I purchased my 2002 X about 2 years ago and it only had 30K miles on it. I was told the previous owner would leave it parked at his hunting camp for long periods. After I bought it, I changed all fluids, plugs, and general maintenance items and it is in great condition. About 6 months ago, I had some hard starting issues and after reading some nice posts here, I diagnosed my problem as a bad valve on my fuel pump. I tried to purchase a Bosch but I couldn't find one anywhere. The best quality available at the time seemed to be the NAPA one. The replacement went well and it immediately fixed that issue. I no longer needed to turn the key on/off 3-5 times to prime the pump in the morning. After a couple of days, the starting issues returned but it was different. A cold start seemed to have too much fuel. Hot starts became more difficult as well. Again back to the forum and I found the TSB for heat-soak issue.
I purchased the white cylindrical insulators recommended by the TSB and they have had some effect. Convinced this was my problem, I purchased the DEI Kit and will replace the heat shield with the DEI one which is thicker, the fuel rail sleeve, and the injector wraps.
Yesterday, after wrapping just the #3 injector with the insulation, I was surprised that I didn't see a more significant hot-start improvement. Also my morning cold start still wasn't great and it seemed to take about 3-4 seconds to fire up and chugs as if too rich. After it starts, runs great and has since the first day I bought it.
I have come up with a theory of what is happening and I would appreciate constructive input. After reading tons of posts here and other places, I'm thinking that the new fuel pump and valve that now keeps fuel pressure constant has revealed a leaky fuel injector. Anther guy had similar issues to mine and replacing the injectors did the trick. I have ordered some Bosch re-manufactured injectors and plan to install them this weekend along with the full DEI kit. For $100.00 it seems worth it to try it out. I will send an update Sunday evening hopefully with positive news.
Lastly, I have seen others flash or reset the PCM after installing new injectors. Is this required for it to relearn? The service manual didn't mention the reset as a requirement after replacement and I didn't know if the 2002 4.0 was any different.
I do apologize for all the detail but I wanted to provide as much information up front. Also, this has been frustrating and hopefully my issue and your responses can help the next person with a similar issue.
I purchased the white cylindrical insulators recommended by the TSB and they have had some effect. Convinced this was my problem, I purchased the DEI Kit and will replace the heat shield with the DEI one which is thicker, the fuel rail sleeve, and the injector wraps.
Yesterday, after wrapping just the #3 injector with the insulation, I was surprised that I didn't see a more significant hot-start improvement. Also my morning cold start still wasn't great and it seemed to take about 3-4 seconds to fire up and chugs as if too rich. After it starts, runs great and has since the first day I bought it.
I have come up with a theory of what is happening and I would appreciate constructive input. After reading tons of posts here and other places, I'm thinking that the new fuel pump and valve that now keeps fuel pressure constant has revealed a leaky fuel injector. Anther guy had similar issues to mine and replacing the injectors did the trick. I have ordered some Bosch re-manufactured injectors and plan to install them this weekend along with the full DEI kit. For $100.00 it seems worth it to try it out. I will send an update Sunday evening hopefully with positive news.
Lastly, I have seen others flash or reset the PCM after installing new injectors. Is this required for it to relearn? The service manual didn't mention the reset as a requirement after replacement and I didn't know if the 2002 4.0 was any different.
I do apologize for all the detail but I wanted to provide as much information up front. Also, this has been frustrating and hopefully my issue and your responses can help the next person with a similar issue.