When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Troubleshooting & Technical Questions & ModificationsHave technical or modification questions about the Crossfire?
Find out the answer, or give advice in here!
2005 Limited with 245,000 miles. Ive had it about a year now. The car had unknown history and was purchased by myself from a 21 year old kid. So I've dome lots of maintenance so I knew things were new. All parts were bosch if possible. NEW: Fuel pump, filter, and injectors. Intake gaskets, MAF, TB and MAF seals, EGR valve, v8 throttle body and MAF housing, cam and crank sensors, catalytic converters, and all 4 O2 sensors, valve cover gaskets and pcv hoses, RCM.
I've been getting O2 low voltage codes, rich on one bank and lean on the other bank codes. It will run fine for like 6 days and on the 7th it will run rough and the tach will jump up and down with an occasional stall. I can not figure this thing out. The only thing I can say us that when this does occur to me, 99% of the time it is right after work on the drive home. Can anyone help?
With all that missing, I'd not trust the too rich codes and not sure I'd trust the too lean codes. And why is the engine idling at 1800 rpm? Or are you holding the throttle open?
The tach video really does not tell us much unless we know if you are holding the speed up like that, or is the ECU doing that to keep the engine running?
I have two questions:
Did you really do all that work and not change plugs and plug wires?
Have there been any indications of electrical gremlins? (Wing going up when it should not, slow cranking on starter engagement, odd indicator lights on the instrument panel, weird behaviour of the AM/FM head, etc.)
I must have forgot to list those... I replaced plugs, wires, and coils as well... my bad.
That was not at idle, the vid was taken in low speed traffic on my way home from work. My idle is just over 500 rpm.
The only electrical gremlin that I have noticed is that when I hit the lock button on the key fob and the lights flash once, the drivers side amber does not flash. But it operates with the parking lights on and when the turn signal is on.
The consensus on the XF group on FB is that the V8 throttle body and adding the stock MAF sensor to the V8 housing work fine without any tuning needing to be done... although my logic says that the MAF being in a larger housing would require a tune, but I'm not well versed in Mercedes like I am with Ford.
The consensus on the XF group on FB is that the V8 throttle body and adding the stock MAF sensor to the V8 housing work fine without any tuning needing to be done... although my logic says that the MAF being in a larger housing would require a tune, but I'm not well versed in Mercedes like I am with Ford.
When troubleshooting ANY complex system, it is always a good idea to configure the system from a known reference point. In this case, that would mean OEM parts and modules. If something ELSE is out of spec and you added an admittedly out of spec module, you may be taking a parameter so far out of spec that the ECU cannot compensate. This is NOT to say the larger TB is the problem, but that it is masking the problem.
I've been troubleshooting complex electronic communications systems since 1983, I've never used concensus to troubleshoot anything, and certainly not in the case where NONE OF US is there to look at what is going on - only YOU are standing there.
Do you want to fix this or not? If so, restore the car to factory and see what you have. Capturing live data with something like a CP123 or Bosch 1100 may also help lead you to the answer. That's all I have.
I know I have those parts among my mess here somewhere. I'll get those swapped back and clear the codes when I can. My scan tool saves the freeze frame data if that might help, i can screenshot it and post it. It will stream live data, but not save it.
If the TB and MAF were new you may be okay but if used, you never know. I test drive after each change to see how it does. Surging is usually a mixture issue or leak.
The TB is used, the MAF sensor is new, it was just swapped into a V8 MAF housing. My biggest puzzler is trying to come up with a reason that it only seems to occur approximately once a week, but not coinciding with the day i fill up the gas or anything like that. Other than it seems 99% of the time it is after work on my way home.
The TB is used, the MAF sensor is new, it was just swapped into a V8 MAF housing. My biggest puzzler is trying to come up with a reason that it only seems to occur approximately once a week, but not coinciding with the day i fill up the gas or anything like that. Other than it seems 99% of the time it is after work on my way home.
Your statement "the MAF sensor is new, it was just swapped into a V8 MAF housing." If I remember, the SRT-6 MAF housing into an SRT-6 TB feeding your NA intake manifold (for a HP gain with the SRT-6 TB) uses the N/A MAF sensor in that SRT-6 MAF housing. Is your MAF housing from an SRT-6 setup (if it is used for a V-8 MB, and is it the same as the SRT-6 MAF housing?). Second, is the MAF SENSOR you are using the one for the 3.2L limited motor, that IS installed into that SRT-6 MAF housing? Finally, the TB from the SRT-6 crossfire is (as far as I know) the ONLY TB swap for the crossfire N/A motor (used in the extra HP mod many have used), that you have installed in your limited? Please CLARIFY what you have and what you have installed. It does matter what is on/in your crossfire limited intake path...Thanks!
.
Last edited by GraphiteGhost; Oct 17, 2023 at 05:19 PM.
I have a Bosch 3.2 N/A MAF sensor inside the V8 MAF housing and a V8 N/A Throttle body. Now that I'm rechecking sources (needswings & the files on the fb group) I don't see anything mentioning the V8 Throttlebody. But the parts interchange for the TB according to rockauto says they are the same.
Good luck I've been getting the same codes. Mine is stock I've replaced everything. Mass air flow spark plugs and wires,Throttle body, o2sensors. Still haven't figured it out..
Good luck I've been getting the same codes. Mine is stock I've replaced everything. Mass air flow spark plugs and wires,Throttle body, o2sensors. Still haven't figured it out..
Have you had any issues aside from the codes? Like actual symptoms?
From the gasket between the top engine cover & TB, to just about every vacuum hose on the engine (and maybe a couple more like the fuel system vapor recovery system), these motors do not like vacuum leaks. Intermittent running like this is a bane of a few owners that seems to take quite a while to troubleshoot/fix. Vacuum leaks can be found within the engine area if ether (or) carb cleaner is targeted sprayed (but not overdone, slow but sure) in short bursts until idle is interrupted/stumbled (in most cases). One definite place to check is the "O" ring between the TB and intake, that ring slips out the 'groove' (I used petroleum jelly to hold mine in place) while attaching the SRT-6 TB, causing many members a stumbling/rough idle issue. Good luck solving this!
Help diagnose intermittent rough running
Your statement "the MAF sensor is new, it was just swapped into a V8 MAF housing." If I remember, the SRT-6 MAF housing into an SRT-6 TB feeding your NA intake manifold (for a HP gain with the SRT-6 TB) uses the N/A MAF sensor in that SRT-6 MAF housing. Is your MAF housing from an SRT-6 setup (if it is used for a V-8 MB, and is it the same as the SRT-6 MAF housing?). Second, is the MAF SENSOR you are using the one for the 3.2L limited motor, that IS installed into that SRT-6 MAF housing? Finally, the TB from the SRT-6 crossfire is (as far as I know) the ONLY TB swap for the crossfire N/A motor (used in the extra HP mod many have used), that you have installed in your limited? Please CLARIFY what you have and what you have installed. It does matter what is on/in your crossfire limited intake path...Thanks! 
