XJ Mods VSB 14

[alexbrown64]

Thanks Mark, I’m looking forward to fitting the RTC.
The shop said they want to redo the ball joints free of charge.
Something didn’t quite go as planned, so owner wants to recheck everything and get it right.
That’s good service. Touch wood it drives better next adjustment, and then I can fit my damper.

Hope your cooling system gets sorted this time. With the flush, ZJ fan, and all your other new parts..it should be great!

Cheers,

[alexbrown64]

Soooo.... Jeep is booked in to get the steering re-sorted out. Unfortunately, with the Corona virus lurking around, it might not get done for a while due to work etc..
I have the Tough Dog RTC ready to go once the steering is sorted. This should help any residual problems.



Here is a YouTube video on them. They work differently than a normal damper.

You Tube

As well as checking the engine out with the OBD1 scanner, i am going to have a look at my overhead console computer. It went off in a puff of smoke a few years ago. There is a forum where i guy repaired his one by replacing the capacitors. I am going to give it a go..



https://www.cherokeeforum.com/f46/ma...240326/index7/

Anyway, just got home from working away, so can tackle a few small projects..

Cheers,

[alexbrown64]

So i pulled the centre console down and took my non working Temp/compass gauge out.
What a mess!! The PCB was blown up in various areas, capacitors cooked, micro tactile switches melted, zener diodes and tracks burnt up.

I tested most of the tracks/traces and components and i think with a bit of patients, i can repair it. Apparently, the very small board mounted capacitors don't have to be replaced, even though they are all burnt up. The 4 larger ones will need replacing, 1 x diode, 2 x switches and a few other bits. No guarantee it will ever work, but a fun little project. Jaycar has most of the components.

Have a look at the pic below and you can see the burnt damage on the board..
Wondered what those puffs of white smoke were coming from my overhead console all those years ago.

P.S. Anyone have a spare board??

Cheers,

[awg]

I saw this one time, blurb sounds good, you would have to contact them about whether they ship to Oz..the unit is my spare Limited is not working


https://www.ebay.com/itm/91-96-Jeep-...-/132930598603

[alexbrown64]

Thanks Tony,

I have seen his service, and coincidentally, i emailed him earlier with some questions. My hope is to try get the board working and if i cant, then send it to him if he will post back to Australia.
Its not a priority, but just anther nice to have in keeping my XJ in perfect running order.

I think they are all fried now. Just the heat from the roof over the years and the age of the components. Some boards are just worse than others. Mines got some big burns, but not impossible to fix with some parts, time and testing..

Cheers,

[awg]

I will follow your progress with much interest, as I am a qualified electronics technician by trade, although its 30yrs since I did that work.

Please photograph and document your investigations

A schematic diagram would be most helpful ?

also need one of those magnifying holders (and a few other tools)

Have a good soldering kit though !

[alexbrown64]

I got the Snap-On scanner out today and had a play.

It recognized the Jeep and gave me a series of parameters to look at as the XJ was running. I have added a few pics below of what the data looks like.

Initial report is pretty good:

She is going into open/closed loop.

O2 sensor is cycling between 0.35v to 0.70v. This seems OK and is making the Exhaust reading go between Rich and Lean.

Injector pulse is a healthy 4ms.

There are two fuel readings. One just says Fuel%. It is reading -5% which is within parameters, but means the Jeep is leaning out the fuel for a perceived rich running condition. Map sensor, O2 sensor or Coolant sensor problem.

Idle Adap (us), is fuel as well. This is reading 0, so its smack where it should be.

Manifold Vac is 21hg which is a perfect idle pressure at sea level.

TPS voltage at idle is 0.76v which is smack on. At WOT i could only get it to go up to 3.79. Should go up to 5v. Not sure if that is a problem, but it may not be letting my throttle open fully.

IAT-intake air voltage was 3.79v. It goes from 0-5v, so its working, but not sure how accurate it is, and what the voltage should be at a given temp.

The coolant temp on the scanner was showing a 5C hotter temp than the Engine Watchdog i have installed. This gauge is used by the computer to help set fuel ratios.

I have brand new, good quality spare sensors that i may swap out and see what kind of readings i get.
I am reasonably happy, but curious.
The coolant temp sensor should be accurate and inline with the Watchdog. I think my O2 sensor should be cycling at a greater range. Documentation states 0.1-0.9v while running.
TPS might need cleaning or swapping out to get a 5v reading at wide throttle.
Map sensor might need cleaning or swapping out to help reduce the perceived rich condition.

I will spend a day playing with the sensors and seeing if anything changes.







Overall, pretty easy to use, and gather quite a lot of information. Not as good as OBD2, but she is 25 years old now, so not bad tech for the time.

Cheers,