jumph4x

This is what it all looks like when the car is warm:

http://www.youtube.com/watch?v=zt3SnXfqstE
http://www.youtube.com/watch?v=DV3v_bAxo_Y

Here is a list of [potentially] relevant information:

• Problem ONLY occurs on a hot start. Cold start is perfectly fine. 15 minutes is sometimes enough. Sometimes even 5 will do.
• Ocassionally, under hard acceleration, the car will flunctuate as if it momentarily cut fuel. Almost like a suddenly short transmission slip.
• Once started and stable, the car has never just stopped running.

Here is what has already been done\tried:

• 2 types of OBD-2 scanners. No codes. No CEL.
• Engine Harness
• Camshaft Position Sensor
• Mass Airflow Sensor
• Battery

Next steps:

I have a single clip Crankshaft Position [Reference] Sensor on its way. If that doesn't work a member from these boards is willing to make a trip to around where I live and swap the ECU as mine has been flashed by Powerchip, but we are reserving that one as the least probable cause.

MarcusF

Try dumping the codes with an OBDII reader.

jumph4x

Good call, forgot to add that.

AMS Performance

crank position sensor... usually it fails to start when car is warm, its cheap and simple fix.

jumph4x

Just returned from the mechanic. We installed a genuine Bosch Crank Position Sensor.

Car started ****ty right after we did it. Restarted it a lot of times one right after another and it seemed okay.

On my way back the car stumbled once on hard acceleration.

Stopped to get gas. I knew this is the tricky part so as SOON as I turned of ignition, I re-started the car. Seemed fine.

Got gas. So about 5 minutes passed. Wouldn't restart for the life of it. Tried like 20 times.

After 35 or so minutes it did finally start.

Spoke with a guy at the gas station who seemed to know Mercedes, said he worked a a rep for them. He said it is something with the fuel delivery system. He specifically mentioned the Fuel Pressure Regulator (fuel thinning out due to temperature changes) and also said to knock out some easy stuff like the fuel filter.

EDIT: Well doesnt this blow... I cannot edit original post and add new information? What's the problem?

jumph4x

This ALL began after I sent the ECU to PowerChip. I think I will call them...

jumph4x

Bought a fuel pressure gauge kit. Made a modular jumper with a 15A inline fuse.

The fuel pump(s) seems fine. Very nice barely audible hum. No weird noises.

With engine not running and pump forcefully jumped, the FPR makes a rather loud whooshing sound. If I unplug the vacuum line I can easily smell gas.

With fuel pump working off the jumper, fuel pressure stays at a solid 61PSI. As soon as I disconnect the jumper, all fuel pressure drops to 0. Bingo. Our cars are supposed to hold 2.5 bar of pressure for up to 24 hours.

Next step will be to pinch fuel supply and\or fuel return lines to figure out of its the FPR, the fuel pump check valve or a leaking injector. Or some combination of these.

jumph4x

Pressure is being held just fine.

Changed all spark plugs to brand new Bosch Platinum 2's today. No change.

All fuses check out. Testing relays next.

kinghais

i had some starting problem when i upgrade my ECU chip. sometimes it would just cut off when i'm driving, all i did was send my ECU back to guy to get it fix, waste my money with that stupid speedtunningusa.

steve s

u pay what u get... have no exp with powerchip, but some volvos with speedtuning have experienced bent rods from poor maps...

swap out that powerchip b4 u spend more $ trying to find the cause.

jumph4x

Powerchip are probably the last ones to blame. Spoke with them. Seem like knowledgeable people. Travis being super enthusiastic and polite with a lovely accent and Matt being the down-to-earth rather to the point (if you ever care to speak with them).

Got my OBD2 hooking, did some logging\monitoring. Nothing out of the ordinary.

Things that checked out fine:

• Engine Fault Codes
• Coolant Temperature Sensor
• Air Intake Temp Sensor
• Throttle Position Sensor
• Mass Airflow Sensor

I think I am onto something though. Those of you who have owned an M103 powered Benz may know what I am talking about here. Teaser attached.

johnhef

little OVP issue eh?

jumph4x

Don't know yet. Sort of a 50/50% chance. I tried cleaning it myself with vodka, but I didn't resolder the contacts. Didn't help anything.

I'm picking up a new one soon, ain't like these things are expensive.

EDIT: Holding my new OVP Relay. Too bad its freaking snowing like crazy.

jumph4x

New OVP Relay did NOT help. Surprise!

Car did throw this code, however: P0327.

jumph4x

Replaced Knock Sensor #1. Completely took out throttle body and cleaned it thoroughly with DeepCreep and a toothbrush. Fuel rails out.

Injectors sent to Injector-Rehab for flow test, cleaning and new seals.

jumph4x

This is just great. Getting my car from the shop today.

Confirm problem: Engine ECU, looks like PowerChip ****ed this one up. That, or the shipping damaged something. Here's something even better: 1-800-495-0777 (PowerChip number in North America) is INVALID today. Calling it gets me an automated message about the line not being in service.

Oh boy...

jumph4x

Their local numbers worked fine. Sent it to them overnight. They were good on the phone and now we're waiting to see where this leads.

appatula

Glad to hear this might be the end of a long looong headache!! Was looking into powerchip but now I'm second guessing....keep us posted

jumph4x

Looks like that was it.

Overnighted it to them, git it back in a day. Popped it in and since burned 2 gas tanks. Traveled to Long island and back (160 miles on way). Not a single hick up.

They did all the warranty work for free and were very courteous on the phone.

AMG140.6

Thats really good to hear they got it all squared away.

Are you happy with the tune ? Is it noticeable w/ the ole butt dyno ?

As w/ most NA tunes, its usually more fuel more spark, and ~ 10% gain is the norm....so 24-27hp at the crank sounds doable.....

Thanks and enjoy the car now that its sorted.

PS- FWIW-I did a before and after dyno pull when I had my 91 BMW m5 which is rated 310bhp stock.

We installed a Turner Motorsports/Conforti chip which claims 35hp increase....and we went from 263 whp/258 wtq ( Dynojet ) to 278 whp/27x wtq . I felt it most at midrange once it was on the cams sweet spot.

jumph4x

This tune was really expensive, but I'm happy in the end. I have an accelerometer and I timed a 5.65s 0-60 twice. This is also with a short ram and lighter wheels.

I also have chipped my 1993 BMW 325i with a Turner chip and that DEFINITELY made a difference. That engine now LIVES above 3.5K. Will never regret that chip because I got it used for $100.

AMG140.6

The PC price is what stopped me from getting it when I had my C36 which I eventually sold.

I still remember the grin on my face after the Conforti chip went it. Much better than the Dinan one.

If I end up getting this C36 we should have a mini-meet as I'm in Hartford at least a few times a month. I'd love to get a ride in yours for a comparo.

Through the years Ive driven at least 6 C36's of different years, and its amazing how different they all pull. All with pretty much the typical miles for a 14-15yr old car...in the 100-120K range.

My 96 was a bull.,but peaked after 100 mph, this one I'm considering isn't as punchy from a dig, but pulls like a Scud rocket all the way to Vmax. To the point where I think it could've run w/ my M5.