98 taking a long time to start

It just started happening after I replaced my upstream o2 sensor. It take about 7-10 cranks to start the jeep, i've been reading that it could be a cps, but the guy at autozone STRONGLY suggested that if it were bad it would not run at all. Anyways, i'd like to take care of this before i end up stranded somewhere when it actually doesn't start. What could it be ?

Hey, for a change, the autozone guy may be right. Is this hard starting all the time, only when hot, only when cold? What year? 4.0 auto?

98 4.0 auto, and it just started happening ever since the sensor was changed, never before then. Also, it doesn't matter if it's warm, cold, just ran, hasn't ran, or if it's dirty or clean.

Still have your old o2? Just a crazy idea!!!!!!! Don't change them in the exhaust pipe, but just unplug the new one, and plug in the old one. Check if it starts better then?

No i tossed it, the jeep was barely running with that o2. It was bogging down, running insanely rich, and backfiring.

It is possible that the extended crank is completely coincidental and not related to the replacement of the oxygen sensor. The oxygen sensor isn't even in play (uses default mixture values) on a cold start so I really don't think it's that.

Your vintage (98) is very prone to check valve failure on the fuel pump assembly inside of the gas tank. Try this.

1. Turn key to on position (fuel pump will energize and run for 2 seconds). Do not crank the engine.
2. Turn key to off position
3. Replace above steps a couple of more times
4. NOW actually crank the engine.

Doe it start quickly (and cleanly without stumbling)? If it does, you're experiencing a loss of fuel pressure somewhere, maybe because of the check valve although there are other possibilities. The check valve symptoms most often occur on a cold start but I'd try the above prime test anyways. Gotta start somewhere.

BTW, the Autozone guy was right; this problem is NOT crank sensor related.

EVen if i just turn the key to the on position and wait 3 or 4 seconds it starts fine. I guess there's a time for everything.

camarors8992 said:

EVen if i just turn the key to the on position and wait 3 or 4 seconds it starts fine. I guess there's a time for everything.

Click to expand...

Maybe I'm misreading this but if you turn the key on and wait 3-4 secs, then crank it starts fine? If so, you have a fuel pressure problem. Check the pressure at the rail port.

Saudade said:

Maybe I'm misreading this but if you turn the key on and wait 3-4 secs, then crank it starts fine? If so, you have a fuel pressure problem. Check the pressure at the rail port.

Click to expand...

Sounds like the fuel is draining back into the tank.

Install a check valve, $14 on ebay and two clamps.

my 98 has the same problem. When installing an in-line check valve, is there anything special you have to do before cutting the fuel line (besides relieving the fuel pressure of course)? Or is it as simple as cut the line, install the valve, and reconnect?

Obviously use some GOOD hose clamps and retighten them a few times as they seat in.

To extrapolate upon this problem. I have a 98 with the exact same issue. My XJ has 201,000+ miles on the original pump (as far as I know, not the original owner). My fuel gauge is also erratic at best. Anything under 3/4 of a tank and the needle is all over the place, assuming it's moving off of the E-needle stop at all. I'm planning on replacing the fuel pump so I can get the new level sender as they are all in a modular unit from most places. Am I correct in assuming that this would also cure the check-valve problem as well as the erratic fuel level readings? Also, what is the best brand of replacement pump to buy? The last thing I need is to be changing it on the side of the interstate with a full tank of gas seeing as how I live and work 3 hours apart.

If you go to Rockauto.com, you will see many complete assemblies and separate pumps. Bosch is often recommended as the best, but they only show the pump, not the complete module.

My 95 is doing the same thing...only on cold starts

I just went out ,tried to turn it on for 3 seconds before starting and it cranked but wont start

first start (attempt) of the day

i am not completely based on the pump/check valve as my jeep once had a fuel filter thats rusted through and leaked, but still starts right away after sitting a while

my .02 cent