cruiser54

Ditch that piece of crap right away as suggested.

Grab a WJ booster and master and be done with it. Somewhat simpler and works great.

Leave the CPS alone!! I was just curious. Good job. Keep us informed.

Good news, Tom. Couple of questions. Was the old CPS covered with material from the clutch? Did you drill the upper mounting hole of the new CPS? How about the firewall ground point?

In my experience the OE injectors are undersized from the factory to run lean which adds more power and better fuel economy but the adverse effect is the manifolds crack due to the lean conditions and you can verify this yourself if need be... running a little rich is safer for the engine but will cost you a little more in fuel... This^^ is what I have an issue with. Hence my responses. They run at 14.7 to 1 in closed loop which happens quite quickly. At WOT, actually about 80% throttle or more, the AFR is not controlled by the O2 sensor anymore. That's open loop. So, the injectors are not undersized to run lean. They're correct for the application and the ECU controls them. The manifolds do not crack due to the air fuel ratio being too lean. It isn't too lean at 14.7 to 1. If the injectors were indeed the cause of cracked manifolds because of their size, that would mean everyone who has a cracked manifold has it because they ran the engine at WOT for extended periods of time with too small of injectors. They cracked because they were of poor design, had no give in the system, and people ran for long times with bad motor mounts.

Just so ya know, I have set up fuel injection systems, not unlike Renix, with forced induction. I do know about injectors, headroom, need for more fuel at WOT etc. I have driven with a boost gauge zip-tied to one wiper blade, a fuel pressure gauge to the other wiper, and had an AFR gauge in the dash. I also know that too large of injectors can sometimes not be trimmed enough by an ECU to pass emissions while they do supply plenty of fuel at WOT. That's why there are piggyback controllers to assist with that. As to the info I provided on the 4.0s, it is accurate. There are plenty of proven plug and play options out there for the crappy Siemens-Deka leak-prone pieces of crap that came with our Comanches.

They are not too small and indeed do have more headroom. The Renix runs lean as you call it because of computer control, not injector size. Injectors are sized so the ECU can reduce the duty cycle down small enough to get an idle, but provide enough fuel at WOT. The only reasons to go larger are if you build a stroker or add forced induction.

What about automatic subscriptions to threads we post in?

0 280 155 746 Volvo injectors work best in the Renix engines.

Stock injectors have plenty of "headroom". The ECU controls them via "duty cycle". The air to fuel ratio is NOT controlled by the injectors, but by inputs to the eCU which are translated into outputs to the injectors.

Do 3, 5, and 7. In that order.

Tom, of my Tips, which have you completed?

Test it. 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

I just pull the whole harness out.

How about just looking at the lever position?

What are you saying?

Most all Renix haters have never owned one...........

Yep. Relying on ghost trouble codes............

Care to elaborate? I believe the popularity of the HO builds are due to their abundance and not to any real technical advantage. Yup .Koolaid drinkers.

Many folks drank the HO Kool-Aid.

I'd love to have rear discs. I have the dual diaphragm booster and an adjustable prop valve for the rear. Swapping discs to a Dana 44 isn't as easy as doing it on to an 8.25 though. I have a spare load sensing valve BTW.

Oh no you didn't LOL That cartoon was given to me by the guys at JeepTech when I worked as Service Manager at a Jeep dealer. I sent a copy to Hornbrod. Hornbrod changed the sign wording though. It originally said "Chrysler Jeep/Eagle School for the Gifted."

AMC 20 cover is perfectly round.

More than likely a contract to buy the 2.8s from GM and passing emissions. Perhaps adaptation and development of transmissions from different suppliers. A lot goes on behind the scenes.

No part number. They surely have them at other parts stores.