Potentiometer

[siteunseen]

It got rid of my stumble up 2,500 rpm.  That's got me wondering, what Zed said about the WOT increase in fuel.  That's where the TVS clicks on the front contact. The WOT contact.  Uhmmm?

Bob I played with mine on the interstate a few times.  I could make it run cooler on the temp gauge, better MPG all by slightly leaning it out.  I wish I had a pyrometer in my header or something similar with a gauge in the cabin. Can't think of what guys are using to tune their carbs.  Seems like Madkaw has two?

For the few dollars you have a new toy to play around with.  I just hope it helps your sniffer test.  Win win.

[rcb280z]

Yeah its a learning experience and me likes that .

Cliff I think you are talking about the AFR gauge etc. setup right?

[Captain Obvious]

9 hours ago, rcb280z said:

Took some measurements today, they are as follows.

The readings (that I understand) look perfect.

It's a 1K Ohm potentiometer, so you should see zero at one extreme and about 1K Ohms at the other. Those look great.

Your CTS cold sensor indicates about 60F, and your CTS hot sensor indicates about 180F, so (assuming it was about 60F in Ventura County at that time) those look great too.

The only thing I'm not sure about is the 1.82K Ohms your getting on that other reading... What do you mean with "CTS ECU harness"?

[rcb280z]

26 minutes ago, Captain Obvious said:

What do you mean with "CTS ECU harness"?

Its from the bullet connectors of the harness leading back to the ECU. Not sure I did that right though. I was reading both wires at the same time, if that makes sense. I shouldn't of had any reading right? So is that resistance reading at the ECU?

And yes it was 60F in my garage this morning.

Edited January 18, 2018 by rcb280z

[siteunseen]

16 minutes ago, rcb280z said:

Yeah its a learning experience and me likes that .

Cliff I think you are talking about the AFR gauge etc. setup right?

Exactly!  Thank you.

amazon has one with good reviews for around $100.

[rcb280z]

1 minute ago, siteunseen said:

Exactly!  Thank you.

amazon has one with good reviews for around $100.

Yeah I've been wanting to do the same thing.

[Captain Obvious]

I don't know what the input resistance is looking into the CTS circuit on the ECU.

If yours is working correctly, I'm gonna say it's about 1.8K Ohms. 

[rcb280z]

Cool. I'm running with that.

So now that I know my "cold" start system is right it's on to figuring out why I have a difficult starting problem on warmer mornings after it has sat overnight, having to crank it a few time before it starts. Kinda like a cold carb with no choke. Will start a new thread after searching this forum first.

Thanks to all for the help. 

[Captain Obvious]

First thing I would check is to see if your fuel pump check valve leaks a little and is allowing the fuel pressure to drop off overnight. If you don't want to go through the hassle of installing a fuel pressure gauge, you can get an idea if that's what's going on simply by pressurizing the fuel system before you try to start the car.

On those mornings when the problem "would normally occur", pull the starter solenoid wire off and turn the key to START to get the fuel pump to run without engaging the starter. Then after a couple seconds of that, put the wire back on and then try to start the engine normally. If it starts instantly, then that's probably what's happening. If it still takes just as long to start even after making sure there is fuel pressure, then maybe there's an issue somewhere else.

I've removed my cold start injector, so mine takes a couple cranks to start because of that. I'm OK with the delay as a trade off for fewer leak locations and simplicity.

[rcb280z]

21 minutes ago, Captain Obvious said:

First thing I would check is to see if your fuel pump check valve leaks a little and is allowing the fuel pressure to drop off overnight. If you don't want to go through the hassle of installing a fuel pressure gauge, you can get an idea if that's what's going on simply by pressurizing the fuel system before you try to start the car.

On those mornings when the problem "would normally occur", pull the starter solenoid wire off and turn the key to START to get the fuel pump to run without engaging the starter. Then after a couple seconds of that, put the wire back on and then try to start the engine normally. If it starts instantly, then that's probably what's happening. If it still takes just as long to start even after making sure there is fuel pressure, then maybe there's an issue somewhere else.

I've removed my cold start injector, so mine takes a couple cranks to start because of that. I'm OK with the delay as a trade off for fewer leak locations and simplicity.

Have done all that. I do have a fuel pressure gauge installed.

I have an aftermarket fuel pump installed. Not sure there is a check valve like the OE pump has. I usually power the pump thru the afm, the cover is held in place with zip ties. It always pressurizes the system right away so I know flow is good.

I'm just being anal about it probably. It used to work so I feel it should still work and that there is probably something wrong if it isn't. Know what I mean? 

[rcb280z]

6 hours ago, rcb280z said:

pull the starter solenoid wire off and turn the key to START to get the fuel pump to run without engaging the starter

Wont that fire the injectors if I do it that way? Or does manipulating the afm flap do the same? I thought the afm flap only pressurized the fuel rail. Why am I confused about this right now. 

Edited January 18, 2018 by rcb280z

[Zed Head]

The engine won't spin so there won't be any spark.  No spark = no Pin 1 pulse = no injection.

Can't answer the last question.......................................................

Edited January 18, 2018 by Zed Head