O2 Sensors
Thread Starter
Staging Lane
Joined: Jun 2018
Posts: 68
Likes: 6
From: Anchorage AK
O2 Sensors I don't know where to start so here it goes. I had my LQ4 tuned in Houston by house of power. I was told that l had no O2 sensors. They tried 2 different types and ran the wires but could not get them to work. I inherited the car from my brother and the engine/computer were done over 14 years ago. I upgraded the heads and cam and then had it tuned. Is this unusual? Sometimes when you start it, it stumbles a little bit then its ok. I tried to get answers out of the dyno place but they were not very helpful. Only good at charging me a lot of money. To be fair it runs great when stepped on. No traction in first and second. But should l look into getting another ecm or just dump it for a holley system?
There are upstream and downstream O2 sensors.
Upstream: Before the catalyst
Downstream: After the catalyst
In most off-road racing applications the catalyst and rear O2s are tuned out on the ECM with the aid of tuning software.
Need pictures of your exhaust setup to see what you got going on there.
Upstream: Before the catalyst
Downstream: After the catalyst
In most off-road racing applications the catalyst and rear O2s are tuned out on the ECM with the aid of tuning software.
Need pictures of your exhaust setup to see what you got going on there.
If you have no o2's, did they delete the MAF also? Some places tune specifically in speed density (no need for MAF and o2's) and some applications benefit from it. If you are trying to add sensors, it simply requires correct wiring and possibly a tune to use them effectively.
Thread Starter
Staging Lane
Joined: Jun 2018
Posts: 68
Likes: 6
From: Anchorage AK
There are upstream and downstream O2 sensors.
Upstream: Before the catalyst
Downstream: After the catalyst
In most off-road racing applications the catalyst and rear O2s are tuned out on the ECM with the aid of tuning software.
Need pictures of your exhaust setup to see what you got going on there.
Upstream: Before the catalyst
Downstream: After the catalyst
In most off-road racing applications the catalyst and rear O2s are tuned out on the ECM with the aid of tuning software.
Need pictures of your exhaust setup to see what you got going on there.
Last edited by gordoalf; Dec 18, 2019 at 01:21 PM.
Thread Starter
Staging Lane
Joined: Jun 2018
Posts: 68
Likes: 6
From: Anchorage AK
If you have no o2's, did they delete the MAF also? Some places tune specifically in speed density (no need for MAF and o2's) and some applications benefit from it. If you are trying to add sensors, it simply requires correct wiring and possibly a tune to use them effectively.
According to the tuner they added wiring and O2 sensors (1 each side) and could not get it to work. Tuner was not very helpful as to why etc and l stopped him when the bill reached $1500.00. This was Houston House of Power. Not helpful at all when l asked questions. Now car is in Anchorage and lm trying to figure out what to do with it. It runs for the most part ok but sometimes stumbles at idle.
That was my next question. Does it have a MAF or has it been converted to Speed Density?
If it's tuned Speed Density it may run okay down in Houston but in Alaska that's a whole new ballgame.
If it's tuned Speed Density it may run okay down in Houston but in Alaska that's a whole new ballgame.
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Thread Starter
Staging Lane
Joined: Jun 2018
Posts: 68
Likes: 6
From: Anchorage AK
I asked the guy who tuned it that why did he not make sure that he ohmed out the system before he attempted to put in the O2 detectors. He said that he did. So according to him they wired the O2 detectors to the ecm. and it did not work. I put a halt to the work because the charges were becoming too high. Very disappointed in this shop Chuck would not answer questions about improving it etc claimed that was between me and my engine builder. I guess this is what I get for building a car long distance. Can this be fixed with another ecm or should I bail from this system and convert to the Holley system?
Thread Starter
Staging Lane
Joined: Jun 2018
Posts: 68
Likes: 6
From: Anchorage AK
Cost wise, you might want to think about putting a Holley Terminator system on it. By the time you pay a shop to figure out the issue(unless it's really simple)then pay for a retune the Holley system will probably be cheaper. You can install the Holley system yourself, set it up on the handheld and be done.
As cheap as these systems are, how easy they are to set up and how well they work. IMO, it's not worth the money or time to mess with a stock ECU anymore. Especially on a car with an LS swap.
Just my .02
As cheap as these systems are, how easy they are to set up and how well they work. IMO, it's not worth the money or time to mess with a stock ECU anymore. Especially on a car with an LS swap.
Just my .02
Do it yourself.
Taking apart ECM connectors and adding terminals isn't hard. There are many resources online you can search for the pinouts on your ECM as well as purchasing terminals for the connectors and tools for crimping and assembly.
You will need to copy the wiring from whatever car the ECM came out of. Typically the 4 wire sensors have a heater circuit, and high and a low signal wires to the ECM.
You may also want to invest in hptuners or efi live.
You can really only test the o2 sensors for response if they are hooked up and working, otherwise they will just send out a solid voltage when heated to operating temp since the ECM is not in closed loop and adjusting STFT's.
Taking apart ECM connectors and adding terminals isn't hard. There are many resources online you can search for the pinouts on your ECM as well as purchasing terminals for the connectors and tools for crimping and assembly.
You will need to copy the wiring from whatever car the ECM came out of. Typically the 4 wire sensors have a heater circuit, and high and a low signal wires to the ECM.
You may also want to invest in hptuners or efi live.
You can really only test the o2 sensors for response if they are hooked up and working, otherwise they will just send out a solid voltage when heated to operating temp since the ECM is not in closed loop and adjusting STFT's.
Last edited by dreadpirateroberts; Dec 20, 2019 at 11:54 AM.
Thread Starter
Staging Lane
Joined: Jun 2018
Posts: 68
Likes: 6
From: Anchorage AK
Do it yourself.
Taking apart ECM connectors and adding terminals isn't hard. There are many resources online you can search for the pinouts on your ECM as well as purchasing terminals for the connectors and tools for crimping and assembly.
You will need to copy the wiring from whatever car the ECM came out of. Typically the 4 wire sensors have a heater circuit, and high and a low signal wires to the ECM.
You may also want to invest in hptuners or efi live.
You can really only test the o2 sensors for response if they are hooked up and working, otherwise they will just send out a solid voltage when heated to operating temp since the ECM is not in closed loop and adjusting STFT's.
Taking apart ECM connectors and adding terminals isn't hard. There are many resources online you can search for the pinouts on your ECM as well as purchasing terminals for the connectors and tools for crimping and assembly.
You will need to copy the wiring from whatever car the ECM came out of. Typically the 4 wire sensors have a heater circuit, and high and a low signal wires to the ECM.
You may also want to invest in hptuners or efi live.
You can really only test the o2 sensors for response if they are hooked up and working, otherwise they will just send out a solid voltage when heated to operating temp since the ECM is not in closed loop and adjusting STFT's.
If there's something not right with your setup the tuner should be able to diagnose the root cause of the issue. I purchased HPTuners from Patrick Guerra and with his help I got to learn a little about the HPTuning software. I gave him my stock tune file along with my build information and he emailed me back a start up tune. I wrote the file to the car and it fired up on the first hit of the starter and let me just say that words cannot describe the feeling I had hearing that engine fire up after seeing that car sit for so many years. I made some idle adjustments and began logging and after a few logging sessions he had me up and running well enough to drive it to Victoria. If your tuner can't tell you whats wrong then I'd be looking for another tuner.
Thread Starter
Staging Lane
Joined: Jun 2018
Posts: 68
Likes: 6
From: Anchorage AK
Ok so I reviewed all the emails that I received from the tuner and apparently there is another issue besides the O2 sensors. The torque converter lockup is not working either. Would it be best if I order a new harness for the car? According to the tuner that is what he believes the problem is from what I gathered from the emails. Why he could not fix it is beyond me but this is what I have to deal with.