How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Amedee Your Own Question
Amedee
Amedee, Dodge Technician
Category: Dodge
Satisfied Customers: 24399
Experience:  ASE certified tech advanced level specialist. Wisconsin certified emissions state inspector
279429
Type Your Dodge Question Here...
Amedee is online now
A new question is answered every 9 seconds

I have a 2002 Dodge Ram 1500 4x4 quad cab 4.7 liter engine

Customer Question

I have a 2002 Dodge Ram 1500 4x4 quad cab 4.7 liter engine with very low mileage, truck did not get driven often and we only start it and ran it for a bit every month or two and then last year we went to get it registered and it would not start, it cranks real strong so I started searching for answers, I've replaced the fuel pump, throttle body sensor, Fran and cam position sensors and I have tested fuel pressure and and all that, if tested fuel injectors to see if they are getting power when the engine is being cranked and the answer to all is they are working, if I spray starter fluid into the throttle body it fires right up and runs for a few seconds until the starter fluid is burnt off but still it will not start and there are no codes at all in the pack please help
Submitted: 1 year ago.
Category: Dodge
Expert:  Amedee replied 1 year ago.

Hello and welcome! What size engine do you have? Are there any codes in the computer?

Expert:  Amedee replied 1 year ago.

What is the fuel pressure at when cranking?

Customer: replied 1 year ago.
I am not sure what the fuel pressure is, the pump is a brand new high end pump with lifetime warranty and it is spinning up and is getting good pressure to the fuel rail, I have the 4.7 liter engine, there are no codes even after disconnecting the map sensor and trying to start the engine and then plugging it back in.Bill
Expert:  Amedee replied 1 year ago.

Ok, well, we need to check fuel pressure to start with. Maybe we have low voltage to the pump, restricted fuel line or filter or some sort of restriction in the fuel rail. Just because the pump is new does not mean the fuel pressure is good. We need to start by checking fuel pressure.

Customer: replied 1 year ago.
What pressure range should it be in? I can't get it to start so I can't take it to a mechanic to get it tested and I don't have a test gauge but could order one but don't know what pressure range it needs to be able to handle is a 100psi gauge be good enough or do I need a higher range gauge? I've read dozens of ran owners with this exact problem and none have found a fix for it other the replacing fuel pump, cam sensor, crank sensor, and throttle body sensor? It seems to be costing me more and more, so my only option is to order a fuel pressure gauge so what pressure rating does it need to handle??
Expert:  Amedee replied 1 year ago.

Fuel pressure should be 44 to 54 psi.

Expert:  Amedee replied 1 year ago.

Please call me so I can assist you over the phone.

Customer: replied 1 year ago.
ok a gauge that reads up to 100psi will do right? Until I can get a test gauge there's not much else to do, so I will try to get it here by tomorrow or Wednesday if possible and then go from there so can we keep this open until then??Bill
Expert:  Amedee replied 1 year ago.

YES and YES

Expert:  Amedee replied 1 year ago.

However, if we talk over the phone now, I can explain how the system works so you will know what to check next depending on the fuel pressure readings.

Expert:  Amedee replied 1 year ago.

I do work during the week so it might be better to talk on the phone now.

Customer: replied 1 year ago.
Can it wait until I get the gauge, that way I can have all the information fresh in my mind, I will have to wait to call, I will get back through here or on the phone as soon as I have the rest gauge and go from there
Expert:  Amedee replied 1 year ago.

Sounds good. Have a good night.

Customer: replied 1 year ago.
Thank you, ***** ***** good night too
Expert:  Amedee replied 1 year ago.

.

Expert:  Amedee replied 1 year ago.

Hello! It's Amedee from just answer. I am just checking in to see if you need any further assistance?

Customer: replied 1 year ago.
ok the test gauge kit got here and.i just tested the fuel pressure at the fuel rail and it's at 40psi, should I release the line pressure or bleed off any possible air in the lines? Maybe that's what's causing it? I'm guessing if the fuel pressure is too low it went have enough pressure to open the injectors to spray fuel, right?
Expert:  Amedee replied 1 year ago.

Hello! 40 psi while cranking?

Expert:  Amedee replied 1 year ago.

The fuel pressure specs are between 44 and 54 psi. Although that it out of specs, the engine should still start and run on 40 psi. Ths injectors should still open up while cranking.

Customer: replied 1 year ago.
Well I don't know because I can't crank it and watch the gauge at the same time, I hooked it up and the pressure was at 5 psi and then I cranked it for a few seconds and left the key in the on position and checked the gauge and it was at40psi, if I need to be cranking the engine and watching the gauge at the same time I'll have to wait til tomorrow when I can have someone who can crank it while I watch the gauge
Expert:  Amedee replied 1 year ago.

YES, we will need to check fuel pressure while cranking.

Customer: replied 1 year ago.
Yeah it just seems like something is stopping them from opening up, would one bad injector cause them all to fail? I am just very confused because the truck started perfectly every time and started strong and then to go out one day and it just won't start shouldn't happen, there had been nothing by done from the last time it ran to the next time I tried to start it
Expert:  Amedee replied 1 year ago.

You would need to check injector pulse using a noid light to see if the injectors are pulsing while the engine is cranking over. You would use a tool called a noid light.

Expert:  Amedee replied 1 year ago.

No, one bad injector will not prevent the rest of them from firing.

Customer: replied 1 year ago.
Alright I will have to have someone help me tomorrow and I'll send you the info as soon as I have it so have a good night and thanks again, maybe you could think on some of my questions like could air in the fuel line cause it not to start? I never did any bleeding off for air in the line and all I did was replace the fuel pump and reconnect everything back up and that was it
Expert:  Amedee replied 1 year ago.

Air in the fuel line will not cause this issue.

Customer: replied 1 year ago.
Yeah I bought a noid test kit but none of the tools fit my injector plugs but it did hook up a multimeter to the plug while I had someone crank the engine and the voltage would fluctuate, I don't remember the exact voltage levels but I can check that too tomorrow?
Customer: replied 1 year ago.
the pressure at the full rail will be different while cranking the engine?
Expert:  Amedee replied 1 year ago.

YES, with the pump off the fuel pressure will be less.

Customer: replied 1 year ago.
I mean logically it doesn't make sense that the fuel pressure would change between the engine cranking/running because the fuel pressure is regulated by the pump which is ran off battery voltage so a running engine shouldn't effect for el pressure, I mean at least logically it doesn't make sense but hey I'm no mechanic and don't know all the ins and outs of how the fuel system works so that's why I'm talking to you
Expert:  Amedee replied 1 year ago.

Just please check fuel pressure while cranking and reply back to me tomorrow.

Customer: replied 1 year ago.
Ok I'll get you the new readings tomorrow as soon as I can, what about the pulse voltages on the fuel injectors, what should they pulse at with the engine turning over? I just remember that the voltage would alternate from high to low when the engine was crankin
Customer: replied 1 year ago.
Ok see you tomorrow
Expert:  Amedee replied 1 year ago.
Customer: replied 1 year ago.
That's nice and all but I don't have a set that fit the Dodge Ram fuel injecto plug, maybe I can run jumpers from the wire harness to one of the noid tools, or if you tell me the make and model I can order the same noid test kit that will work with my dodge truck? I have jumper wires with probes and alligator clips that I could use to clip on on to one of the noid tools in my kit
Expert:  Amedee replied 1 year ago.

You can get a universal noid light..

http://www.amazon.com/Lisle-27800-Universal-Noid-Light/dp/B0002SR57Q

Or you can use the same set I have.. It has all of the application in it. YES, one of them will fit your truck.

Click here

Customer: replied 1 year ago.
Ok fuel pressure while cranking is 45psi, I used a multimeter to check the fuel injector harness and it's pulsing from 0 volts to 2.4 volts repeatedly, I'm guessing that's what a noid light does is tell you with blinking light of the injectors are pulsing on and off right?
Expert:  Amedee replied 1 year ago.

TO be honest, I have never used a voltmeter to check the ground signal trigger to the injectors from the PCM. I dont even think you will get a relaible reading. You need to use a noid light.

Customer: replied 1 year ago.
Let's just go with them as working for now because I got a pulsing 2.4 volts to zero volts on time, I'm sure noid lights are awesome and I bought a set and none fit my Dodge Ram truck and I can't afford to keep buying tools especially ones that do not fit my truck so what's the next step after the fuel pressure and fuel injectors please?
Customer: replied 1 year ago.
Oh I also used a probe that lights up and when I hooked that up too it pulsed I Fr and on repeatedly until I unhooked it, which isn't that exactly what a noid light does, it blinks off and on to let you know there is a pulse signal going to the injector?
Expert:  Amedee replied 1 year ago.

The test light will tell you if there is power to the injectors while cranking. It can also check the ground signal trigger going to the injectors but it is very tricky. You need to hook it up backwards and look very very close for a flashing light. It is very dim. This is best done at night or in a dark garage so you can see it flash. Again, it will be extremly dim and will flicker as the engine is being cranked over.

Ok, lets stay that there is injector pulse and everything is working good. So there is fuel pressure and injector pulse. This means the engine has fuel. That only leaves no spark and or no compression. We would need to check those next.

Expert:  Amedee replied 1 year ago.

But if it runs on starting fluid, this means it has spark and compression. Maybe you have bad injetors or even bad gas??

Customer: replied 1 year ago.
Bad gas? How old would the gas have to be to be bad gas?
Expert:  Amedee replied 1 year ago.

If the engine runs on starting fluid and your sure it has injector pulse, then either the engine is flooded, not getting enough fuel because the injectors are not opening up enough or you could simply have bad gas. I supoose the injectors could be bad.. but what are the chances all injectors went bad at the same time? I have seen gas sitting around for a year still work just fine. This means something could have been mixed with the fuel.. such as water??

Customer: replied 1 year ago.
Hmm I'm willing to take the leap of the bad gas, I mean the gas is old in the tank because the truck doesn't really get driven, but that wouldn't account for it starting a month earlier and then not start 30 days later would it? I even put in octane booster just in case the gas was getting old, I could try to find a way to drain the old fuel and then put in new and try it that way
Expert:  Amedee replied 1 year ago.

Well, if the vehicle sits and it was raining during this time, this could be it. Something could have allowed rain water to get in the tank..

Customer: replied 1 year ago.
I guess it could be bad gas, it's been over a year since this started and the gas was already pretty old at the time it stopped starting, it smells like strong gas but even old gas would smell like gas, but then again even if it were getting to be bad gas the fuel injectors would still open up and spray gas into the combustion chamber, right and that should start it combusting once the engine is running on the starter fluid, but it's still like it's just not getting gas and as you said if there is fuel pressure and the pulse on the injectors they should open and diary so maybe 2.4 volts isn't enough to open them up, but also timing issues would stop it from starting wouldn't it is the cam and crank sensors were bad but I replaced both of them and the throttle position sensor, I wish there was a way to hook up a gas can to the system instead of having to drop the tank and drain the fuel which could turn out to be ok and it still not start so are you positive the link you sent wth the noid test kit will fit my 2002 Dodge Ram 4.7 liter truck?
Expert:  Amedee replied 1 year ago.

Hello and sorry for the delay! YES, the noid light in that kit will fit your truck. If what you are telling me is true, then it has to be bad gas. However, you would not want to drop the tank without knowing for sure.. so be sure to check injector pulse first.

Expert:  Amedee replied 1 year ago.

You could jumper the fuel pump relay to run the fuel pump constantly. Disconnect the fuel line at the fuel rail and drain the fuel into a bucket. Once all of the fuel is out of the tank, you could then add fresh gas and see if tht does the trick. You could then take a close look at the gas that came out of the tank. Just an idea..

Customer: replied 1 year ago.
My test kit came with some extra connectors and hose so maybe I can rig something up with them to drain the fuel? One question, can't I pull a fuel injector and put it in a cup or something and turn the key on and see if it squirts fuel out and wouldn't that tell us if there is at least fuel getting through the injectors and if nothing comes out of the injector we would know at least that information? Oh I orderd the universal noid light tester and it'll be here tomorrow, anyway I'll see what I can do about draining the fuel from the tank, I don't know what else to try for now but I'll try and check out the fuel draining idea, how would I jumper the fuel pump to run constantly? Doesn't it run as long as the key is in the run position or is it only when the engine is running that it pumps fuel?
Expert:  Amedee replied 1 year ago.

Lol.. I think that was more than just one question. :)

You can remove the fuel pump relay and jumper the relay to allow contant power to the fuel pump.

No, it should not run contantly with the key on.

Expert:  Amedee replied 1 year ago.

YES, you could unbolt the fuel rail and lift the injectors up (still attached to the fuel rail) and see if they spray while cranking the engine over.

Customer: replied 1 year ago.
ok I got the universal noid light today and waited too it wasn't too sunny out to make sure I could see the light and it pulsed off and on as long as I let the engine turn over, just for shits and giggles I was thinking I hadn't actually tested the spark by spraying started fluid into the throttle body so just to make sure I still had spark and all that I hit it a couple times with starter fluid and it cranked right up for a half a second or two and died but it did fire right up, so I now think I'm going to try and jumper the fuel pump relay, which I need you to tell me which relay is the fuel pump relay as well as what sockets to jumper to have the fuel pump run, I need to order another fuel pressure tester that has a bleed off hose so I can bleed off the gas into containers, where do I dispose of old bad fuel by the way? Because I don't want to have two or three five gallon gas cans full of old bad gas just sitting in my shed especially with winter gett By ready to set in soon and I definitely need to get this truck running before winter sets in and it starts to snow, anyway I'll order the tester with bleed off valve, or I can just cut the hose in half on the t ages I alr day have and use the T adapter that came with the kit but I'd also need another fitting and longer hoses to bleed the fuel into a gas can so maybe spending another $30.00 for one that has the bleed off valve is a better option?Thanks for your help and I pray you can help me fix this thing before I need to drive it, one other thing I had a thought about, it turns over strong but the battery isn't ever at peak voltage, it's high enough to crank it for a few tries but then it starts dragging so I had thought maybe it needs a full hit of voltage to open shit up? I have a really good top of the line charger slash jump starter unit that will push the starting amps up to higher levels, as for keeping the battery charged on a daily basis I use a battery maintainer that does keep it at decent levels but I'm just thinking it might need a higher voltage to kick the computer or injectors or something in the ass to get it working? I'll try it tomorrow early in the day, I'm not overly optimistic but at this point I'm willing to try about anything to get it to start because we know it's not getting fuel to start which means the injectors aren't spraying the fuel for some reason? What about the IAC? It's one thing I haven't tried to replace yet but I know the first kit I bought to diagnose had the noid and iac testers but don't fit my truck, so could it be the idle air control possibly causing the problems? Sorry for the long message, I just needed to rant and bounce ideas off youThanks
Bill
Expert:  Amedee replied 1 year ago.

Hello Bill! IF the IAC is bad, all you have to do is step on th gas pedal a bit while cranking and the engine will fire up. This will allow air into the engine (if the IAC motor is stuck closed) and it will start with no problem. YES, this is possible.. but I would have thought you would have tried to step on the gas pedal just a bit while cranking?

Expert:  Amedee replied 1 year ago.

If the noid light is flashing while cranking, then yes, the injectors should be opening up while cranking.

Expert:  Amedee replied 1 year ago.

IF the battery is strong enough to crank the engine over, it is strong enough to open the injectors.

Expert:  Amedee replied 1 year ago.

IF there is plenty of fuel pressure while cranking, there is no need to check the fuel pump relay. But you can always use a different fuel pressure gauge just to be sure you are getting a correct reading.

Expert:  Amedee replied 1 year ago.

Any shop in your area should be able to dispose of the old gas for you.

Expert:  Amedee replied 1 year ago.

I know we have been working on this a while now and I have not yet been compensated for helping you. I would appreicate a positive rating for my time and knowledge I have shared with you thus far. We can still continue our conversation even after you rate my answer. No extra charge.

Expert:  Amedee replied 1 year ago.

I will be looking forward to your reply.

Customer: replied 1 year ago.
Nonono I meant I need a fuel pressure gauge that hasa bleed off valve on it so when I do jump the relays pins to make the fuel pump keep running it will siphon the fuel out of the tank and into gas can via the bleed off valve and hose built into the pressure gauge, and yeah I've tried pumping the gas pedal and holding it to the floor while cranking, yeah I figured if the battery could crank the engine it would be good enough, I was just grasping at straws and crap
Expert:  Amedee replied 1 year ago.

If you can get your hands on a fuel pressure gauge that has a vlave that you can open and leave open to allow fuel to flow freely out through a tube so you can take a fuel sample or just simple drain the fuel tank, then yes, go that route. If not, just unscrew the fuel pressure line from the rail and run a hose to a container.

Customer: replied 1 year ago.
Oh ok but I thought the whole deal with this website is I pay the mechanic that helps me when my problem is solved, you guys give me the. Info and I do the work, and when my problem is fixed I pay the fee? Not that I don't want to pay you, because I do, but I want to get my problem fixed too and once I pay you have no obligation to keep helping me because to give the feedback before the problem is solved doesn't make sense unless your not able to help me any further? It does seem like we've been working on this a while but it's only been a week or less and only a couple minutes every other day or two while I wait for a new tester to come in and then perform the test with negative results and then order another tool and wait for it to arrive and then spend two minutes to use the tool and your pretty much telling me that your out of ideal because I'm now getting ready to drain my fuel tank and put in new fuel, I mean yeah the fuel injectors are passing the flashing light test, I did only test one fuel injector, may win supposed to test all of them? I don't know, I have read the posts from other mechanics and telling their customers that they are under no obligation to pay them if they haven't fixed the problem? Or am I at the wrong website and I am obligated to pay whether you help me or not? But I don't think I should give a positive rating as if my problem has been solved when it hasn't been, I'm a disabled veteran and I I have very limited financial resources and I came here expecting to get a mechanic that would help me fix this problem and I'm still in the exact same position I was in before, I had swapped all the parts which cost me a lot of money and tested the reassure and the fuel injector and everything else and don't know what to try next, I'll sleep on it and if you want to get paid fine I'll pay and try a different mechanic here and hope they can solve this problem
Expert:  Amedee replied 1 year ago.

Good morning! Thank you for that long reply with a lot of detail. YES, I understand the problem is not fixed yet. However, just because you dont have the right tools to accomplish this diagnoses does not mean I have A) not spent a lot of time with you and B) that my answer is not correct. Does that make sense?

Expert:  Amedee replied 1 year ago.

YES, I will continue to work with you for as long as you need. All I ask is that you provide a positive rating once we are done here and that you do all of the tests correctly that I need in order to diagnose this problem.

Expert:  Amedee replied 1 year ago.

Hello! It's Amedee from just answer. I am just checking in to see how things are going and to see if you need any further assistance? I see you have read/veiwed my last post but you have not replied back. Is there anything else I can assist you with? Is there anything I can clear up for you? Please let me know so I can help. Thank you!

Related Dodge Questions