icpr4u

Had some time to adjust the timing yesterday. It looks like the base timing was set to 10*BTDC. So I adjusted it down to about 7-8. Seems the stock setting is 6. No she idles at about 750RPM
After plugging in the EST wire the idle still fluctuates quite a bit. Between 600-1000. Looks like I still have to get the TPS dialed in. I will get to it today or tomorrow and report back.

icpr4u

Here's the latest info.
I could not get the TPS to stay dialed in. I would set it at .525v and when I would operate the arm and return it to the rest position it would return to a lower voltage. This happened whether I used the throttle linkage or moved the arm by hand.
Also, the voltage would change by what seemed like a lot every time I tightened/loosened the bolts at all. (.05v for even the slightest turn, maybe 1/32 of a turn)

When I ran the car it seemed to reasonably steady but then as soon as I shut it off the readings would drop. It was like it was leaking power.

Since I managed to snap the heads off of one of the screws I did some testing and here are the readings for the TPS (removed form the vehicle) and it's respective harness from the car (key in RUN)
Maybe they will provide some insight to one of you smarter than me.

Harness
A-B = 0v
B-C = 3.63v **this number seems odd**
A-C = 5.52v

TPS
A-B =5.25k olms
B-C = 1.02k olms
A-C = 4.24 olms

I followed the factory service manual chart for the TPS. It says to run the car w/o the TPS and check the trouble codes. I did and got a 22/low TPS voltage.
Wouldn't it get a low TPS voltage EVERY time if it was run without the sensor in place?

It also said to "probe circuit 452 (pin "A") using a test light to 12v"
I used the positive pole on the alternator and probed pin "A". When I did that the test light illuminated. According to the manual this means it's time for a new TPS. When I checked the TPS resistance readings they seemed in line with what another member posted for a new unit. I ran the TPS arm slowly to it's limit and readings seemed smooth and returned the initial number.

Was that the correct procedure? Am I missing something? Why would it not return to its initial setting?

Buccaneer

Your base setting can go higher on a stock motor and 10*-12* is ok as long as it does not start pinging at WOT or part throttle. If it does, just back it off 1* at a time.
1,000rpm is high with a warm motor. 1,200-1,300rpm is normal at cold start and should idle down as it warms up to 600-650ish is fine. If you play with the balance of the TBs, you MUST reset the TPS since you are changing the blade angle and idle. The ECM needs to know where idle is via the TPS.

If you got 4.24v on ckt 417 and did not have a short or open in the harness and the black ECM connector is ok (pin not corroded causing a resistance issue), you may have a bad ECM. Since a TPS is not expensive, I would give it a shot first and then retest ckt 417 for the same results. If they are the same the ECM would be suspect.

A TPS sensor can be a little finicky when you set it as you tighten the screws. You have to play with it sometimes. If the value is changing a fair amount after moving the throttle and back to idle from the value you set, the TB shafts are probably worn and the angle the blade is resetting to is changing, evidenced by the changing value of the TPS. You will generally only see a value change just a little bit by maybe .001-.002 volts or so and that's about it.

Also, if the shafts are worn, you will never be able to balance the TBs, it will always be off. I hope this helps a little.

icpr4u

I'll check the voltage to circuit 417 at the ECM tomorrow.
The 4.24 you are referring to is the resistance reading from the tps removed from the vehicle

I had 0v on pins a-b at the harness. That is the "TPS" wire and the "sensor ground" according to the manual.
So you are telling me I need to make sure there is no short in that wire by checking at the ECM connector?
Any quick way to check the play in those shafts?

Buccaneer

Oops, I looked at the wrong reading, it is your 5.52v, but the rest I posted is correct. Sorry about that. Just like the manual says on page 6E-42, to check for open or short to ground on ckt 417 from the TPS to the ECM.

Yes, go here and have pdf sent to you. Select the pdf you want, TB shaft test is there. http://crossfireinjection.net/how_to.htm

icpr4u

AWESOME INFO. !!!!!
Thank you!!!

hugie82

If this is your first 82 and you plan on keeping it, there's a few fixes you should look into. Usually a stock CFI that hasn't been messed with doesn't fall out of adjustment. Ie; tps, throttle blades, fuel pressure and so on. Once it's set, it's set.
The few must fixes are vacuum leaks. Head lights and vac canister often leak. Some oil on the seals in the headlight actuators helps and replacing all the vac lines with a quality kit. Next must fix is the plenum gasket. The top plate on the intake manifold was silicone on at the factory. They all leak and will leave you stranded if it gets bad enough. Felpro makes the gasket and it's not hard to do, just time consuming.
Last, these cars like more advanced timing. GM backed it down for emissions but bump it up to 10 degrees advanced with good gas and you have a good runner.
I use the Hypertec prom/chip stage 1 in my car. Best $150 I ever spent! Drives like a totally different car. Good luck

icpr4u

todays findings include results from the test for the CORRECT trouble code...yup I did that.
I'll redo them for sanity's sake but the end result is that the manual says it's the ECM/ECM connector.
Any Ideas on how to confirm w/o throwing a new ECM at the thing?

terry82

pull the connector, clean the connections put back together .see how it runs .no change..... order ecm

icpr4u

silly question; how do I clean the connections on the ecm?

terry82

http://www.ehow.com/how_5136312_clea...onnectors.html

icpr4u

got it thanks

icpr4u

Here's the latest update:
Worked yesterday to confirm some findings with the TPS. For some reason I could not get voltage after removing and replacing the ECM connections to verify the 3 circuits were intact. I jumped the wires as stated in the manual.
***NOTE** the manual initially has the jumper placed on the 5v wire and the ground then references removing the jumper from the 5v wire and the TPS wire. It makes more sense to jump the 5v to the TPS circuit in an effort to send 5v to the ECM thereby eliminating the TPS from the equation, correct?
Anyway, after that I could not get the 5v between wires A and C so I cleaned the contact surfaces in the ECM and connector as best as I could.
Tested the TPS ground circuit and had 1900 olms to a bare metal ground.
Tested the MAP sensor ground. (It is supposed to be on the same circuit.) 0.5 olms
Inspected and tested the Ground wires from the coolant sensor, TPS and MAP to the firewall- no physical damage and 0 olms.
Resistance for those grounds to ECM connector. 0.5 olms.
Gave the ECM connector for that circuit a little bend in an effort to make a more positive contact.
Everything seemed to be right on track. TPS set at 0.55v, TPS ground to bare metal 0.5olms and 5.52volts between pins A-C
She idled great for 10+min. Took it for a short test drive and it died at the third stop light. Died again at the next turn.
Here is the data from winALDL from that drive and from the test in the garage after. (The TPS croaks at time:155ish and the car died around the 180.7)



What makes the battery voltage go from 18 to 6v like that? It seems fine at idle and working the throttle in the garage.
Why does the TPS reading just dump like that and return to normal in the garage?
Is that a function of the low voltage?
Can it be an intermittent ground? One that cuts contact with increased temp?

Bigredwing

I agree with Buccaneer on trying a new TPS. I have not shopped for an ECM, but I think you might have other issues with the car if it was bad. Contacts can get corroded but the location of the ECM is well protected unless your battery has exploded or the car has been underwater. My original TPS had flat spots on the variable resistor and if I got it adjusted and then moved the throttle linkage the output voltage would be all over the place. The new one does not snap back to exactly .525V every time but is very close and the car idles at about 800 RPM. I still need to rebuild my TBI's and have noticed it surge 100 RPM occasionally but I can live with that until Winter.

Just read your latest post. Heat can affect the resistance value of the TPS if it is bad. I had the same experience.

Bigredwing

"What makes the battery voltage go from 18 to 6v like that? It seems fine at idle and working the throttle in the garage."

Any idea what the source for the voltage is with the winALD tester? I don't have one so I'm not familiar with it. In my experience as a technician 5V is usually a logic voltage especially on something as old as an '82. The .525V is a reference so the ECM knows where the idle throttle position is. It probably has an algorithm as part of the program to use the varying input voltage to control the fuel injection. 18v is really high and I don't believe there is a power amplifier in there anywhere. Maybe I am just showing my ignorance though in this situation.

icpr4u

The winALDL program connects to the diagnostic connector then to your laptop via USB
I am not sure exactly where power comes from
I agree an 18v battery reading seems high

icpr4u

Any Ideas on the voltage irregularity?

Bigredwing

Wish I had a OBD1 reader and could help you out more. I compared the two logs and there are some definite differences between them (call me Capt Obvious).

Just looking at the log and what I could easily find it seems to me that the Battery V should consistently be somewhere around 12V to maybe 13.5V. Is your console Voltage Gauge steady? Looking at the Service Manual on page 8A-87 it looks like the winALDL Battery V is part of the Serial Data to the OBD1 connector since there is not a dedicated pin for V. Yours is from 5 to 18V which like you I do not understand. If the ECU uses the voltage shown in the your log files for it's logic circuit it is no wonder the car is not running. My '09 Silverado batteries were low once and although the truck would idle I had all kinds of weird indications and it would barely drive until the voltage came up. I had a bad alternator.

I still think you have a TPS problem but it's looking more and more like an ECU problem to me now. Hopefully you will get more input from the forum soon. Continued good luck with it.

Tom400CFI

Two things jump out here;
1. if it runs good cold, but not warm, the first thing that I'd check would be the Coolant temp sensor.
2. Typically on a CFI car, a vacuum leak results in a high idle. Not no idle.

Bigredwing

Question then would be is a high or low temp reading bad? Looking at the log his intake manifold water temp is averaging 122 degrees where as idling in the garage it is 163 degrees. So it is reading something.

I'm also wondering how winALDL computes speed from the serial feed since it is a mechanical speedometer? That number may be irrelevant on our cars.