dolucasi

Is yours a single pump car or the more common 2-pump set-up. My original relay is at 200Kmiles and I have a 2 pump set-up. Car has not seen extreme temp conditions though.
I believe in the single pump set-up the pump is beefier and takes more current.
Since you are into electronics, it is possible that the condition I described exists and your joints are a victim of electromigration. One can not tell that the currents are too high in metals/joints by just visually inspecting in that case and it my not have the smell.

That being said though, I do read now and then relay problems, but generally it is the pumps that wear them out as people end up replacing pumps as well. Yours is a bit different though....

DLL

​​​​​​​Tried some of this. Key on, car not running, no effect at all from shorting any combination of pins for TPS switch (and yes, accessed near IACV)​​​​​​​EHA, yes, about 20MA on the circuit, key on not running. Volts showed about 4.5

dolucasi

Sorry, I was not asking you to short anything. I was asking you to unplug the TPS connection and make measurements with an ohmmeter. And I was describing the expected results of those measurements.
Shorted = zero ohms expected resistance

Ok, so the EHA current with ignition on engine off is correct.
Do me a favor and with the current meter still connected, crank your engine when stone cold and report on your measurements while cranking and after the engine starts and for the first 30 seconds.
I want to see if the fuel enrichment is happening when idling cold. Also when cold pull on the throttle cable and see if the EHA current jumps way high (if so that is your AFM pot in action). Remember all this needs to be for a cold engine.

- Cheers!

DLL

OK thanks, when you said shorted to1, shorted to 2 etc I thought that's what you meant. I'll take another shot in the next or 2

DLL

I haven't done a further running test yet.On the TPS I just tested both functions with an ohm meter, and the meter did not move from baseline at all, nor audible signal when I tried that. I tried closed and open throttle on both settings with no changes at all.

dolucasi

Make sure you are making measurements on the Throttle position Sensor and if so, I think you found a culprit. However, you said you tried shorting pins randomly and nothing changed.
Find out which pair needs shorted with the closed throttle. And unplug the connector and short those pins at the harness to the ECU side. Let me look up which pins need shorted and let you know.

DLL

I used the connection to the TPS near the IACV. When unplugged 3 pins. My research said centre ground, the one near front of engine idle, rear WOT.
I had someone move the throttle while I was connected with no change in readings.
I tried with key on and off, no difference either way.

DLL

Further to above, I just did the same tests on a non running parts car (but it did idle previously), and, got solid audible readings, variable by throttle application

dolucasi

Good. So there is something (TPS) you need to replace. Perhaps check the wiring from the TPS to the connector as well since you just can not get any plate closed or wide open signal.
BTW the WOT is not too surprising after 30+ years. Why? Because it hardly gets activated and a small amount of corrosion or dirt my make that happen. My original was like that and I manually exercised it and after many iterations, it started working.

Make sure that the throttle actuator is letting the plate close all the way by manual inspection. If it passes your inspection you can swap your non running car TPS to this one.

DLL

Sounds good, I'll look into the connections.
Turns out, the parts car one I have is different, so on the hunt for the right one.
I'll update when I have news on that.

JohnLane

Guys conspicuous by absence is any mention of checks for false air. AKA vacuum leaks which famously befuddle K-Jet.

DLL

That was one of the first things I checked, even underneath the fuel distributor assembly

dolucasi

Yes we went over that way early in this thread and we are going on the assumption that the intake has no leaks. Also all the electrical testing done so far is pointing at electrical gremlins.
If IACV voltage is zero, that is all electrical, will not be affected by vacuum leaks.

DLL

I located another throttle body, with position switch. Multimeter bench test showed it works. I replaced that assembly today. Unfortunately, no joy, possibly worse. I can only occasionally get the car to run 5-10 seconds before stalling out, does not restart.

dolucasi

Too bad. But early we knew we are battling multiple issues. Good to have this one out of the way. Is the behavior the same? Cold starts at around 1000rpm than slowly drifts down to 400rpm and eventually dies? IACV voltage still zero volts from start to finish? Meaning unplugging it does nothing?

DLL

I haven't worked back, re checked IACV voltage, good idea.After swapping the throttle body it doesn’t run at all. Occasional 5 second bursts while starting, but doesn’t stay running, doesn't readily re start.
So no, not the same idling speeds etc, it doesn't run enough to idle.
It still seems to be fuel related. When it wouldn't start after the work today, I poured a small amount of fuel directly into the intake, it fired briefly.

dolucasi

It does not idle but does it run down the road if you keep it off idle? It does sound like you have some fueling issues so it should not drive well either.

DLL

Now, it doesn't run at all. Max 5 seconds occasionally. Doesn't run long enough to move. Occasionally starts for 5 seconds, doesn’t stay running or readily re start

dolucasi

That is odd. Almost sounds like something else happened (maybe a new issue unrelated to the throttle body)
Do me a favor, to get back to the original throttle body you can just disconnect the plug. Since your old one was on open circuit on all 3 pins.

Let's see if it reverts back to the old way, (Runs/idles cold but barely idles after warm)

DLL

Ahh, yes, I'll try that tomorrow

DLL

Embarrassment, egg on my face, one step forward two back.So, I couldn't figure out why after replacing throttle body I was worse off than before - so wondered if I made a mistake somewhere. ​​​​​​​Yes I did. I took it apart again today and discovered the rubber bottom of the fuel distributor assembly was not seated properly on top of the throttle body.Re installed, triple checked along the way.Tried to start, was kinda catching. I poured a little fuel directly into the intake to help prime or encourage it.I then noticed a leak in the seam where the throttle body meets the intake. I guess the old gasket didn't survive the re and re. I jjust ordered one from the dealer, probably next week when I get it.Will update after I install it.​​​​​​​Thanks !!

dolucasi

Sounds good. Let us know how the new boot seal works out. Makes sense though something else had to have gone bad in the swap rather than the TPS.

Cheers!

JohnLane

Wonder why I asked about false air.... hmmmmm.....


Hope she runs well soon.

DLL

For clarity, the improper installation of fuel distributor assembly was detected after it was re and re to change throttle body. ​​​​​​​I'm quite certain that it was OK previously. ​​​​​​​I'm basing that on differences of how it sat on the mounts, nut installation etc (That was what haunted me to take another look this time).Thanks

DLL

The Throttle Body Gasket arrived, re and re everything, installed today.
The first start was really difficult, possibly because fuel leaked out in the process of re and re, try another cold start tomorrow. At first it was running a few seconds and stalling. Initially idling about 500rpm. After running a bit, it idled at about 1100 rpm. After warming up it revved fairly smoothly, initially it was backfiring through the intake. After warming up I tried disconnecting the TPS - no change, POT - no change, EHA - idle dropped to about 500 rpm, almost stalling, kept running. I was able to rev it with EHA disconnected. It is smoother and sounds better than in a long time, but a faint 'miss' is still audible. When warm, turning off and restarting, idle initially about 5-600 but picks up again to 1100. It felt good enough to try a test drive, smooth at low / moderate acceleration, full throttle fine until about 4000 then it starts to miss / sputter / jerk before upshift.
So, better, not 100% yet.