• Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

Hard starting ... AM only ??? HELP!

G

gr8lite

NAXJA Forum User
Location
SO.ME.
OK stock powered 94 XJ. Only in the AM first startup of the day. It cranks for quite a while ( 20-40 sec) then starts and runs very rough sometimes stalls. The rest of the day it is fine. Any Thoughts ?
 
Random thoughts:

1. How old is your O2 sensor?

2. Are you letting the fuel pump run until it shuts off before you crank the engine?
 
Cracked distributor cap
 
i had a 94 that did the same thing, i fixed it by getting a 99. actually, i never did figure out what was wrong with it.
 
I go by Eagles rule-
I double prime mine.
turn key until pump cuts off, turn key off, return key until pump cuts off again. usually the second time is enough to bring the pressure up to full...winter time sometimes takes 3 turns.

without primeing, about 15 seconds.
with primeing, about 5.
 
I will try the key on / fuel pump test. However this has not always been the issue. This rig has been fine since last May. This has just started. I don't think the manner in which the key is turned has changed. It was fine all winter. Good call on the cap, I will check it! I wasn't thinking outside the FI system. Thanks for all the help guys , we'll see what happens.
 
gr8lite said:
I will try the key on / fuel pump test. However this has not always been the issue. This rig has been fine since last May. This has just started. I don't think the manner in which the key is turned has changed. It was fine all winter. Good call on the cap, I will check it! I wasn't thinking outside the FI system. Thanks for all the help guys , we'll see what happens.
Click to expand...

I had a 66 mustang, chased that cracked cap for almost 3 months on an off. condensation got in it over nite thru the crack. Once the moisture was cooked of it was fine.
 
Most if not all FI systems don't use the O2 sensor data until the engine has gone closed loop. The engine runs open loop when starting and until it warms up to a certain temperature.

Your problem sounds like a coolant temperature sensor to me. The PCM thinks the engine is warm, so it doesn't supply enough fuel to start the cold engine.

I have owned hard starting engines where the only problem was ignition related.
 
Sparkman said:
Most if not all FI systems don't use the O2 sensor data until the engine has gone closed loop. The engine runs open loop when starting and until it warms up to a certain temperature.
Click to expand...

Good point.

If it isn't the distributor cap, the next thing I'd think about is the CPS. Usually they just fail, but sometimes they do strange things for awhile before giving up completely.
 
FUEL PUMP

there is a check ball in the fuel pump that holds the fuel in the line.

When it starts to fail, fuel drains back to the tank overnight and you have to wait for fuel pressure in the AM

To check for this, install a FP guage and start the engine, shut it off and watch fuel pressure over a 20 min period... If it falls off more than 10 psi, the check ball is bad and needs replacement.


To check for this if you have no guage, in the AM, turn the key on then off for ten seconds, then on again.... do this 3 times then crank the engine after the last time. If it starts right away, replace the fuel pump.
 
Digger and ED sounds like you may have got it. I had her try the turn key on / off / on then it fired right up! I figured it must be losing pressure somehow after she called back to update me. We'll attempt a fix real soon! Thanks to all who contributed. I will post with a fix if I can find one! :wave1:

Thanks Guys !
 
gr8lite said:
It cranks for quite a while ( 20-40 sec)
Click to expand...

Don't ever run your starter that long. It is designed to run for 15 seconds MAX. If you have it on for 40 seconds it will be way overheated...
 
Well this issue is beginning to be a big pain! When the key is turned to the on position there is almost a 1 min wait for the fuel pump to "pressurize" the system. Sometimes the key must be turned on / off / on a couple times at the 1 min interval to get it to pump.
It almost acts like there is a poor connection to the in tank pump. Does anyone know where if any there is a connector in the wiring to the in tank pump? The price for the pump is outraegeous! Is there a good source for less than the dealer (holy crap) price? Thanks to all !
 
jneary said:
digger87 is probably right the fuel pump bleeds back and takes a while to bring the system up to pressure after long shut offs.
Click to expand...

Yes, but I suspect there's something else wrong, because it should only cycle for a few seconds, and a couple of 5 second cycles should bring it up. I'd check the voltage at the pump and the pressure out of it, and don't forget the fuel filter.
 
In the am , turn key to on position, wait in the on position for as much as 1 min before pump cycles (for 5 sec or less). Sometimes you must turn key on / off / on a couple times at the 1 min wait time before the pump runs. If the fuel filter were "clogged" would that make the pump sense pressure ? Therefore NOT run? Boy I really thank all of you helping me out on this one.This is my GF's rig. She is really getting fed up with this and wants to take my CJ.HELPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPp !!!
 
you should get fuel pressure when the key is turned on and while cranking, once fuel pressure is achieved, see how long it takes to bleed off. i think about 5lbs in 15 minutes is bad, but i cannot remember the specs on that.
 
You must log in or register to reply here.

Similar threads

N
New Engine is Hard to Start
Replies
0
Views
33
NGThomas
N
F
Stumped on this one!
2
Replies
29
Views
4K
Bent
Bent
N
New Engine is hard starting
Replies
0
Views
16
NGThomas
N
S
2000 STFTs stuck at 98% ??
Replies
8
Views
2K
RCP Phx
R
G
1997 Sport running rough after warming up
Replies
8
Views
2K
Gilpine
G
Back
Top