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03 c320 crank no start

3K views 19 replies 3 participants last post by  rudeney 
#1 ·
Hello all! New to the forum and new to MB. I'm having some problems and I am seeking some help. Little background so far:

Did an engine swap about a week ago (thew a rod). It would do a single click and shut down. Changed the starter and it cranks but doesn't start.
Checked battery (good)
Changed CPS (thanks to these forums). Still nothing.
Checked voltage at CPS and ECU. Readings are 2.0A at CPS and 1.7-2.0A at ECU.
Fuel pump works and has good fuel pressure at rail
Coils are getting power from ignition but not ground signal.
Fuel injectors are the same as coils.

Could the CPS still be the problem? We have tried 2 different CPS (one from old engine and the one that came with this engine) and there is no difference. Could it be an ECU problem?

I'm at my wits end with this car and I have searched google until my eyes bled and nothing seems to be working. Many thanks in advance to any and all advice!
 
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#4 ·
It's either going to be a fuel delivery problem, an ignition problem, or the ECU. Does the engine suction fan run at high speed when the ignition switch is in position 2? If so, this can signify an ECU problem. Do you have SDS? Pulled codes?
 
#5 ·
can it still be a fuel delivery problem even if I have pressure in the fuel rail? and no, the fan isn't even coming on at this point. pulled a few codes a few different times. the last set we got was p0335 (even after replacing the CPS), and p0117 are the only two the keep popping up. the only thing we haven't checked is an ignition problem only because I've read that if it's an ignition problem, my key wouldn't even crank it.
 
#7 ·
ok so we finally got a scanner to check the RPMs of the engine and the number is all over the place and it takes quite a while to actually get that number. it has stayed over 200 but it goes from 200 to 296 to 250. so, I'm not sure what that means. everything checked out ok. I don't have a fuel pressure gauge but I pushed the valve on the rail and it squirts everywhere so the fuel pump is working. My next question is, what is the "a circuit". since I'm getting the p0335 code, does that point more to a wiring issue rather than the actual CPS?
 
#12 ·
so it's been a couple of days but......got a fuel pressure tester and its at 55 PSI, put a brand new fuel filter on, fixed the ac compressor (wasn't keeping it from starting but at least I can put my belt back on), and replaced the wiring for the CPS. it has actually been turning over so we have spark and fuel but now it won't stay running. it's sputtering and killing after about 30 secs. the most it has stayed running was about 2 mins. So, i'm at a lose again :-/
 
#14 ·
the only code is p0335. and the plugs and coils are good. all plugs are getting fire like they are supposed to. the engine was tested in the car before it was shipped to us and the coils, plugs, and wires were already on it when we got it so I would assume everything is good there.
 
#15 ·
IF you clear the P0335 codes, does it come back? If so, then it's a CPS issue. When you installed the engine, how did the process of mating it to the transmission go? If you "pull it in" with the bolts for the torque converter, you can damage the flywheel, which has the timing marks for the CPS. Is it possible that happened?
 
#16 ·
Yes the code comes back after we clear it. And the engine and transmission mounted together pretty easily. Actually easier than a lot we have done. So I don't think anything got messed up in the process. I have ordered a brand new BOSCH CPS so we shall see if the one that was on the engine when we got it was actually faulty. I know it was an OEM one so I wouldn't be surprised. If that's not the problem though, am I looking at an ECU issue??
 
#17 ·
Check the wiring harness for the CPS, too - they can break when working with them. I guess it could be an ECU problem, but I'd think you;d have more codes and other symptoms. When the ECU dies, it's normally a total failure and nothing works. This will cause the engine suction fan to run at high when you switch on the ignition because it gets no signal, so it goes into "default" mode, which is high-speed.
 
#18 ·
Well it's definitely a little bit of a relief to know that the ECU is an all or nothing kind of thing. And we did replace the wiring for the CPS, including the connector. We do have a new CPS on the way so hopefully that is the problem. If not, I'll be back with more questions. Lol. Thank you so much for all the advice so far! I greatly appreciate it!!
 
#19 ·
Well good news, SHE'S ALIVE!!!! I'm not 100% sure what it was but it's running. All I know is that we changed out the CPS for yet another one and put the old wiring harness back on. Apparently the pins on the wires that plug into the computer were not snug anymore so all we did was close them a little tighter and viola! Started up quick and purrs like a kitten. So glad it was something simple because I'm pretty sure the next step would have involved a match and some gasoline �� Thank you so much for all the help!!
 
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