I swapped out the IAC and the surging went away, Hooray! Took her out for a test run, everything was fine. Stopped off and upon resumption of test surging stopped but idle raced up to 2000 rpm. I have another so will swap it out again. I'll let you know how things work out.

 

Would be valuable if you could tap into the OBD2 port and tell us what % the throttle was at. Should be around 12-13%, any higher, and you have an issue with the TPS, or throttle body butterfly. I like to see that because if you're pulling a voltage, you're not getting the full story. Pulling the % from the OBD2 port will reveal what the ECU is seeing.

 

Took her out yesterday and she started surging again, I pulled over and got under the hood an the butterfly was not closing all the way. I forced it back and she ran ok after that, so do you know where I can pick up the revised return spring ?

 

Some have taken the original return spring and pre loaded it by the way they mounted it to have more force

There is a good pic and description on how to do this

some have added a external sping like in the pic below

 

Thanks Parker can you direct me to the picture - instructions please ?

 

Still looking

 

This is not the one looking for but gets you some info on a external spring

No-Cost Solution to Sticky Throttle Return Spring; H/T to Motorcarman! - Jaguar Forums - Jaguar Enthusiasts Forum

not yet but some more

Throttle body questions - Jaguar Forums - Jaguar Enthusiasts Forum

 

I couldn't find the one thread but here on this one that Motorcarman ( Bob ) describes it

Sovereign 4.0 throttle return spring - Jaguar Forums - Jaguar Enthusiasts Forum

 

I couldn’t recall reading if you have ever removed the throttle body and cleaned it?

 

Yes I did, it wasn't to dirty. I also shortened the spring and all is good on that now, unfortunately I now have a new issue. From cold, started her up and she would not stay running with foot off the accelerator she kept cutting out on me. After several attempts she stopped cutting out and rap good after that. Yesterday went out in her and she started fine but at every intersection she would cut out and stall. She then ran fine after about 4 times. Any suggestions ?

 

Have you run live data on a test drive as a running graph or log to get a snapshot when this acures ?

Missing any pinching tabs on the sockets on the ECU connectors ?

Live data look ats :

TPS , expect it to not get below 13 % at the butterfly idle closed stop

MAF , 4 grams per second at the correct idle speed < you will probably have to multiply the data value by 10 or 100 because of a software error

Engine coolant temp , 88 Degree C ( 190 F ) is the cross over from open loop to close loop ECU regulation from what I've read

Short Term Fuel trims , target 0 . 0 through all throttle / load ranges

EGR error % , target 0

IAC valve, you should see it schedule down closed but it will modulate

Voltage stable as a whole car ? you can see this as a perimeter ID ( PID ) on our tester and the instrument gauge has a dampener so you may not see a sudden change

Have you jumperd the fuel pump relay for test run drive ? this will drain the battery as it is hot at all times with the keys in your pocket so plan accordingly

 

Thanks Parker, so no more cutting out until today. I got to an intersection and she died on me. Started right up again and all was ok. I did notice variation in the idle rpm which started off around 850 then after a while reduced to 650. I did an odb2 reading and here are the results these are all that were offered.
adaptive offset 15
air thermistor voltage 3.04
battery voltage 16.57
exhaust gas recirculation position 0.88
exhaust gas recirculation thermistor voltage 5.00
stepper position 141
transmission ignition retard pulse width modulation 17.25
closed throttle position TMS 12.16
water thermistor voltage 3.14
that's all of them, this is from Autel with the jaguar download. Not very comprehensive I know.
I have not jumped the fuel relay as she started right back up so I don't think that is the problem.
I feel the TPS or IAC are responsible with the variation in idle rpm, but they are both brand new the IAC could be suspect as it is a generic cheap one.
Thanks for all your suggestions.

 

" I have not jumped the fuel relay as she started right back up so I don't think that is the problem

The FP relay or the control circuit wires may be intermittent

The FP enable during driving is from the Crankshaft position sensor

Your battery voltage is high and should be between 13.5 and 14.5 with the alternator turning

This high voltage should not effect "most ? of the sensors including the TPS as they are feed a very controlled 5.0 volts DC from the ECU

I recently posted a 521 page official Jaguar service manual in 6 parts in the following link coming in post # 4

Repair Manual - Jaguar Forums - Jaguar Enthusiasts Forum
The CKPS can fail in some components of its use of the single signal but still not give you a CEL code

An example would be fuel pump enable but the tach still working

For free you can clean the CKPS connector , clean the face of the sensor of debris and open the wire loom as it goes over the fuel rail and inspect the wire splice in that area

One interesting note is the fuel pump enable goes through the Papa Indy 1 or 61 connector under the hood that is subject of a Jaguar TSB

05.1-14 (jagrepair.com)