Hot starting - V6 mixture?
Discussion
My wedge has always had a hot starting problem, as I'm close to getting it back on the road, I thought I'd better investigate.
Testing the Thermotime switch showed that it had approximately the correct resistance characteristic change between hot and cold, but no power going to it. Possibly not enough resistance change when warm, but I should change the batteries in my multimeter.
So I traced the loom back and found that the reason for the lack of power was that one of the wires was connected to the Cold Start Injector, but nowhere else. But I did find I has 2 spare wires, Brown and Red/Black. The unconnected wire is Brown/White. The brown wire is at 0V, the Red/Black at 12V. I've traced the wiring back to adjacent to the air flow meter, before the wires go into a multiplug and turn black (early Tasmin wiring).
Just tried connecting the red/black wire to the thermotime switch and CSI. It's fair to say it certainly has an effect.
When cold the car still starts from cold, but runs very rough (not previously a problem) and the exhaust is very visible. Unplugging (elctrical connector, not fuel I'm not that suicidal) the CSI gets it running as normal, the roughness returning when it's plugged in again. So it's fair to say the CSI is working and not stuck. Plugging the CSI in when hot causes very rough idle and stalling.
My current guess is that the mixture is too rich, but ideal for cold starting. Although from what I've read it apparently isn't possible to change the mixture on a K Jetronic, there must be some way and I think this is my next step.
At the back of my mind there is the thought that there is a reason why someone disconnected the feed for the CSI and Thermotime switch. Also of course have I done right in connecting the Red/Black wire to the Brown/White CSI and Thermotime switch.
Thanks in advance for helping.
Todd
Testing the Thermotime switch showed that it had approximately the correct resistance characteristic change between hot and cold, but no power going to it. Possibly not enough resistance change when warm, but I should change the batteries in my multimeter.
So I traced the loom back and found that the reason for the lack of power was that one of the wires was connected to the Cold Start Injector, but nowhere else. But I did find I has 2 spare wires, Brown and Red/Black. The unconnected wire is Brown/White. The brown wire is at 0V, the Red/Black at 12V. I've traced the wiring back to adjacent to the air flow meter, before the wires go into a multiplug and turn black (early Tasmin wiring).
Just tried connecting the red/black wire to the thermotime switch and CSI. It's fair to say it certainly has an effect.
When cold the car still starts from cold, but runs very rough (not previously a problem) and the exhaust is very visible. Unplugging (elctrical connector, not fuel I'm not that suicidal) the CSI gets it running as normal, the roughness returning when it's plugged in again. So it's fair to say the CSI is working and not stuck. Plugging the CSI in when hot causes very rough idle and stalling.
My current guess is that the mixture is too rich, but ideal for cold starting. Although from what I've read it apparently isn't possible to change the mixture on a K Jetronic, there must be some way and I think this is my next step.
At the back of my mind there is the thought that there is a reason why someone disconnected the feed for the CSI and Thermotime switch. Also of course have I done right in connecting the Red/Black wire to the Brown/White CSI and Thermotime switch.
Thanks in advance for helping.
Todd
)No worries, I found an even better one on the same site (should have read it first). It shows where the mixture setting is, so it may have sorted my query.
www.ford-capri.fsnet.co.uk/whiterose/Injection.htm
www.ford-capri.fsnet.co.uk/whiterose/Injection.htm
On my 'none blacker' wired tasmin the wires to the injection system are as follows:
black yellow from the starter relay to the cold start device and the thermo time switch (12v supply)
brown/white between the cold start device and the thermo time switch
red/black from the impulse module to the cold start device (provides a return path when the engine is hot)
As an aside, I have just fixed a long standing hot starting/running problem. Originally the car just ran rough for a while after hot starting. This degenerated into an extreme reluctance to start after being left for more than 10 minutes or so. Fixed by replacing the Fuel Accumulator which prevents fuel vapourisation when the engine is hot.
black yellow from the starter relay to the cold start device and the thermo time switch (12v supply)
brown/white between the cold start device and the thermo time switch
red/black from the impulse module to the cold start device (provides a return path when the engine is hot)
As an aside, I have just fixed a long standing hot starting/running problem. Originally the car just ran rough for a while after hot starting. This degenerated into an extreme reluctance to start after being left for more than 10 minutes or so. Fixed by replacing the Fuel Accumulator which prevents fuel vapourisation when the engine is hot.
Tried connecting the red/black wire to brown white. It certainly had an effect. Where as previously it ran fine cold, it was now very rough and hot it continually wanted to stall, disconnecting the cold start returned to normal running. According to the Capri articles I found the cold start system should only be live during cranking. On my car I found the red black was permanently live.
I am considering connecting the cold start to the starter motor, so that it is only live when cranking. From my understanding of the Capri articles this is what should be feeding the cold start. Bearing in mind that someone has worked on (over?) the car previously, so the offical wiring may nolonger be true.
I think my car has been set rich to allow cold start, and just able to idle when hot. I've just reset the height of the air flow sensor plate, but not had a chance to run it yet (left the cold start connected and wondered why it ran rough with such a small tweak).
Geddy - is your red/black wire permanently live?
Fuel accumulator sounds like it may be another culprit.
I am considering connecting the cold start to the starter motor, so that it is only live when cranking. From my understanding of the Capri articles this is what should be feeding the cold start. Bearing in mind that someone has worked on (over?) the car previously, so the offical wiring may nolonger be true.
I think my car has been set rich to allow cold start, and just able to idle when hot. I've just reset the height of the air flow sensor plate, but not had a chance to run it yet (left the cold start connected and wondered why it ran rough with such a small tweak).
Geddy - is your red/black wire permanently live?
Fuel accumulator sounds like it may be another culprit.
The fuel accumalator is at the back next to the fuel filter and pump. The pump output goes to the accumulator and then the filter before heading to the front of the engine to the fuel distributor.
The Black yellow goes to the 'live'side of the cold start device and thermo time switch and should only be live when the starter is operated (from the starter relay).
This is earthed when cold starting through the thermo time switch. The 'gnd' side of the cold start device goes to the 'gnd' side of the thermo time switch via a brown white wire.
The red black wire goes from the impulse module to the 'gnd' side of the cold start device and is probably always at 12v unless warm starting when it should pulse to ground.
I have a number of different guides to the injection system operation but the wiring details are from the circuit i made by buzzing out the electrics.
Of course all the above is liekly to be different since the factory seemed to change design virtually on a car by car basis.
Let me know if I can help any further
The Black yellow goes to the 'live'side of the cold start device and thermo time switch and should only be live when the starter is operated (from the starter relay).
This is earthed when cold starting through the thermo time switch. The 'gnd' side of the cold start device goes to the 'gnd' side of the thermo time switch via a brown white wire.
The red black wire goes from the impulse module to the 'gnd' side of the cold start device and is probably always at 12v unless warm starting when it should pulse to ground.
I have a number of different guides to the injection system operation but the wiring details are from the circuit i made by buzzing out the electrics.
Of course all the above is liekly to be different since the factory seemed to change design virtually on a car by car basis.
Let me know if I can help any further
by the way. The warm start operation of the cold start system (!!) is covered in the Haynes Granada manual. The idea is that the time switch has stoppped the cold start injector operating (engine hot ) but the impulse module allows the cold start injector to put 'pulses' of additional fuel into the engine to improve warm starting. The impulse module is a green relay and sits on the top row of the relay board, at the front.
if you have an impulse module it should be green and taller than a normal relay. Top row of the relay board in the engine bay. Mine has 3 devices: from front to back
Thermal cut out for the heated rear window
hazard flasher
impulse module
I will confess mine had a normal balck relay in place when i bought it. A process of deduction, hopefully correct, suggested this should be an impulse module.
Thermal cut out for the heated rear window
hazard flasher
impulse module
I will confess mine had a normal balck relay in place when i bought it. A process of deduction, hopefully correct, suggested this should be an impulse module.
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