'miss' at lower rpms...

[adam74]

Ok thanks for the help!

 

[rockenthebowtie]

De nada

 

[adam74]

ok so figured out I hooked the vacuum line for the heater core valve up to the vent for the egr control valve (the one with three ports). definately got rid of the 'miss' for the most part. went ahead and plugged off the supply for the egr and not much of a difference in driving although I do think the truck ran at less rpms at same speed if thats possible? hard to tell cuz tags arent up to date and the roads are a lil hilly round here. not sure where the vacuum line for the heater core control valves hooks to though, didnt see anything obvious.

 

[lesterl]

My 95 vac supply for the HC coolant flow valve came from the intake manifold between the distributor and the TBI had a 6 sided screw in port that was 1" tall IIRC....

 

[adam74]

Ok thanks Ill check on that tomorrow

 

[adam74]

my vacuum off the intake by the distributor only had one port that is hooked up to the egr system. didnt see any other ports.

 

[lesterl]

EGR system hooks to front of TBI base....

 

[adam74]

thanks for the diagram, its not coming off the tbi its a single port that comes up off the manifold in between the tbi and the distributor. Im pretty sure it went to the egr system but I will double check on that and I will check the hoses according to the diagram tomorrow when its light outside.

 

[rockenthebowtie]

Thats why your getting to much egr at low rpm getting the misfire but I still wouldn't rule out the egr vacuum control solenoid also early egr can also be a result of retarded timing so you might want to check that too

 

[lesterl]

I (for now) have a 95 with the TBI, that port goes to the vac valve for the HC bypass valve. The EGR comes off a port on the TBI (it doesnt have vac on it all the time..)

 

[rockenthebowtie]

Yeup.. should be ported not manifold vacuum to the EGR vacuum control solenoid

 

[adam74]

ok lester I know for sure the one that comes out of the manifold does not currently go to the heater core c/o valve like it should. it has a factory made hose coming off it going to (I believe) the egr system definately not the heater system.
rockenthebowtie yeah that would explain it alot. got better after unhooking the vent port but could still feel a lil bit of a miss compared to how smooth it ran at 3k rpms.

 

[rockenthebowtie]

How exactly is the EGR system hook up as far as vacuum circuits ? Is there anyway you can post a pic

 

[lesterl]

Sounds like he has full manifold vac to solenoid and from there to EGR.......

 

[rockenthebowtie]

@ lester yeup sure does

 

[adam74]

Tryin to upload pics from my phone but not lookin like thats working

 

[lesterl]

Use the go advanced button, and click on the manage attachments, make shure the filesize is smaller so it wont knock it out....

 

[adam74]

#1



vacuum from back of tbi to map sensor

 

[adam74]

#2





vacuum from tbi to egr selonoid valve then to egr

 

[adam74]

#3



vacuum from the tbi to the evap can purge selenoid then to evap canister