S4 hot power loss, glowing cats.
#46
Rennlist Member
Thread Starter
Thanks Rob. I have a maf. But I'm. Not sure about its condition.
I wonder whether it's chip-related. Do you have the MAF screens and Ken's other recommendations? Colder plugs? 89+ octane?
Recommendations (from liftbars.com):
- Rebuilt MAF
- New knock sensors
- New CPS (crank position sensor)
- New TPS (throttle position switch)
- New hall sensor (cam position)
- Cam timing: 0° (-2|0 cold, PK32V'r)
- New OEM O2 sensor (not universal)
- Bosch WR5DC (7992) spark plugs
Required:
- S4 camshafts
- MAF screens installed
- 24# injectors (special o-ring)
I can still pop an LH and a known good MAF in the mail later today, am gone for a week starting tomorrow. I know it would be rich with the 24's but a good O2 sensor might get it close enough to at least run semi-normally (?)
Recommendations (from liftbars.com):
- Rebuilt MAF
- New knock sensors
- New CPS (crank position sensor)
- New TPS (throttle position switch)
- New hall sensor (cam position)
- Cam timing: 0° (-2|0 cold, PK32V'r)
- New OEM O2 sensor (not universal)
- Bosch WR5DC (7992) spark plugs
Required:
- S4 camshafts
- MAF screens installed
- 24# injectors (special o-ring)
I can still pop an LH and a known good MAF in the mail later today, am gone for a week starting tomorrow. I know it would be rich with the 24's but a good O2 sensor might get it close enough to at least run semi-normally (?)
#47
Rennlist Member
Thread Starter
I have swapped out the ignition modules and it made no difference.
The glowing cats bit , reminds me of the 1989 > 928S4/GT/GTS that have old age trouble with their Exhaust Temp Monitoring system ( ETM ) ,that cuts out the ignition on one ignition bank ( kills one coil /module)
So if its a 1988 year type then there is no ETM , but it doesn't mean you do not have an issue with ignition on one coil bank , and yes they do still idle ( very low ) running on 4 cylinders( which makes the cats glow ,because of raw fuel still being injected) & yes they very much feel like they are being pulled back
Quick check for you to do with the engine idling }
Disconnect one of the two mutiplugs from the ignition modules ( next to the engine lid lower catch)for just a few seconds , reconnect then disconnect the other , again just for a few seconds ( this just stops their relevant coils) , if both ignition modules/coils are working then you will see little no difference in disconnection one as compared to disconnecting the other , meaning on a 928S4 that is idling at the correct RPM , all that happens is a drop in RPM , the idle control motor compensates immediately and raises the RPM , mild vibration from the imbalance , but the engine still idles , so in a case where both ignition banks are correct you get same result with disconnecting either module
Now if one module is not working , if you disconnect this one ( multi plug ) you will see do difference at all , because its not working , however if you then disconnect the other one then the engine cuts out , because its the only one working
And yes we see a few ignition modules play up every year( be it 944S2 , 928S4 , 964 etc etc ) as they reach old age & yes only replace with the correct Bosch type , because the non Bosch ones give us the most trouble
Ignition module 928 602 706 01 ) Bosch 0 227 100 124
So if its a 1988 year type then there is no ETM , but it doesn't mean you do not have an issue with ignition on one coil bank , and yes they do still idle ( very low ) running on 4 cylinders( which makes the cats glow ,because of raw fuel still being injected) & yes they very much feel like they are being pulled back
Quick check for you to do with the engine idling }
Disconnect one of the two mutiplugs from the ignition modules ( next to the engine lid lower catch)for just a few seconds , reconnect then disconnect the other , again just for a few seconds ( this just stops their relevant coils) , if both ignition modules/coils are working then you will see little no difference in disconnection one as compared to disconnecting the other , meaning on a 928S4 that is idling at the correct RPM , all that happens is a drop in RPM , the idle control motor compensates immediately and raises the RPM , mild vibration from the imbalance , but the engine still idles , so in a case where both ignition banks are correct you get same result with disconnecting either module
Now if one module is not working , if you disconnect this one ( multi plug ) you will see do difference at all , because its not working , however if you then disconnect the other one then the engine cuts out , because its the only one working
And yes we see a few ignition modules play up every year( be it 944S2 , 928S4 , 964 etc etc ) as they reach old age & yes only replace with the correct Bosch type , because the non Bosch ones give us the most trouble
Ignition module 928 602 706 01 ) Bosch 0 227 100 124
#48
Rennlist Member
Thread Starter
Car would barely run cold or warm last night after a drive. I think its rich missing.
The plugs look like this:
It runs very rough, like you can hear individual hits of combustion.
I have a video I am uploading for your entertainment if anyone is still listening.
I have, with no change (except its now worse since the drive yesterday and has not gotten better with any of these changes) - swapped:
Coils
Ignitors
Coil wires
MAF
unplugged 02. Plugged 02 back in.
The plugs look like this:
It runs very rough, like you can hear individual hits of combustion.
I have a video I am uploading for your entertainment if anyone is still listening.
I have, with no change (except its now worse since the drive yesterday and has not gotten better with any of these changes) - swapped:
Coils
Ignitors
Coil wires
MAF
unplugged 02. Plugged 02 back in.
#49
Rennlist Member
Thread Starter
#50
Inventor
Rennlist Member
Rennlist Member
Try plugging in the CO adjuster I include with the S4 chips. Turn it CCW a few turns (ships at 382 ohms).
I hope you get it running right. I am having a blast with the new chip update. Drove to the awesome road below and back, 375 miles, a/c mostly on, 22 mpg avg! Going on another road trip today. Will see what flat hwy mileage is now.
https://rennlist.com/forums/11580975-post22.html
I hope you get it running right. I am having a blast with the new chip update. Drove to the awesome road below and back, 375 miles, a/c mostly on, 22 mpg avg! Going on another road trip today. Will see what flat hwy mileage is now.
https://rennlist.com/forums/11580975-post22.html
#51
Rennlist Member
Thread Starter
Its worse than this now. I'll swap the other maf back in.
#52
Rennlist Member
Thread Starter
Try plugging in the CO adjuster I include with the S4 chips. Turn it CCW a few turns (ships at 382 ohms).
CCW is leaner, right? That will increase the ohm measurement?
I am concerned now that I Have replaced so much it may actually be the computer itself, but its not following normal failure patterns.
#54
Rennlist Member
Thread Starter
I don't have that plug. I do not recall that being in the package. I don't think it has anything to do with the chips.
#55
Rennlist Member
Thread Starter
Putting the rebuilt maf back in allows the car to at least run. But still basically like the video.
#56
Chronic Tool Dropper
Lifetime Rennlist
Member
Lifetime Rennlist
Member
These are exactly the same symptoms my car suffered as part of the brain failure. I hope I somehow get super rich for a while too before my own brain fades away. Meanwhile, for a couple daysbefore I admitted that the brain was the cause, operation started to seteriorate seriously as yours is, until it would barely start and only run for a few minutes. Plugged in the spare/rebuilt/test brain, and everything was good again.
#57
Rennlist Member
Thread Starter
I somehow have an 88 brain sitting on the shelf. I have no clue why I have this or when I got it.
I will put Ken's updated chip into this LH and run that to see how it goes.
If its not this, I am utterly out of ideas.
I will put Ken's updated chip into this LH and run that to see how it goes.
If its not this, I am utterly out of ideas.
#58
Rennlist Member
Thread Starter
No Difference ( actually worse - won't start with 88 ECU with Ken's updated S4 chips or idle when you put your foot in the gas to make it run).
Old 88S4 ECU lets it start, starts to warm up, gets worse and worse, until you are sitting there at idle like the video shows.
THIS IS seeming INDEPENDANT of the ECUs -
Smells very rich, but now there are no cats, so its hard to tell what level of eye water-ingly rich is wrong.
Once SOMETHING gets warmer, it stops working properly.
Ohmed Temp II. Within spec (not quite hot, but warm - 300ohms at the sensor)
New coils
New coil wires
different ignitors
TPS tests fine
Different ECU not much change
Grounds good (though I may check again)
Switched MAFs - rebuilt one ohms properly and is better than other one I have.
I'm not a quitter, but this is just a stupid waste of time.
Old 88S4 ECU lets it start, starts to warm up, gets worse and worse, until you are sitting there at idle like the video shows.
THIS IS seeming INDEPENDANT of the ECUs -
Smells very rich, but now there are no cats, so its hard to tell what level of eye water-ingly rich is wrong.
Once SOMETHING gets warmer, it stops working properly.
Ohmed Temp II. Within spec (not quite hot, but warm - 300ohms at the sensor)
New coils
New coil wires
different ignitors
TPS tests fine
Different ECU not much change
Grounds good (though I may check again)
Switched MAFs - rebuilt one ohms properly and is better than other one I have.
I'm not a quitter, but this is just a stupid waste of time.
#59
Rennlist Member
Thread Starter
Its too naive to think that this could be a case oft he only known EZK failure. And its running, so how could it be a relay?
#60
Inventor
Rennlist Member
Rennlist Member
Both terminals on the Temp II ohm to ground the same-ish?
Unplug the O2 sensor and the LH. Plug the LH back in, leave the O2 unplugged?
O2 may have been killed from too much fuel running w/24# before you put S4 chips in?
Unplug the O2 sensor and the LH. Plug the LH back in, leave the O2 unplugged?
O2 may have been killed from too much fuel running w/24# before you put S4 chips in?