I checked it with my analog meter, and I'm right on the money for the TPS.

(What is "self ranging, anyway?)

I'm still at the same point- low RPM's it's gutless, but when it gets into higher RPMs it takes off like a rocket.

Unfortunately, almost all of my driving is at low RPMs, which makes it pretty aggravating.

Not sure what to check next.

I don't think I'll ever wash the engine again in this thing. I've washed engines hundreds of times in other vehicles with no ill effects, but this thing has me stumped.

 

Self-ranging means it does it automatically and you don't have to select the range on the meter.

Check the output voltage of the engine side of the TPS with your analog meter as you open it slowly.

 

Well. Another update.

Still having the same problem. No guts/power until the engine reaches 3000 rpms, then it takes off like I'm giving it a shot of Nitrous.

When it's cold, it runs almost perfectly. When it gets up to temperature, it barely keeps running at low RPMs with a lot of backfiring in the throttle body.

I've been going through a lot of checking hoses, connections, etc, etc, without finding anything odd or out of place.

Now I am ashamed to admit a glaring error.

If you remember, when I bought the beast, I bought and installed all new sensors, because all of them had been disconnected by the previous owner, who had figured out how to make it run without them.

In my quest to return it to stock, the plan was to install all new sensors, which I did.

Yesterday, when I was going through my boxes of parts, I found the new Crankshaft Position Sensor I had bought back when I started this project.

Yep... I forgot to install it.

Open the hood, check the wires, and sure enough, the CPS wire harness is melted and making contact with the exhaust manifold.

I wonder if that has anything to do with my problem? (I feel like an idiot)

So, today is change the CPS day.

Let's see if that's the goose that lays the golden egg.

I'll be back in a bit...

 

Ya gotta be kidding!!

 

Here:

 

Yep. You heard it here first. What a schmuck!

The old one was in really bad shape. I'm guessing when I washed the motor, the wire got knocked over onto the exhaust manifold.

Two wires had the insulation melted off, and one of the only had two or three copper strands left. The bare wire was clearly contacting the manifold.

Getting the new one installed went a lot easier than I thought. I'd say it took less than half an hour from start to finish.

What a difference. Starts easier, runs a lot better. There still seems to be a very slight flat spot before it really takes off at 3000 rpms, but it's hardly noticeable.

Let me ask you this: Since the CPS was in such bad shape, and was obviously affecting performance, do you think it would be a good idea to calibrate the TPS again?

Also, I've got a can of sea foam laying around. Is it worth using it?

 

I agree with you on the probability that water pushed the CPS harness into hostile territory.

TPS shouldn't need readjusting, but not a bad idea anyway. Ever done post 5 of my tips? Actually, please refresh me as to which of my Tips you have done so far.

Seafoam is snake oil.

Have you ever changed injectors or run BG 44K through your Jeep via the fuel tank?

 

I or my electrician have done most of the tips as I was going through the process of changing sensors. I am half tempted and go through the electrical stuff the electrician did again for ****s and giggles.

Changed all the sensors, new coil,base, grounds cleaned, extra ground cables installed, IAC, TPS,oxygen sensor..

Of the list, I have not done 2,12,13,16,17,21-25 and 27.



I did have a problem with it this morning. When I tried to start the engine, it was dead.

I wiggled/rotated relays(that are all new), and that did the trick. That is indicating a loose connection somewhere, although I've gone through that whole thing with a fine tooth comb. I have found wires in less than optimum condition when I installed new connectors, so I may also have more that are corroded inside the insulation.

I'm going to do the list again, step by step, myself, just to confirm.

 

I would suggest doing 1 through 5 YOURSELF, and maybe 27 if you're up to it.

Did you get the CPS harness routed correctly per the diagram?

 

I'm gonna do a lot more than 1 through 5 again myself. You got that right.

I didn't route the CPS harness like the diagram. Instead, I brought it up and to the right and looped it over the wiring harness that runs across the firewall, then plugged it in.

Now it is suspended in midair and isn't going to be rubbing against anything. I'll shoot a pic and post it in a little bit.

No need to do 2 or 27, since mine is a 90 and doesn't have the C101 connnector.

Again, thanks for your continuing help with the beast. Maybe you and some of the other guys should come down to the sunny Caribbean for visit. I got some cold stuff and a couple of stogies for ya!

 

That works.

 

#1 Done.
#2 N/A
#3 Everything looks great at the relays, but some wires are looking a little worse for wear. I'm going to change the relay bases. Relays are new.
#4 Coil and ICM were both replaced with OEM a few months ago. Everything nice and clean.
#5. Grounds seem OK after repeated jiggling/moving/pulling. Gives .4 resistance with my crappy meter (that goes to 0 when you touch the wires together) The .4 doesn't change no matter what I do.
#6 PENDING
#7 New CPS - gives .4 when tested (turning over engine) I'm a little concerned about that.
#8 TPS - New. Meter doesn't read two digits - only one. Thinking about new meter. TPS is voltage is where it should be (.4 something)
#9 ECU is new. All plugs checked and cleaned.
#10 Trans connectors are clean and great condition. Transmission seems to be shifting well.

So far, so good. Stay tuned.

 

CPS output voltage is a bit low, but you need a better meter.

TPS should be in the .17 range on the engine side connector. Again, you need a new meter.

 

I agree. So I went to Amazon, and bought one of these:


Tell me, oh wiser one than me, did I do OK? If this one doesn't cook your grits, what would you recommend?

This little guy gets really good reviews (something I use to try and make intelligent decisions) I also noted it's cheap Chinese.

I'm extremely limited in choices here on the rock. Worse, everything is "make you crap your pants" expensive.

Once that puppy gets here, I'll recheck the CPS output and the TPS.

 

Ya done good.