Oizarod115 Posted October 26, 2007 Share Posted October 26, 2007 had the truck tested for emissions this week and my results were as follows: 1989 comanche 4.0l 5spd. 25/25 test 50/15 HC-ppm 223/189 FAIL 259/194 FAIL CO% 6.56/2.36 FAIL 6.48/1.74 FAIL NOx ppm 129/1233 PASS 177/1340 PASS which, according to my book from school (auto-tech school) an increase in CO/HC and a decrease in NOx emissions points directly to a rich mix. and also i pulled the new o2 sensor out after 2 days and its covered in black soot. (points to a rich mix) however, i tested the MAT, MAP, and CTS, all of which are within spec (tested using methods described here http://www.lunghd.com/Tech_Articles/Eng ... ostics.htm) the only thing i can't get a reading on is the o2 sensor which is new, and should be good. however i'm getting 12v to the sensor... is that right? it should be 5v right? i can't get a reading of anything comin out of the sensor. assuming the o2 sensor is ok since it's new, what else controls fuel-air ratio? or what else could cause these types of emissions Link to comment Share on other sites More sharing options...
jtdesigns Posted October 26, 2007 Share Posted October 26, 2007 didn't you put ford 5.0 injectors in? Link to comment Share on other sites More sharing options...
Oizarod115 Posted October 26, 2007 Author Share Posted October 26, 2007 didn't you put ford 5.0 injectors in? yeah, but they're 19lb/hr injectors... same as a renix 4.0 injector no change at all Link to comment Share on other sites More sharing options...
jtdesigns Posted October 26, 2007 Share Posted October 26, 2007 didn't you put ford 5.0 injectors in? yeah, but they're 19lb/hr injectors... same as a renix 4.0 injector no change at all ok I thought they had a larger flow. I wish I knew more about these systems to help you out.... sorry Link to comment Share on other sites More sharing options...
Oizarod115 Posted October 26, 2007 Author Share Posted October 26, 2007 didn't you put ford 5.0 injectors in? yeah, but they're 19lb/hr injectors... same as a renix 4.0 injector no change at all ok I thought they had a larger flow. I wish I knew more about these systems to help you out.... sorry nah thanks though, its not a performance upgrade other than the fact they have 4 holes opposed to the stock 1 hole injectors. does anyone know, i think my problem is I'm puttin 12v to these o2 sensors. which 9320696% of the other sensors run off 5v (map, mat, cts, tps) if i'm puttin double+ to the o2 sensor maybe thats why my new one (bench tested out of the box at 60* and 4 ohms) now has NO resistance through it 4 days later. Link to comment Share on other sites More sharing options...
Eagle Posted October 27, 2007 Share Posted October 27, 2007 the only thing i can't get a reading on is the o2 sensor which is new, and should be good. however i'm getting 12v to the sensor... is that right? it should be 5v right? i can't get a reading of anything comin out of the sensor. assuming the o2 sensor is ok since it's new, what else controls fuel-air ratio? or what else could cause these types of emissions I guess I must be getting old faster than I thought, and perhaps senility is catching up with me. I missed something here: If the O2 sensor tests bad (or doesn't test good), WHY would you "assume" that it's good? It was manufactured by humans, right? Ever hear of a defective product before? Link to comment Share on other sites More sharing options...
JeepcoMJ Posted October 27, 2007 Share Posted October 27, 2007 with good sensors (within spec) elsewhere, you're left with the 02 sensor causing the rich fuel mixture most likely. or a faulty PCM... Link to comment Share on other sites More sharing options...
Oizarod115 Posted October 27, 2007 Author Share Posted October 27, 2007 I guess I must be getting old faster than I thought, and perhaps senility is catching up with me. I missed something here: If the O2 sensor tests bad (or doesn't test good), WHY would you "assume" that it's good? It was manufactured by humans, right? Ever hear of a defective product before? i'm not "assuming" the o2 sensor is good... i meant, assuming it IS good, what else CAN cause a rich fuel-air ratio. 5-90 on naxja said the heater circuit through the sensor should be getting 12V and there should be anotehr 5v lead or something else going on. i'm not getting any Ohm reading on the heater though (terminals A-B) so idk whats going on. lemme run this idea by yall: what if i were to wire around another sensor (say the CTS) with a small resistor so that that sensor would lean out the mixture. would that even work? Link to comment Share on other sites More sharing options...
JOMJ87 Posted October 27, 2007 Share Posted October 27, 2007 don't the block temp sensor for the ECU cause a real rich idle if bad. I know on my 91 YJ MPI 2.5 motor it does but I'm not sure about your specific motor cause i am to stupid to remember right now. Cole Link to comment Share on other sites More sharing options...
Oizarod115 Posted October 27, 2007 Author Share Posted October 27, 2007 don't the block temp sensor for the ECU cause a real rich idle if bad. I know on my 91 YJ MPI 2.5 motor it does but I'm not sure about your specific motor cause i am to stupid to remember right now. Cole i tested that one, its in spec Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 27, 2007 Share Posted October 27, 2007 Why don't you just build an adjustable voltage module for the MAP sensor 5V input? Easy and cheap to do. My stroker was running rich, getting piss poor mileage, and the plugs were slightly sooty when ever I checked them. I cranked the voltage down to about 4.7V to the MAP, and the plugs are looking good. Another option is to install an adj. fuel pressure regulator, which I am also running at 37PSI vs. the preset 42PSI. My injectors are 24#. But I have an HO; don't know if this will work with the Renix systems. Link to comment Share on other sites More sharing options...
Oizarod115 Posted October 27, 2007 Author Share Posted October 27, 2007 Why don't you just build an adjustable voltage module for the MAP sensor 5V input? Easy and cheap to do. My stroker was running rich, getting piss poor mileage, and the plugs were slightly sooty when ever I checked them. I cranked the voltage down to about 4.7V to the MAP, and the plugs are looking good. Another option is to install an adj. fuel pressure regulator, which I am also running at 37PSI vs. the preset 42PSI. My injectors are 24#. But I have an HO; don't know if this will work with the Renix systems. ooh, good idea, i hadn't thought of that, just use a variable resistor on the input wire then? that'd do her right? then adjust as necessary. i know tomorrow's project. Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 27, 2007 Share Posted October 27, 2007 I built mine with a voltage regulator chip and the biasing resistor, adj. pot, and a toggle so I could bypass it if it went belly up. It can go from 1.5V to 6.5V, and is similar to the one on GoJeep's site. But since all you need to do is drop the 5V as an experiment, a simple 1K ohm pot in series with your MAP 5V input should work fine. Link to comment Share on other sites More sharing options...
Oizarod115 Posted October 27, 2007 Author Share Posted October 27, 2007 I built mine with a voltage regulator chip and the biasing resistor, adj. pot, and a toggle so I could bypass it if it went belly up. It can go from 1.5V to 6.5V, and is similar to the one on GoJeep's site. But since all you need to do is drop the 5V as an experiment, a simple 1K ohm pot in series with your MAP 5V input should work fine. a 1k ohm resistor in series with the MAP would send 5/1000s of a volt to the sensor... no? Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 27, 2007 Share Posted October 27, 2007 Not sure on that w/o measuring the amps through the circuit. If you put a 1K ohm potentiometer in series (one leg and the center slider connections) w. the 5V MAP input, you can adjust the voltage in. I'd start with about 4.5V and see if it leans it out. It's lind of like how the ballast resistor works for the fuel pump, a voltage drop, only the ballast resistor is fixed. Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 27, 2007 Share Posted October 27, 2007 Did a little refiguring: a 0-10 ohm or 0-25 ohm pot would be better assuming 1/2A of current. You could adjust from 1V - 5V. Link to comment Share on other sites More sharing options...
Oizarod115 Posted October 28, 2007 Author Share Posted October 28, 2007 where do i buy one of those? Link to comment Share on other sites More sharing options...
Oizarod115 Posted October 28, 2007 Author Share Posted October 28, 2007 i can't find anything but 10K 5K 50K 1K ohm potentiometers on radioshack.com... and thats HELLA high resistance, what on earth would you need 50K ohms for? or am i missing something here? is this the thing i want? http://www.radioshack.com/product/index.jsp?productid=2062307&cp Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 28, 2007 Share Posted October 28, 2007 The 1K will work from RadioCrap, but you will be down in the lower end dirt when adjusting the voltage. But since this is kind of an experiment, get the 1K, wire it in, and set the voltage to 4.5 to start. Monitor your spark plugs frequently to find to optimal setting. When you find the optimal voltage that does make you run leaner (but not too lean), measure the ohms on the pot and get a fixed resistor to finish it off. That's what I'm doing with my MAP adjuster, and it takes some time and driving to get it right. Link to comment Share on other sites More sharing options...
Oizarod115 Posted October 28, 2007 Author Share Posted October 28, 2007 http://gojeep.willyshotrod.com/HowtoMAPsensor.htm thats a pretty slick write-up there, he's using a 1k ohm potientoeriehtng. err... thingy. :roll: but i think i'm gonna try it your way... his is just way to complicated. Link to comment Share on other sites More sharing options...
Oizarod115 Posted October 28, 2007 Author Share Posted October 28, 2007 what about a rheostat? http://www.radioshack.com/product/index.jsp?productId=2062299&cp Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 28, 2007 Share Posted October 28, 2007 Yes. that will work too. Link to comment Share on other sites More sharing options...
Oizarod115 Posted October 28, 2007 Author Share Posted October 28, 2007 Yes. that will work too. thanks man, looks liek i'll be trying that. i wish i could gank one of the fluke meters from school, as opposed to my analog meter :roll: however, at least he lets me use them for w/e i want while i'm there :brows: Link to comment Share on other sites More sharing options...
Oizarod115 Posted November 1, 2007 Author Share Posted November 1, 2007 well i did this adj map sensor thing with a 25 ohm rheostat from radioshack and i can only adjust it about .1 and that only puts her at perfectly on 5. which i suppose is better than nothing, i wish i could find a 100ohm or 250 ohm one to try that might work better... and I'm wishing now i hadn't soldered all the connections becuase i'll have to heat them off to try a different one. Link to comment Share on other sites More sharing options...
HOrnbrod Posted November 2, 2007 Share Posted November 2, 2007 well i did this adj map sensor thing with a 25 ohm rheostat from radioshack and i can only adjust it about .1 and that only puts her at perfectly on 5. which i suppose is better than nothing, i wish i could find a 100ohm or 250 ohm one to try that might work better... and I'm wishing now i hadn't soldered all the connections becuase i'll have to heat them off to try a different one. First rule in electronics - smoke test first before finishing. Aree you sure the rheostat is connected right? There are three terminals on the rheostat. You need to connect the middle terminal (the slider) and either one of the end terminals in series with the 5V input wire to the MAP. If you used the two end terminals, this is wrong. And the 5V input wire to the MAP should be VIO/WHT. Turn on your IGN and make sure there is 5V on this wire. Link to comment Share on other sites More sharing options...
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