6.1 Swap Won't Rev Past 3K HELLLLPPPPP!!!

-
BadAss71

BadAss71

Let's Go Brandon
Joined
Jun 13, 2010
Messages
1,584
Reaction score
122
Location
Pueblo West
Some may know the build but here are the particulars. 06 6.1 Hemi backed by a 727. Aftermarket harness built by who knows. Using the 04 APPS so we could attach a kick down cable for the 727. Street and performance ECM. The car runs great until you get to 3k rpms then hits a rev limiter? In park, neutral, or in gear its the same. I have run the calibration between the APPS and the throttle body with success, using the latest Snap On scanner. For the life of me I cannot figure out what the problem is. I am trying to get some contact info for the guy that built the harness, but haven't had any luck. Has anyone experienced this problem? Any ideas? Any help is much appreciated!
 
Here is a picture of the car. Not that it will help lol!
 

Attachments

  • 001.jpg
    109.3 KB · Views: 991
  • 002.jpg
    84.8 KB · Views: 1,168
  • 005.jpg
    126.5 KB · Views: 984
  • 003.jpg
    96.5 KB · Views: 993
Can you read any codes off the PCM? (assuming it's a factory computer) sounds like it's going into a limp mode. Have you attempted to reset the PCM? (ease any codes first if possible) remove the ground from the battery and turn the key on (to power up the PCM) then wait about 1-2 min turn key off and reconnect battery and see if it helped. If not read codes again and report back. If you want a fresh set of eyes on it let me know and I could meet you some weekend, and look at it with you.
 
johnparts said:
Sounds like the pcm doesn't know its in gear so it is in park rev limit
Click to expand...

X2 was the ecu out of an automatic equipped vehicle. You'll need to get one from a stick or find a way through the schematics, possibly a single throw switch controlling a latching relay to convince your ecu that you're in gear each time you start. Might be easier to find the correct ecu.
 
The only codes present are for battery temp, evap selonoid, and down stream 02s. I also thought about the trans issue but the ecm is for a 05 ram hemi 5 speed so there is only three ports on the ecm.
 
The harness is setup for down stream oxygen sensors. These are not being used and the connectors are just tucked away. Could this cause the ecm to go into limp mode?? It also has a 5 second crank time before it will fire.
 
I believe that the ECM is indeed looking for the downstream O2 sensor input, but it would throw a code if that were the case. Can you connect the upstream convertor O2 sensor to both up and downstream inputs? I would think its looking for a delta between the up and downstream and if its not seeing anything its in limp mode. You running cats? Sounds like you are in for a flash of your ECM or some sort of bypass. If you could regulate the 12V heater voltage off the 3-4 pins down to .45V (big *** resistor or a seperate regulated .45V power supply) and run that voltage back on the 1 or 2 pin (whichever is not ground) then you could fool the ECM that you are at stoich, but fooling the ECM on O2 levels messes with the duty cycle of the entire fuel injection so you are going to need some sort of plan, ie cats and the right sensor hookups. At WOT, these are not supposed to be even refferenced, but if your in limp, then itll never get to WOT.
 
It does have codes for the downstream oxygen sensors. So do you think being that these connectors are not hooked up that it is putting it into limp mode?
 
yeah, there are 4 listed, 2 up and 2 down, they are about $24 a pop at rockauto. the entire EFI is based on the inputs of these O2's especially the upstream as they tell the ECU the duty cycle of the injectors to get the proper A/F ratio. downstreams are mainly used to determine the condition of the cats. without O2 sensors the ECU is always in cold loop mode and perhaps that 3K rev limited.
 
The upstream sensors are there. I know the downstream sensors are for monitoring the cats efficency, I just dont know that without them the ecm would go in to limp mode.
 
BadAss71 said:
The only codes present are for battery temp, evap selonoid, and down stream 02s. I also thought about the trans issue but the ecm is for a 05 ram hemi 5 speed so there is only three ports on the ecm.
Click to expand...


Where the heck did you find one of those? I could have sworn they quit offering 5 speeds behind the gassers after the 360 went away are you sure you dont have a ECM for a 5 speed AUTOMATIC ram?
 
64drtGt said:
Where the heck did you find one of those? I could have sworn they quit offering 5 speeds behind the gassers after the 360 went away are you sure you dont have a ECM for a 5 speed AUTOMATIC ram?
Click to expand...
03,04 had manual trans options but i dont believe 05 did and if they did you still need to set up a clutch signal to the pcm
 
johnparts said:
03,04 had manual trans options but i dont believe 05 did and if they did you still need to set up a clutch signal to the pcm
Click to expand...

John ur correct but you can disable the 05 ecu to think it's a manual and not plug anything into it. That's what I'm doing with my build,, AJ or Chris at hotwire can do this.
 
Yeah the downstream O2's are only for cat efficiency, and should not cause a limp mode. I have worked on a bunch of rams that they were unplugged and it still ran just fine.

The manual trans has always been offered in a 2500. It's just a rare option. And the pcm's are hard to find. I have a feeling yours is an auto PCM though, I say that because of the egr code. I'm not 100% but I don't think the 2500 had egr. For any year. I could be mistaken though. I would hook up to it and pull the vin and cross it with carfax. You can see basic info without paying and see if it's a 2500 or 1500. If it's a 1500 I guarantee it had an auto trans. They never offered a manual with the Hemi in a 1500.
 
Even if it's an auto u can have people in the know disable the last plug to act as if it's a manual. That's what I'm doing along withal ing it think it's a 6.1 PCM
 
The thing is this pcm only has three plugs. The fourth one is blank. The last two we got from ben at plum floored all had four connectors. The pcm in the car came from street and performance and was claimed to be a plug and play pcm. Well it plugged right in and the car runs perfect, besides the fact that it wont rev over 3 grandish. It doesnt have an egr code, just the evap code. I really have a feeling that the wiring harness is the culprit, but trying to get in contact with the guy that built it is impossible at this point. The douche bag that sold it to us wont return any emails or phone calls. At first I thought it had something to do with the TRS signal wire, but after grounding it straight from the pcm the same problem still exists.
 
funwithfuel said:
Extended crank time says maybe faulty cam sensor. Worth a perk.
Click to expand...
I am going with that also. Same thing happened with my Sebring last year. Would not rev above a couple grand and no light or codes set. Replaced the cam sensor and all was good.
 
Well I had dad pick up a cam sesnor at dodge today. Its installed and no change. We are still at a loss here.
 
Same throttle cable problem others have with engine swaps ? Just a wild guess. Good luck
 
Couple of thoughts:

I'd suggest you find someone with the FACTORY scan tool, the factory scan tool will give a lot more information than any aftermarket scan tool.

Perhaps the computer is looking for a speed sensor and thus is enabling traction control / or retard to control phantom wheel spin?

For example, I think with the factory scan tool you can turn on and off the manual transmission / automatic transmission.

Have you contacted Street and Performance?

Regards,

Joe Dokes
 
Great looking car.
Just a couple ideas not mentioned that might not throw a code.
Not sure what setup you are using, but have you checked fuel pressure?
Any chance you have some plugged injectiors?
 
You must log in or register to reply here.
-

Back
Top