Update: I am going to order this IAT2. I had thought that cleaning and reseating the connector has sorted it out, but no.
A roadtrip of approx 200 miles in total over the weekend and it threw the error 3 times in the space of an hour. Reset and all is fine for another hour or 3 or driving. Really odd.
The worst bit was it happening in front of about 3 XJR6 drivers :-(

 

Hi Guys
Long time - no update. Been on other things...

New IAT2 fitted. Genuine Jaguar part in a sealed bag from Jaguar.

All is ok, 40-50 miles and the same problem pops up. Restricted Performance - P2601 Coolant pump control circuit range/performance.

Checked the pump was running when we pulled over on the side of the road.
Reset it and all was ok for 20 minutes then it came back again.

I am at a total loss on this one. The pump is running ok. Tried 3 OEM Hellas, 2 Bosch-type aftermarkets, new IAT2.

I am now wondering if there is a blockage/restriction in the pipework, maybe a kink in a pipe that is restricting the flow.... The engine had been out before we bought it so there is a chance something has not been put back correctly.

Does anybody have any tips on this? Opinions and tips are most welcome.
Thanks
Next step, off with the supercharger and take off all the pipes and inspect. Good time to replace any that look suspect.

 

well shoot...you have a strange one....you could take the hoses off at the charge coolers and blow air thru the coolers and see what happens....then do the same with the hoses and look at them on the inside to see if they have swelled internally....have you had a look inside the charge coolers where the charger outlet connects....i am wondering if they are packed full of oil residue...that is all i can think of other than the intercooler it self being restricted....i had a similar problem once but no code.....just suspected the flow was not right...i took off the charge cooler outlet hoses at the charge cooler and ran the pump.....coolant was just drizzling out....i knew the pump was good because i checked flow coming out....i removed the 2 charge cooler hose assemblies and found internal swelling on both...replaced both assemblies and all was fixed......check flow like i suggested and go from there i guess

 

are the coolers hot?

 

Still unknown is the root cause for this code being flagged.

Is the intake air being cooled insufficiently after the supercharger? If so, the fault code is accurate. There would be some mechanical issue (collapsed hose?) limiting cooling.

Or is the actual air temperature fine, but an inaccurate temp value is causing a false code?

Can you get an infrared thermometer on the ducting by the two temp sensors? Post #35 had some values you should expect to see.

Even though you've replaced IAT2, perhaps the problem is in the associated wiring (corroded connector?) and not the sensor itself.

Your scanner doesn't display IAT2, right? Can you measure resistance of both temp sensors? Don't know for sure, but would think they're both the same electrically. In other words, X degrees = Y ohms. Let the engine rest overnight so both sensors are at ambient. If my thinking is correct, both should have very similar resistance. If comparable when measured directly at the sensors, reconnect them and measure from the connector at the computer. This will test all associated wiring.

IAT1 does show on your scanner, right? Is the value close to ambient?

Did you ever do a pressure test of the cooling system? Not sure this is it, but is one of the basics that should be covered when troubleshooting.

 

You can watch IAT2 in some tools.

SDD of course but also others - even torque pro (there's a thread I think in another forum, maybe Gen Tech, about the formula etc).

 

exactly...i see it on my icarsoft....iat2 is always way higher than ambient on the supercharged vehicles after it runs a while....usually over 100F.....as xalty asked are your charge coolers hot to the touch after running a while or lukewarm.....they should be lukewarm to warm but easily touched while running....hot means a water flow problem....after shutoff they will get hot to the touch because of no water flow

 

no need to take the charger off as of yet....maybe the inlet pipe to the throttle body and the charger outlet horn thing to inspect the charge coolers thru the opening....the gaskets are reusable unless they fall apart...they are steel covered in rubber....use can always use a coating of loctite aviation gasket maker or equivalent as an extra good seal....i love that stuff....aka perma seal from the old days

 

Thanks for the info here, I need to do some tests.
Something I can tell you is my son said the coolers are hot, really hot. Not lukewarm. He almost burnt his hand on one.
Sounds like a restriction in the coolant then. I am guessing it is time to pull the charger off and check all the hoses and the charge coolers too.
Will do a temp check first on the IR thermometer.
Thanks

 

How accessible are the coolant lines without any major disassembly? If not too bad, maybe you could post a pic and label some places to take some temp readings. Then a kindly forum member with a similar model could post their readings for comparison.

What about the SC radiator out front? I never realized SC models had a second radiator for the intercoolers. (Yes, I know it's shocking to think there was something I didn't know... ) Inspect the front of this radiator. Maybe you'll get lucky and find a plastic bag or piece of roadkill blocking airflow.

I still suggest doing a pressure test of the cooling system, too. It's possible to have a minor leak up high on the engine so virtually no coolant escapes, only air, but the system can't build up normal operating pressure.

 

it takes some serious heat to set a p2601

i drove with a dead ic pump for a while and it never set

 

On your model are the charge cooler hoses towards the front or rear of the engine. If front it is easy to take them off for inspection i think. Looks like hoses are at front from photo i found so checking them would be fairly easy and then you could shoot water thru the charge coolers. I bet you will find a restriction somewhere. Best of luck. I know draining the coolant time and time again aint cheap so check any in the supercharger cooling system you can. Worse case scenario is taking the bumper cover loose and rolling it forward and get access to everything super easy. Even the charger intercooler radiator to check flow

 

Hi
Update on temps.
Getting the following:
The metal casings of the charge coolers are reading 180F.
The pipes at the front were about 150F.
SC rad about 150F.

All in all, incredibly hot. We suspect a blockage/restriction in the pipes or charge coolers.
No blockage in the front of the rads.
Sounds like strip-down is looming.
Cheers

 

Just thinking out loud, but what about debris blocking airflow on the face of the intercoolers? I realize this isn’t likely, as it’s all downstream of the air filter. But maybe you had a filter self-destruct in the past. Or perhaps there was a non-stick coating on the SC impellers that has been shedding.

At my day job (aviation maintenance), when there’s poor performance from a heat exchanger, the first thing to check is the presence of debris. Granted, this is unfiltered cooling air, similar to airflow through an automotive radiator. But it’s very common to find plastic bags, hats, and even the occasional bird carcass. So if there’s some feasible means for debris to accumulate beyond the air filter, this would be world inspecting.

 

OK, I think we are going to schedule a tear-down in a month or so.
Visually insect everything, maybe replace as many hoses as needed, especially the ones under the charger.
Does anybody have any part numbers that would be useful? A hose kit maybe? Gaskets needed?
Thanks

 

Hi All

Long time no updates. Sorry.

There was not much to report until recently.
Work is still in progress and is now hampered by the need to find a friendly garage service that will loan/rent a bay for a couple of days.

A few things have been found which may have caused or influenced this.
1. The charge cooler pump had been mounted upside down. Well, I know now it is supposed to be so that the output flow points down. When we bought the car somebody had mounted it with the output facing up. That now makes no sense and down makes a lot of sense. No wonder we burnt out 2 (or more) new pumps, with the totally restricted flow. Should have checked the diagrams, but went with what was there. Mistake, lesson learned.
2. Took off the SC and found the hose running underneath was squashed and restricted. Not good. That may have contributed to the occasional throttle problems until it had got up to full temp. Not actually sure this would cause the error we were getting but may have influenced it.
3. As a result of 1 above, the pipes are misshaped now and somebody has bent the metal entry point into the charge cooler radiator into a squared shape. Very odd.
Oh, and the weirdest problem found, (but not influencing the error we had while removing the SC, my son found that 4 or 5 (maybe more) of the bell housing to transmission bolts were missing. Not loose, missing. How the hell somebody did this is beyond us. However, now we want to take the engine out and check what else may be missing or dangerous.

I guess we have to ask ourselves why Clyde the orangutan was been working on this car.....

Not sure how long it will take to complete this now. Get back to you at some point. Lots to do and no space to do it.
Thanks