mikezi

Baffled, best describes it. (86 TPI - 40,000miles) ran like a champ last summer, over the winter I pained it, NOW it refuses to run correctly. Symptoms; Idle hunting, popping thru intake, stalls out. It starts right up, runs for a few seconds, then it dies.
Checked for vacuum leaks; visual, spray, and smoke- no vacuum leaks, "I did check the brake booster also"
New items: IAC, TPS, Temp sensor, intake temp sensor, egr,
No codes
IN OPEN LOOP, it will not idle, UNLESS I unplug the coolant temp sensor.
It is suffering form a very lean condition.
Fuel pressure is great 40/47 and it does climb slightly when I open the throttle.
Its as if the computer wasn't giving it enough fuel.
ANY THOUGHTS?????????????????MIKE

aklim

Maybe the CTS is reading wrong or maybe the CTS unplugging compensates for another problem. Scan it and hit it with an IR Thermometer and see if they are reporting right. See what the other sensors are saying too.

mikezi

Thanks man, but I do not have a scanner. trying to borrow one.
Do you know?- if the MAF is bad, how does the ecm know how much air is entering the engine? (in open loop)

mike

mikezi

Should the ERG be opening in open loop? cause mine is.

aklim

Don't borrow. Buy. If you keep this car, you are going to need to have a scanner and not a paperclip or code reader.

Try this. If you pull the MAF plug off and if it settles down, you have an issue.

mikezi

I did try that, no difference .
Because its so far out of balance, I can only get it to idle if I;
1.pull the IAC connector (after I have jumpered the data link) you know, the IAC set procedure
removed the data jumper
2. unplug the MAF
3. unplug the CTS
4. unplug the EGR solenoid
If I do all that, it will idle with some stability, but if I throttle it, it hesitates, and pops thru the intake. Like its crazy lean.
If I clear all codes and plug everything back together, it idle hunts like crazy.
timing is 6degrees

mike

mikezi

One thing that puzzle me in particular is,

no matter where the throttle blades are set, I can not get the TPS to read the .54volts. I can get it to .45 but then Im out of available TPS adjustment. no where to go.

thanks for the thoughts,

aklim

86 is MAF and supposedly it has quite a bit of adjustment before it freaks out. How far out you are, IDK.

I know the procedure. It is for a stock system where there are no mods and everything is working as it should. IOW, it ASSUMES that the ONLY thing out is the TB blades position. There must be NO air leaks, Tach reading right, everything functioning as it should and NO mods. The more mods, the less it is worth. I set mine using a scanner and the IAC counts.

How do you know it is crazy lean? Is your O2 sensor fresh and what is the reading?

I really think that before people mod, they need to consult the guy tuning the chip and do their legwork. Many will ask "What is the best cam for...." and "What is the best intake for....", "What is the best heads for....", etc and then slap all together and make it work. That is probably how clown suits get done. Talk to the guy doing the dyno tuning and ask him what his experience is with his SYSTEM. Sure, you can ask him questions about "Will this cam work with....". but try to make it a SYSTEM otherwise it might have undesirable results. What I would suggest is finding a tuner to help you out with the ECM. That will lead to the least frustration.

BTW, how were the injectors? Did you get stock size or went back with stock Multecs?

aklim

What are you saying? That if you depress the pedal, you cannot get any more than 0.45V? IF so, there is something else wrong. You sure you got the sensor arm set up right?

mikezi

No modifications to car,
out of balance means, the throttle blade set screw is turned all the way in. FULL OPEN just to get it to idle around 500rpm
TPS it ohms up and down smoothly with no jumping around BUT with the blades fully opened, I can only adjust it to .45V (key on, engine off, in a static position I can only realize .45V)

mikezi

I think it crazy lean, because it smells lean, its popping through the intake, and the plugs are white. it just seems like (even in closed loop) its just not getting enough fuel

Tom400CFI

What if you unplug the EGR vacuum line and plug it...then will it idle?

mikezi

I have not unplugged the Vacuum Line, but if I unplug EGR connector at the control solenoid, the car will idle. If I plug it back in, the car stalls. That's whats very strange to me,. I thought that the EGR stayed closed until the car went into closed loop?????
all of my messing with this car have been done (I think) in open loop, because the engine never gets hot or even warm really. Im still tring to get this thing to just hold an idle.
WHY is the EGR opening in open loop?
Why will this car not idle with the temp sensor plugged in?

Like I said earlier in this thread, before I painted it, (last winter) it ran awesome. But after the paint job, it wont even idle. I changed nothing, mike

KyleF

You do not need a scanner... you can use a Laptop, WinALDL (Tuner Pro or other) and a cable. The software is free. Trust me... You can see the MAF signal, BLMs, integrator, O2 Voltage, TPS voltage and CTS's all in real time by what your computer sees. Even if you can get readings at the sensors, does not mean it is returning the signal to the computer correctly. Tryign to do this without seeing this information results in just tossing parts at it.

The TPS has some adjustment in it's mounting screws. If you can't rotate it counter clockwise and set the idle screw out and not reach a .5V, either the TPS is bad or the voltage getting to the TPS is out of spec (5V).

Have checked the injectors? While your fuel pressure may be good, doesn't mean the spray is getting into the intake runner. Was the gas treated? Are you sure the injectors have not varnished up? Here we are in October and you are stating you had it set over the winter for a paint job. What has happened over spring/summer this year? You may want to disconnect your fuel line and pump the system dry and start with fresh gas with a cleaner in it... but man that TPS just sounds wacky.

The OEM injectors have proven to be about a 30 year injector in the F-Body world.

Red 91

Many times the battery gets killed during a paint or body job. Sounds lean, injectors, vac leak could be under manifold, cts. I would ohm out the cts, if thats ok then check ex manifold for cold/dead cylinders, batt 12.7 v fully charged? then back to vac leaks. Good luck!

VikingTrad3r

unplug the egr control module and do the minimum idle set procedure.

ak is right that the min idle set isnt perfect but it should give u an improvement and get close unless u have something real weird out.


its possible you have a rupture in your egr valve.

Tom400CFI

EGR should stay closed until cruising operation. However, if the EGR solenoid circuit were shorted to ground, the EGR would be open all the time....and you'd have a major vacuum leak (of mixed air and exhaust).

Check the EGR by disconnecting the vacuum source and plugging. If it "fixes" the car, then you need to test for a short to ground on the EGR circuit.


.

aklim

I agree you don't need to buy a dedicated scanner and you can use something from 1320 electronics with ALDL scan which is free but it has a steeper learning curve.

Multec vs ethanol is an interesting match.

VikingTrad3r

jv9999

What he said. Otherwise you're just hunting around in the dark.