No fuel pump; only all new injectors
lol
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It had to do with the O2 sensors and getting the exhaust properly sealed. Now we are down to the joint between the exhaust manifold outlet and the Y-pipe leading to the catalytic converters. There is no gasket in the '08 model year.......just metal-to-metal. It's sort of ball shaped, so if anything is even slightly out-of-round a leak occurs.
BTW: I did find some hi-temp gasket material if anyone wants to try it:
Percy's High Performance Carbon Gaket Material #68006. Cost $10.95 for a 10" x 10" sheet from Summit Racing. If I every need to make a custom gasket for that particular exhaust joint, that is what I plan to use.
Service manager believes the O2 sensor response time error band is too tight. That is, if it were opened up just a bit, there would be lots fewer DTC's. These DTC's go through PENDING, then SET. If there are not 2 cycles of PENDING, the DTC clears and no MIL appears. Unfortunately, that algorithm is burried deep in the PCM and so is classified as "emission-related" for EPA purposes. As a result, Jeep will not allow dealers to alter it.
I believe many of the changed components really did not need to be replaced. However, the Chrysler technical representative (and there were several during this period) wanted to do it to eliminate the other possibilities. The HEMI is under lifetime limited powertrain warranty, so essentially no cost to me, but it was a complete PITA taking the HEMI in every week to try something else. :banghead: I couldn't demand that Chrysler do a particular fix or I would have had to pay for all of this. I recorded the problems and had to let the technical service representative determine what to do next.
For the last year, it had been pending O2 sensor 1/1 & 2/1 slow response DTC's (P0133 and P0153). Just had those joints re-tightened about a month ago (no charge) and the symptoms disappeared (again). :clap:
I think working with the dealer's Service Manager and lead technician was my greatest asset. I've been through the '08 FSM cover-to-cover (all 6 volumes) several times. As an engineer & gearhead, this is very intriguing.....as an owner, I should not need to go through torture.
I believe this mess has cost MOPAR 2-3 times the original sale price of the Grand Cherokee Limited. I had offered to give them this one and substitute an '09 under lemon law provisions (because the '08's were out of production by that time). They insisted on trying to fix it.
The cash register continues to ring up to MOPAR's account (at ~96K miles currently), but I have done everything they have asked (and more), so no bad feelings on my part for holding Chrysler to the warranty provisions.
Passed the 5-year warranty inspection with no issues. At the time of the mandatory 5-year powertrain warranty inspection, I gave them back a complete service history, maintenance log, and list of replaced components. Since they had done 95% of the work, it wasn't really a big surprise.
I know this is verbose, but maybe another WK owner new to the HEMI world will benefit from my experiences.