Guest Anonymous Posted January 22, 2003 Share Posted January 22, 2003 Bought and installed a Summit Racing air fuel gauge. Looks identical to the Norskold units and others rebranded and sold under various names. 10 led gauge. Tapped the o2 wire running to the ecu and presto, the gauge works great. Very interesting to see what the ecu is doing. Problem is, the car runs like crap, misses at idle and during gentle acceleration. Nail the throttle and the car (81zxt) runs great but at part throttle, she runs very poorly. If I unplug the gauge (yup, when I tapped the o2 lead I installed a t-type plug) the car runs and idles well, just like always but plug in the meter and the problem returns immediately. I'd like to be able to use my air fuel gauge and I plan to run my megasquirt in parallel with the factory ecu to have the factory ignition. Any ideas or suggestions? dan Quote Link to comment Share on other sites More sharing options...
Guest greimann Posted January 22, 2003 Share Posted January 22, 2003 Installing another O2 sensor would be your best bet. These little things don't put out much current at their maximum of 1 volt, attaching more than one device to it is going to throw the cross counts off enough to cause fuel ratio problems. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted January 22, 2003 Share Posted January 22, 2003 Would have to agree with Greimann. Looks like the meter is loading down the circuit. That is why you need a quality digital multimeter to work with these devices. If it takes too much current to run the meter, then the voltage output will not be accurate. You could probably run a gauge in parrallel with the computer if it has a high enough input impedance. Could try a higher quality meter or if you have an electronics bud around have them build an op-amp driver circuit to isolate your existing meter from from the O2 sensor. Quote Link to comment Share on other sites More sharing options...
Owen Posted January 22, 2003 Share Posted January 22, 2003 Hmmm, just found this site yesterday, http://www.gadgetseller.com/gauges/home.htm , meters modded for WOT instead of cruising speeds, I wish they had a combo one. These things are fairly cheap and have a small mounting area, maybe I'll get one for each exhaust bank. Owen Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 23, 2003 Share Posted January 23, 2003 Thanks for the posts guys. I'd wondered if a digital meter such as Owen posted might be a better solution. The op amp idea sounds good, I wish I knew more about electronics. It all seems kind of odd tho, if I understand the o2 sensors correctly, they all put out the same current and voltage so I wonder why I don't see more posts like mine considering the number of air fuel gauges that are installed. Thanks again Dan Quote Link to comment Share on other sites More sharing options...
Owen Posted January 23, 2003 Share Posted January 23, 2003 Not all the sensors put out the same voltage, even from the same manufacturer there are going to be differences. Read Pete P's information on calibrating the Autometer gauges. Here's what I got back from Gadget Seller. ------------------------------------------------- Owen, The rectangular gauges will all work well at both full throttle and while cruising. They are full range gauges unlike the narrow-band modified Autometer gauges. Any O2 gauge will work with the gauges. The existing sensor in your car is usually fine. If you do not have a sensor, I would suggest a Bosch or any reputable manufacturer. The gauges I sell will not disrupt the signal from your O2 sensor. You could connect 5 of the gauges to one sensor if you wanted. You do not need a seperate gauge for the gauge and the car's computer. ------------------------------------------------- Don't really believe the statement about 5 sensors...cars are like computers, everyone has a different opinion on the best setup. I think one day I'll get two of these gauges and two sensors and put one in each bank. Owen Quote Link to comment Share on other sites More sharing options...
Tim240z Posted January 23, 2003 Share Posted January 23, 2003 I think one day I'll get two of these gauges and two sensors and put one in each bank. Why not just get one gauge with a switch to toggle betwwen the two O2 sensors? Tim Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted January 23, 2003 Share Posted January 23, 2003 Don't really believe the statement about 5 sensors If he made them right there is no reason you couldn't use mulitple gages in parrallel. Think of a high quality gage as a single christmas tree light and a cheap one as a set of 500 watt off road driving lights. Do you really think you will see a load on your battery from a single christmas tree light? Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted January 23, 2003 Share Posted January 23, 2003 Originally posted by Owen:Hmmm, just found this site yesterday, http://www.gadgetseller.com/gauges/home.htm , meters modded for WOT instead of cruising speeds, I wish they had a combo one. These things are fairly cheap and have a small mounting area, maybe I'll get one for each exhaust bank. Owen That would be a trick if you could get a gauge to read mixture at WOT using the stock or normal narrow band O2 sensor. They are accurate at 14.7:1 ONLY. If you think you are reading 10:1, it could be anywhere between 13:1 and 9:1, there is NO WAY to know. Reason being the sensor responds to oxygen in the exhaust. Guess how much oxygen is in a mixture of 13:1? 9:1? That's right - NONE! All the oxygen has been consumed, it's a rich mixture. The only way to tell the difference in the mixtures is to measure the CO content. Quote Link to comment Share on other sites More sharing options...
Owen Posted January 23, 2003 Share Posted January 23, 2003 What if a wideband O2 is used? Won't that read a much broader range? Owen Quote Link to comment Share on other sites More sharing options...
Mudge Posted January 24, 2003 Share Posted January 24, 2003 Yes of course, but a wideband is not compatible with a narrow band setup. Voltage input/output and pinout is not the same. Wideband has a range of approximately 10.0-20.0:1, basically anything you could want. Narrow bands as said, were created to ONLY work within stoich, supposedly this also includes 14.6:1, but they are made to be higly sensative in that very small range, which is why they titter back and forth between minutely lean/rich. Quote Link to comment Share on other sites More sharing options...
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