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4g63 Mechanics

Joined
Dec 18, 2021
Messages
5
Hi, If anyone sees this. I am the owner of 1992 580/1000. I am kinda in over my head. I am located in Lincoln Illinois near springfield, and was wondering if anyone knows anyone or a shop near there that could diagnose the issue. It starts, but has a rough idle. I dont know if it is a vacumn leak or the dsm link tune. Anything helps thanks.
 

yubh8tn

Well-known member
Joined
Aug 21, 2019
Messages
195
Location
coeur d alene, idaho
Welcome! You can quite easily check for vacuum leaks yourself if you feel capable. A boost leak tester and a bottle of soapy water should be able to sort it all out for you. If you don't find anything and the issue persists, it could likely be a tune or possibly something more major like timing. Keep us updated!
 

vrpower

Member
Joined
Nov 7, 2010
Messages
21
Location
Chicago, Illinois
Hi, If anyone sees this. I am the owner of 1992 580/1000. I am kinda in over my head. I am located in Lincoln Illinois near springfield, and was wondering if anyone knows anyone or a shop near there that could diagnose the issue. It starts, but has a rough idle. I dont know if it is a vacumn leak or the dsm link tune. Anything helps thanks.
About 150 miles and 2 and a half hours...away....hmmm.
 

yubh8tn

Well-known member
Joined
Aug 21, 2019
Messages
195
Location
coeur d alene, idaho
Can you explain what you are searching for about timing? I think I may be able to help. As for the unhooked vacuum line, that could definitely be affecting your idle. Could you post the clearest pictures possible showing where each end of the line currently is?
 

yubh8tn

Well-known member
Joined
Aug 21, 2019
Messages
195
Location
coeur d alene, idaho
Well, I don't remember what that bung on the manifold goes to and my car is apart so I can't find out, but you could always just remove the T and connect the one line directly to it. From factory that bung only has one hose coming off of it, that line might just go to something that isn't used anymore. Are you running a MAF or have you converted to Speed Density? It looks like there's possibly a MAP sensor on your firewall with that 3 post orange connector going to it. If it is a MAP, make sure it's connected to the vacuum system otherwise it could be the cause of your rough idle. It's possible that unhooked line with the screw in it goes to it. You can adjust your base timing with the CAS, which is the circular shaped sensor on the non-timing end of the intake cam. If you want to change more than your base timing, that would be a tuning thing which I have no experience with. Also, how does the car act during higher RPM's? Is the car driveable? Also, why do you have two blow off valves?
 
Joined
Dec 18, 2021
Messages
5
Its smooths out between 1000 and 2000 rpm. We havn't tried driving the car as to not hurt it just in case. I dont know why there are 2 bovs it just came that way. I think the tuning reset. So i will try having a base tune put on.
 

yubh8tn

Well-known member
Joined
Aug 21, 2019
Messages
195
Location
coeur d alene, idaho
Its smooths out between 1000 and 2000 rpm. We havn't tried driving the car as to not hurt it just in case. I dont know why there are 2 bovs it just came that way. I think the tuning reset. So i will try having a base tune put on.
Good luck, let us know.
 

BigT

New member
Joined
Aug 12, 2022
Messages
4
Location
Kansas city
in order to tune it properly u want to start with a good running engine as baseline. otherwise your chasing your tail. however you can try flashing the factory ECU image to see if its tune related. if you do this BACKUP your current ecu image, post it here if so.
MAF sensors dont like unmetered air, Base idle screw o-rings good? any leak is a big deal. fix any vacuum leaks even if your on speed density / using a MAP sensor, maybe the line with the screw was for a boost gauge ? fuel pressure regulator is hooked up?
Timing belt skipped timing wouldn't really be my first suspect, but i suppose its possible to skip a tooth without catastrophic failure, in which case you would know, id hope as your covers already removed
 
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