a bum with money Posted August 17, 2018 Share Posted August 17, 2018 6 hours ago, STLHD said: all good ideas not sure why the mileage is so off if you all are saying it should be around 19mpg. we are at 5000 feet and everything from there is up the truck has 4.88 gears and 33'' tires and will be going to a 35'', Frame Plated, bumpers tire carrier winch, long arm, and center skid plate, so i have added some wait and i am sure the mileage has suffered. i have been around jeeps my whole life and have never seen a 4L with larger than stock tires get 19mpg ( just my experience ). Any ideas to improve the mileage I'm all ears. thanks all just throwing in my recent experience, I had recently replaced the coolant temp sensor (CTS). was getting terrible mpg and wouldn't pass DEQ but ran pretty good. the CTS was sending fake news to the ECU. runs great now. just something else to look at. Link to comment Share on other sites More sharing options...
STLHD Posted August 17, 2018 Author Share Posted August 17, 2018 not sure but it will be replaced tomorrow, you mentioned it before and i already picked up the part. I have read some stuff on cold air intakes, injectors and hotter ignitions as well. are they worth the noise and money? i have also considered the newer motor swap as well but i have a hard time getting rid of the Renix, it has 223k on it and still has 75 PSI oil pressure, and runs great, and i am okay with the power it produces ( getting older and don't need the speed anymore) . If injectors and air intake are recommended what brands have you seen do well and not kill the bank? Link to comment Share on other sites More sharing options...
STLHD Posted August 17, 2018 Author Share Posted August 17, 2018 and the Temp sensor was replaced about two months ago. I keep a couple on hand as this thing goes through one about once a year, not sure if this is because of low quality parts or some other issue. Link to comment Share on other sites More sharing options...
Eagle Posted August 18, 2018 Share Posted August 18, 2018 2 hours ago, STLHD said: and the Temp sensor was replaced about two months ago. I keep a couple on hand as this thing goes through one about once a year, not sure if this is because of low quality parts or some other issue. Which temp sensor did you replace? Link to comment Share on other sites More sharing options...
STLHD Posted August 18, 2018 Author Share Posted August 18, 2018 well i have changed air temp sensor as well as coolant temp sensor. is there something else i should look at? and any thoughts on the injectors and such? Link to comment Share on other sites More sharing options...
Eagle Posted August 18, 2018 Share Posted August 18, 2018 27 minutes ago, STLHD said: well i have changed air temp sensor as well as coolant temp sensor. is there something else i should look at? and any thoughts on the injectors and such? WHICH coolant temp sensor did you replace? The Renix Jeeps have two. The one on the back corner of the head (which I'm going to guess is what you replaced) only provides input to the gauge on the dashboard. The one that sends data to the ECU is down low, on the driver's side of the engine block. Link to comment Share on other sites More sharing options...
STLHD Posted August 18, 2018 Author Share Posted August 18, 2018 temp gauge has always worked fine so i have never replaced that one, just the one on the block. Link to comment Share on other sites More sharing options...
Eagle Posted August 18, 2018 Share Posted August 18, 2018 44 minutes ago, STLHD said: temp gauge has always worked fine so i have never replaced that one, just the one on the block. Okay, good. When was the oxygen sensor last replaced? What temperature thermostat are you running? Link to comment Share on other sites More sharing options...
STLHD Posted August 18, 2018 Author Share Posted August 18, 2018 o2 will be replaced tomorrow I have owned this truck for three years not sure on the last time it was replaced but I have not. Thermostat I have replaced and I believe it’s a 180 or 190 the truck does have a 97+ coolant system in it, not sure if that changes anything on this. One thing I can confirm is the fuel tank in it is definitely not an 18 gallon tank ran the truck completely dry yesterday and the pump shut off at 14.5 gallons not sure what tank is in it at this point but it’s not taking 18 gallons. I do like how the tank sits in it though it has an aluminum skid plate and it is high in the truck and does not hang below the unibody so I will be fabing in a second tank where the spare tire once lived hoping to keep it high as well and at least getting another 14 gallons. Link to comment Share on other sites More sharing options...
DirtyComanche Posted August 18, 2018 Share Posted August 18, 2018 9 minutes ago, STLHD said: o2 will be replaced tomorrow I have owned this truck for three years not sure on the last time it was replaced but I have not. Thermostat I have replaced and I believe it’s a 180 or 190 the truck does have a 97+ coolant system in it, not sure if that changes anything on this. One thing I can confirm is the fuel tank in it is definitely not an 18 gallon tank ran the truck completely dry yesterday and the pump shut off at 14.5 gallons not sure what tank is in it at this point but it’s not taking 18 gallons. I do like how the tank sits in it though it has an aluminum skid plate and it is high in the truck and does not hang below the unibody so I will be fabing in a second tank where the spare tire once lived hoping to keep it high as well and at least getting another 14 gallons. Get a picture of the tank. My bet is your pickup is not in the bottom, or the vent tube is too long. Unless somebody has swapped some random tank out of something else in there. In which case you can get 4 more gallons just buy ordering the Spectra tank for $65. Oh, put the right thermostat in. Link to comment Share on other sites More sharing options...
HOrnbrod Posted August 18, 2018 Share Posted August 18, 2018 9 minutes ago, DirtyComanche said: Oh, put the right thermostat in. The right thermostat is the Mopar 83501426 from the dealer, not Stant, not Crown, or any other C.R.A.P. Also when replacing the O2 sensor, Mopar or NGK is best. Link to comment Share on other sites More sharing options...
DirtyComanche Posted August 18, 2018 Share Posted August 18, 2018 1 minute ago, HOrnbrod said: The right thermostat is the Mopar 83501426 from the dealer, not Stant, not Crown, or any other C.R.A.P. Also when replacing the O2 sensor, Mopar or NGK is best. I haven't had any issues with the 'better' Stants. P/N 45359. The 13009 is the cheap one that everyone buys (currently listed for $1.88 CAD, that's like $1.25 US) and complains is a POS; well, when you pay less for the thermostat than you do for a can of Coke from a vending machine, you shouldn't expect good results. But, as I've explained before, I can't really buy Mopar stuff for any sort of reasonable price. Crown, Omix-ADA, Rugged Ridge, etc, can stuff it. Link to comment Share on other sites More sharing options...
Eagle Posted August 18, 2018 Share Posted August 18, 2018 1 hour ago, STLHD said: o2 will be replaced tomorrow I have owned this truck for three years not sure on the last time it was replaced but I have not. Thermostat I have replaced and I believe it’s a 180 or 190 the truck does have a 97+ coolant system in it, not sure if that changes anything on this. The cooling system doesn't matter, but the temperature does. The coolant temperature sensor in the block is what tells the Renix ECU when to switch from open loop (pre-mapped fuel curve, set rich for warm-up) to closed loop (computer/sensors control air/fuel mix). I don't remember what the temperature required for the switch-over to take place is, but I think it's around 175 or so. So you need to be sure that the system is functioning correctly and keeping the temperature up. Most people don't understand the role of the thermostat. The cooling system is to keep the temperature down, but the thermostat is to keep the temperature UP. If it's too cold, or if it sticks open, you're stuck in open loop mode and the fuel economy goes out the tailpipe. Link to comment Share on other sites More sharing options...
STLHD Posted August 20, 2018 Author Share Posted August 20, 2018 thanks all, truck is running a lot smoother now. changed out the o2 sensor and just because changed out temp sensor as well. is there any benefit to running a 20psi injector? if so what brand ? thanks again for all the help. Link to comment Share on other sites More sharing options...
saveevryjp1998 Posted August 20, 2018 Share Posted August 20, 2018 He may already have the Spectra tank. For those that have gone the Spectra route such as I both swb and lwb, the firat thing you notice is the slosh pits are much different than stock. There is no build in for the bottom rubber stop on the pickup for the pump. So therefore it will already lose some fue pickup in tank 1 and 2 the major downside is the sending unit is completely suspended/suported by the lockring only. If the rubber tip is actually still on your sender when you pull it from the old tank to do the swap remove it. It will eventually fall off in the tank of the new Spectra version. I can only speak of the aftermarket Spectra tanks since I have no experience with any others other than the rusted out factory ones I changed out. Link to comment Share on other sites More sharing options...
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