i'm lost with these scanmaster numbers

T

trixdout

Active Member
Joined
Sep 4, 2012
O2 millibolts 378-402
af 12-13 This sin't right, it's supposed ot be around 6-7. How do I bring it down?
L8 45-46 then goes up to 91,99
bat 13.8-14.0 when the idle is high, as it drops the voltage drop to 12.8-13.1
int 128 stays the same the whole time
blm 128 stays the same the whole time
coolant temp was 117-121 and thats as high as I got it
air temp 45
rpm 750-850
tps .42
iac goes down to 18 then right back p to 87. It got up to 90+ but I turned the screw in some more and it went down to 87 and turned it some more and went down to 78

I don't know what to make of it

I've read around on how to tune the car to good tps readings and can't seem to dial in the iac. I got a video i can show you that shows how the iac dropped all the way down to a little under 20 and then slowly went back up to 81 and stayed there. At that point the idle screw was screwed all the way in and the spring did not let me go any further. Prior to replacing the iac with a pepboys replacement, i reset the stock on. Still no dice and the same issue with the idle. After pulled off the original iac I cleaned out the passageways and everything including the throttle blade (completely gunked up with carbon buildup/oil). I have a leaky turbo which caused all this. Changed the pcv valve to the rjc racing pcv.

Other changes to the car, maf translator with a 3" lt1, only the downpipe connected and not the cat or the 4"exhaust. I also have a vac/boost gauge, oil pressure, and fuel pressure as well as the afpr that kirban sells.
RJC power plate, CR43ts plugs all new, taylor blue spark wires (came with the car), KB headers, 3" external dp. Fuel pressure was set to about 40psi, hits 45psi at ignition on, then drops to 39, then slowly drops thereafter.

Things I did to fix the issue was changing out all the spark plugs to cr 43ts, changed out all vacuum hoses, cleaned out iac valve and motor and the whole assembly, cleanned out the throttle blade and the plenum, clean air filter, set the fuel pressure to about 40psi. It was 30 psi before from the stock regulator.

I can't even get the car to start and the battery is fully charged. When the car does start it idles and then jsut shuts down after about 2-4 seconds. If I do get it to run, the idle will rise to 2000 and very slowly drop down to 1000 and then it might go to 500 and then rise back and go like a see-saw. Before taking things apart and moding the tps was set to .38 but unsure of the iac setting. Prior to modding it the car did idle like crap it would stumble. It had the stock maf as well. I would need to press the gas pedal a bit for it to start and then it fire right up. Idle would be high but slowly drop and almost stall and then rise right back up, and keep going back and forth like that. Can anyone help me? It doesn't sound right and not sure what to make of any of this.

Can't seem to figure out how to upload the video. Got it uploaded to photobucket, but not sure from there.
Here's the link.... http://s93.beta.photobucket.com/user/polskipete9690/media/Condensor and Shocks and Springs/IMG_1922.mp4.html

Any and all help would be greatly and dearly appreciated. I got tons of good beer I can send you (craft) as a thank you.
 
Alot going on here...first off the car needs to be at full ops temp before adjusting IAC and such. Suggestion of doing more research on these cars as to what makes them tick as it seems you may not have it really grasped yet by your post.

What chip do you have ?

Cant have any leaks in the intake tract after the MAF.

If you adjust the minimal air blade screw for the IAC then the TPS is altered.

The MAF is reading way high so check your settings in your translator. Or try a known good MAF from a freind, etc.

What does the MAF read on SM with key on no start?

My preferred way to do the IAC is (assuming tps is set right and maf is working right)

TPS to proper range .42 ish at idle and 4.30 or higher at WOT

Engine to full ops temp then shut engine off

Then paper clip to jump the upper right 2 ports on ALDL port with a paper clip or equiv then key on no start. (fan will come on during this and ses will flash)

Now disconect the IAC with the car in this state and leave unplugged.

Turn key off and remove jumper from aldl.

Start car and adjust minimum air blade screw to 750 rpm (I have a friend help and and they hold the brake while its in gear while i adjust the screw just be careful and use wheel chocks and ebrake as well)

Shut car off, plug in IAC, then key on no start and adjust TPS back to proper spec.

Turn key off and reset computer via orange wire at batt by unplugging it for a few seconds then plugging back.

Start car and see what you have...IAC should be 10-50 higher end of range in gear.

This may take a couple of trys.
 
I cant even get the car to run right to get it to operating temps. And i know the tps changes when adjusting the screw. I readjust the tps everytime i adjust the screw. Also maf t is set right i double checked that already and ive been resetting the iac with the paper clip jumping of top two ports multiple times. The chip ill check tomorrow, i can only assume it was stock, being that the car has 100k original miles with all the original parts still: tensioner, chain, and everything.
 
Fuel pressure was set to about 40psi, hits 45psi at ignition on, then drops to 39, then slowly drops thereafter.
Well, there's an issue. Most chips (do you have an TT chip?) want 43psi at idle with the vacuum line off the regulator (it's adjustible right?). Try resting the pressure and checking the pressure. It should drop back to about 38 with the line back on but it should stay steady. If the fuel pump can't hold steady pressure it may be all done. That will mess you up big time.
If the coolant temp stays that low even after idling for long enough for the engine to be all warmed up then the sensor might be bad and telling the chip to add fuel and drownding the warm engine. You can put a thermometer in the radiator and see if it's getting hotter than 120 or use an infra red temp sensor. (Harbor Freight has a some for under $40)
BLMs and INTs are going to stay steady at idle.
Here's a site for you to read over and over. http://www.vortexbuicks-etc.com/index.html Check the "basics" part on adjusting the TPS and IAC.
Make sure you have the MAF translator set to the right setting for the LT1 MAF.
Make sure you don't have any vacuum leaks.
 
If it's running (even badly) long enough it should get to operating temp.
The IAC screw is sensitive, use small adjustments.
 
Pronto said:
Fuel pressure was set to about 40psi, hits 45psi at ignition on, then drops to 39, then slowly drops thereafter.
Well, there's an issue. Most chips (do you have an TT chip?) want 43psi at idle with the vacuum line off the regulator (it's adjustible right?). Try resting the pressure and checking the pressure. It should drop back to about 38 with the line back on but it should stay steady. If the fuel pump can't hold steady pressure it may be all done. That will mess you up big time.
If the coolant temp stays that low even after idling for long enough for the engine to be all warmed up then the sensor might be bad and telling the chip to add fuel and drownding the warm engine. You can put a thermometer in the radiator and see if it's getting hotter than 120 or use an infra red temp sensor. (Harbor Freight has a some for under $40)
BLMs and INTs are going to stay steady at idle.
Here's a site for you to read over and over. http://www.vortexbuicks-etc.com/index.html Check the "basics" part on adjusting the TPS and IAC.
Make sure you have the MAF translator set to the right setting for the LT1 MAF.
Make sure you don't have any vacuum leaks.
Click to expand...

I shut the engine off within seconds of ending the video.
 
turbo nasty said:
Alot going on here...first off the car needs to be at full ops temp before adjusting IAC and such. Suggestion of doing more research on these cars as to what makes them tick as it seems you may not have it really grasped yet by your post.

What chip do you have ?

Cant have any leaks in the intake tract after the MAF.

If you adjust the minimal air blade screw for the IAC then the TPS is altered.

The MAF is reading way high so check your settings in your translator. Or try a known good MAF from a freind, etc.

What does the MAF read on SM with key on no start?

My preferred way to do the IAC is (assuming tps is set right and maf is working right)

TPS to proper range .42 ish at idle and 4.30 or higher at WOT

Engine to full ops temp then shut engine off

Then paper clip to jump the upper right 2 ports on ALDL port with a paper clip or equiv then key on no start. (fan will come on during this and ses will flash)

Now disconect the IAC with the car in this state and leave unplugged.

Turn key off and remove jumper from aldl.

Start car and adjust minimum air blade screw to 750 rpm (I have a friend help and and they hold the brake while its in gear while i adjust the screw just be careful and use wheel chocks and ebrake as well)

Shut car off, plug in IAC, then key on no start and adjust TPS back to proper spec.

Turn key off and reset computer via orange wire at batt by unplugging it for a few seconds then plugging back.

Start car and see what you have...IAC should be 10-50 higher end of range in gear.

This may take a couple of trys.
Click to expand...

Ill try this stuff tomorrow and see what happens.
 
Will the engine run long enough to get to operating temp?
 
First thing I would do is get rid of that rjc racing pcv valve if you still have it on.. I had one on my car and it caused all kinds of problems. You'd be surprised how much air actually gets sucked into the engine from there.. had me going crazy for days trying to figure out why my idle was so messed up... There is something very interesting going on in your video too... I see you have a vacuum gauge and its only reading 8 inches of vacuum and its moving back and forth a bit. Vacuum at idle should be anywhere from 15 - 22 inches and holding steady. I would definitely look into a compression test as you may have a serious problem on your hands...
 
lolo86GN said:
First thing I would do is get rid of that rjc racing pcv valve if you still have it on.. I had one on my car and it caused all kinds of problems. You'd be surprised how much air actually gets sucked into the engine from there.. had me going crazy for days trying to figure out why my idle was so messed up... There is something very interesting going on in your video too... I see you have a vacuum gauge and its only reading 8 inches of vacuum and its moving back and forth a bit. Vacuum at idle should be anywhere from 15 - 22 inches and holding steady. I would definitely look into a compression test as you may have a serious problem on your hands...
Click to expand...

I think i mentioned in the post the vacuum reservoir was not connected. I did connect it after the video and got a steady 14.
Silver Fox said:
That sounds right. How are the four dip switches set?
Click to expand...

Up, up, up, down
 
I would start by resetting the IAC as outlined in the post above.

When making adjustments to the IAC adjustment screw, only turn it 1/8'' at a time and let it settle out a few minutes before turning it again. Set the TPS to .38 while setting the IAC. Also you don't have to make adjustments to the TPS while doing this,just keep an eye on it so it doesn't get out of the range of .38 to .44. Once the IAC is finally set then make the final adjustment to the TPS, i like it set at .44 to .45.

You might want to read this if you haven't already. Take your time and get it right,don't rush. Make sure all of the vacuum hoses are connected and not leaking. Spark plug wires are on correctly and the spark plugs are not fouled. Take note of the IAC adjustment screw threads protruding through the lever side of the throttle body there should be 1 - 1 1/2 threads, how many threads do you see showing there?

IAC (Idle Air Control) Adjustment
The IAC function maintains idle quality through commands from the ECM, but, has NO impact beyond the idle range. Further, the IAC reading means nothing once the car is off idle.
Idle speed is set by the chip, not by the IAC adjustment screw. Looking at the inside of the throttle body, there are two holes in the lower portion fore and aft of the throttle blade. At idle, the blade is essentially closed and air enters the front hole, goes past the IAC plunger, and exits behind the throttle blade into the plenum. The IAC plunger is pulsed by the ECM to maintain a steady idle with varying engine load.
When the IAC is adjusted, we seem to typically look for IAC counts on our scan tool somewhere between 15-25 when the car is in Park, the engine fully warmed up, and the A/C is off. The lower the IAC number, the less control the ECM has over the idle as the throttle blade begins to be opened. This setting may not be as critical as we often make it. You may find your car idles just as well at 40 counts as it does at 15.
With car in Park, engine fully warm, A/C off, look at the IAC counts on the scan tool. If you wish to lower the count number, turn the adjustment screw clockwise. To increase the counts, turn it counterclockwise. Turn the screw a small increment, turn the engine off, and restart. This insures that the IAC resets and confirms the adjusted number. Continue until the desired number is achieved. Often, on stock set ups, about 1-1 1/2 threads of the adjustment screw will emerge thru on the lever side of the throttle body. Restarting also rezeros the tps as stated in the prior section and removes any effect on idle speed that may have occurred due to tps movement. The IAC counts will probably be 30 counts, or more, higher on a cold engine than on a warmed up engine. The counts will also be much higher in gear as compared to Park, and, higher with the AC turned on.
Remember that the IAC adjustment will change the TPS and that if the TPS moves past 0.46 volts, the idle may increase in speed as the ecm no longer thinks the car is in idle range. Therefore, if you are going to decrease IAC counts very much, it is a good idea to first lower the TPS down to 0.38 volts or so in order to prevent it from rising out of the idle range as you adjust the IAC.
It is not a bad idea to clean the throttle body out periodically with carb cleaner to keep the passages clean and to insure that the IAC function works correctly. Remove the IAC from the housing and clean any carbon or gum off the tip of the plunger and clean the seat as well. Don't power up the IAC when the unit is not installed. Otherwise, you may find the plunger is pushed out of the sensor. When reinstalling, very little torque is required. Just tighten enough to compress the gasket to prevent an air leak. Over tightening may crack the plastic interior of the IAC.
 
lolo86GN said:
First thing I would do is get rid of that rjc racing pcv valve if you still have it on.. I had one on my car and it caused all kinds of problems. You'd be surprised how much air actually gets sucked into the engine from there.. had me going crazy for days trying to figure out why my idle was so messed up... There is something very interesting going on in your video too... I see you have a vacuum gauge and its only reading 8 inches of vacuum and its moving back and forth a bit. Vacuum at idle should be anywhere from 15 - 22 inches and holding steady. I would definitely look into a compression test as you may have a serious problem on your hands...
Click to expand...
Vacuum leak.
 
Put a TT chip on your Christmas list!
 
If it's having a hard time idling, the IAC will want to rise naturally to help it idle. I think you may have another problem causing the rough idle. The MAF reading is very high for idle.
 
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