1990 928s4 gremlin list after first few runs
05-17-2016, 08:46 AM
#1
1990 928s4 gremlin list after first few runs
ok so finally got the car on the road ! registration came on Saturday so got plates and have finally been out properly in the car 
as usual few small issues came up - you guys have prob seen these before so maybe a few quick pointers can sort these out
1. Hot air - seems to come thru a bit even with slider at coldest setting , it does get a lot hotter when moved up the scale but not as cold as it should be at the lowest setting - seems odd ... stuck something ??
2. Auto box - I set all the cables etc etc seems pretty good two things thou a)doesn;t seem to always way to kick down when I floor it - seems random if it works or not ie could be stuck slowly accelerating in top gear when trying to pass ! not good !
b) seems very laggy ie I accelerate and revs build but doesn't really feel like its moving much even when it does kick down - this could just be a perception as a while since I drove an auto kinda hard to describe but just not very sharp pickup ?? - like having turbo lag !
well those are the big ones - not bad - if I can get the auto shifting/perfoming better i'll be well pleased !
cheers
Johnny
as usual few small issues came up - you guys have prob seen these before so maybe a few quick pointers can sort these out
1. Hot air - seems to come thru a bit even with slider at coldest setting , it does get a lot hotter when moved up the scale but not as cold as it should be at the lowest setting - seems odd ... stuck something ??
2. Auto box - I set all the cables etc etc seems pretty good two things thou a)doesn;t seem to always way to kick down when I floor it - seems random if it works or not ie could be stuck slowly accelerating in top gear when trying to pass ! not good !
b) seems very laggy ie I accelerate and revs build but doesn't really feel like its moving much even when it does kick down - this could just be a perception as a while since I drove an auto kinda hard to describe but just not very sharp pickup ?? - like having turbo lag !
well those are the big ones - not bad - if I can get the auto shifting/perfoming better i'll be well pleased !
cheers
Johnny
05-17-2016, 09:31 AM
#2
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No 1. seems like a leaking Heater Control Valve. There are lots of posts on here about checking it, tieing it closed for the summer, etc. It's a pretty simple replacement and not expensive. Might want to check for other vaccuum leaks in the HVAC system while you're at it.
No 2. I will leave to those far more knowledgeable than me. Not sure if vaccuum leak could cause those symptoms...
No 2. I will leave to those far more knowledgeable than me. Not sure if vaccuum leak could cause those symptoms...
05-17-2016, 09:58 AM
#3
Rennlist Member
The trans is very sensitive to fluid level and quality. Check the fluid with the trans at full temp and the car level. Being at all low will cause strange behavior. If that checks out good do a fluid change including draining the torque converter. Be sure to carefully torque the pan to avoid leaks.
Mike
Mike
05-17-2016, 10:42 AM
#4
Rennlist Member
ok so finally got the car on the road ! registration came on Saturday so got plates and have finally been out properly in the car
as usual few small issues came up - you guys have prob seen these before so maybe a few quick pointers can sort these out
1. Hot air - seems to come thru a bit even with slider at coldest setting , it does get a lot hotter when moved up the scale but not as cold as it should be at the lowest setting - seems odd ... stuck something ??
2. Auto box - I set all the cables etc etc seems pretty good two things thou a)doesn;t seem to always way to kick down when I floor it - seems random if it works or not ie could be stuck slowly accelerating in top gear when trying to pass ! not good !
b) seems very laggy ie I accelerate and revs build but doesn't really feel like its moving much even when it does kick down - this could just be a perception as a while since I drove an auto kinda hard to describe but just not very sharp pickup ?? - like having turbo lag !
well those are the big ones - not bad - if I can get the auto shifting/perfoming better i'll be well pleased !
cheers
Johnny
as usual few small issues came up - you guys have prob seen these before so maybe a few quick pointers can sort these out
1. Hot air - seems to come thru a bit even with slider at coldest setting , it does get a lot hotter when moved up the scale but not as cold as it should be at the lowest setting - seems odd ... stuck something ??
2. Auto box - I set all the cables etc etc seems pretty good two things thou a)doesn;t seem to always way to kick down when I floor it - seems random if it works or not ie could be stuck slowly accelerating in top gear when trying to pass ! not good !
b) seems very laggy ie I accelerate and revs build but doesn't really feel like its moving much even when it does kick down - this could just be a perception as a while since I drove an auto kinda hard to describe but just not very sharp pickup ?? - like having turbo lag !
well those are the big ones - not bad - if I can get the auto shifting/perfoming better i'll be well pleased !
cheers
Johnny
1. Given you live in the "Land of Bog" your a/c should freeze your nuts off and if it does not then it is likely that you do not have enough gas pressure in the system. There is a low pressure switch that prevents the system from engaging the solenoid operated clutch if the pressure is too low. Similarly, the solenoid clutch itself could be toasted [easy to check if it clicks on/off] and the "piece de resistance" is when the HVAC relay located behind the control panel goes **** up as they invariably do at this age.
I doubt there is a problem with the temperature control valve given you can feel it heating up as you increase the setting thus suggesting it is modulating but..?
2a- Fully agree with the transmission fluid level- very critical. Any signs of ATF [red oil] leaking around the gearbox area?
2b- Given you do not have a turbo then the turbo lag will be a pretty long wait! I rather suspect you need to resolve point 2a before delving further. Remember the 928 is a bit quirky- the auto box has quite wide ratios and the broad torque band enables it to pull such. Thus compared to a modern vehicles with 6 speeds it is not changing gears as often and maybe you are conditioned to such? The real measure is "how long does it take you to get to 60 mph"? The answer should be about 6 seconds flat. If you cannot do this then something is wrong. To put things into perspective my Cayenne Turbo S can hop to 60 in a tad under 5 seconds but it is not 26 years old!
Rgds
Fred
05-17-2016, 12:06 PM
#5
Chronic Tool Dropper
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Johnny--
Pull the cover over the engine control units, side wall of the passenger seat bulkhead just forward of the passenger door opening. On the side of the bracket that supports the controllers, there's a "ignition protection relay" that selectively shuts down 4 of the 8 cylinders when it detects one ignition has failed. Without digging for your history on the car, if work has been done in the engine bay there's risk that one ignition is not firing. Might be a coil wire not seated or other malady. The protection relay has red and green LED indicators on it that light when protection is active. Look for one of those after you've driven for ten minutes or so, and you may find the root of the low apparent performance.
On the gearbox shifting --
The transmission will downshift based on a change (drop) in control pressures. That pressure is managed by a combination of the governor, plus throttle position, plus a kick-down switch under the throttle pedal. The connection between pedal and transmission is adjustable at the throttle quadrant on the side of the intake manifold, where two cables pull and two are pulled. The outer of the two "pulled" cables is the TV (throttle valve) cable to the transmission. There should be only a small amount of slack in that. Adjust the cable shorter to make transmission more responsive. A turn or two makes a big difference, so adjust that carefully.
The kickdown switch under the throttle is activated by a little arm from the pedal itself. Take a look to see that the arm is activating the switch when the pedal is fully depressed. The arm sometimes gets bent up to the point where it no longer activates the switch.
While you are playing with pedal and cables, verify that the pedal is able to open the engine throttle completely. The cables stretch and wear, and the one to the throttle from the quadrant wraps around a pulley. Verify the correct and free routing of that cable before making any adjustments. Keep in mind that adjusting the pedal cable affects the adjustment on the TV cable too.
Pull the cover over the engine control units, side wall of the passenger seat bulkhead just forward of the passenger door opening. On the side of the bracket that supports the controllers, there's a "ignition protection relay" that selectively shuts down 4 of the 8 cylinders when it detects one ignition has failed. Without digging for your history on the car, if work has been done in the engine bay there's risk that one ignition is not firing. Might be a coil wire not seated or other malady. The protection relay has red and green LED indicators on it that light when protection is active. Look for one of those after you've driven for ten minutes or so, and you may find the root of the low apparent performance.
On the gearbox shifting --
The transmission will downshift based on a change (drop) in control pressures. That pressure is managed by a combination of the governor, plus throttle position, plus a kick-down switch under the throttle pedal. The connection between pedal and transmission is adjustable at the throttle quadrant on the side of the intake manifold, where two cables pull and two are pulled. The outer of the two "pulled" cables is the TV (throttle valve) cable to the transmission. There should be only a small amount of slack in that. Adjust the cable shorter to make transmission more responsive. A turn or two makes a big difference, so adjust that carefully.
The kickdown switch under the throttle is activated by a little arm from the pedal itself. Take a look to see that the arm is activating the switch when the pedal is fully depressed. The arm sometimes gets bent up to the point where it no longer activates the switch.
While you are playing with pedal and cables, verify that the pedal is able to open the engine throttle completely. The cables stretch and wear, and the one to the throttle from the quadrant wraps around a pulley. Verify the correct and free routing of that cable before making any adjustments. Keep in mind that adjusting the pedal cable affects the adjustment on the TV cable too.
05-17-2016, 05:59 PM
#6
Sorry guys before I investigate with the great advice posted from up guys I have number 3 to add ! As you know I'm in Ireland do it rained today ! And guess what water started dripping in a above rear seat at hatch edge just where the rear sun visitors are ! Now my first priorty to fix ! Might get quick look tonight
Cheers
Cheers
05-17-2016, 06:23 PM
#7
Team Owner
to fix the leak you need some hondabond 4 and some spray cleaner and a brush.
remove the battery ground strap.
remove the two rear sun shades,
remove the upper interior hatch lamp, mark the wires.
remove the upper hatch interior trim panel 5 clips hold it on.
Once this is done then you can remove the hatch seal.
spray the cleaner on the seal scrub it with a brush to remove the dirt ,
rinse off in hot water.
lay the seal in the sun for a few hours to reform it.
Wipe down the seal rib on the hatch remove all traces of dirt.
Get tube of Honda Bond 4 and put the thin tip onto it.
put a bead into the groove along the top edges of the seal, and about 10 inches down each side smear some on the rib on the car .
install the seal ,
NOTE optional to put a bead into the whole seal ,
work in small sections so the sealant wont run out and drip onto the carpet
refit all other pieces in reverse order.
remove the battery ground strap.
remove the two rear sun shades,
remove the upper interior hatch lamp, mark the wires.
remove the upper hatch interior trim panel 5 clips hold it on.
Once this is done then you can remove the hatch seal.
spray the cleaner on the seal scrub it with a brush to remove the dirt ,
rinse off in hot water.
lay the seal in the sun for a few hours to reform it.
Wipe down the seal rib on the hatch remove all traces of dirt.
Get tube of Honda Bond 4 and put the thin tip onto it.
put a bead into the groove along the top edges of the seal, and about 10 inches down each side smear some on the rib on the car .
install the seal ,
NOTE optional to put a bead into the whole seal ,
work in small sections so the sealant wont run out and drip onto the carpet
refit all other pieces in reverse order.
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05-17-2016, 09:07 PM
#9
Chronic Tool Dropper
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It's an adhesive/sealant useful for more than a few things on the cars. Handy stuff!
05-17-2016, 10:03 PM
#10
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Look at post #1 here for good advices on adjusting the auto trans.
https://rennlist.com/forums/928-foru...justments.html
Like others have already said, start with a trans. oil/filter change (if not done recently) and then adjust carefully every cables at the quadrant.
The 928 is a different car with a well adjusted transmission (cable and modulator).
https://rennlist.com/forums/928-foru...justments.html
Like others have already said, start with a trans. oil/filter change (if not done recently) and then adjust carefully every cables at the quadrant.
The 928 is a different car with a well adjusted transmission (cable and modulator).
05-18-2016, 10:52 AM
#12
Rennlist Member
Mine is usually short circuited but I can reverse it any time I choose to go back to a more stock set up but even then the kick down cable is wound tighter as i advised earlier.
Rgds
Fred
05-18-2016, 07:48 PM
#13
Quick update
Rear seal seems collapsed along hinge end very flat and doesn't spring up so looks like new seal is only way to resolve ....
On the full throttle switch yep I see switch and can manually press it but metal lever on pedal doesn't reach it to compress it when floored !! Prob not helping my full power !
Is there supposed to be any plastic fitting on the metal part behind pedal that's supposed to. Make contact with switch there's no way mines reaching it !
Cheers
J
Rear seal seems collapsed along hinge end very flat and doesn't spring up so looks like new seal is only way to resolve ....
On the full throttle switch yep I see switch and can manually press it but metal lever on pedal doesn't reach it to compress it when floored !! Prob not helping my full power !
Is there supposed to be any plastic fitting on the metal part behind pedal that's supposed to. Make contact with switch there's no way mines reaching it !
Cheers
J
05-19-2016, 05:30 PM
#14
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Maybe it needs to be adjusted.
See post #6338 here:
https://rennlist.com/forums/928-foru...today-423.html
This was posted today.
See post #6338 here:
https://rennlist.com/forums/928-foru...today-423.html
This was posted today.
