low volts, rough idle. no fun.
09-13-05, 01:02 AM
#1
MP T-70 = Fun
Thread Starter
Join Date: Dec 2004
Location: Charlotte and WCU
Posts: 1,049
Likes: 0
Received 0 Likes
on
0 Posts
low volts, rough idle. no fun.
well i have been driving my new setup on my 87tii with a j-spec. ~50k on motor.
base map... no other tuning yet.
vac is 20" at idle
my idle is at 11.2:1 a/f
a/f ranges from 10.2 - 13.0 while crusing.
temps stay around 190F
the car has been running good... have put about 40 miles on it since adding everything... haltech, t70, blah blah.
well tonight on the way home the volts were at 13.8... normal. i came to a light and the idle was kinda rough.... could feel the motor shaking some and it was making the exhaust tap on the bottom of the car (its custom and touches in some spots.)
i looked down at the volts and it was at 11.3v. I took my radio face off and it didnt really change. the only thing that i can think of that could have caused the drop in voltage was my e-fan came on. this efan is "new"... well junkyard new.
i had gauges, wideband, radio, headlights and efan on/running when i noticed the low voltage.
The battery is a new optima red top.
So i have a few questions:
1. can the rich conditions listed above will foul plugs and cause the rough idle?... but run smooth at crusing rpm/load?
2. Think something is wrong with the efan or is my charging system that sucky?
I think im gonna clutch fan it up... dunno if it will fit now tho.
turbo is way up there.
base map... no other tuning yet.
vac is 20" at idle
my idle is at 11.2:1 a/f
a/f ranges from 10.2 - 13.0 while crusing.
temps stay around 190F
the car has been running good... have put about 40 miles on it since adding everything... haltech, t70, blah blah.
well tonight on the way home the volts were at 13.8... normal. i came to a light and the idle was kinda rough.... could feel the motor shaking some and it was making the exhaust tap on the bottom of the car (its custom and touches in some spots.)
i looked down at the volts and it was at 11.3v. I took my radio face off and it didnt really change. the only thing that i can think of that could have caused the drop in voltage was my e-fan came on. this efan is "new"... well junkyard new.
i had gauges, wideband, radio, headlights and efan on/running when i noticed the low voltage.
The battery is a new optima red top.
So i have a few questions:
1. can the rich conditions listed above will foul plugs and cause the rough idle?... but run smooth at crusing rpm/load?
2. Think something is wrong with the efan or is my charging system that sucky?
I think im gonna clutch fan it up... dunno if it will fit now tho.
turbo is way up there.
09-13-05, 08:46 AM
#2
Locust of the apocalypse
Join Date: Apr 2003
Location: Directly above the center of the earth (York, PA)
Posts: 2,553
Likes: 0
Received 1 Like
on
1 Post
that car has got to be getting like 6 mile per gallon......
I assume that you are using a wideband to get these readings...
Well as to fouling out plugs.. GEEZUS yes.. that thing is running pig rich and you will definately mung up some plugs like that!!! And Yes... It can affect Idle and seem fine under load..
Ratoarys LOVE to run at 13.0 under load... they LOVE it..... however, there is no need to run that rich on the highway while cruising.... you'll kill you wallett.. Get the thing Dialed in so that under anything greater than 10" of vac is like 14.0 to 14.4 A/F From 10" to 0" I like to run it down in hte mid 13' 0 to 5 PSI.. low high 12's... above 5 PSI.. low 12's when you get close to 15PSI.... 11.75
THEN.. get yerself an o2 sensor.. set the closed loop mode for about 27% throttle max, 6 cycles per correction, abd target voltage to about 650 mv... (you can then use the wideband to verify that the haltech is function and fine tune the Target so that the car runs about 14.4 on the highway)
20" at idle?? How high are you idling it???? and... how efficient is you FMIC... that seems like really high vac for idle on a TII...... 16-17 is the norm.... seems like you have a restriction somewhere....
shoot for 12.8 AFR at idle for a TII If the A/F is to lean.. the motor will hunt, too Rich it will Dance Yours must be doing a tango!!!
Finally......... DITCH THAT E-FAN until you get an FD alt..... s4 alts just can't handle the load... especially if you were running the computer, the wideband, the stereo the e-fan at once.... If you'r car is running rich and fouling plugs.. low voltage at idle will really mess it up.. You can also try idleing it at 1K.. that'll keep the altenator spinning a bit faster and help with the low voltage.. (but, an FD alt is the only real fix) if you HAVE an FD alt... Idle the car higher and play with the Voltage Correction map in the haltech!!!!
I assume that you are using a wideband to get these readings...
Well as to fouling out plugs.. GEEZUS yes.. that thing is running pig rich and you will definately mung up some plugs like that!!! And Yes... It can affect Idle and seem fine under load..
Ratoarys LOVE to run at 13.0 under load... they LOVE it..... however, there is no need to run that rich on the highway while cruising.... you'll kill you wallett.. Get the thing Dialed in so that under anything greater than 10" of vac is like 14.0 to 14.4 A/F From 10" to 0" I like to run it down in hte mid 13' 0 to 5 PSI.. low high 12's... above 5 PSI.. low 12's when you get close to 15PSI.... 11.75
THEN.. get yerself an o2 sensor.. set the closed loop mode for about 27% throttle max, 6 cycles per correction, abd target voltage to about 650 mv... (you can then use the wideband to verify that the haltech is function and fine tune the Target so that the car runs about 14.4 on the highway)
20" at idle?? How high are you idling it???? and... how efficient is you FMIC... that seems like really high vac for idle on a TII...... 16-17 is the norm.... seems like you have a restriction somewhere....
shoot for 12.8 AFR at idle for a TII If the A/F is to lean.. the motor will hunt, too Rich it will Dance Yours must be doing a tango!!!
Finally......... DITCH THAT E-FAN until you get an FD alt..... s4 alts just can't handle the load... especially if you were running the computer, the wideband, the stereo the e-fan at once.... If you'r car is running rich and fouling plugs.. low voltage at idle will really mess it up.. You can also try idleing it at 1K.. that'll keep the altenator spinning a bit faster and help with the low voltage.. (but, an FD alt is the only real fix) if you HAVE an FD alt... Idle the car higher and play with the Voltage Correction map in the haltech!!!!
09-13-05, 08:50 AM
#3
Locust of the apocalypse
Join Date: Apr 2003
Location: Directly above the center of the earth (York, PA)
Posts: 2,553
Likes: 0
Received 1 Like
on
1 Post
PS... I got a new FD alt from Malloy Mazda and got it wired correclty for an S4 car... and BINGO... my idle is at 950 and the voltage WITH THE LIGHTS and brakes on... is 14.2v!!!!
09-13-05, 08:22 PM
#4
MP T-70 = Fun
Thread Starter
Join Date: Dec 2004
Location: Charlotte and WCU
Posts: 1,049
Likes: 0
Received 0 Likes
on
0 Posts
wow thanks for all the info... now i know what to aim for.
yea the car is getting crap for mileage. i leaned out the idle today to 12.5 it was happy there. now i need to adjust all the other areas.
the low voltage was my old used alternator... it took a crap. I got a new one.... little paper it came with showed where they tested it and it put out 90amps.
The new alt fixed it and i have 13.8v at 850 idle.
The vaccume reading at idle was wrong. my boost gauge is junk..... the haltech says ~17.5" at idle.
and yes i do have a wide band.
again thanks for the info.
yea the car is getting crap for mileage. i leaned out the idle today to 12.5 it was happy there. now i need to adjust all the other areas.
the low voltage was my old used alternator... it took a crap. I got a new one.... little paper it came with showed where they tested it and it put out 90amps.
The new alt fixed it and i have 13.8v at 850 idle.
The vaccume reading at idle was wrong. my boost gauge is junk..... the haltech says ~17.5" at idle.
and yes i do have a wide band.
again thanks for the info.
Thread
Thread Starter
Forum
Replies
Last Post
Donald Hampton
2nd Generation Specific (1986-1992)
5
09-17-15 03:13 PM
The1Sun
1st Generation Specific (1979-1985)
0
09-07-15 10:21 PM
