I6 4.0L hard starting

beerbelly17 · 06-23-2010, 10:50 AM

my motor is a 1998 i6 4.0L and for some reason it just doesn't want to start i can either sit there and let it crank over perfectly fine for 45sec or let it crank over for a little bit then turn the key a 2nd time and it starts right up. also sometimes when it starts to start it sputters then dies. i had a mechanic take a 5 sec look because he just thought i had old spark plugs but he said they look newer. Any ideas on how to make it start better?

JJ 03 Rubi · 06-27-2010, 12:43 PM

Having the exact same problem on my 03. Seen one idea on ROF that said "Precats are plugged" apparently it is common and is a 80,000 mile warrannty issue. It said Precats are backordered because of Hi demand.
I myself was hoping to hear something much easier to resolve the probblem, but no luck yet.

**oakmckinley** · 07-02-2010, 03:25 AM

My 99TJ does something similar and I heard it was a fuel problem. I can't remember the exact name of the "thingy" but it has something to do with keeping/holding the fuel pressure while its turned off. If the "thingy" is bad it takes a few seconds to build up fuel pressure to start.
Sorry about not knowing the name of the "thingy", I don't have the time to search for the post with the correct name.

RubiconBlack · 07-02-2010, 04:54 AM

Fuel pressure regulator is the name for the "thingy"! lol Try turning the key on and off a couple of times before cranking the engine. Then try starting it up. If it fires up right away then you know that the regulator is allowing fuel pressure to bleed off while the vehicle is shut off. Hope this helps.

beerbelly17 · 07-06-2010, 07:56 AM

Quote:

Originally Posted by RubiconBlack

Fuel pressure regulator is the name for the "thingy"! lol Try turning the key on and off a couple of times before cranking the engine. Then try starting it up. If it fires up right away then you know that the regulator is allowing fuel pressure to bleed off while the vehicle is shut off. Hope this helps.

ya i tried that and it starts right up where could i get a new pressure regulator and how hard is it to replace it or is it not even worth it.

RubiconBlack · 07-09-2010, 04:43 AM

The regulator is on top of the fuel pump sending unit. I'm not sure how much it would be in your area but thru Napa it is $164.45 part number CRB 219735. You can live with it, I know of a lot of Jeeps with this issue. My 95 ZJ had this issue and it had over 240K and I lived with it.

**oakmckinley** · 07-09-2010, 07:38 AM

My 99TJ has been doing this for 8 yrs now and it's been fine. At first I thought I might burn out the starter buts it hasn't happened. I usually try and crank it 2-3 secs (knowing it's not going to start) then go to the off and then crank it again and it always fires up.

jeep rio · 07-09-2010, 02:15 PM

Have you checked the fuel pressure at the schrader valve on the fuel rail yet, That should tell you if your having a fueling issue atlest from the injectors back.

cleanslate · 07-09-2010, 07:54 PM

My 96ZJ does the same thing from time to time. I get out my thumpin stick and start rapping on the gas tank and the thing starts right up. If that don't work then I need somebody to turn the key while I'm beating on the tank. Then when it starts up it instantly revs up to about 2000-2500 and comes right back down as if somebody had their foot on the throttle when the engine fired.

GGibson · 07-14-2010, 04:37 PM

99.9% of the time when this is happening you will end up replacing the fuel pumps.....especially on the wranglers....They are notorious for low volume fuel and rapid drain backs into the tank and causing very hard starts and long crank times....Put a fuel gauge on and turn the key on and then turn it back off and see how fast the fuel goes back....You shouldnt loose too much pressure

**dagr8tim** · 07-14-2010, 06:15 PM

It could be the check valve in the fuel pump/regulator assembly, or a leaky injector.

I've read a good test is to start the Jeep and once it's running, turn it off and put a set of vice grips on the fuel line. If awhile later you can remove the vice grips and start it with no issues, then it's the regulator. If not, it's probably an injector that's leaking into a cylinder.

The above procedure can also be performed with a mechanical gauge. If the fuel pressure drops with the vice grips in place, then leaky injector. If not then it's most likely the regulator.

peteandjo · 09-24-2010, 05:47 AM

I have a 2001 stock Cherokee which for two years was hard to start. It would turn over fine but not fire. Replaced the fuel pump twice and the crank sensor once. Finally it failed to run on all 6 cylinders and we determined it was a fuel injector. Replaced all 6 injectors ( and spark plugs while there) and it now starts fine.

chainbrain2002 · 09-26-2010, 06:25 PM

sounds like the anti-drainback valve on the fuel system. or a leaking fuel injector. i agree with the above test of
pinching off the fuel line before the rail and seeing if it starts up or not on the first try.