So I have this 94 4.0 I'm trying to get offroad ready. It has a long crank to it. It starts everytime and runs perfect with not a single hesitation. Usually takes 2-4 seconds of cranking before it will start. Once in a while starts instantly, these are very random. I replaced the ignition module( part that sits on bottom of distributor cap) and didn't change anything. Any ideas? I'm thinking maybe the whole ignition control module (computer part) but don't want to go buy one if its something smaller. Any input is greatly appreciated

 

knock on wood and then dont ever talk about it starting everytime again.

 

Mine takes about that long as well. i changed various sensors and it seemed to help. I was also told that compression has something to do with quick starts. I have a ton of miles on mine so who knows.

cps changed
o2 sensor
iac
tps
thats all
and new cables with fresh grouns

 

Often it's caused by a small leak in the fuel system. No you won't see it leak, it's internal.
Or - It could be the fuel pressure regular's check valve - dirty, worn etc. Clean or replace.
But often it's in the tank - the fuel pump.

The pump has a short rubber hose on it 4" long?- all the aftermarket pumps save a penny or two by using a rubber hose that's not fuel hose. (Inside the tank.) Eventually the gasoline dissolves the hose a little, when you stop the engine the fuel drains back to the tank out that leak. You'll find it turned to a sticky mush!

Make sure you have used most of the fuel in the tank, remove the 8 screws holding the pump in the tank, carefully extract the pump.
Replace that hose with QUALITY FUEL HOSE, clamp it securely, replace. Done. Enjoy!

 

Lol, I guess the word "everytime" can really bite ya in the ***. Yea, I think I will do an affordable overhaulon it and change every sensor out so at least I know they are all good. The long crank may stick around but I guess I can deal with it as long as all my parts and sensors are in new

 

Fuel system leakdown is the primary suspect.

Try this simple test: It is called the "poor mans prime"

1. Turn the key to the ON position (not start)
2. The fuel pump should energize and run for about 2 seconds
3. Turn the key to the OFF position
4. Repeat steps 1-3 twice more

NOW try to start the engine. If it starts quickly and cleanly, you have confirmed a fuel pressure leakdown. Now you just need to find out where; often it is the fuel pump assembly.

The other thing to do is to freshen ALL engine grounds. Life starts with electrical. You can't tell a thing by looking at them. You must remove them, clean the contact points until shiny and reattach.

 

Alot of guys find that splicing in a certain BMW check valve will solve the problem.

 

I have this issue also. Would love more on fixing it. I always thought it was a renix thing.

 

Look into the BMW check valve.

Its after 2000 or something when you can't use it anymore.

 

Do I have to drop the tank or anything major?

 

Also. Part number or even what BMW to get one for.

 

No, splice it in. Run a search...

 

This check valve is hit or miss and it is NOT recommended for 1996 and newer when the fuel system design (return) changed. In fact, it has caused a fire on a couple of newer XJs.

I'd generally recommend replacing the fuel pump IF you have done the proper troubleshooting that tells you that the check valve is the culprit.

 

What are those tests.

 

check fuel pressure with tool...or let jeep sit for few hours or overnight then go to fuel rail where injectors are and press valve in...if you got heavy spray the regulator /check valve is good...but if your hissing air and smallflow of fuel, then regulator is bad. this really only tests the fuel pump assembly