it is a bit over 600 normal.
had tos reset just recently.
scanner shows idle at 610-620.
tach reads around 675.

replacing iacv can be done easy. Can buy a chinese special from ali express for under $50 au.
tps looks more a hassle tho.

maybe it might be worth unplugging and spraying some contact cleaner into all the under bonnet connections. Just incase.

it could be mass air flow sensor i suppose. I did swap that recently after having an issue when car would not crank.
it was swapped with one from a car that was running perfect.
could be faulty tho
if i disconnect the MAF i should expect to see it run worse? Or better?

 

There is an art to connector cleaning and leaving them in a good state to not pose future problems / issues

There is the crimp of the connector individual pins / sockets on the raw wires on the back side of the face of the connector that gives issues over time and missed

If you disconnect the MAF the information it provides would be missing so the engine regulation defaults , would be less than optimum ( worse ) if even running at all

The MAF return signal ( middle wire ) is on paper 1.2 volts DC at the proper idle speed and increases toward 5 on throttle up , there is a wire splice under the hood that powers the MAF as battery B + voltage ( alternator voltage regulation ? ) . There could also be an issue with the items spliced into the power source is " sucking down " the MAF return

Those other items are X , Y , and Z

 

would i be right in saying if it is the IAC that is failing the car would start fine with the throttle slightly open?
the reason i say this is obviously the IAC allows air past and holding the throttle open does the same thing.

the reason i query this is it that when it stalled this morning and took quite a while to restart opening the throttle whilst turning the key had no effect. and i was under the impression if the IAC was to blame then this would circumvent that.

 

i see in another thread parker that you mention something i was unaware of due to cam shafts in the 95. with 110 v 114.
what exactly were the idle issues that these camshafts caused that led jag to change them?
i ask as my as having a 95 with engine number 129001 i fall 103 engines before these cams were changed.

 

This is from the XJS manual:

A manual reset of the IACV seems to just be a test to see if it is working, but give it a go:

1. Run engine until you reach normal operating temperature.
2. Switch ignition off.
3. Switch ignition on, wait 5 seconds, then disconnect the connector to the idle speed controller.
4. Switch ignition off.
5. Wait 15 seconds then reconnect idle speed controller.
6. Repeat two more times.
7. On last repeat, do not reconnect idle speed controller.
8. Start the engine.

Check the base idle speed, which should be at 550-600rpm. If it is, I believe the IACV is working. Once you shut the car off, it will resume behaving badly because something else is at fault.

Switch ignition off and reconnect the idle speed controller. Start engine and check to ensure that the idle speed is between 650-800rpm…it probably won’t be, but if you were successful in the previous step, I think the IACV can be ruled out.

 

In my opinion the early cam idle issues were livable as they were designing and testing the car

But the customer after having paid so much for the car would complain hence the upgrade

A fixed solid cam angle is a compromise in what is the best angle at the low idle and different best angle at higher RPMs for exhaust gas clearance out of the cylinders and get the most power on high end

On the high end the amount of oxygen consumed after combustion gasses not cleared ( there will always be some left behind going back into intake stroke ) effectively reduces the cubic displacement of the engine cylinders

The management wanted the best horsepower numbers for the sales brochure compromising the idle end ( Andy ? )

Hense the variable cam , it's got me dreaming here at the Center for the Institute of Postulation

When I looked at my cams for a part # what I saw didn't make sense until someone mentioned it is the raw unmachined forged blank stock part # before machining

Where was that engine serial # again ?

 

done that and all appears good

 

replaced the crankshaft sensor today.
lets see how it goes.
she drove well today before doing that.
might take a while to feel confident if the sensor has made an impact or not.

 

check the resistance of the water temp sensor. Mine was open circuit and should have been 380 ohms when engine was hot. ECU was falsely thinking engine was cold. therefoe issued a very rich mixture.

 

Another slightly related question.

how long should the jag take to warm up?
esp on a cold morning.
i drive 20 mins to work and noticed this morning the car was still not warm (according to guage) by the time i got there.
It was about 5 degrees celcius this morning

it had dropped from cold start idle to normal idle within a few mins of start tho.

 

Sounds like a stuck open thermostat.
My 3.2 was very slow to warm up until I replaced the thermostat but now hits normal after 5-10 min even on the coldest mornings.
The thermostat I got was supplied with a rubber sealing ring - DO NOT USE THE RING AS IT BREAKS THE THERMOSTAT HOUSING WHEN TIGHTENED.
Tried the crankshaft position sensor yet?

 

thermo should be fine. replace 2 years (12500kms) ago.
I think it was just slow to warm today as it was really cold and I had the heater on full.
this is not something I have noticed previously.

I installed the crank sensor yesterday. it ran fine today. lets see how it goes after the next little while and I will report back.

When I installed the sensor I did notice what appears top be an oil leak somewhere around near where the camshaft sensor sits.
I cleaned it all up, and will keep an eye on it over the next little while to try and see where exactly the leak is.

 

Checked the spark plugs today just to make sure all was good.
Gave em a bit of a clean, i think all is good car starts to run a bit more **** whenever and is disconnected so they are all sparking fine.

disconnected the maf while the car was running and there is not really any change to how the car was running. There was a slight splutter then it returned to running ok.
with the maf disconnected the car will not start tho. And if it does start it instantly dies.
Same result with 2 different mafs.

on my parts car (which is suffering from real low idle (amongst other things) when the maf is disconnected the car immediately stalls.
tested both mafs on this car and got same results.

so both 2 mafs i have appear to be functioning just fine as they give different results on each car but both give the same results on the same cars.

 

On the removing the MAF while running the ECU lets you run getting you back home

From a start it won't let you go out of the driveway

 

I am relatively new to Jaguars. In case it helps, wanted to share my experience with these exact symptoms on two other cars that were not Jaguars. Both were fuel pump related. One vehicle had one pump which was in the tank, the other had two, one in the tank and one midway between the tank and the engine. Both problems were caused by the pumps in the tank.

I am not sure about Jags, I believe most OBD2 cars will trigger a check engine light code if the IACV, MAF, or CPS are failing. I notice yours is a 1995 so it's probably not OBD2. For what it is worth, I've had other vehicles with IACV and CPS failures. Both continued to run but had obvious idling or acceleration related issues but did not randomly stall or present with no start issues.

 

The 1995 X300s (6 cylinder, at least) were indeed OBDII but there are some bugs. Over the years Jaguar techs posting here have described the 1995 OBDII as "not fully developed" or similar.

I had a '95 for many years and can attest that the OBDII system was the source of some frustrations.

Apparently the bugs were fixed for 1996 as you don't hear complaints.

Cheers
DD

 

yeah fuel pump was my first thought…. Lets see how i go for now and fuel pump will be next on my list. Pain to change .

 

my car is a 95 but has had ecu swapped and has an ecu from 96 fitted.
wonder if this fixes the obdii bugs

 

Ok so, it is running rich and it does seem the thermo is stuck open. Car not warming up even after 30 mins idling in driveway. (My parts car warm in 5-10mins)
so gotta replace thermo (even tho this one less than 2years and 15k km old)

and did relay swap.
fuel pump relay in boot.

ingnition coil, ecu, secondary air injection relays under bonnet.

swapped with relays from parts car.

not hopeful but lets see.