1992 4.0 xj40 .
Idle good hot and cold , no problems while driving, even in kickdown.
But when i am in park or neutral if i give a strong push to the gas pedal from idle for a moment (1 second) the engine hesitates like too much fuel arrives at the cylinders , if i push the gas gently no problem at all. I am wondering if i have to check spark plugs, injectors ot other stuff.
Check/replace the sparkplugs can be a good idea, depends how much kms they have done.
How’s the air cleaner?
Fuel pressure ok? No leaks in the intake?
All connecters ok, no corrosion?
my impression is that this problem is related to the water temperature sensor. Sometimes i had the fuel 14 error and when the light is on the problem is worse. My idea is that the sensor does not detect the temperature of the engine correctly, so it enriches excessively the mixture. sometimes i feel some smell of fuel when the engine si hot, like the mixture is excessively rich. I will change the sensor and check again the situation
It’s also possible the Lambda / oxygen sensor is faulty, especially if the problem only occurs when the engine has reached correct operating temperature. If the temp gauge on the dash is remaining steady in the ‘N’ position during normal driving and also at idle it’s definitely worth checking the Oxy sensor heater relay and the Oxy sensor itself.
yes casso engine temperature is just always stable in the center of N… but if the lambda is defective should the engine light comes on with different error? can i buy a universal lambda sensor or i have to buy a specific model? the idle is perfect hot and cold.
You can check the function of the Lambda sensor before you pay out for a replacement, I’m not sure, but I think the procedure is detailed somewhere on the forum, one of the more experienced members will know, it entails using a multi meter with a pin probe fitted.
My advice, if you find yours is faulty is to replace it with the recommended DBC1074 Bosch sensor if only for peace of mind.
In my own experience, the indicated error codes don’t always relate exactly to the problem, they’re more of a guide to point a technician using the ( now defunct ) rather primitive diagnostics equipment available at the time of production in the right direction.
Code 14 does indicate an engine temp sensor ’ out of range ’ which could lead to fooling the EMS that the mixture is too rich or too weak therefore increasing or lessening the fuel being delivered, and as it is so easy to change and relatively cheap, that would be the first thing I’d do in your position.
Also, bear in mind, the reading on the gauge is separate to the information the EMS receives from the actual CTS, so even if the needle remains in the ‘N’ position, the CTS could still be supplying incorrect info to the EMS.
That’s a good point, Casso. The 2-wire sensor in the thermostat housing provides the data for the engine control module while the single-wire sender supplies the engine temperature gauge. If I ever heard why there are two different devices rather than just one that performs both functions I don’t recall.