Car runs richer when fogs are turned on
07-12-2010, 07:50 PM
#17
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is the whole system that is not getting a good ground, grounding the maf wont fix your issues, let me see if I have a picture of my engine bay with the grounds. I had the power perfect and and a wb, but I took the car to a dyno to verify the accuracy of my wb and surprise as soon as I turned the lights the car went rich so my wb was accurate.
Pics would help tremendously...
07-13-2010, 09:03 PM
#19
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That's good, but the bad grounds aren't causing the rich condition under full throttle, or at least I wouldn't think. I can understand bad grounds causing the car to run richer when a load is put on, I.E. fog lights and such...
07-13-2010, 09:44 PM
#20
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Due to faulty grounds, I have seen a positive voltage as high as 0.5Vdc at the MAF ground connection (as well as other ground connections). The MAF output signal will be offset by the same value. I will use the 0.5V in the following example..
Instead of having MAF signal of "X vdc" now you are getting "X + 0.5V". The DME will richen the mixture, as it calculates the Air Flow based on "X + 0.5v". (Higher voltage = more flow = more fuel). However, with a good ground, the MAF signal should be "X" not "X + 0.5V"
A bad ground can cause all sort of issues, not just MAF or rich/lean related problems. A bad ground affects ALL sensors.....
07-13-2010, 09:49 PM
#21
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I am going to check some of the grounds with my meter to see if I can get any readings out of them. I would still like to see some pics if anyone has any of where they added extra grounds to their cars.
John, by moving my MAF ground to the negative terminal on the battery my AFR's improved at idle and partial throttle greatly, it seems to only go super rich now when I give it full throttle and get into boost.
John, by moving my MAF ground to the negative terminal on the battery my AFR's improved at idle and partial throttle greatly, it seems to only go super rich now when I give it full throttle and get into boost.
07-13-2010, 10:14 PM
#22
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I am going to check some of the grounds with my meter to see if I can get any readings out of them. I would still like to see some pics if anyone has any of where they added extra grounds to their cars.
John, by moving my MAF ground to the negative terminal on the battery my AFR's improved at idle and partial throttle greatly, it seems to only go super rich now when I give it full throttle and get into boost.
John, by moving my MAF ground to the negative terminal on the battery my AFR's improved at idle and partial throttle greatly, it seems to only go super rich now when I give it full throttle and get into boost.
By grounding the MAF directly to the battery ground terminal, you isolated the MAF ground, however there are other sensors that require a good ground. Even the DME itself must have a good ground.. Look at the ground points at the bell housing, firewall, by the headlights,... Cleaning the ground connections may solve many issues. you could also have bad ground wires which should be replaced.
To make this task easier, think of a bad ground as leaving HP on the table. With good ground, you can reclaim lost HP.. Now, that'll get you going
07-13-2010, 10:15 PM
#23
I had about the MAF ground hooked to one of my strut tower bolts. After cleaning the headlight grounds I put the MAF ground to the negative battery post and all is well. Before I made the change I tested the ground with my multimeter from the black wire on the MAF and the negative post on the battery. I had 0 volts with the car in the off position on the ignition. About .02 volts with ignition in the on position and about .09 volts with the headlights on.
Just wanted to say Thanks to John for helping me with this same issue. He'll steer you in the right direction.
Just wanted to say Thanks to John for helping me with this same issue. He'll steer you in the right direction.
Last edited by gcb951; 07-13-2010 at 10:16 PM. Reason: more to add
07-13-2010, 10:25 PM
#24
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I had about the MAF ground hooked to one of my strut tower bolts. After cleaning the headlight grounds I put the MAF ground to the negative battery post and all is well. Before I made the change I tested the ground with my multimeter from the black wire on the MAF and the negative post on the battery. I had 0 volts with the car in the off position on the ignition. About .02 volts with ignition in the on position and about .09 volts with the headlights on.
Just wanted to say Thanks to John for helping me with this same issue. He'll steer you in the right direction.
Just wanted to say Thanks to John for helping me with this same issue. He'll steer you in the right direction.
You are welcome!
Ideally you want the MAF ground wire as short as possible. I assume, you reconnected it back to chassis once the ground wires were cleaned up?
07-13-2010, 10:52 PM
#25
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This tells me you have a grounding issue. Rich at WOT could be many things.. I would fix ALL ground issues before moving forward.
By grounding the MAF directly to the battery ground terminal, you isolated the MAF ground, however there are other sensors that require a good ground. Even the DME itself must have a good ground.. Look at the ground points at the bell housing, firewall, by the headlights,... Cleaning the ground connections may solve many issues. you could also have bad ground wires which should be replaced.
To make this task easier, think of a bad ground as leaving HP on the table. With good ground, you can reclaim lost HP.. Now, that'll get you going
By grounding the MAF directly to the battery ground terminal, you isolated the MAF ground, however there are other sensors that require a good ground. Even the DME itself must have a good ground.. Look at the ground points at the bell housing, firewall, by the headlights,... Cleaning the ground connections may solve many issues. you could also have bad ground wires which should be replaced.
To make this task easier, think of a bad ground as leaving HP on the table. With good ground, you can reclaim lost HP.. Now, that'll get you going
07-14-2010, 01:15 AM
#26
John,
I haven't got around to changing the ground yet. But the car has been parked and I only drove it about 2 or 3 miles for a test run. Do you have any good suggestions for where I should ground the MAF? Should I make my own ground to the chassis?
I haven't got around to changing the ground yet. But the car has been parked and I only drove it about 2 or 3 miles for a test run. Do you have any good suggestions for where I should ground the MAF? Should I make my own ground to the chassis?
07-15-2010, 02:17 AM
#29
Question about the extra rich A/R on WOT. If the ground is bad, does the reading on the wideband show an accurate number or is it off by the voltage that is leaking from the system? Or put it this way, with the wideband showing 1.5 to 2.0 more points on the wideband with WOT, is that an accurate reading of the air fuel ratio?
07-25-2010, 11:26 PM
#30
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gcb951, I believe the wideband is telling the truth when there is an electric load on. I am having the same problem and when i start to turn accessories on, I hear a change in idle quality as well as watching the afr drop on my wideband. I'm going to start to clean some grounds on my car.
any update to this thread?
any update to this thread?