Fixed vacuum leaks, and now runs horribly
06-24-2018, 12:06 AM
#1
Racer
Thread Starter
Fixed vacuum leaks, and now runs horribly
1982 928s euro auto w/o cats. 65k miles
I fixed some bad intake leaks and now my engine won’t run for squat. The PO and smog shop “tuned” it dramatically to get it to pass smog, so I have no idea where any settings are. I think it’s rich from the exhaust.
I’ve been turning the idle screw CCW and the idle is slowly coming up (maybe 500 rpm now). It almost runs on it’s own, so I’ll probably resume that tomorrow until it idles around 800. Then, move on to the mixture screw.
Does that sound reasonable? Other ideas?
Thanks,
Camelman
I fixed some bad intake leaks and now my engine won’t run for squat. The PO and smog shop “tuned” it dramatically to get it to pass smog, so I have no idea where any settings are. I think it’s rich from the exhaust.
I’ve been turning the idle screw CCW and the idle is slowly coming up (maybe 500 rpm now). It almost runs on it’s own, so I’ll probably resume that tomorrow until it idles around 800. Then, move on to the mixture screw.
Does that sound reasonable? Other ideas?
Thanks,
Camelman
06-24-2018, 02:54 AM
#2
Team Owner
Do you have the tool to adjust the CIS mixture
if you removed air leaks then the mixture must also be leaned out then the idle screw should be adjusted
my 79 USA car was running like this extra rich to account for all of the extra air once the extras were eliminated I readjusted the mixture now the car runs great
you should use a co meter to adjust the mixture if you done have one you can use your nose you will be able to smell if ifs close to a proper mixture
if you removed air leaks then the mixture must also be leaned out then the idle screw should be adjusted
my 79 USA car was running like this extra rich to account for all of the extra air once the extras were eliminated I readjusted the mixture now the car runs great
you should use a co meter to adjust the mixture if you done have one you can use your nose you will be able to smell if ifs close to a proper mixture
06-24-2018, 04:53 AM
#4
You can call me Otis
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I don't have any useful information, other than maybe blame Kibort, ... You'd think he was Trump or something.
It's all Kiborts fault!!!
....anyway..., just my rant.
It's all Kiborts fault!!!
....anyway..., just my rant.
06-24-2018, 12:25 PM
#5
Addict
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CCW is lean. Move slow and remove the took prior to giving it some light revs between adjustment.
pushing down on the adjustment screw will cause a very small but temporary air leak as well
pushing down on the adjustment screw will cause a very small but temporary air leak as well
06-24-2018, 03:57 PM
#6
Team Owner
NOTE you should have made no more than about 1/2 a turn or less to the MIXTURE screw on the FD,
when you gently press it into the housing against the spring, it may make the engine die if you do this while running.
CCW is leaning out on the mixture screw
you may need a helper to keep it running while your adjusting it,
then the idle screw will be adjusted to the correct idle
On that screw CW will decrease the idle, this screw is infront of the throttle body
when you gently press it into the housing against the spring, it may make the engine die if you do this while running.
CCW is leaning out on the mixture screw
you may need a helper to keep it running while your adjusting it,
then the idle screw will be adjusted to the correct idle
On that screw CW will decrease the idle, this screw is infront of the throttle body
06-25-2018, 11:12 AM
#7
Nordschleife Master
I don't know a whole lot about CIS, but I do know this:
Start from the beginning. Get a set of pressure gauges and set your pressures correctly. Then play with the mixture settings.
The 928 Classics site has all the proper procedures for this.
If the shop 'tuned' it way out of whack to pass smog with the air leaks, starting at the beginning will be simpler than trying to 'undo' whatever they did.
Start from the beginning. Get a set of pressure gauges and set your pressures correctly. Then play with the mixture settings.
The 928 Classics site has all the proper procedures for this.
If the shop 'tuned' it way out of whack to pass smog with the air leaks, starting at the beginning will be simpler than trying to 'undo' whatever they did.
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06-25-2018, 11:26 AM
#8
Shameful Thread Killer
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^^^This is correct^^^. CIS pressure is everything. You can't just start turning **** and expect it to start running right. Do the pressure settings, and if they are not in spec, get them in spec. Once that's done, you can then set the idle air bypass right, and once that is done, you can start messing with mixture. But - start with pressures. If the car has been sitting for a while, it will run bad because the screens and the injectors on CIS do not like to sit. They will clog easily.
06-25-2018, 11:35 AM
#9
Racer
Thread Starter
Thanks for the advice, and I’ll go through a proper tune up once I get it out of the garage. It ran much smoother yesterday, but I didn’t have time to mess with it.