nomeaculpa

Now that somebody's calmed me down about that SNAP gunshot going off in the cab.

I need a new computer. What's the score on buying new OEM vs. refurb? Other than about 500 dollars... If I go with a refurb, who is the most reputable place to buy from?

Second, I've got a 97 model. When the brakes are cold, they tend to lock up when I apply them for the first couple of miles. Tap them lightly and tires squall.

I figure it's just a quirk, and it doesn't bother me much, but curious if this is a common thing, or maybe something I should chase when I have some spare time.

Thanks.

notop46

It is not normal for the brakes to at up for the first few miles. If multiple wheels are locking up, look at what they have in common (master cylinder circuit, proportioning valve...) If it is only one wheel, you may have a warped rotor, or sticking wheel cylinder.

thorguy57

The brakes on the rear of my 2000 Cherokee would always lock up when I first drove it after it rained. After the first few applications it was better. I doubt it was right but never looked into it. Just tried to stay out of the rain

ragged1

My 2000 xj does the same thing.

dev_daddy

Or because when the metals are cold, they bite and stick together a lot harder than a really hot brake pad and rotor? Just what i was taught

nomeaculpa

I think this is what's happening. Hell, I've had them replaced three times over the years, and it still happens.

Maybe it is a warped rotor. Feels like it might be the front right, but can't say for sure.

It's not a big deal. They warm up and start working right pretty fast. Never been a safety issue.

dev_daddy

Yeah its been that same way on every vehicle I've ever driven. I enjoy it. You get to have super good brakes for a few minutes haha

nomeaculpa

No, this is much more pronounced than any other vehicle I've ever had, and I've had several dozen over the years. This sucker locks up tight for the first mile or so.

Pulled out of a parking lot one day, and these kids were wanting to cross, so I gently hit the brake. SCREEEECHHH!! They're laughing at me like I was showing out, and I'm laughing at me because I barely hit the dang brakes.

nomeaculpa

Guys, this is the pertinent question. I'm leery about buying a refurb ECM from just anyone, and haven't ever bought one before. Junkyard's not an option, as these Massachusetts jokers want more for used than I'd give for a refurb online.

Should I be concerned about a refurb? If I should go new OEM, as much as I hate to spend that much, I will. And if I do go refurb, is there a trusted dealer y'all know about?

Thanks.

dev_daddy

Whoa lol sounds intense. But much better than having no brakes!

tjwalker

First, detail why you need a new computer. Symptoms, things tried, parts replaced.

Many computers are purchased, only to find out that the problem is something else. A very high percentage of exchange computers returned test out fine.

For computers, I look at them as a "diagnosis of exclusion", meaning that EVERY other possibility has been looked at before buying a computer.

nomeaculpa

Good question. I'm in Massachusetts, so the inspection is hanging over me like the sword of Damocles.

CEL goes off, and I'm getting PO700 and PO705. Replace both O2 sensors, transaxle range sensor, and another sensor on the tranny I can't recall at the moment. Every time I replace a sensor, yet another one goes off, over and over. Right now I'm getting low voltage to the TRS. Put a meter on it, and sometimes it shows voltage, sometimes not. Flaky and intermittent. Also, the CEL will go out for fifty miles, then come back on again. Took it in to be re-inspected once, and the CEL came on in the parking lot. Took it in another time, and the damn hood latch came off in the mechanic's hand. Comedy of errors, and it's gone on so long now that I'm starting to roll my eyes and laugh about it.

You and I discussed this in another thread, and you told me I need an electronic specialist. And you're right, but it's not an option at the moment.

The way I've got it figured, if it were a short in the harness, I'd only be seeing this on one sensor. Since it's freaking out here, then there, and then back here again...I figure the computer's wigging out.

Add that the one fender bender I've had (with another Cherokee, no less...go figure), I took a shot to the driver's side quarter panel. Right behind the computer.

Maybe it's a long shot, and I'm all ears if you have another idea. All I know is, I've got a big ticket in my future if I don't get this one sorted out quickly.

nomeaculpa

::bump::

Anybody got a preferred vendor for an ECM? Anything I need to look for on this?

Is there any reason I should not just buy from a random online refurb dealer? The money is WAY less. $150 for one at a couple of places online.

Thanks.

nomeaculpa

Okay, so made a little headway on this one today.

The TRS code went away, but then the NSS gives me a CEL. On and on and on...

Took the electrical connections off the computer today, and found that connectors one and three have broken retaining clips. The tiny little catch that the connector snaps over is busted off both of them, and they're loose.

Cleaned 'em out with electronics spray, and wrapped them up with electrical tape when I put them back on, but that's a kludge.

So, my questions now are, does that plastic retaining deal come off? Replaceable? I couldn't see a way to do it, but that doesn't mean anything.

And if not, back to my original question, is there such a thing as a reliable aftermarket ECM, or am I in for $800 on this one? Is it worth looking for a remanufactured one? I've seen some for $150, and that's why I'm asking.

Thanks.