Willowsjeep

Hey Troops!
First I apologize if this issue has been addressed elsewhere in the forums. But I can’t seem to find this exact situation so I thought I’d make a post!

My Wife’s 96 Grand Cherokee ( 4.0 I6, Auto Trans) with 242 k on the odometer starts within 2-3 cranks when the outside temperature is 60 or above but when down below around 55 it is a grump when it comes to starting.

Since it is so clean and rust free we had decided to keep the Jeep and use it for a local-use rig. So far the only fluid it burns is gasoline, even though the engine does sound a bit relaxed and loose inside!
Following is a list of the parts that have been replaced due to as much preventative maintenance as to the fact that they have failed or not!

(Taking a big breath New battery, alternator, ignition coil, distributor which came with rotor and cap, new wires, new plugs, new idle air control valve, new air filter, SEAfoam intake manifold cleaner application, new fuel pump, fuel filter, radiator, crankshaft position sensor x-2, main engine computer or ECM which was recommended by the local Jeep expert mechanic which was a rebuilt from a Jeep specialist in Texas.
Also cleaned in the throat of the area where the IAC would function vigorously cleaning out any grease and other things that were in the area.

I have tried the poor man’s prime with turning the key on and letting it sit until the fuel pump quit humming. Weirdly enough when it’s cold the fuel pump runs for quite a long time before finally shutting off. When the jeep is warm the fuel pump homes for maybe a second or two and then shuts off and the jeep fires up instantly.
The part I’m going to put it on today as it just arrived is a charge air temperature sensor from Walker. Maybe somehow the sound is not sensing the right outside air temp.

ANY suggestions would be MOST welcome as I love to help keep My Wife’s ZJ Happy for Her as She is Stll a Keeper after 21years of marriage!
Thanks in advance,
Ed
PS: Will update if the temp sensor fixes the issue.


UPDATE:
10/11/2022
Just replaced the intake air temp sensor and it does not seem to make any difference in the cold start issue! The old sensor was VERY oily and grimy!
Next, will replace the coolant temp sensor

Ricthewrench

Check your fuel pressure

Willowsjeep

Thanks for the reply!
Will see what the fuel pressure is...I wasn't aware that the ambient temp affected the fuel pressure.
Really appreciate the input,
Ed