2001 3.2 v8

Ok here's a puzzle (to me anyway)
driving perfectly then suddenly revs drop to 1100-1200 rpm
error messages show gearbox failure, engine failsafe mode,asc not available and trac not available. No noises or forwarning cannot rev the car at all. the reduced revs seem to have no power either as it will only move extremely slow not like the idle "creep" you normally get. I turn engine off and it will start no probs but all the above still happens...after a few ignition on off cycles hey presto back to normal like nothing has happened.
Pulled the codes and all I got was

thermostat low temperature
p1000 unknown error code

this has happened 4 times today twice soon after starting and twice while driving

any ideas anyone?(its going back tomorrow to the guy that fitted the used engine & it would be nice to go for-armed so to speak!)

 

Hmmm...not good, and you must be really annoyed.

Hopefully some of our more tech minded gurus can help >>>>

 

Thanks for the reply

yeah annoyed covers it ..cos I just know the guy will say "ah thats nothing to do with the work I have done" the fact that prior to the engine replace the only code I got in 2 years was a temperature warning -oh and a miss fire.
I just pray it doesn't decide to play up at a juntion !

 

My 200 xj8 just did this for the second time in 10 years- the first was 5 years ago. Also, no stored codes in the OBD group. I will read it with IDS this weekend, but I suspect the problem is in the transmission to ecu communication or disagreement of measured parameters between the two.

 

What OBD code # was the 'thermostat low temp'?

When I had an intermittent connection, due to corrosion in the throttle position sensor connectors, the same thing would happen to me - all the failure displays, from trac to gearbox and limp mode... so I suspect when the ECM sees a series of out of range readings it throws all possible errors and goes into limp mode... the actual OBD code (not the description) may help show us where your problem occurred.

 

the only codes I am getting are
P0128
and
p1000

 

I think Sparky's on the right track, it could be gearbox cable adjustment, it may be different on the XJR, I had a very similar roll of errors and cleared them by ever so slightly adjusting the gearbox selector cable. Like I said the switch is probably different on the 3.2 but that's where I'd be looking first.

P1000 is a non entity code, nothing to worry about.

 

ok just had kitty on the proper jag computer...it showed only a couple of spurious codes like air con pressure low blah blah..
The codes that were there were all leftovers from having the engine out/in etc
The guy checked a couple of connections but we (he) found nothing that we can say...ah thats it! Hasn't done it since though...

Thanks for the input Sean another place to check !

Though now I am going to go and have a real good lunch ....hic!

by the by these real computers are awesome.

 

I cant say for sure, but it seems almost like the modules are unable to communicate with each other properly. It could be the data network circuit has an intermittent open or short. It could also be an intermittent power or ground problem. There is a possibility that while the engine was going in and out, a wire was partially broken or skinned. How long has the new engine been in there? On most American cars with the can-bus networks that have a daisy chain (series) configuration, if one module goes out, it can knock out all of the other modules from being able to communicate.

You really need to have a capable scanner available to see what modules you can and cannot communicate with whenever the problem is present. This will help narrow things down or at least let you know if you are on the right or wrong track.
-Rob

 

Thanks for the input
Th engine has been in a week now and done about 250 miles.
I did wonder about a stretched wire or a crushed one (I have done it myself on more than one occasion but not on a jag )
It has been on a pucker Jag scanner and it all checked out ok ..agreed that was without the fault. The thing is although it happened 4 times on friday it has not happened since. I cannot 'force' the fault and there's no warning to it happening.
The computer the guy used is obviously at his workshop so it needs to fail there as when the fault shows the car is not drivable and cannot even be limped in !
Here's an intresting thing the engine goes into "failsafe" but I am not sure how "safe" it is to lose all drive and power just when you have pulled out at a T junction!!!!!
(don't ya love irony?)

 

Yeah I hated it when my jag would throw a gearbox fault and failsafe to 5th gear. Talk about slowwwww acceleration. I imagine a restricted peformance error on top of that would make things even worse!

 

THe P0128 implies an out of range measurement from the Engine Coolant Temp sensor - so there may be a loose/intermittent connection there; but this error is not supposed to throw the system into limp mode, so your primary issue is elsewhere.

 

Indeed it is. I solved the coolant temp yesterday by putting in a new thermostat.

So far the other stuff has not returned.(insert a fingers crossed icon here ).
I am hoping that when the guy jiggled some connectors he made a good contact somewhere!

 

ok the guy jiggling stuff did not make it all better.

Where the h*ll do I start to look for stretched/bruised wiring?

What wiring do I have in the engine bay area that are likely to get snagged or forgotten to be disconnected ?

I think I need to make up some kind of check list that I can slowly work through and tick off etc.

All any help would be SO appreciated

 

note I'm no expert on the NA engines, but if it's swapped, there's only the connections at the back of the engine, and it's own loom connector that could throw these codes.
I'll list the ones I think can give you headaches....
Take off the middle engine bay accessory cover, the one that covers the wiper motor.
You'll see a big black block, the engine loom joins the car's main loom, it should have a bolt running through it and it should be hand tight, too tight cracks the plastic housing.

There are connectors low down over the bell housing, these 4 are the O2 sensors.

Throttle body connector, these can give oddness.

Maf sensor

Starter and Earth, these connections are found underneath the car earth is bolted with a strap across the chassis transmission tunnel. Starter is best checked either through the wheel well with the wheel off or from underneath also.

If you disconnect - clean - wd40 and connect back up, see how it goes.

Having covered 250 miles without issue, the motor seems good as was the install. It does sound like something not 100% connected electronically, but being intermittent is the tough one.

 

I would have a real careful look at the transmission interface cable (left side , I think) and the harness it is in. My idea is that while fitting the engine the tranny could have been displaced enough to put that connector under a strain- It is reportedly got little slack anyway. Have you read the transmission stored codes- the TCU? What scanner are you using. In investigation of my problem, I am coming up with the idea that the fault condition is a result of disagreement between the engine and transmission controllers, so the control strategy is to go to restricted performance to prevent screwing up some mechanial component.
I'm betting you find bent pins or loose wires in the tranny electrical connector.

 

I came back to add what Ross has already said, but probably not as clearly described!

I wondered if the old engine and box came out, old box to new engine went in, and the issue is as Ross suggests. Maybe ask the fitters how they went about it with regards to the gearbox and wiring?

 

Thanks guys I REALLY appreciate this help!

I too think its a "connection" problem.
The issue started 3 days after engine was put in (about 80-100 miles)
NO "real" codes are being stored at all. I don't know the name of the scanner that the guy used on saturday but apparently its the real thing or one sold in America as the official Jag one is not generally available here.

The engine itself is running sweeter than ever.

Have emailed the guy that did the work for any ideas where I could start.
I am going to try to tackle only ONE connection/thing/area at a time so hopefully I will be able to say for sure what/where the problem is..I will start with the tranny thingy bits.