Shane Gomes

So, quick rundown bought a 01 xj lwith 210k miles, in the 25k miles I've put on it, I've done plugs, could pack. Filters, new starter, alternator, fuel pump, a/c compressor, water pump, thermometer, purge control valve, new hoses, brakes F and R. Changed the fuelbpumona few months ago, got a evap gross leak code after that, finally dropped fuel tank again and the seal hadn't seated correctly so forth, new seal, good to go or so I thought. The Jeep has always had a hard start issue. It's never gotten worse or better till now. Literally replaced pump seal, fixed broken foglight wire, and topped off battery water, and NOW, it's got a REALLY hard start, and dies right after crank, unless I give it gas for a minute or so. I've noticed that my stereo clock resets if it's off overnight. I'ma test battery 1st, clean throttle body, but if that doesn't work I'm guna start replacing sensors. IAC, MAP, CPS, figure at 235k miles they will need soon enough anyhow. So do I stick with Mopar?does it not matter? Are there brands to absolutely avoid? Thanks and any pointers or suggestions srenappreciated

tjwalker

You are on the right track with "load testing" your battery. One of the number one causes of stalling at idle is a battery that is starting to fail. I've seen it a number of times. If your battery is resetting overnight, I'm betting that your battery is about shot. All automotive electrical life starts with a good battery. Any question or even if it's just old, replace it.

Once you have either a tested good battery or a new battery, then see where you are at. If you are still symptomatic, in the absence of codes, you need to test fuel pressure. Even though you replaced the pump. It is not that unusual to have a new(er) part fail. For your 2001, you need 49 psi, plus or minus 5 psi. If you don't have a fuel pressure gauge, they can often be rented at many parts store inexpensively. Call around for availability. What brand fuel pump did you install? Hope it's not an Airtex! A search of this and other XJ forums will tell you why; their reliability is pretty poor.

I wouldn't just start replacing any sensors without them testing bad or with check engine light codes and or symptoms pointing directly to that sensor. Is the check engine light on or have you ever seen it on? If so, pull codes with a code reader or a scan tool. Got a manual and a meter? Every XJ owner needs those two things for diagnosing engine management. Sometimes you can go backwards with introducing a new sensor on a guess so don't throw parts at this. And for the 4.0, I really like Mopar sensors. Aftermarket are hit and miss, especially with the crank sensor. The additional cost of the Mopar sensor is well worth it.

Good luck and keep us updated!

Shane Gomes

Hey, thanks for the info. Well today before I had battery tested when I 1st cranked it up I got a p0306 code for #6 cyl misfire and the CEL was flashing. I cleared it and recranked and no CEL. had battery tested, bad. only 225 amps out of the 800 it's rated for. Installed new battery, cranked up MUCH better, but still slow like it was from day 1. So I'ma find a fuel pressure tester and do that next. Haven't done before so based off what results are, will I know what part of the fuel delivery is failing? Injectors, rail, etc? Got a manual and meter and enough tools to pay for my MAC man's sons ivy lague college tuition. Going to do a compression test as well just to make sure we're where we need to be there. As for the fuel pump I got a carquest one (advanced autos brand). Coulda got a Bosch online for a little more, but I didn't wanna wait and carquest has a "lifetime" warranty, which alrdy saved me $30 on that pump seal. Thanks again and I'll post up results of fuel pressure and compression hopefully within the week, and go from there. Also, on that battery, I got a 34(?) I believe, same size as what came out, but it was an interstate thay came out and new 1 is a Walmart everstart Maxx. Has fewer CCA (650 I believe) than the interstate which had 800ish. As I understand oem recommends 550cca. Battery was just over $100 with a 3 yr warranty so hopefully I won't regret going cheap there. My Jeep maintenance allowance for time being is getting pretty streched. Splurged on a flowkooler water pump, so that ended up being a little pricier job that initially thought lol.
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