cold temp operation (its starting to scare me!)

[MY85pontiac]

not too long ago i put on some moroso blue max wires and noticed an increase in power, "wow, this engine is running pretty well" (i also had a miss and i'm sure that was part of the problem) a couple of weeks after that i put on a newly rebuilt carb "wow this thing is running nice and smooth now!" now when i did this i found there was a vacuum leak UNDER the carb and the EFE heater plate (i hate that thing! glad i got rid of it, stupid restriction) and the engine has run much better after that.

now its getting into the 40's and 50's at night and this engine is simply begging me to flog it! for an engine with 135,000+ miles it still pulls like its brand new. i was out driving last night and it was in the mid 50's and the car was acting like it had an extra shot of HP, i mean a noticable difference in behavior. i do have a black magic fan and i noticed its FINALLY cycling off and on. i have a 160 degree thermostat and i think since putting this fan in i've been able to effectively lower the temp and i feel that is part of the reason why its running so well (along with better fuel mixture and lack of a vacuum leak). now this is a 2.41 geared car and i was making wrong wheel drive cars look like they werent even moving. there was a hyundai that tailgated me and i left them back about 100 feet on a turn and did it again on another turn (i figured maybe they werent expecting it the first time but the second time? he should have known better, guess they figured a 17 year old car cant take a turn and cant accelerate), they were acting like they were in a big hurry or something (thus the reason why they wre tailgating me) but at least they didnt do a fly by, they just went past me a tad over my speed. did i mention they had a wing on it???

anyway this isnt a kill story.....i do have a couple of concerns about my carb.....

first thing is when its kinda cool, shouldnt the carb be on fast idle when i first start it??? i adjusted the fast idle to 1500 RPM but the past few days its been starting and running at 750 which is my curb idle. is my fast idle simply not working? now the emissions sticker says to have the fast idle at 2200 RPM on the highest step but isnt that a bit high? should i adjust it to 2200 RPM on the highest step of the fast idle cam? if its not starting and runningon the highest step it MIGHT explain why the car seems to act like it has a miss when i first take off after starting it, sluggish but after it warms up it acts fine.

another problem is when i turn it off it wants to diesel. i dont know why. at first i thought the curb idle was a tad too much and it was (first adjustment was at 850 RPM) but even after i adjusted it down to 750 it still does this. NOW the carb is idling around 900 RPM. i'm beginning to think that the carb is on one of the lower steps of the fast idle cam and is causingthis. the car has been running nice and cool at 170 degrees although i cant imagine that would cause this behavior but i wont discount it either.

any suggestions? i can adjust the fan to come on at a slightly higher temp like 180 or 190 and see if that helps and adjust the fast idle up to their specs.

 

[MY85pontiac]

noone has anything to suggest???? come on now!!! give me a little help here.

 

[86cut]

first of all, I think 160 is too cold for the winter. Set the stat to 180 so your engine heats up enough. I have my fast idle set around 1500 also. I cant see setting it to 2200! Just don't seem right. When you start your car, do you pump the gas a few times? This can cause the fast idle not to work. In my haynes manual, it says to floor the gas pedal once and the fast idle will become active..BUT I cant start my car with only stepping on the gas once. So I have learned to control it. Istep on the gas fully once and then half way down. This seems to work, but it hasn't been to cold here yet, so I dont know. You just hafta see what works for you, and sometimes you might screw up and worst case scenario, you can step on the gas and make the idle go to 1500 by yourself.

 

[MY85pontiac]

yhea i was gonna turn the fan up to 180 after it gets a tad colder, the highs are coming back up to low 70's at the moment.

i only depress the pedal once and thats it! now i did this when i adjusted the fast idle and i did checked and double checked and it was on the highest step of the fast idle cam when i started the car and adjusted it up to 1500. i'll have to check to see what step its on when i start it now. because for the past couple of days when i frist leave the driveway it acts like it has a miss in the ignition (its not, i checked double checked and triple checked that) and the car will shake like a crack baby and even sounds like it has a miss or two but it doesnt, i just freshened up the ignition right before i put on this carb and the problem didnt happen until after i put the carb on.

and i found out tonite the idle is SURGING!!!!

at a redlight it will idle at 500 RPM (good car! ) then it surges up to about 650-700 RPM (bad car! ) and then back down and then back up and then back down......and then back up......and then well you get idea...its annoying and i dont know why its doing this, it didnt start doing this until a few days ago.

when i put the car in park and the car is at its normal operating temp remember i have a 160 thermostat and a fan set to come on at 160 as well (i will adjust it when it gets a smidge colder) it want to idle around 900 RPM. and erratically it will go down to 750 RPM. a couple of weekends ago the car wouldnt stay above 500 RPM when started for some reason, partially warm and wouldnt stay above 500 (even in park) unless i laid into the pedal so driving home that day was quite a challenge! im not use to having to use both pedals at once and putting enough pressure on one to keep the rpm up until i can get home and adjust it and putting enough pressure on the brake pedal so i dont ram the person in front of me mad for a harrowing adventure especially when i decided to take the highway home (that'll be easy right???? yeah sure!) and then found out that they closed 6 lanes down into two lanes and i had to stay on the brake and stay on the gas. i'm starting to hate this carb.

 

[86cut]

Dont hate the carb- I went through the same crap.
As far as the surging problem goes:
Check for vacuum leaks first,
if there are none, then you may need to reset your Iac and maybe the tps.
I just reset mine because of a surging problem. It is simple. let me know if you need help.
My fast idle doesn't work whenit is warm out, and my car will idle low sometimes when I start it.

O, check to make sure you are not leaking gas from anywhere, which can cause a surging problem.

 

[MY85pontiac]

reset the IAC? never heard of this but i'm starting to think its the IAC because the original carb was having the same problems except the fast idle was sticking but even after it was "unstuck" it still did it but it wasnt surging.


i have check for vacuum leaks, as a matter of fact i fixed a few of them wqhen i put the carb on, the line going to the egr vacuum switch was soft and rotted and i replaced that and replaced some other hoses while i was at it and i double and triple checked everything before i put the carb on because i wanted to make sure a vacuum leak wouldnt make me pull my hair out. i had one previously right under the EFE heater plate and i couldnt stand it!!! throttle response is still good (except during the surging) and i dont hear that big sucking sound (thats a nice term for great big frigging vacuum leak!!!) before the car reacts to me hitting the throttle, it runs smooth and gives me more power than the original carb did (it had 135,000 miles on it) but its the idle i'm having a problem with, its too high, its too low and now this surging. when the surging started tonite (didnt do it earlier in the day) i thought maybe it was a vacuum leak.


i will check for a vacuum leak but i highly doubt its a vacuum leak. i'm thinking maybe its the IAC motor.


i'm good at rebuilding carbs, i SUCK at tuning them! lol

 

[86cut]

to reset the iac motor................
1. Ground ALDL diagnostic lead (short the top two rightmost pins in the ALDL connector).
2. Turn on the ignition (but don't start the car).
3. Wait 30 seconds.
4. Leave ignition on and disconnect the IAC connector.
5. Remove the grounding from the ALDL connector.
6. Start the car. The car will probably run rough and may stall. Just restart and try again.
7. Adjust the throttle stop screw to set the idle to 500 RPM +/- 50 RPM.
8. Turn the car off and reconnect the IAC connector.
9. Turn ignition on and adjust TPS to proper settings. (.42-.44 at idle is typical)
10. Repeat procedure until the 500 RPM +/- 50 RPM in step 7 can be maintained while TPS is at proper idle setting.