Hey guys, sorry i haven't written. Here's what's been going on. I checked the battery and it was fine, even after 2 weeks of no start, it still put out about 13v. When I tried to start the car there was no drop in the voltage either. I was checking through other forums and I read that people had problems because of the electronic ignition switch causing no crank. I eliminated this because both the keys worked to unlock the steering and I was able to shift out of park into neutral, two things that apparently shouldn't happen if the ignition switch was at fault. Also putting the car in neutral and trying to start showed no change, eliminating a faulty neutral switch. So I called this place that I found on the web and spoke to the tech there who apparently was a mechanic at mercedes. He said it was most likely the CPS. I ordered one off ebay (another 2 weeks) and for the life of me I tried and just couldn't replace it, so I left it and decided instead to call AAA. In the meanwhile in my frustrated state of mind, I forgot to attach the cable back on the sensor. When the AAA guy came he asked for the key and try to start it himself and lo and behold it started cranking but wouldn't turn over. Then I remembered I didn't attach the cable. After reattaching the cable the car started up fine (I was surprised the battery still had juice after 4 weeks of no running). I drove the car around for 20 miles and had no problems (keeping my fingers crossed). So I know you guys said it probably wasn't the CPS because the car would still turn over, but now I'm wondering if somehow maybe it was. I'm going to a friends shop to have the CPS replaced tomorrow and then I can finally get my sister off my back (hopefully) . I keep you guys posted in a week if the car is still running smooth. Sooner if the problem arises again.

 

Hi,

I assume the following was a typo.
Quote " it started cranking but wouldn't turn over."
Presumably it cranks BUT won't start.

If so do you also confirm that the battery voltage was OK whilst the engine was actually cranking i.e. Under load.

If so I have to conclude that if all you did was to disconnect some wires and then replace them AND the problem was resolved that this was likely a poor connection.
Can't remember my original response but likely I pointed out many ECU's get changed when they are not the "real" cause but poor connections which get "resolved" when units are changed.

If I were you I wouldn't change the CPS yet.

Not sure exactly what you mean by the CPS?
The main engine ECU? or the EIS (Ignition switch?)
In fact I'm not even sure what model we are talking about!

Wait till you get a reoccurrence otherwise if the problem occurs again sometime after changing the "CPS" you won't be sure whether the "new" CPS is part of the problem.

Did you touch any other bits of the wiring?

Stuart

 

Hi, i guess that was a mistake. It was cranking but wouldn't start. I'm sorry I should have been more clear. The CPS I'm referring to is the Crank Position Sensor. The model is 99 E320 (w210). And no I didn't touch any other wiring. I didn't replace the wiring either, I simply unplugged it and plugged it back. It's weird because I had unplugged it before and plugged it back (thinking also it may be a loose connection) several times and there was no crank. But when I left it unplugged, it began to crank (but no start). When I plugged it back after that it cranked and then started. Very weird. Because the CPS is the only thing I fooled around with, I thought it may be a faulty CPS. But everyone said if it is faulty, it would still crank but not start. Also it shouldn't cause the cause to go into 'limp' mode. I don't know, I'm just happy right now I do have to be my sisters driver. When the problem does return and I finally do find out what the cause is I will definitely post it up. In the meanwhile, thanx for all the help guys. See you soon!!

 

I was being a bit thick this morning!! Senior moment.

CPS gives hot start problem. No signal so ignition doesn't know when to fire.
CPS sometimes gets very bad and prevents cold start.

However it doesn't play any part in no crank.

No crank is Key, battery or EIS.

 

Hmm, well key is eliminated because we tried both original and spare. Battery is eliminated because I get around 13v on crank (also before when the car didn't crank, the battery voltage never dropped, like it wasn't even being told to send power to crank). So the last option is the EIS. Well, it's running great now, but if and when the problem does arise again I'll keep that in mind. Thanks again snanceki, don't worry bout laying it thick, we all have our moments. I do appreciate the help! Take care!

 

Hi,
Last try.
I'm still not sure we have got this sorted. You seem to have both a "No Crank" AND a "No Start" problem.

No Crank = Key, Batterey, EIS fault. Note: Key won't TURN is a special case of "No Crank".
No Start ius caused by either No Spark or No Fuel:

No spark = Battery (low crank voltage). CPS (usually when hot), Bad engine harness insulation, Plugs / leads, EIS, engine ECU. Need more than one coil pack to go down to cause "No Start".
No fuel = Tank (level), pump (operating?), pressure valve (full open), filter, injectors, EIS, engine ECU

Next time you have a "No Start" remove just one plug and view whether you have a spark (when out of the cylinder but touching the block) during cranking.
If you have a spark then check the fuel rail pressure to see whether there is any!

I still suspect that the EIS MAY (please note MAY) be showing the first signs of going bad but I wouldn't spend money on a new one until you have better evidence of what IS OK and what is NOT OK>

Good diagnosis is all about eliminating possibilities until you are left with just one which you are able to demonstrate that you can "Turn ON / OFF" at will.
At this point you have no option but to put your hand in your pocket....unless of course you can repair the component.

Stuart.

 

My oh my, all this posting and time investment. This is why you take it to the Authorized Mercedes-Benz Dealer.
They have the resorces to find and fix these problems. I've stood by technicians and team leaders scratching their heads when the test equipment wouldn't give them a definative answer to system problems.
As the technician teams get together and suggest this and that and they draw parts from their parts department and retest, parts not needed are returned to the parts department, they have access to factory tech support.
These electronic systems are complex and if you need an EIS you can't buy one over the counter it has to be ordered by the Dealer and installed and encoded at the dealer.
Believe me, take it to the dealer. Ask for an itemized written estimate of repairs.

 

Hey guys remember me? Even after 1.5 years no solution to this problem. We took the car to the dealership and they replaced they transmission switch plate. The car worked for about a month then went back to the same problem. Then they replaced the ignition switch and it worked fine for 2 weeks before returning to the same problem. After spending nearly 2000 dollars to try and fix this car, I'm pulling my hair out about this. My sister gave up on the car and just gave it to me. The car has just been sitting in the driveway. I did notice something though. Although the car won't start right away, if I leave the key in the on/run position (or I just hold the key in the crank position) for about 15 seconds it will eventually crank and start, but then I still have the problem where the car won't shift out of 1st/2nd. Still no codes being thrown. I'm really beginning to hate this car when I used to love it....

I'm not taking it the dealership again since even they can't diagnose it, and after spending 2k with them. Instead I'm going to someplace called willi's in LI who comes highly recommended by a few people on the benz world forums. I'll let you guys know what happens.....

 

hello guys!!! i have a 2000 e class and i drove to my in laws house and when i got back in the car it wouldn't start I tried to get out and lock and unlock the car because the alarm keeps going off and the steering wheel is locked up. Should i find the battery and unplug it? Please help its the holiday and I'm stuck without a car!!! Also the lights do come on so not sure about the battery being dead maybe its low, if i unplug the battery will the codes mess up? Please help Stranded

 

Hey everyone! Car is finally running good, great I should say. I took my car to ****** in great neck long island (516)773-3542. When I pulled up all I saw were mercedes in the lot so I knew this was the place I was looking for. I left the car with him for a month. We changed the battery, tried swapping in a new tcu but that didn't work. finally he pulled the shifter out and saw a bunch of water in the bay where the shifter was sitting. The pins connecting the tcu to the shifter were corroded. The car wouldn't start intermittently because the shifter was probably sending a signal that I was was in drive. Or maybe no signal at all. In either case they car runs fine now. He said somehow some water got into the shifter. I asked my sister and she said 'well....I do remember leaving the moonroof open once and it rained pretty bad. I cleaned it up and it was running fine for months, so it can't be that!' Boy I cant wait till she's married and her husband can deal with her. But in the meantime, car is running great and has been for about 2 months. She took a few long trips in it too (5+ hrs), not even a hiccup. 140K on the clock and I expect many more.


Thank you to everyone who helped me through this. I know someone mentioned before that there may be water in the shifter. I schooled my sister on the importance of proper maintenance. one good thing that did come out of all this is now she's actually interested in learning about basic mechanics and maintenance because SHE doesn't want to go through this again.