? I’ll do some research and see if that might be something I can accomplish in my driveway.

Also, I forgot to mention that I am getting no error codes and I’ve ruled out bad gas already.

 

[Jjrich04]

Heading out soon to grab a fuel pressure gauge which is the only method I could find to check for a leaking injector. I’ll post results in a few hours if I can figure out how to do this properly.

 

[Jjrich04]

Heading out soon to grab a fuel pressure gauge which is the only method I could find to check for a leaking injector. I’ll post results in a few hours if I can figure out how to do this properly.

Not seeing a test valve so I might have to wait on the mechanic to check for leaking injector/s. Only have 8k on the truck so I would be surprised if this were the case.

 

[BowDown]

You'd have a fuel smell under the hood. What you describe is the exact scenario of a leaking injector though.
The injector leaks due to fuel line pressure ax the vehicle sits. After the engine has cooled, the fuel no longer vaporizes, it pools in the cylinder and that's why cold starts are difficult.

When the engine is hot and shut off, the leaking fuel vaporizes due to engine heat and restarts normally.
A cheap way to test is to pull spark plugs and look for a wet plug

 

[BowDown]

Not seeing a test valve so I might have to wait on the mechanic to check for leaking injector/s. Only have 8k on the truck so I would be surprised if this were the case.

You connect the fuel pressure guage to the end of the fuel rail, there should be a schrader valve on one of the rails

 

[41magmag41]

i wonder why put headers on a new truck that only has 9000 miles and screw with the factory warranty? seems like a waste of money until shes out of that factory warranty.

 

[PowerJrod]

i wonder why put headers on a new truck that only has 9000 miles and screw with the factory warranty? seems like a waste of money until shes out of that factory warranty.

Unless he's trying to build a racing Ram lol. Honestly though...sounds like a fuel pressure issue which could theoretically be caused by the tune. Just because the issue is still there after going back to factory tune doesn't mean anything. Even if you did a chop job installing the new headers...I can't see them causing a hard start every single time. I'd get a second opinion regarding the tune...if the fuel injectors are fine.

 

[BowDown]

i wonder why put headers on a new truck that only has 9000 miles and screw with the factory warranty? seems like a waste of money until shes out of that factory warranty.

Headers don't void the warranty. May void the exhaust warranty but nothing else

 

[Jjrich04]

You connect the fuel pressure guage to the end of the fuel rail, there should be a schrader valve on one of the rails

Thanks, will check for this again in the morning.

 

[Jjrich04]

i wonder why put headers on a new truck that only has 9000 miles and screw with the factory warranty? seems like a waste of money until shes out of that factory warranty.

I think most of the activity I see on this forum is people wasting their money on their trucks. I get it though, the tune and headers were not an economically advantageous purchase. Perhaps I’ve been locked up in this house too long.

 

[Hockeygod1225]

Headers can alter your air fuel ratio. Also everything is computer controlled on these trucks. It o2 sensors are reading differently the engine could also be cutting spark or closing the throttle blades.

 

[Jjrich04]

Unless he's trying to build a racing Ram lol. Honestly though...sounds like a fuel pressure issue which could theoretically be caused by the tune. Just because the issue is still there after going back to factory tune doesn't mean anything. Even if you did a chop job installing the new headers...I can't see them causing a hard start every single time. I'd get a second opinion regarding the tune...if the fuel injectors are fine.

Ha! I suppose it could turn into a racing Ram. I haven’t really made any long term build plans. Just having fun at this point (minus the current mishap).

I’m interested in your comment on how going back to the factory tune wouldn’t rule out the tuning. I’m more of a layman when it come to this kind of stuff so I’m having a hard time wrapping my head around how it wouldn’t be ruled out.

 

[BowDown]

Headers can alter your air fuel ratio. Also everything is computer controlled on these trucks. It o2 sensors are reading differently the engine could also be cutting spark or closing the throttle blades.

Headers will not alter your AFR beyond predefined norms already in the PCM. You need a full to get every last drop of power that the headers can give but they do not alter AFR enough to be a problem. The only real thing they will do is improve cylinder fill in the upper RPMs and expose the intake system limitations. I drove my Z06 for 10 years with headers and no tune and the plugs never looked lean or rich beyond what was expected/stock.
O2 sensors are there to adjust the injector pulse width within a preset range, thats it. No connection to throttle body or ignition

 

[BowDown]

I think most of the activity I see on this forum is people wasting their money on their trucks. I get it though, the tune and headers were not an economically advantageous purchase. Perhaps I’ve been locked up in this house too long.

Exactly, this is no different than mud flaps, tint, tonneau covers, CAI, Pedal Commander BS, ect, do what you want and enjoy it. The only reason I wouldn't do it is because I've gone down that road and what started with headers ended with a fully built stroker motor then a fully built trans/rear and a car that I can only drive with Toyo R888Rs or better as it spins through 4th gear.

Ha! I suppose it could turn into a racing Ram. I haven’t really made any long term build plans. Just having fun at this point (minus the current mishap).

I’m interested in your comment on how going back to the factory tune wouldn’t rule out the tuning. I’m more of a layman when it come to this kind of stuff so I’m having a hard time wrapping my head around how it wouldn’t be ruled out.

I still believe you have a leaking injector, the question is what caused it, dirt, mechanical failure, the tune? The only way I can see a tune causing this is if the tune was too aggressive with fuel and took the injector at the top end of its duty cycle. I dont know what size injectors are on these trucks but If they are say 30-35lb injectors and you really needed say 45lb injectors, the tuner would have altered the injector pulse and increased the duty cycle. As a rule, you don't want the injector operating past 90% duty cycle, deal is 80% or less. Operating at a high duty cycle means the injector is open and firing FAR more than its closed and can cause mechanical failure of the injector. The injector can fail open (they usually do) and dump fuel into the cylinder causing the fuel to:
1. Wash down the cylinder, washing the oil film from the cylinder wall, no lubrication.
2. Hydrolock the cylinder, dumping so much fuel that the piston is literally compressing a liquid instead of air
3. Fail and leak constantly
4. Fail closed and not fire at all.

Yes a tune could have done this, a tune cannot adjust your fuel pressure, thats a mechanical change, IE bigger fuel pump like a Walbro 450 or a FORE pump or modification of the FPR (fuel pressure regulator) which if I'm not mistaken may be on the pump in the tank.
Going back to the factory tune WOULD eliminate the tuning unless the tuning damaged the injector

 

[Ellisstrong]

Ha! I suppose it could turn into a racing Ram. I haven’t really made any long term build plans. Just having fun at this point (minus the current mishap).

I’m interested in your comment on how going back to the factory tune wouldn’t rule out the tuning. I’m more of a layman when it come to this kind of stuff so I’m having a hard time wrapping my head around how it wouldn’t be ruled out.

Slightly off topic as I’m no help with your issue, what headers did you install and how hard were they to?

 

[RSConsulting]

Headers don't void the warranty. May void the exhaust warranty but nothing else

But unlocking the ECM to tune it will. Unless you get a NEW/UNLOCKED one - and swap it in.

I was considering the MOPAR CAT-back & CAI - with an ECM and Tune. But I really don't need a 7Klbs truck to move faster. I like how quiet it is.

Which is not to put-down others that choose to spend $$ on performance upgrades. I typically try not to mess with my "daily drivers", and get a "toy" to mess with (said the guy with a Polaris Slingshot - Supercharger/headers/cams - 05 corvette with blower/cams/etc - 17 Subaru BRZ blower/headers/etc. - so I'm no stranger to blowing obscene warranty voiding $$ on toys).

That and I already get (what I consider to be) crappy mileage (even when I try to keep my foot out of it). Anything that tempts me to use my right foot even more - isn't going to help in that department either.

More power (pun intended) to those that choose to. I can live vicariously via your wallets...

Rick

 

[PowerJrod]

Ha! I suppose it could turn into a racing Ram. I haven’t really made any long term build plans. Just having fun at this point (minus the current mishap).

I’m interested in your comment on how going back to the factory tune wouldn’t rule out the tuning. I’m more of a layman when it come to this kind of stuff so I’m having a hard time wrapping my head around how it wouldn’t be ruled out.

Go for it! Wipple supercharger next?
As far as the tuning is concerned...when you tune the engine, you're basically adjusting the ECU to yield better performance gains, etc...it's all in the computer. Think of it this way...let's say you have a high tech laptop, you upgraded to the latest software and then decide either you don't like it or it's causing some issue with a few of your programs. Now...in order to get rid of that software update...you need to do a factory reset. Well...during a factory reset you wipe everything else on the computer and start from scratch. The only way to truly make sure the tune wasn't the culprit is to drive around with the factory tune for about a week...maybe a little longer while the computer re-adjusts to the stock parameters. Hope I'm making sense here lol. Like a reset laptop...the computer is going to relearn certain parameters (which takes time) and in a Ram ECU...that's even more advanced than your everyday laptop or desktop. So just going back to the stock tune isn't going to tell you anything unless you've been driving around with it for almost 2 weeks.

 

[Jjrich04]

You connect the fuel pressure guage to the end of the fuel rail, there should be a schrader valve on one of the rails

I’m not seeing a valve on here anywhere. Pics below. I’m guessing I need some sort of adapter which doesn’t come with the kit they have at the the local auto parts store.

No fuel smell under the hood but I do smell it from the exhaust on that first start in the morning. Still seems to fit what you’re suggesting.

I’m curious if depressurizing the fuel system before I go to bed would yield any useful info. I suppose if the injector is stuck open it would still leak the residual fuel into the fuel rail?

I might order something if I can find a testing kit that will work the truck.