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Evap Delete?

A

adl2494

New member
Hey all, Im new to the forum, however not new to the grand prix or cars, straight forward question here, the Evap system on my car though I realize is not likely to cause any real performance issues, does from time to time trip my CEL and what not, the system doesnt bother me, however I dont care if its working or not, so, I believe Ive worked out a delete for the whole thing, never have the ecm run an evap test again, some if not all evap tests only run if the tank is between 15% and 85% full so my idea, is to trick the ECM into thinking the tank is always 100% or 0% by inserting a fixed resistor in the sensor circuit 40ohms would indicate to the ecm that it is empty and 250ohms that it is full, or visa versa, id have to look it up, regardless, easy fix right, the slightly more difficult question and the thing Ive been pondering is how then to bypass the ECM and connect the sensor directly to the IP cluster, it may be as simple as doing exactly that and wiring straight from the level sender to the IP, idk, I havnt been able to find much info regarding the signal sent from the ecm to the IP Im probably going to bust out my multimeter and see If I can work it out, but In the mean time, any suggestions or ideas?
Also this is on an 02 GP 3.1L
 


be way easier to find someone who can tun your car, then they can set the evap codes to not report, scrap the evap system. never see a cel for it again. and still pass inspection.
 
That is accurate that is only runs EVAP tests in that fuel range and tricking the pcm with a resistor would stop it from running the test. But the cluster gets its fuel level data from the ECM via class 2 or GMLAN, depending on the year, so tricking the ECM will also trick the cluster. The only way to get the light to stay off is to fix it or do like Scott said.

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Based on what Ive seen Im 90% sure that the analog fuel gauge in an 02 pontiac grand prix operates off of some kind of a varying voltage/current, I could be mistaken, like I said Ill pull some data off with a multimeter when I have time.
 
On an 02 the gauge is run with a variable voltage signal from the ECM. The ECM reads the fuel level sensor though. I can't say it's not possible to rig the level sensor directly to the gauge but I find it very unlikely. I would think the fuel signal to the cluster is PWM which you won't be able to reproduce with the sensor. Get a meter on the signal and see what it reads for voltage and frequency.

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Did ya replace the as cap? Lol, you didn't mention if you tried any simple fixes to the problem. ; )
 


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