It doesn't tie into the fuel guage at all, if you are not running emissions you can have it tuned out. My assumption is that it is gauging that there is fuel in the tank by the pressure. It is part of the LS harness and connects only to the GM PCM. It does not tie into my Jeep harness at all. I have a spare TJ tank with the sensor in it already if you need.From what I understand, the fuel pressure sensor has to know the fuel tank level. Is this correct and if so, how did you tie into the fuel gauge?
You are partially correct, if you are not trying to be emissions compliant you could tune it out. Doing so is illegal whether you have to undergo inspections or not. For those who are striving to be emissions compliant the fuel tank pressure sensor (ftps) is used to detect EVAP system leaks. This is accomplished by closing the EVAP Vent Valve, pulling vacuum on the system and monitoring the ftps. If a vacuum threshold cannot be achieved or decays too rapidly once the vacuum source is removed it is assumed there is a leak. For the large leak test the source vacuum is engine vacuum via the EVAP Purge Valve. For the small leak test, engine off natural vacuum is used. For the test to be accurate the fuel level must be between 15% to 85% and that's where the fuel level sensor comes into play. No fuel level input to the GM ECM means the EVAP tests never run and the EVAP readiness monitors never complete. In Colorado they do not require the EVAP monitor to complete for a regular E-Test, but they do require it when recertifying a vehicle for an engine conversion. I am retrofitting a GM fuel pump assembly (w/ a GM fuel level sensor) to fit in the Jeep tank and adding the Jeep fuel level sensor to it for the gauge.It doesn't tie into the fuel guage at all, if you are not running emissions you can have it tuned out. My assumption is that it is gauging that there is fuel in the tank by the pressure. It is part of the LS harness and connects only to the GM PCM. It does not tie into my Jeep harness at all. I have a spare TJ tank with the sensor in it already if you need.
Good point, I think the trans has to match here in CO too, which in my case it does. I'm all for being clean and actually wanted to be emissions compliant but i think this is a little overboard. I think they changed the rules on me since I first started looking into this too. When I first talked to the tech center they were like no prob, get a donor same year or later, swap the emissions components over and have us check it. Now they're like match every aspect of the Escalade and good luck it will be hard to pass inspection. I'm too far in now, I'll get it as close as possible and see what they say. We're not "Commie-fornia" yet but getting closer and closer. I may be **. It may be time to move to the mountains where they don't require inspections😄.In Commie-fornia, the referee said to me that the headpipe needs to be completely stock out of the donor vehicle, no mods. Same with the manifiolds, and they check the numbers on the manifolds and verify they fit the calibration you are trying to get through. Any cat/s need to be OEM or have the CARB-EO for the application, too. Going through this on a 5.9l magnum swap in a '97TJ.(98 5.9l Limited ZJ parts fit perfectly). The trans needs to match, too.
I don’t have a mid arm lift but if you go to the end of my video you can see how I recently routed my exhaust and maybe that will help you planAnyone running a 50 states legal Gen 3 V8 TJ with a Savvy Mid Arm lift? I'm currently putting a LQ9, 6.0L in my 04 Rubicon with LS3 exhaust manifolds and Novak weld in mounts. I have the Mid Arm kit on order but it's not here yet. I'm trying to figure out how to route the exhaust. The engine is in the Jeep and it looks like the outlet of the drivers side exhaust manifold is right about where the Mid Arm LF UCA frame bracket will be. I'm in Colorado and per the Emissions Tech Center Technician, the exhaust from the rear O2 sensors forward must be pretty much as it was in the donor vehicle (routing, carb or oe cats and distances between O2's, cats and manifold). The donor is an 04 Escalade which has an exhaust circuit with a cat on both sides of the trans so slipping the drivers side under the oil pan will not be allowed. Technically as far as emissions goes I should be running the OE Escalade manifolds or a CARB certified header but I'm hoping with the OE style cast LS3 manifolds they won't notice. I am open to different manifolds but they can't look too out of place or they may raise suspicion during the initial inspection. C6 or GTO manifolds would put the outlet in a better place I think but I don't think they will clear the engine mount brackets. Anyone run across this and found a solution or better suited manifold? Any suggestions or insight would be great. Thanks
I watched the video and that looks great, actually pretty much what I was initially planning but after talking to the inspector in CO further it doesn't sound like it will pass inspection. What state are you located in and have you passed inspection with it yet?I don’t have a mid arm lift but if you go to the end of my video you can see how I recently routed my exhaust and maybe that will help you plan
Thanks for the input and you may be fine in Texas, I'm sure their rules differ from CO.Texas and no I haven’t since I haven’t gotten a drive cycle done yet, it might actually be the fuel level issue posted above this thread. The shop ordered the cats from a GM vehicle (can’t remember which one) and they said my suburban donor had the same style so I think mine should pass but we’ll see.
I am putting A/C into my 5.3 swap. Novak wiring harness has two wires that need 12v when A/C is on and they suggest having independent sources. One is obviously the compressor clutch signal but I'm not sure where to pull the second signal from, seems like the blower might be the only other place but there are resistors along the way so I'm unsure of a solid 12v signal to tap into. Any thoughts?I paid $500 for custom hoses, new dryer and leak test, later paid $150 for charge, leak test and cycle adjustment.
The wiring harness has a wire than runs in series from the high and low a/c pressure switches so that part will be the same as the stock tj. They also want a 12v signal to turn on the fan when the a/c kicks on.Normally a low pressure cut-off switch needs to be on the suction side of the system. Prevents the compressor from burning out if the charge goes low. Assuming the Painless harness is supplying a signal to an OEM PCM to control the A/C clutch, it might need a pressure transducer to sense high pressure too. Might have to match the donor PCM's original A/C circuit
On a stock TJ the low pressure switch interrupts the A/C Request signal to the PCM telling it to turn the clutch on.
If you want to make the A/C system old school stand alone, you put the low pressure cut off in either the 85 or 86 pin clutch relay control circuit to the A/C clutch relay to prevent it turning on with low pressure. These switches go open with low pressure, usually around 20 PSI. A high side switch can also be placed in the discharge hose. These are normally closed switches that go open when the pressure hits something like 400 or so PSI. The two switches would then be able to be wired in series allowing the clutch to operate between 20 psi on the low side and 400 psi on the high side.
I figured this out, turns out I was reading instructions incorrectly. The harness needs one input of 12v when a/c kicks on, then the other wire actually supplies the 12v to the compressor, simple wiring job.The wiring harness has a wire than runs in series from the high and low a/c pressure switches so that part will be the same as the stock tj. They also want a 12v signal to turn on the fan when the a/c kicks on.