3200 GT Limp home mode fix

MRichards

Member
Messages
278
My year 2000 car has gone into limp mode. Inspection of the throttle body butterfly valve confirms this.

Most cars have a quick fix to get the car out of limp mode by turning the ignition key several times,e.g. three( Ferrari) or five (Lotus) times. Does the 3200 have a similar facility ?

Is there any other way of quickly getting the car out of limp mode ?
 

davy83

Member
Messages
2,809
if you can get an ODB reader onto the CAN bus system (not simple on the pre-2000 cars) you can reset the limp home mode. I have a 2001 facelift car with an IDBII compliant port, and i always carry a reader in the car, so i can make a note of the problem and reset it on the spot, 7 times out of ten it does not come back. I am not aware of any manual limp home mode resets.
 

MUC3200GT

Junior Member
Messages
127
but some of those (knock sensors) come back immedeatly after startup, so driving a while in limp mode or just restarting immedeatly will fix it by luck (my experience), or not (also my experience). Limped home already 200Km with 80..120km/h but lowest fuel consumption evre 12.5l/100km , which feels like a 86` Golf II with 55HP especially in hilly areas, than at home , one restart: back to normal...

Also pre- OBD reading and resetting doenst help, when it is present it will re-appear (my experience). Either new TB (contactless) or Knocksensors- but some time ago I had coolant in the V , so I am wondering whether some sanding of the knock sensors would help as well, But I know - once one is there one replace to new ones. No experiments
 

davy83

Member
Messages
2,809
knock sensors getting stuffed because of coolant in the VEE is the most common problem and once they are wet they don't recover.

" Knocksensors- but some time ago I had coolant in the V"
 

allandwf

Member
Messages
10,958
They are basically vibration sensors. I would have thought they would be potted, water should only effect the plug/socket or does it manage to get internal?
 

alfatwo

Member
Messages
5,517
They are basically vibration sensors. I would have thought they would be potted, water should only effect the plug/socket or does it manage to get internal?

Your dead on there al, but these Bosch sensors were never designed to last nearly 20 years! they do out of sync over time..

Dave
 

MRichards

Member
Messages
278
" but some of those (knock sensors) come back immedeatly after startup, so driving a while in limp mode or just restarting immedeatly will fix it by luck (my experience)"
That has been my experience. Twice the car has gone into limp mode & a restart has cleared the error. This time it's become a permanent limp !
 

RobinL

Member
Messages
456
" but some of those (knock sensors) come back immedeatly after startup, so driving a while in limp mode or just restarting immedeatly will fix it by luck (my experience)"
That has been my experience. Twice the car has gone into limp mode & a restart has cleared the error. This time it's become a permanent limp !

The problem with sensors throwing codes and 'limp home' is that mostly the codes that show an engine warning 'only' are emissions codes which are set after the ECU detects an error condition for a pre-set number of cycles (pending error code) - so resetting the code or battery disconnect will work and give you back the number of cycles before you need to reset again (it doesn't fix the faulty sensor).
Some newer programming only allows a certain number of 'resets' before throwing a permanent code which would be a dealer reset (I hate those).
Are there recommended replacement cycles for sensors - mostly no - they are designed to last the 'lifetime of the vehicle' - question is what is that 'lifetime'?
In general the 'lifetime' of the vehicle is considered by manufacturers as the period of their guarantee so a guarantee of 50,000 miles or 3 years means that is what you can reasonably expect all parts to perform against!
Do sensors age? yes they do, particularly those in 'hot places' - general advice would be to put away a small amount of the obligatory 'spares and repairs' budget for sensor replacements - if they are easy to get at then fix on failure, if they aren't then be prepared to replace when opportunity arises.
Also as a caution - don't always assume that the sensor has failed - it may be doing its job perfectly and detecting a fault - a faulty MAF or MAP could give knock conditions - so don't blame the knock sensor - simple OBD readers report codes, dealer set ups report the sensor parameters so easier to spot the good or bad sensors!
I loved my first car - a 1966 Ford Galaxie - it had almost nothing electric onboard just a stuffing great 7L V8, wires to and from the battery and alternator, ignition / coil wires - nothing else. How times have changed :-(
ps I don't miss the 8 track cartridge player!
 

MUC3200GT

Junior Member
Messages
127
knock sensors getting stuffed because of coolant in the VEE is the most common problem and once they are wet they don't recover.

" Knocksensors

How old are the knock sensors?

Dave

Actually I don`t knowthe age of the knocksensors. I own the car since 6 years and they have been in all the time. However last limp mode due to knock sensor have been last year when air temperature was "autumn" type (colder and humid), and since than it didnt re-reapear. Water in the VEE was 3 fixed 3 years ago. Air conditions are now cold and dry or warmer and dry . Potentially I am wrong but I feel that kock sensor error detection could be related to contact condition sensor/block (as far a is remember there is a tigthening torque defined for them), so maybe some corrosion could play a role on reliability ?
 

allandwf

Member
Messages
10,958
Actually I don`t knowthe age of the knocksensors. I own the car since 6 years and they have been in all the time. However last limp mode due to knock sensor have been last year when air temperature was "autumn" type (colder and humid), and since than it didnt re-reapear. Water in the VEE was 3 fixed 3 years ago. Air conditions are now cold and dry or warmer and dry . Potentially I am wrong but I feel that kock sensor error detection could be related to contact condition sensor/block (as far a is remember there is a tigthening torque defined for them), so maybe some corrosion could play a role on reliability ?

indeed, contact condition, corrosion, or anything that alters contact resistance, will have an effect as the sensors will work on a voltage and a corresponding tolerance or thresh hold before throwing up a CEL.
 

davy83

Member
Messages
2,809
When i replaced the knock sensor on my car i reckon they has started to take in water. there was no corrosion so speak of around the mounting area, and although a poor mechanical connection would affect the readings, i think its unlikely to make the sensor fail, or create an error. I think the problem is the sensor itself fails, and i suspect its not designed for long term immersion in water, so if you have a leak that last for any length of time you will have a problem. Hard to say for sure, because they are not servicable parts. I dont remember them being particularly expensive or hard to get either?

Actually I don`t knowthe age of the knocksensors. I own the car since 6 years and they have been in all the time. However last limp mode due to knock sensor have been last year when air temperature was "autumn" type (colder and humid), and since than it didnt re-reapear. Water in the VEE was 3 fixed 3 years ago. Air conditions are now cold and dry or warmer and dry . Potentially I am wrong but I feel that kock sensor error detection could be related to contact condition sensor/block (as far a is remember there is a tigthening torque defined for them), so maybe some corrosion could play a role on reliability ?