owned the Zed for about 4months- thought I would do a ECU check to see if all is well. Before checking, car ran fine apart from a little hesitation when pulling away, nothing to worry about, revs only dropped a couple of hundred rpm.

 

Hmmmm. Lesson 1:

On a Sunday afternoon don't play if its not broke!!!!

 

Followed twin turbo Zs of Dallas website and found a couple of things wrong.

 

a)-Code 13-engine coolant temp. sensor circuit.

b)-Code 34-detonation sensor circuit.

c)-Right o2 sensor not functioning.

 

a)-I knew the cabling above the engine coolant harness was suspect as if you move it backwards and forwards the fan kicks in.

Took it for a good run, lots of hesitation on pulling away(nearly stalling) and a little hesitation when accellerating before pulling fine. Parked up, came back 1 hour later, car wouldn't start. This car has NEVER not started.

 

Checked ecu was left in anti-clockwise position. Yes but I thought I would turn clockwise and then back again. Car started!!! Coincidence or related ??????

 

Got home-hesitation all the time on pull away.

Thought perhaps as all I have touched is ECU and engine coolant harness then a reset of ecu couldn't hurt. Disconnected battery for 90mins. Car started, took for a run, hesitating like mad-no difference. Put it in drive from standstill and it cuts out. Still showing codes 13 and 34.

 

So with little knowledge of ECU's can the coolant sensor cause this problem on its own????

 

b)-Code 34- I have got no idea what this is, apart from a detonation sensor circuit. !!

 

As for o2 heated Oxygen sensor I am also in the dark, all I know is that the ecu led flashes when in the anti-clockwise position at 2000 or more rpm and in the right position it doesn't.

 

Its now been put in my garage untill next weekend, leaving me 7 days of pondering!!

Any advice would be grateful!!

First point of call I presume would be to take apart wiring and harness of coolant sensor and re-check or replace.

On mine, faulty wiring to colant temp sensor caused the exact hesitation you have described. I cold also hear the elec fan running. Replacing this cured all.

 

HTH (a bit)

Cheers mate.

 

My electric fan is running all over the place when it feels like it. Could be onto a winner here!!!:D

a) Yep the coolant circuit will cause hesitation etc, and make the fan run randomly.. best to fix that one sooner rather than later..

 

b) Code 34 - the dreaded detonation sensor.

 

Basically, either the sensor itself or the wiring to it is dead - the ECU simply tests for the sensor being 'visible' to it. In this state, your car will be running in safety boost - assuming you don't have a boost controller fiited.

 

That is, the boost will be left at 7psi (the mechanical set boost of the wastegates) and not raised to the full 9psi, by leaving the BCSV (Boost Control Solenoid Valve)'s shut.

 

The ignition will also be considerably retarded to further reduce power output.

 

i.e. Your car will be slooowwww... (You won't think it is - but when you fix it.. You'll realise!)

 

All you can really do to sort this out - unless it happens to be a reasonably obvious wiring fault, is to replace the detonation sensor and short wiring sub-loom that goes to it. Which means removing the upper and lower plenum's - i.e. a fair bit of work. Dropping the transmission might give you access from the back of the engine & underneath the car. There is a tech on TTnet about relocating the detonation sensor - which is easier - and I can dig that up for you if you want. Det sensor is about $160 from Courtesy, by the way -so it's not cheap either.

 

c) The O2 sensor. Either there is a wiring fault (most likely) to the O2 sensor in question, or the sensor itself is dead. There's a good tech on diagnosing/replacing them here;

 

http://www.twinturbo.net/ttnetfaq/FAQpages/O2s.html

 

HTH.

Cheers for the useful advice.

 

First job to sort out that coolant circuit on the weekend.

 

I thought I might not get such easy advice for code 34. The car does feel quite quick, but reading this forum and hearing about wheels spinning constantly pulling away I started to believe my right foot was a bit of a wuss!!! as my car hardly steps out of line with regards to the rear wheels.

 

This now makes sense.

 

So I'm running on safety boost. Should be smiling when fixed. Should I favour the expert to sort this as a man who thinks he knows a reasonable amount about cars but is this out of my league.

That tech would be really useful if its not too hard to locate.

 

Cheers again

Hello Andrew,

 

Here's one on testing the sensor circuit.

 

http://www.zhome.com/ZCMnL/PICS/detonationSensor/detonationSensor.html

 

It shows how to bypass the circuit but that's not always a good idea. As aaronjb says, the best option is to maybe locate it elsewhere. (remember seeing the tech document but can't find it)..................

 

Found it - http://www.angelfire.com/geek/vg30dett/DSR/DetSenRel01.html

 

Vijay

Cheers Vijay

 

Now I know where the connector is I'll check for obvious corrosion and/or bad wiring in hope and then recheck ecu.