How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Juan Crespo Your Own Question
Juan Crespo
Juan Crespo, ASE Certified Technician
Category: Jeep
Satisfied Customers: 1513
Experience:  A.S.E. Master Technician, Advanced Level, Emissions - Asian, Domestic, & European
19298667
Type Your Jeep Question Here...
Juan Crespo is online now
A new question is answered every 9 seconds

Grand Cherokee: 2002 Grand Cherokee, sometimes won't start,or

Customer Question

2002 Grand Cherokee, sometimes won't start,or does,maybe start then stall out, runs fine then begins to run very poorly. very intermittent. was told could be the ECM. replaced it seemed to run fine for part of the day but the problem re-occurred. might not start in park, but may fire up in neutral.this is all info from my daughter who's vehicle it is. wiggled wiring to the crank sensor,it did'nt stall out. any ideas???? HELP! Mark in Michigan
Submitted: 1 year ago.
Category: Jeep
Expert:  Juan Crespo replied 1 year ago.
Hi Mark. Welcome to our site. First thing we'd need to do is find out if there are any fault codes stored in the computer's memory. After that, we'd need to determine what is missing when the engine won't start; fuel (pressure and injector pulse) or spark. Are you equipped to do that?
Customer: replied 1 year ago.
No fault codes, the vehicle usually starts after not starting.
Expert:  Juan Crespo replied 1 year ago.
Thanks for that information. How about the second part of the diagnosis: "After that, we'd need to determine what is missing when the engine won't start; fuel (pressure and injector pulse) or spark. Are you equipped to do that?"
Customer: replied 1 year ago.
the issue has never left a code in memory. this is extremely intermittent. I was thinking something kind of obscure,bizarre or kind of not so obvious. have you at anytime experienced something so phantom-like. I've had it looked at by a pretty good mechanic but something obvious was not found. this seems electrically related as most of these issues are........ What ya got for me Juan???
Expert:  Juan Crespo replied 1 year ago.
Well, I'm afraid our work is kind of boring; all car computers are preprogrammed to make actuators work in a preprogrammed way based on preprogrammed sensor signals. There are no obscure, bizarre or not so obvious things. If your mechanic hasn't been able to find the issue, then I'm affraid he's not as "pretty good" as you may think.What I got for you is a regular no-frills diagnostic process which is sure to take us to the root cause of the problem. It starts with using the right tools to determine what is missing when the engine won't start; fuel (pressure and injector pulse) or spark? Do you or your mechanic have those tools (fuel pressure tester, Noid Light, ignition tester) so I can guide you or him through the appropriate tests?