08 surge @ WOT/ help needed please...

[M_viper]

Hi guys..

I've been having this problem on my 08..

theres a surge in every gear 1-2-3-4..it starts from any rpm but you could only feel it and hear it from the exhaust at WOT..

I got balenger headers installed
Mopar PCM
K&N filter..


I recently had a knocking noise after 4500 rpm in third and in forth but it went away after mixing c16 VP racing fuel with our pump gas..but i think the knocking noise came because the car was just parked for almost 2 months..

but after a couple of days this surge came..its like theres something holding the car back at WOT

I never had this issue before..not on my previous 08..


so I tried cleaning the map air sensors..but nothing happened...

the O2 sensors where locked in tight..so I'll try and see if those need cleaning too..any other suggestions to what could be causing the problem..

I checked the wiring for the o2 senors and they look good..the problem is that the surge keeps getting worst every time I go out..but mostly on WOT..you hear a little surge at idle but I was guessing that was normal..

The sound Im talking about guys comes from the exhaust..I cant see it on the RPM..I could feel it and hear it just in the exhaust..

Thanks guys..

 

[EZ 2B Green]

I think it would be a good idea to monitor your fuel pressure to see if it's low/dropping.

 

[M_viper]

I think it would be a good idea to monitor your fuel pressure to see if it's low/dropping.

do you mind please telling me how to do that..?

 

[EZ 2B Green]

Since this involves special tools/guages and fuel at potentially high pressure you should bring the car to a professional. Sorry if that's not the answer you wanted to hear.

 

[M_viper]

Since this involves special tools/guages and fuel at potentially high pressure you should bring the car to a professional. Sorry if that's not the answer you wanted to hear.

but what would a fuel pressure show me..??

or what would it tell me..?

I know what you mean now..I could hook up a oressure fuel guage but I highely doubt it would show me anything..

do you think I should reset my mopar pcm..?

 

[EZ 2B Green]

It would indicate a problem with the fuel pump or clogged fuel pickup.

 

[Sonoman]

Surging is often an indicator of a lean condition, which could be brought on by a lack of fuel. However, given your recent mods, I would look at the intake side first and see if there are any air leaks due to loose hose clamps or loose vacuum hoses. Any intake air leaks beyond where the mass air sensor takes its readings is going to cause a lean condition. Yes, you would generally feel this at idle (roughness), but I have seen where the hose only separates and creates a leak when the engine is torqueing over to one side on its rubber mounts (due to heavy load at full throttle). Pull on all the hoses connected to the intake manifold and check clamps carefully. Knocking is never a good sign so don't overdo it on test runs while trying to go after this one, best to get a Viper tech involved if nothing obvious is wrong and the car continues knocking or running excessively lean. Good luck and let us know if you find a fix...

 

[M_viper]

Surging is often an indicator of a lean condition, which could be brought on by a lack of fuel. However, given your recent mods, I would look at the intake side first and see if there are any air leaks due to loose hose clamps or loose vacuum hoses. Any intake air leaks beyond where the mass air sensor takes its readings is going to cause a lean condition. Yes, you would generally feel this at idle (roughness), but I have seen where the hose only separates and creates a leak when the engine is torqueing over to one side on its rubber mounts (due to heavy load at full throttle). Pull on all the hoses connected to the intake manifold and check clamps carefully. Knocking is never a good sign so don't overdo it on test runs while trying to go after this one, best to get a Viper tech involved if nothing obvious is wrong and the car continues knocking or running excessively lean. Good luck and let us know if you find a fix...

Thanks Sonoman for jumping in...I'll check on the hoses and see if anything is loose..

 

[Timnineside]

Yeah I would also double/triple check anything that has been changed or modified recently. More often then not in my day to day job this is the problem. You may have a cat issue, or exhaust blockage. I don't really know what it could be off hand, but if there was a knocking noise/and this problem that both weren't there prior my guess is somewhere in there.

Good luck!

-Tim

 

[M_viper]

Thanks guys..I'm guessing this would be some sort of missfire..but the problem with the Mopar PCM I probably would get a cell..

well the car was running perfectly until I had it parked for a while..and then this problem occured...

does anyone know what kind of spark plug other then champions are used..? and what heat range?

 

[M_viper]

update

Took the car to the dealer to find out if there are any codes..and there where a bunch..

after clearing all of them out..went again for a test run..and came back in to diagnost the car..and there was a code that was stuck..

" Loss of comm w/ Venom "

and that kept on going after every time I did a test run..and came back in..after earasing it..it kept on appearing...

we tried reseting the ECU but it would still appeared after a test run..

I'm guessing that the Mopar PCM isnt reading..so Im thinking that the whole surge thing came because it wouldn't read..

anyone know what could be the solution..?

 

[mjorgensen Woodhouse]

Unplug and re plug the connectors on the PCM, it could also be a bad PCM altogether or you got a voltage spike when you installed it with the battery connected, that would take it out if so.

 

[M_viper]

Unplug and re plug the connectors on the PCM, it could also be a bad PCM altogether or you got a voltage spike when you installed it with the battery connected, that would take it out if so.

update

Did what you said Mark, the code went away...took the car for a test run and the code is no more..

but the surge is still there...

I'm having them checking the O2 sensors and the connections...

The plugs seem to be good..but I'll have them change that..

Is the PCM relearning at the moment..I only took the car for a test run and that was it..the surge or missfire as the tech says is still there..

but no codes where available..

 

[mjorgensen Woodhouse]

It will learn short term trims again, but I'm willing to bet this has something to do with the mixed gas you used. Let us know what the dealer finds with the 02 sensors AND the cats.

Can't remember did you tell me that you had tried the stock PCM also to rule out the Mopar one? That would definitely be high on my list to check out. There have been a couple PCM's that have been damaged during installs or with voltage spikes.

 

[M_viper]

It will learn short term trims again, but I'm willing to bet this has something to do with the mixed gas you used. Let us know what the dealer finds with the 02 sensors AND the cats.

Can't remember did you tell me that you had tried the stock PCM also to rule out the Mopar one? That would definitely be high on my list to check out. There have been a couple PCM's that have been damaged during installs or with voltage spikes.

yes the surge is on both PCMs

Stock and Mopar

The PCM seemed to connect and no codes came after that..