cruiser54

And then a "how to": Cruiser’s HO into Renix Swap This swap is easier than some will lead you to believe, generally those who have never done it. Those of us who have done it, like myself, will share with you the things that need to be done for a successful swap. Just think of it as swapping in a long block. The HO and Renix have some differences but none that can’t be overcome very easily. Any HO engine from an XJ or ZJ through 1999 can be used. One running change was that the rear of the head was no longer drilled and tapped for the temperature gauge sender beginning in the 96 model year. The sender can be relocated to the threaded hole in the thermostat housing taken from the HO engine. You’ll have to extend the wire to that location. Some brave souls even drill and tap the HO head for the sender. You will be using the intake and exhaust manifolds from your Renix, along with all your sensors and wiring. Since the intake ports of the HO are slightly different, you use the Renix gasket. Exhaust ports are identical. You will need to use your Renix distributor as it is different than the HO because they use different fuel management systems. The flywheel or flexplate from the Renix must be used so your CPS gets the correct signals. The valve cover from the Renix allows you to keep your CCV system intact and requires no modifications. The HO block will have a plug in the coolant galley on the driver’s side of the block, closest to the front, which needs to be removed so your Coolant Temp Sensor can be installed in it’s place just as it is on the Renix. It requires a 5/16” square drive or a modified 3/8” drive that has been ground down to fit. Do this before installing the engine. As for the knock sensor, which is located just above the oil pan on the driver’s side of the engine about mid way, all the blocks I’ve seen are threaded for it. If not, I’ve heard they may be drilled but not tapped. Tap the hole if that’s the case. Revised 03/28/13

Here's some clarification: XJ Cherokee and ZJ Grand Cherokee 4.0L engine blocks interchange. 2000+ TJ Wrangler and WJ Grand Cherokee 4.0L engine blocks interchange. XJ/ZJ blocks and 2000+ TJ/WJ blocks do not interchange without significant modifications. (1991 to 1995 YJ and 1997-1999 4.0L TJ Wrangler blocks will interchange in XJ/ZJ and visa-versa). TJ/WJ 4.0L Engine blocks underwent clean sheet design changes effective in the 1999 WJ Grand and 2000 TJ Wrangler. These blocks are not interchangeable with XJ/ZJ engine blocks. The reason is motor mount bolt holes and belt driven accessory mounting bolt holes are in different locations, or not present at all, TJ/WJ vs. XJ/ZJ. XJ: "Regular" (not Grand) Cherokees 84-01 ZJ: Grand Cherokee 93-98 (Gen1) WJ: Grand Cherokee 99-04 (Gen2) YJ: Wrangler 87-95 (Gen1) TJ: Wrangler 97-06 (Gen2)

I had the "wire" issue on my wife's XJ, only right after filling the tank and the gas would slosh against the loose fitting wire.

2 things come to mind. The engine control grounding system and poor signal through the C101 connector. Click on the link in my signature and read the write-ups on ground refreshing and C101 cleaning. Takes less than an hour to do both.

Have you ever cleaned the throttle body and IAC? Made sure your intake manifold bolts are tight?

The air conditioning? You mean a vacuum supply through the firewall? Is the vacuum storage cannister behind the passenger side bumpeer?

I'll bet that's the reason. Dealer installed AC.

Or brake cleaner. Click on the link in my signature to see 25 Mostly Renix Tips, with photos. C101 was only used through 1988 BTW. Ground refreshing is a must!!.

Imagine that.... Get the Napa cap just as a precaution when you get a chance.

Do like Eagle says and drive it. You shouldn't have to add more than once. But use the Napa cap!!! This whole thing of bleeding/burping Renix systems is an old wive's tale that has lived on in perpituity.

Yup.

Not necessary. Did you read the quote from the Factory Service Manual? Did you know I was a Service Manager and Shop Foreman at a Jeep dealer since when these were new, and I nor my techs EVER bled/burped a Renix cooling system?

It's not necessary to bleed it. good bottle, and a good cap will be fine. Get that Napa cap!!

If rapping on the tank got the pump to start running once, and now it's loud, the pump is probably taking a dump soon.

It's very possible that the bottle IS the problem. If you don't replace it, at least replace the cap with a 703-1396 from Napa. The old one "popped" off because they are chinese pieces of crap. Here's what the FSM says about filling your cooling system: Only fill to the top of the little pipe inside the bottle. Check this out from the FSM This system does not have a radiator pressure cap. Instead the pressure cap is mounted on the coolant pressure bottle. System coolant flows directly through a fully pressurized Hot-Type expansion bottle. Coolant flows through the pressure bottle at all times during engine operation whether the engine is cold or at normal operating temperatures. Larger coolant volume caused by thermal expansion during engine operation is absorbed by the expansion chamber in the bottle. Air trapped in the system is purged through the pressure cap vent valve during maximum coolant expansion..

Starters don't get sunburned.

actually just more noise from the pump as it spins faster without the resistor. Fuel pressure is regulated by the fuel pressure regulator. The ballast resistors used on old chryslers and other old stuff was to allow 12 volts to the points on canking and reduce it to 8 volts on running so the points would last longer.

Do you have the equpment and an HO to do that on? It would be great to have an alternative to the unreliable ohms test for the HOs also.

The pressure built slowly, but since I didn't have a pressure cap on it (I had the tester on it) it kept building. I get that part. The tester instructions said to turn the engine off before the pressure got to 30 psi. So, if the cap let go at 16, it would have never gotten to 25-30...it'd just blow the pressure...and coolant into the overflow...right !!? Thats correct it will raise normally with temperature and the cap will allow the pressure to release. I see in your signature you have an 88 4.0 is this the truck your working on? Is this the factory cooling system or have you converted to the later cooling system? He's now got an open system.

That's the difference then. Renix is 2 wire AC voltage generating.

No I have not. Would be interesting to test one for AC voltage. Are the HO CPSs 2 or 3 wire? .

From the Snap-On compression tester gauge instructions: • Open throttle plates and choke plate to allow the engine to breathe. Be sure air is not restricted from entering into the cylinders.

Uh, yeah. Drill out the upper mounting hole. Click on the link in my signature so you can view the photos.

Very possible. Read this: Renix CPS Testing and Adjusting Renix CPSs have to put out a strong enough signal to the ECU so that it will provide spark. Most tests for the CPS suggest checking it for an ohms value. This is unreliable and can cause some wasted time and aggravation in your diagnosis of a no-start issue as the CPS will test good when in fact it is bad. The problem with the ohms test is you can have the correct amount of resistance through the CPS but it isn’t generating enough voltage to trigger the ECU to provide spark. Unplug the harness connector from the CPS. Using your voltmeter set on AC volts and probing both wires in the connector going to the CPS, crank the engine over. It won’t start with the CPS disconnected. You should get a reading of .5 AC volts. If you are down in the .35 AC volts range or lower on your meter reading, you can have intermittent crank/no-start conditions from your Renix Jeep. Some NEW CPSs (from the big box parts stores) have registered only .2 AC volts while reading the proper resistance!! That’s a definite no-start condition. Best to buy your CPS from Napa or the dealer. Sometimes on a manual transmission equipped Renix Jeep there is an accumulation of debris on the tip of the CPS. It’s worn off clutch material and since the CPS is a magnet, the metal sticks to the tip of the CPS causing a reduced voltage signal. You MAY get by with cleaning the tip of the CPS off. A little trick for increasing the output of your CPS is to drill out the upper mounting hole to 3/8” from the stock 5/16”, or slot it so the CPS bracket rests on the bell housing when pushed down. Then, when mounting it, hold the CPS down as close to the flywheel as you can while tightening the bolts. Revised 01-26-2013

Describe over-pressurizing.