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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.
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.
Now we come around to the reasons the butterfly may not be returning to the physical idle stop
some have found the throttle cable miss routed or binding or the return spring under performing if the original factory spring is present ( there is a way around acquiring the revised stronger spring ) _
There is 2 A and M marked mounting positions just before the inter cable attaches to the butterfly bellcrank , you may not see the A and M because of the surface age
Then the question on the part # of the EGR valve installed and if it is being controlled correctly with the correct PROM
The EGR ( the EGR has a EGR_ error parameter ID on the ELM - 327 and the target value is 0 as live data but is not perfect ) as well as your EVAP valve ( can be tested with a 9 volt battery ) should be closed at idle
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 ?
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.
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