Replaced timing chain now crank backfire with no start

[Cortra]

I have a 2009 dodge ram 1500 with 4.7 liter and it was stolen a call couple months ago and when I got it back it barely ran when it did it was super super rough and wouldn't idle or stay running without pumping gas pedal I replaced throttle body, map sensor,camshaft position sensor and timing chain all was checked and double checked for proper marks and TDC and was good . Nw I try to start and it cranks will almost fire then backfire and no start . Please help truck is my bread and butter haven't been able to work in 2 months and I'm at a stand still and I know my way around an engine for 35 years . Help anyone please as and thank you

 

[Fast69Mopar]

I have a 2009 dodge ram 1500 with 4.7 liter and it was stolen a call couple months ago and when I got it back it barely ran when it did it was super super rough and wouldn't idle or stay running without pumping gas pedal I replaced throttle body, map sensor,camshaft position sensor and timing chain all was checked and double checked for proper marks and TDC and was good . Nw I try to start and it cranks will almost fire then backfire and no start . Please help truck is my bread and butter haven't been able to work in 2 months and I'm at a stand still and I know my way around an engine for 35 years . Help anyone please as and thank you

Are you sure you have verified and reverified the timing is correct? The cam gears "V8" marks are required to be in the 12 o'clock position. The center idler gear timing mark is required to be 12 o'clock position. The crank gear timing mark is required to be in the 6 o'clock position. Here is a trick that I have used for 4.7's over the years when a customer has a complaint like yours. Unplug the camshaft position sensor in the right cylinder head and see if the engine will start and idle. If the engine starts I would go back and check your timing marks again.

If you have the mechanical timing sorted out then the next step is to get a scan tool connected to the truck. If the motors mechanical's are in proper working order then we need to see the electrical/fuel side of things. When it comes to a no-start condition there is not much you can do as a mechanic without a good scan tool.

 

[Cortra]

So agree with you on that. And yes the V8 marks were at 12oclock and crank gear was at 6 o clock . Is it possible that if on exhaust stroke it would cause a problem and when I remove #1spark plug to check for pressure and spark it cranks and I get no spark until just before it shoots excessive pressure out cylinder with flames of all things with no spark on there and when I got it to start it ran like it had one cylinder and had to constantly pump the gas to get it to fire or run for any amount of time .

 

[Cortra]

I can't get it to start with camshaft position sensor unplugged either so it looks like I might be pulling it apart to check timing marks again correct? Not looking forward to that it was a pain in *** the first time . These sensors and other extras is why I prefer an old school prior fuel injection engine any day lol.

 

[Fast69Mopar]

I can't get it to start with camshaft position sensor unplugged either so it looks like I might be pulling it apart to check timing marks again correct? Not looking forward to that it was a pain in *** the first time . These sensors and other extras is why I prefer an old school prior fuel injection engine any day lol.

If you had the motor set to TDC on the exhaust stroke it wouldn't start at all or it would spot and sputter like what you are experiencing.

If you installed the timing chains with the motor on the exhaust stroke you would have had to of had the crank mark in the 12 o'clock position instead of the 6 o'clock position.

The way to set up a 4.7 is simple. I would start fresh. Rotate the motor over until the cam marks are at the 12 o'clock position and see where the crank mark is located. Next I would remove the chains, reset the oil pressure tensioners and verify the crank mark is in the 6 o'clock position. Line up the chains on the center idler and reinstall. If you are using a quality timing chain kit the chains will have plated links to aid in lining up with the marks on every gear.

Do you have the special tool to hold the cam chains to the center idler? If not I would rent one if you haven't already. It makes things so much easier.

Once you have verified that the mechanical timing is correct and if it is still a no-start you are going to need a scan tool.

 

[Cortra]

I know that when I took it apart the crank timing mark was ii n the 6 o'clock position but the cam marks were not in the twelve o'clock position one was in the 10 o'clock and other was about 2-3 o'clock position and idler gear was out of whack as well but the one that I wanted to for sure be correct to start was the crank .but I will take the time and start over cause it will not start and I thought when I got it together and it didn't start it might have been the exhaust stroke but with the crank shaft set key to hold harmonic balancer is in about the 2 o'clock position the gear goes on to be in the 6 o'clock position. This truck has been difficult since I got it back after it was stolen they really drove it hard and it took tow truck 5 and a half hours to get it out of the field it was in . Thanks very much for your help will keep you upto date on progress and I hope I can ask if have any more questions if I become stumped again

 

[Fast69Mopar]

I know that when I took it apart the crank timing mark was ii n the 6 o'clock position but the cam marks were not in the twelve o'clock position one was in the 10 o'clock and other was about 2-3 o'clock position and idler gear was out of whack as well but the one that I wanted to for sure be correct to start was the crank .but I will take the time and start over cause it will not start and I thought when I got it together and it didn't start it might have been the exhaust stroke but with the crank shaft set key to hold harmonic balancer is in about the 2 o'clock position the gear goes on to be in the 6 o'clock position. This truck has been difficult since I got it back after it was stolen they really drove it hard and it took tow truck 5 and a half hours to get it out of the field it was in . Thanks very much for your help will keep you upto date on progress and I hope I can ask if have any more questions if I become stumped again

It appears that you have found the issue. If your crank timing mark is in the 6 o'clock position and the cams are not in the 12 o'clock position then your timing is incorrect.

Make sure you are resetting the oil pressure tensioners and collapsing the lock and piston before installation.

 

[Cortra]

I for sure will but gonna make sure the piston in #1 cylinder is for sure at tdc

 

[Cortra]

Does anyone know if I need to readjust the timing chain can I discussed nnect the cam chains and if crank timing mark ms at 6 o'clock can I just adjust cams to be in proper position or do I have to turn it all at same time ?

 

[Cortra]

Should the plated links on timing chain line up on timing marks everytime you hit TDC on intake stroke or will they be off from where you set them up when first installed?

 

[Cortra]

All my timing marks line up properly and yet it still will backfire and not start .I have spark but doesn't seem to be sparking when it is supposed to can a person reset the whole system from scratch meaning the ECM/PCM so it can reset and learn from start ? If it is possible .

 

[OCDTech]

Crank sensor ok, did you move it, take it off. Check the wiring to it and connector.Believe thats what determines spark timing.

One symptom of a bad one or disconnected, is backfiring.

 

[Cortra]

Yes I have put a new one in and checked wiring to it .would the crank sensor cause this kind of problem?

 

[OCDTech]

Could yes, its down under the engine by the transmission bell housing. I seen where you said you replaced the cam sensor not the crank sensor.

 

[OCDTech]

http://www.dodurango.net/crankshaft_position_sensor_4_7l_engine-888.html

 

[Cortra]

Yes I replaced the cam sensor is the crank sensor expensive?

 

[OCDTech]

https://www.rockauto.com/en/catalog...2692,ignition,crankshaft+position+sensor,7196

Not saying thats it but i would probably try that if your positive on the timing all lined up. I believe you said you were. Starving for fuel may cause this too, assuming that is good too. Fuel pressure.

 

[Cortra]

I just found out there is another set of plugs in this engine so gonna check those cause they have never been replaced since 2009 lol.

 

[OCDTech]

I just found out there is another set of plugs in this engine so gonna check those cause they have never been replaced since 2009 lol.

Sounds good. Defienately check that first.

 

[Cortra]

Well I fixed the timing mark issue but runs very rough and will not idle .can a crank position sensor cause it to not start .or a catalytic that is plugged up ?