Colorado Crush

Hey all,

Been slowly working through my problems with the 97' 4.0. So far I have replaced the ignition coil, distributor cap, spark plug wires, spark plugs, injectors, battery cables (2AWG), 02 sensors, fuel pump and the ECU/PCM. I redid the harness for the fuel injectors and sensors.

I have an issue with irregular start up. Early in the morning at 6am for work it starts up right away with 1-2 cranks. I drive to work, on my second or third start up of the day it doesn't really start after 5-10 cranks unless I give it some throttle.
If I am driving around, stop the Jeep and start it back up it starts right up with a warm start with 1-2 cranks.

Does anyone have any idea why my second and third start ups are harder than my first? If I can fix this issue it would be the end of a long journey of getting the ignition and base performance of the Jeep where I want it to be. I could then move onto other things I need to work on in the suspension area.

BlueRidgeMark

Test your fuel pressure.


Factory battery cables are 6 gauge. They are fine. 4 gauge is a nice upgrade. Anything bigger is a waste of copper. It buys you nothing at all.

Roler

So, you're saying it starts fine cold as well as warm, but only the second and third starts of the day not so?

When are those?
Cranks slower then as well?
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Colorado Crush

I will get a fuel pressure tester and check it. What kind of readings should I be getting at the fuel rail?

As far as the wire gauge, I upsized because I plan on having accessories and possibly a winch. $40 extra really isn't that much when I am considering buying a Banks Torque Tube and a 62MM Throttle Body.


Okay so basically early morning 6am, after she has been sitting all night, 30F, will fire right up with two cranks and sound super strong.

Lets say I drive to the gas station, stop, get my beverages or whatever and get back in with a 15 minute down time. She will two crank, fire right up and start super strong.

Right around 12pm I go to lunch and its a hard start and if it does turn over the rpms are low unless I throttle. If I just pre throttle while I crank the ignition it will start on the 5-6th crank and obviously rev because I am on the gas.
3-4pm I go home and its the same thing, hard start lots of cranks to start.

Roler

Have you got a fuel.pressure done yet?
49psi +/- a bit you should have.

we can go to great lengths trying to chase this, depends on willingness. It's running ok when driving and the little drop in rpms doesn't make it stall, so it can be a lot of things.

Colorado Crush

I'm going to order a fuel pressure tester off Amazon today. Just doing my research so I don't get a lemon, more so when it comes to dealing with gasoline.

BlueRidgeMark

You may be able to rent one from Autozone, Advance, or NAPA. They do rent some tools.

Your starter cables will know nothing at all about a winch or accessories. That current will never flow through those cables. The winch + and - should be run directly to the battery (where 2 gauge might make sense) and any accessories the same (possibly with relays). The one you need to upgrade is the ground to the inner fender, and that ground point itself, unless you are going to run the accessories with their own ground.


One of these days I need to do a write up on this, with diagrams. Way too many people spending money and time on wasted copper because "that's what everybody says I need to do".

Besides, 2 gauge is a pain to work with.

Colorado Crush

I bought one off Amazon today, will be here tomorrow. Will probably get 2-3 readings through out the day when I know it is doing what its doing. If its the $100 pump going out or doing weird things I am fully prepared to buy a Bosch next week.

Honestly though, I don't mind and I am probably going to buy another 2AWG set for my 99'. Who cares? I'm an electrician and fill bags with romex every day because of people who want to remodel their perfectly fine million dollar homes. I don't care if its a placebo, I am going to most likely upgrade to a 136amp alternator, I just want the extra capacity. This thread isn't about why you think my battery cables are a waste and how thick wire is hard to work with, its about me trying to fix my start up issues.

Roler

Jus went through your first post again
What had been the issues you have been working through?
You have replaced a lot already, including the ECU
WIth the tune up, did you include the rotor as well (not mentioned)?

What you could try as test, is next time you would expect it to crank longer, is priming the fuel pump a few times (turning the key to on (not start), and key off again) before you go and start it. See if it makes any difference.

In all honesty, my XJ has always had a long crank. Priming the fuel pump reduces that somewhat (I know I have leakback valve issue but cant be bothered to replace fuelpump yet)
But for what I know it tends to be a longer cranker

Not sure to what extend you really would like to have this sorted out, if your XJ is otherwise starting and running fine. You've thrown plenty or parts in by now...

Colorado Crush

I was having a misfire in the injector #2 and had a open circuit, re did my wire harness and tried 3 different sets of injectors as well as the tune up. I chased that demon and basically just realized that it was the ECU/PCM, I haven't had a short in the injector circuit since I swapped it. This Jeep was a Florida Jeep and I swear they stored it in a swamp and hardly took care of it because I have been chasing weird issues.

I did replace the Distributor Cap Rotor.

I have a 99' that starts up with 1-2 cranks every time, even if its been sitting for extended periods and even after all the abuse I put it through.

I have been getting a P0441 code the last couple of days and can't determine if its when I fill up or if its a new constant. Could the evap system have anything to do with start up?

Colorado Crush

Tonight I got the pressure tester and hooked it up right after running to get some take out. My pressure spiked up to 49/50 and bled down to 40 within a minute with ignition turned on. Should it be holding 49 as soon as I turn the key and stay there? It stayed at 50ish PSI while running.

Roler

That fuel pressure is okIf it doesn't bleed down more, but it's within spec and sure enough to get it started, so that doesn't seem to be the issue.