Stock srt6 46k miles
Problem:
Car turns over and will not start.

History:
Car has been sitting for 6 months. Battery was dead 2 days ago. Battery was new June of 2022. Fully charged battery with positive terminal disconnected on 2A charger. Today it says full charge. Removed charger, connected battery cable, saw a spark and alarm went off. Key fob would not turn off alarm. Climbed inside and tried to start it. Key would not turn at first. After waiting about 30 minutes with key in ignition, I removed the key and the lock and unlock started working. So I did that a couple of times. Noticed the tow red led blinking on the dash.. hit that button. Then I tried to start it again and this time ignition lock, unlocked allowing me to turn the key. The key turned all the way to engage the starter but no start. The starter cranked quickly letting me know that the battery indeed has plenty of power. Fuel is 6 months old. Car ran last 6 months ago when parked just fine. No water in central vacuum area as I replaced that unit and keys 5 years ago and added a drain hole at that time. I have tried removing fuses 26 and 27, just trying things that said computer on the fuse card paper. I think the car is in a anti-theft scenario? It has been a great car and starts strong usually every time. 4 years ago I was getting limp mode due to a throttle pedal position sensor.. that was easy to reprogram and has worked well since. I have tried applying the brake pedal while cranking. Does the drivers door need to be closed? E brake is set. It will allow me to put the car into neutral when key has been turned but I did not try to crank it from there yet. I do not own a code reader, This scenario has happened to me in the past but it's been so long ago I can't remember what to do, but once I did it, it started up immediately last time. I don't think I'm hearing the 1 second fuel pump sound with key off/on either at the moment.

any ideas?

Greatly Appreciated

 

First, always disconnect and connect the negative, not the positive. The symptoms sound like a bad relay on the RCM. The RCM is plug and play and takes about 5-10 minutes to change.

 

Thank you.

I will research what that is and where it goes.

 

There are videos on U-tube. It is in the box in front of the battery with other modules.

 

Ok,

I will watch the videos.

Do you happen to have a part number handy? Bosch also correct?

Thank you very much.

 

Update,

I have found out where it goes, what it does and the part number.

So when searching for a part, are there good ones and bad ones? Obviously I'm trying to find new one only and what I mean by bad one is.... bad brands or knock off OEM with Mercedes logos? I didn't see a Bosch replacement unless the OEM Mercedes is Bosch.

Thx

 

I pulled the RCM as suggested.
what I found was pitted points on the blower relay. But the fuel pump relay looked brand new. After dressing the points I cleaned the area down in there as best as I could then flipped the board over to check the common 3 pin problem. Those 3 soldier joints look very good. No discoloration, no loose pins on the 3 or any of the soldier connections. That board looked brand new all except for the blower points. All other relays are free to move also and not stuck.

Before:




After:


another before:

and lastly another after:



result: crank over n over and no starting.. not even a pop.

maybe next suggestion I can try myself?

thank you!!

 

Update: I do have a lot of experience with soldiering, board level repairs and robotics / ham radio repair. It still could be the RCM but nothing looked bad in the way of fuel pump relay or connections that I could see.

 

I is the rcm,, I too have lot of experience with soldiering, but I send mine to TJ for repair as he does it every day,,, you and I do it when needed
that is the difference. He has a jig all set set up to check all relays and ALL soldiering, in the mean time get a new one and
when u get this one back keep it in the trunk. most of the time they fail on the road..
Again everyone should carry a spare RCM,,and a Bosch crank and cam sensor

 

OK.

I certainly can do that, any other ideas on why it won't light up during a cranking scenario besides the RCM?

 

if u want to prove it and have another crossfire close to u swap the rcm and 99% says your car will start'''
oh you could put your ear next to the gas fill with cap off and have someone turn on the key,, it will run for 3 to 4 seconds
that way u don't need a new fuel pump,,, but you said wont turn over RCM... jim

 

I have ordered another RCM and a crank sensor for the glove box. Will post the result here after it's swapped out. Where do I ship my old one to for a re-work/test?

Thanks!!

 

got to top of this page click on the big tittle at the very top CORSSFIREFORUM.ORG then go down to

How-To Articles click on to that third sticky down read,,,all of it.

now after reading that go to the top again this time go down to all crossfires read all or those stickies
you will know what we know.

 

I have read previous to my post all messages regarding key fob, anti-theft and won't start messages. Most were the start and then shut off scenarios. I'm not about to read 500 messages about off topic things here that don't have anything to do with my problem. I just came through a bad divorce and want to find some happiness in my car. Trying to quit smoking to so.my vision isn't quite right and prefer not to be told to just read absolutely everything. In my opinion that was approaching rude.

You're crossfired.

 

Send an Email to (tighed1@hotmail.com) for instructions for sending in for rebuild. FCP Euro and Needswings are good sources for parts.

 

speaking of rude ,, most people here including myself answered your question,,,
maybe I should have do a search,, but no I answered your problem,, U WERE /and ARE RUDE but i forgive you
as I am not trying to tell u what to do u said u want happiness with and enjoy your car then learn about it and read a little
500 post is nothing I am 81 and read over that amount ,, so i guess YOU meant YOU are crossfired never forget the name JIM

 

I apologize. Sincerely.

I do have an update for the problem.

While waiting for the rebuilt RCM to arrive we tried a few things. I did listen to the tank with key on/off tried.. no sound at all. Secondly with the RCM relays exposed I had my son watch the relays.. the fuel pump relay didn't move with cranking. So I had him Move the relay manually while cranking and the car started strong. So we wedged a small piece of toothpick and was able to get the car into the garage (steep driveway). So now we have lights and heat to continue. So I'm assuming it's the soldier joints you guys all are talking about. So I'm definitely keeping a toothpick in the glove box too hahaha haha.

I do really appreciate your help, but darn those relays looked so brand new.. and the connections too.. astonishing.

Anyway next update coming after parts arrive.

Damon
(Sandy Oregon)

 

That's alright Damon ,when we all get into our cars and they don't work we get upset, with the car and everyone and anyone.
Glad you found the problem. of course it was the RCM ,for myself I have 4 spare rcm's for only 2 crossfires ,,one being a 600hp V8
the other a srt6 with my spare rcm and sensors in the trunk with tools to change the sensors, i can go anywhere, glad u found
problem and if u have another problem just post your question Jim