I am trying to find the cause of a rich running engine, and I'm running out of ideas of what to do next.
History: Wife bought me and my son this Jeep sight unseen a few months back for us to fix up. 213,000 miles
Initial engine problems identified: Heavy exhaust smell, cracked exhaust manifold, Clogged CCV valves with oil bypass in air filter.
Overall the jeep runs great other than the strong exhaust smell and bluish smoke from exhaust pipe. No noticeable power difference from other wrangler 4.0s i've driven. Haven't driven it enough to report on gas mileage. Smell is too harsh to drive for long periods of time, especially with top off.
Items I have tested or replaced:
1. New CCV valves, gaskets, vacuum lines, air filter - not getting any blow by since
2. New exhaust manifold
3. New NGK O2 Sensor
4. New spark plugs, oil change, oil filter
5. New vacuum line from fuel pressure regulator to intake manifold
6. Compression Test 1:150 2:155 3:160 4:155 5:160 6:160
7. MAP sensor - tested ok
8. Fuel Pressure - 31 psi
9. Fuel pressure regulator - I believe tested ok, disconnected vacuum line and fuel pressure increase 10psi
10. IAT - tested ok, but had blow by residue so ordered new one to replace (not installed)
11. Thermostat - Engine gets up to around 205 per inside gauge and then drops 10deg or so, so thermostat is opening. Heat is working too good for Florida
12. Injectors - Tested resistance in Ohms and they are within range (13.8-14.4), also disconnected each one individually and there was a noticeable reaction from the engine
13. Vacuum Leaks - Have checked and replaced what was cracked. I don't feel there are any leaks.
At this point I'm looking for advice on what to do next:
My plan:
1. Replace IAT just because I ordered a new one (arrives tomorrow)
2. New Cap and Wires
3. Check/ replace coolant temp sensors (both)
4. Probably needs a new CAT, but wanted to get the rich running under control before replacement. Maybe the old cat is non functioning and is the cause of this? I don't feel that this is the cause, but not enough experience to know for sure.
5. Replace injectors?? Maybe a bad spray pattern...clog???
Thank you in advance for any guidance!