2010 5.7 cranks but only starts if gas pedal is to the floor.

[paintballer51]

Hey ya'll, need help.
2010 Ram 5.7, had a collapsed lifter in #7 (P0307). Two years ago I had to put new cam/lifters in her. Ran great since then, until I got the #7 misfire. The lifter was barely squishy and I caught it in time where did not damage the cam lobe.
Ordered the same lifters (non MDS) and got it all back together, programed it with the predator that came with the cam/lifter job and tried to start it. Cranked but no fire, unless I mashed the pedal down but won't stay running.

Had the head machined
New head bolts
New (16) spark plugs
New head and intake gaskets of course
Still doing the same thing, my fuel pump turns on. Didn't check the fuel presure but feel like its fine. Tested the coil packs, took off and cleaned the Throttle Body. Map sensor looks fine. Still the same Random misfire/Mutiple miss fire (P0300)

Any thoughts on what is going on here. Thanks

 

[Jeepwalker]

Can you see what your pre-start TPS voltages are? Sometimes they don't land back at the bottom, if/when they start to flake out. And temp sensor cold/warm. Probably not it, but worth looking into.

Does it run ok once it starts?

 

[paintballer51]

Does not stay running, immediately dies after I let off the gas. Someone else mentioned seeing what the PCM thinks the temp is. I unfortunately do not have a scan tool.

 

[paintballer51]

I just picked up a new throttle body today but hesitant about installing it. That's why I am reaching out for help.

The one thing that definitely changed was I accidentally left my intake outside over night and of course it poured down rain. I had a towel in the throttle body but it rained hard. That's why I was thinking water could have gotten into the TPS.. and/or the Intake manifold runner control....

 

[Jeepwalker]

Rain shouldn't hurt it too bad. Probably cleaned thing off. The TPS should dry out on a hot sunny day. Many of the key sensors should be double-checked because it sounds like you've done your homework in most of the other areas and maybe it's the TIPM that's keeping the engine from starting. I'm assuming you've tripple-checked the engine is timed, 'correct'? I know that's stating the obvious, but sometimes things get off a tooth or two. Been there lol. Then there's the crank and cam sensors worth checking and ensuring the wiring/connectors are good. Yeah, sometimes sensors crap out at the worst time.

You're kind of flying 'blind' on the electronic portion. First, Tripple-check all the connectors ..looking for possible broken internal wires and corroded connectors. Try starting the truck with the MAF unhooked. Now might be a good time to invest in some sort of scan tool. Do you have a buddy with like a snap on scanner? That'll give you all the readings you need. Since you have a 2010, it doesn't need to be a real new scan tool. Or even investing in a regular OBDLink MX plug-in scanner (HERE), would do you fine (and use a smart phone/tablet). It's amazing the amount of info these new scanners give.

Note...the truth is, a scanner is a great tool, but you *can* back-probe & check sensors with a multi-meter HERE. And there are many other videos how to check various sensors with a tool you might have already. Thats how it was done in the old days. And it works. Just takes a little longer. You can use a cheap H/F multi-meter. Nice thing about a scanner is it give the ability to look at many readings at a snapshot. And you can see that the 'computer' is actually getting the sensor signal (in case there were a pinched wire or bad connection). But as I said, you can read most real quick by pulling out a multi-meter and *carefully* inserting some real thin wire from the back of the connector (to connect the probes to). In fact it's a great way to learn the 'basics'.

 

[paintballer51]

No buddy that has one, I should invest in one just never had to have/want one till now.

I can back-probe the sensors, don't know what voltage ranges im looking for though?

And do you think I should just throw this new Trottle Body on there? Just didn't want to put it on unless it's necessary($200) that i probably won't be able to take back...

 

[jws123]

Check your push rods make sure you got them in the correct holes and they are all clicked in every sigle time someone has running issues after a camshaft job its always the intake rods not seated or put into the oil holes instead of the lifter slots.

 

[paintballer51]

I checked last night and it all seemed fine.

 

[paintballer51]

I might pull the valve cover off again to quadruple the check lol

 

[paintballer51]

I don't understand why it will only fire when I put the pedal down. Why wouldn't it fire without touching the pedal?

 

[jws123]

I might pull the valve cover off again to quadruple the check lol

You would be suprised how many times i ahve checked and re checked and found one make sure they all move aswell.

 

[Jeepwalker]

I personally would't throw on the throttle body untill I verified the sensors. Is it one of those deals you can't return once it's installed? Do you have a reason to think the TB is the problem? The tk should still start in open loop.

I would check the crank & cam sensors, and the TB sensors ...along with the temp sensor. Temp sensor is a simple ohm reading which you can compare to a 'Ram ohm/temp chart' for rams (just google it). Unplug it and see. Sensors that keep a vehicle from starting are crank & cam sensors.

 

[paintballer51]

You know, I'm gonna pull it and check again. I'll be kicking my own ass if that's been the issue the whole time...
Kinda hope it is..

 

[Jeepwalker]

IDK, could be programmed to automatically go into open loop that way? Just a guess.

A guy can download the manual for it, right? Do a search on this forum. But you might end up doing a lot of digging and reading. If you're not into that, probably not worth it.

You can find out what the sensor readings should be by watching a couple Ram or Charger videos, or just do a google search. You're looking for readings which are waay off.

 

[paintballer51]

I appreciate the both of you, I'm going to got work on what the both of you are saying. I'll get back to ya.

Thanks!!

 

[Jeepwalker]

Best of luck. Let know how it goes. There are a lot of very wise people (than me) on this forum lol...

 

[Travelin Ram]

I don't understand why it will only fire when I put the pedal down. Why wouldn't it fire without touching the pedal?

In most cases that’s an indication it’s flooded with fuel. Not necessarily in your situation since the engine has been opened.

Do you get gas odor at the exhaust when it cranks but doesn’t start? Does it belch black smoke when it starts? Those would indicate rich on fuel.

 

[paintballer51]

Update, so since my lifters weren't very old, I only replaced the 4 lifters for #5 and #7. That being said the exhaust side are tight and to be believed to have the valve slightly open when they should be closed...

I will pull the head off tomorrow to investigate further, the Intake side looks great. Should be the correct lifters, ordered from the same place I ordered the Cam/Lifter kit two years ago. Kinda baffled at the moment because they both look seated properly.

I'll update tomorrow sometime after work.

Thank you all for the help and pray that I didnt mess up my two cam lobes...

 

[paintballer51]

So today at work I got a hold of an engine builder from AMS, where I originally bought the cam kit years back and where I ordered the lifters for this recent job.

Last night I found that #5 and #7 extaust rockers where both tight when they shouldn't have been. He ask if I soak the lifters in oil before install and I said well of course. He said you do not want to soak them at all, they can get stuck full of oil, then he told me to use the push rod and bailling wire to depress the tiny vavle inside the lifters to squeeze out the oil to make them function properly. Did all that and believe or not the rockers were not tight as hell like they were before under no load..

Felt very hopeful that this was the issue but of course it wasn't, all back together and acting the exact same. Not saying he didn't help a little but I feel very defeated at the moment.

Should I try crankshaft and cam pos sensor for the hell of it.... Lost lol

 

[Jeepwalker]

You're kind of flying blind. You MUST know someone who 'might' have a scan tool, don't you? Do any of the parts stores around you rent an inexpensive scanner? I would test the sensors first (below), at least you can see if they're working. But even so, it doesn't tell you is the *computer* is receiving the signal (e.g. bad/broken/pinched wire). Have you tried disconnecting the batt cables and letting it sit to reset the computer? Do the spark plugs get wet after cranking?

Symptoms of Bad Crankshaft Position Sensor (Explanation Why It Fails)

Symptoms of bad crankshaft position sensor. In this video lesson, I will tell you the function of a crankshaft position sensor, how it works and what cause i...

www.youtube.com

HOW TO TEST CRANKSHAFT POSITION SENSOR WITH A MULTIMETER

In this episode I show how to test a two wire magnetic crankshaft position sensor with a basic multimeter and jumper wires. If you're experiencing no start o...

www.youtube.com

I think your Ram uses a 3 wire crank sensor

How to test a crank sensor with a voltmeter

The tests shown in this video apply to camshaft, crankshaft and vehicle speed sensors on ALL Chrysler models, in all production years. The vehicle being test...

www.youtube.com