Hi all,

I did a quick search on this problem and didn't come up with anything, so my apologies up front if this has been covered.

This past week I suffered my 3rd sudden engine shutdown in the past 2 years. During each event, I was driving at constant speed (once around 35 mph, and the other two times at 65) and suddenly, all the dummy lights came on, and the engine stopped. In the first case, I coasted to the side of the road and after 20 minutes of attempting a restart, I finally called AAA and had it towed to the dealer. The next day, the dealer started the car up on the first try, found no codes, and handed me my keys, no explanation for the failure.

The following two times, the car again would not fire after limping to the side (it cranked, but I detected no signs of ignition). I decided to wait 30 minutes, and while waiting, disconnected the cables of my Unichip (to power down the ECU), eventually reconnected the cables and low and behold the car cranked right up.

I don't believe the Unichip is responsible because the first time the dealer didn't touch it, and the car started right up after the overnight stay.

To me it seems that just waiting the 30 mins or so is what's correcting problem.

On all occassions, the car had been running for a min. of 30 mins, the ambient temp was in the 70's, the conditions were dry, and there were other no indications/lights prior to the sudden shutdown.

I have an '04 MCS with 85K miles. The only mods I have are the Unichip, Webb CAI (recently installed) and the 15% pulley.

Has anyone had a similar problem (with or without a Unichip)?

Thanks in advance for your advice/guidance.

Erick

 

I could be wrong about this, but rather than wait the 1/2 hour, if you turn the key 5 times on and off, this may clear the issue, and the car will fire.

Sorry, have no clue as to what might be causing the problem.

Mark

 

Haven't seen the problem on a Mini although I have seen it on a few other cars. My first thoughts are crank position sensor, cam position sensor, or battery/terminal connections.

I've seen bad battery connections cause the wierdest of problems, like killing power to a fuel pump but to nothing else, inoperative climate control with no other symptoms, and so many more.

CKP/CMP can have that exact problem as well. CKP (crank sensor) is very common on BMW produced Land Rover Discovery II's. The most common symptom being intermittant/random stall, mostly when the vehicle is warm. It can be nearly impossible to replicate until it gets worse, but it does get progressively worse. Unfortunately if the component in question is not misbehaving while being tested results will not indicate a failure.

Good luck.

 

My 05 S stalled on me once three years ago while I was cruising in the fast lane at speed limit - car was less than a year old at the time. Scary - can't believe you've experienced it three times! Pulled over, started back up, drove home, had it towed to dealer. Here's what my service order says:

"...Interrogated fault memory, found fault P1688 - electronic throttle monitoring, level 2/3, air calculation fault. Checked for any leaks in the intake system, none found. As per test plan necessary to replace supercharger bypass valve. Searched bulletins and measures, found M12 200 04. As per bulletin, replace bypass valve due to sticking during operation. Removed intercooler, intake air ducts, throttle body and replaced bypass valve. Installed all previously removed components."

Problem has never recurred. The part replaced was 11-61-7-566-294 valve.

Good luck!

 

Thanks for the comments guys!

I guess any one of these items could have caused my problem. I'll pull the codes this week and see if I can find anything.

I'm wondering if waiting the 30 mins is really helping to solve the problem, or if it's simply because I'm disconnecting the ECU. The last time, I actually didn't have to wait the full 30 minutes before restarting. I think it was only 15-20. The previous time I was less hurried, so I waited the full 30.

I'll post whatever codes I do find.

If anyone else has had this problem, please post. I'd like to see if there's any pattern to the failure.

Erick

PS: By the way Rover38, I'll make sure to also check the batter connections. Just in case.

 

It is the Unichip. Mines an 09, but Ive had my second loss of power today on the freeway....car just died doing 70 in the fast lane. Got it over, and basically took off the chip...started right back up.

It happened once before in the spring... Driving away from a light...just died.
Unhooked the chip and put the ECU cables back on and was on my way.

See I didnt put the chip back on since spring until last night....

I did notice, while troubleshooting in the median, that it wouldnt start back up with the chip connected, but then I pressed and wiggled the harness when it was still connected to the ECU and it did start again...pressed on the harness while it was running, and it died.

They are notorious for faulty harnesses, and I shot them an email this morning to see if they care at all.

basically if your car does die, unhook the chip and youll be able to drive just fine

 

Just wanted to add that I have the exact same issue with my 2006 MCS - car would go into "limp" mode with bunch of lights on, but can be driven after you let it sit for 10 minutes.

Dealership here in Toronto, Ontario has changed my throttle body TWICE in two years (according to them check engine light would always point to the faulty throttle body). After they do the change, car runs fine for several months but the problem always comes back.

So..when it happened again just recently, I brought it back the third time - last week they told me it is the harness leading to the engine that is at fault (apparently they had to send report to the head office cuz they couldn't pinpoint the problem), so I'm waiting til they ship this harness from Germany, should be able to have the car back end of this week (hopefully).

 

Hey Adam,

Thanks for the comment. I'll be really peeved if it does turn out to be the harness. I'll send them an email today to let them know I'm having the same problem as you.

Have you given up completely using the Unichip at this point?

AgentCoop, our problem is not related to the car going into LIMP mode. In my case, and I believe in Adam's case, our car completely shuts down, and won't restart easily. Once it does restart, the car is back to normal operation. Sounds like your problem may be slightly different from ours. Good Luck with the new harness.

Erick

 

well i want to use it...but i drive a lot of rush hour highway, and i cannot be losing power in the middle of it.... heck i didnt know how steep the dropoff was onto the gravel median this morning!...but there was only 2' of pavement and 70+mph traffic everywhere.

no thanks lol

when it worked it was great. I may try it again but i dont know what I could adjust. maybe the tension on the harness a little?...we'll see. Im certain they wont do anything to help me out...im not the original owner of it.

Tonight ill try adjusting wires with the car running to see

 

Adam,

I just spoke with one of the Unichip distributors, and he told me the following.

There are two known and accepted issues with Unichip products. The first is related to the older Supercharged engine version, where the unit will cause an engine shutdown if it experiences a large temperature change. This is for later units, where they went to lead-free components. The fix is to move the unit into the passenger compartment.

There is also a known problem with the harness of the units designed for the newer Turbocharged engines. He said the harness fix is being addressed, but no new harnesses have shipped yet.

So, Adam, it sounds like your issue should get resolved with a new harness. Good luck with that.

Unfortunately, the distributor told me that there have been no systemic problems with units manufactured during the time frame I purchased mine, so I guess I may be out of luck. I'll see if any codes are being stored related to the MAP and crank sensor (which are the sensors monitored by the Unichip).

If anyone else has had an engine shutdown problem with their Unichip (2003-2004 time frame), please speak up.

Thanks,
Erick

 

I don't know about you guys, but I would not ever want to be a rolling or sitting duck on the freeway. If I had a Unichip and I suspected it was the cause of this problem, it's outta there until proved otherwise. My 05 S is stock, by the way, and if the dealer's diagnosis hadn't resolved my problem, I'd be driving an 06 today.

Be safe.

 

and one afternoon he said that it died twice on him. Started up after a couple of minutes. Never happened to me. Of course, now that I wrote this I'm sure the next time I drive....

No codes. No unichip.

Hunting things like this down really suck.

Matt

 

As for my chip, I found the part thats 'faulty'.

On our ECUs there are 3 plugs...2 gigantic ones and a 3rd big one. whenever I lightly press this (furthest to firewall) 3rd one towards the engine block...car dies instantly.

My only guess is they molded this one to not fit the ECUs prongs tightly enough or something.... Maybe thats the reason it has some fancy hook to secure it down vs. the simple push-lock mechanism on the other 2 Unichip plugs.... hmm.

Glad they are fixing it, so we'll see what happens!.. I remain doubtful however lol

EDIT: Update: Tony from Unichip shot me an email explaining that if the connectors are removed too many times the pins can pretty much loosen up and cause this problem. I am going to send the harness back to them so they can have a look, and probably crimp the pins or something. He also said they could do a hardwire kit, but I still have dealer visits and a warranty to look after...

Props to Unichip though for stepping up to help me out

I really look forward to getting it working again as it was a great product while working!

 

Well, 3 weeks ago, just before heading out on a business trip, I ventured out to the parking lot to start my car after work, and ...... Nothing. It wouldn't start. Same symptoms as when it dies suddenly while driving. I removed the Unichip and the car fired right up. Put the Unichip back and... Nothing.

I took out the Unichip and have been driving without problems ever since.

So, I'm pretty sure my problem was being caused by the Unichip, or its harness. Now the question is, how do I get some attention from the folks at Unichip.

Hey IWASHMYCAR, how did you reach those guys? Did you leave them an email, or were you able to make voice contact?

**** EDIT ****
Just spoke with Jack at Unichip. He was very helpful. His thought at the moment is that it's a cracked PCB (a problem that has occurred with other units). I will be sending it back to them for confirmation and to be fixed. Will let you all know what happens.
**** EDIT ****

Erick