The weather has dropped down pretty cold in louisville, ky creating a really rough start with my 2000 xj8. Whenever the car is warm it, of course, starts perfectly rather than the hesitant turnover.
To be honest its embarrassing when an admire stops to look and assumes it hasn't been cared for.
Has anyone experienced something similar and have advice on how to fix this?

 

Hi ratgawd,

When you say "a really rough start," do you mean the engine cranks normally but takes too long to fire and start, or do you mean the engine rotates more slowly than usual or not at all?

Don

 

My thoughts exactly, and my other thought being a tired battery.

Scott

 

Thanks for the response,
I would say it takes longer to fire and start.
Once it does start, as i let her warm up, there's no problem at all and she sounds great. Its just as i said she doesnt want to start right up when shes been sitting in the cold overnight or for a few hours.
What can i do to fix this?

 

Your starter is just not getting enough juice.

Could be as simple as needing a new battery.

The starter solenoid has two copper contacts that burn
out.

All of the main power circuits should be checked for clean
joints positive and negative. The main ground strap is
under the car, to the right, between the transmission
bellhousing and the right frame rail.

 

+1 battery

If not that then check the temperature sensors (ECT & IAT) as cold start fuelling depends critically on them.

 

You might need to run some fuel system cleaner (Gumout Ultra or SeaFoam) to clean the injectors, as well. Also worn spark plugs will cause a hard start i n the winter. This assumes the battery is up to snuff.

 

ratgawd,

What JagV8 is referring to is the Engine Coolant Temperature sensor (ECT), and the Intake Air Temperature sensor (IAT). I agree that if your battery tests well, those would be the next two prime suspects. They can be tested with an ohmmeter (a Digital Multi-Meter (DMM), Volt-Ohm Milliammeter (VOM), Analog Multimeter, etc.). The Engine Control Module (ECM) depends on the signals from those sensors to determine cold-start fuel enrichment, and if the signal from either sensor is off, the engine may receive a fuel mixture that is too lean for cold starting.

It would also be worth cleaning your Mass Air Flow Sensor (MAFS) with a zero-residue cleaner spray designed for that purpose. Do not touch the components inside the MAFS except with the spray fluid. The photos at the links below show how to service the MAFS as part of your service to change the air filter:

Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page


I can't recall if the X308 can store any Diagnostic Trouble Codes (DTCs) related to hard starting that will not also trigger the Check Engine Lamp (CEL), but perhaps others will know if it would be worth having your car scanned for codes that would help you diagnose the problem.

Cheers,

Don

 

Yeah... see my signature ...

I'd use OBD to read them, much easier and tells you what the PCM is seeing.

Merry Xmas BTW!

 

Sounds like I'm experiencing the exact same problem with my 1998 XJ.

Cold start is a bitch it just won't start, yesterday I spend at least 10 minutes and in the end it turned on at full throttle and starting at the same time.

once it has been running it starts like brand new untill the engine gets cold again.
The problem started after the weather changed and got colder, First I put in new sparks with 172.000 km on the speedo that was around the right time I think.

Only other thing I could find is a coolant leak at the thermostat housing, I already have a new aluminum one on order.

Haven't used my code reader yet but I get the idea it has to do with the coolant temp sensor.

Yesterday evening I used compressed air to blow all the leaked coolant from the engine top and parked it close to my garage this morning it took two tries to get it started.

Where is that coolant temperature sensor located on the engine ? does anyone have a photo or is it the sensor that's mounted in the thermostat water outlet pipe (black pipe just below and in front of thermostat housing ) ??

Sorry don't mean to intrude but it sounds like the same issue.

 

Yes, that's it on the crossover pipe. It would be a good idea to replace that pipe and the upper and lower radiator hoses as well as the short hose when you do the housing. All the plastic parts get brittle with age.

When you remove the housing, just break into pieces with locking pliers to access the rear screws. Stuff a rag down first to keep the pieces out of the engine. Use socket head screws and a ball end hex key to reassemble and you will have no problem clearing the intake manifold.

Have the secondary tensioners been replaced?

 

I just might have found a way to test if the coolant sensor is the culprit.
This afternoon my car refused to start again, so after three tries I got out opened the hood and disconnected the coolant temp sensor.

I got in started and it turned on instantly, got out again and connected the temp sensor.
Could have been a coincident, but that will show tomorrow morning with a second try.
It would however be the way to go, with the sensor disconnected it has infinite resistance, I would imagine it would at least show a very high resistance when the engine is cold so disconnecting it has a similar result sending the right signal to the ECU and in turn enriching the mixture for the cold start !!!

Might do the trick for Ratgawd also !!

RJ237:
I have on order: water pump, Thermostat housing (aluminium one) and crossover pipe (complete with sensor)

The rest (hoses and stuff) seem to be in fine condition, they may have been swapped before as the Jag now has 172.000 Km on.

Don't know about the tensioners but there aren't any strange sounds coming from the timing chain.
It's former owner is my lawyer who always had it serviced at the jaguar dealer Don't know if secondary tensioners would be something a dealership would have taken care of ??

 

I would not count on the dealer to suggest it in the US, but it may be different there. Perhaps the dealer would check the service records, but do not fail to either get the history or remove the valve covers to inspect. Waiting to hear noise is inviting a disaster.