Renix help?

[bigdaddyjlove]

Plugs read Ok, tan. No build up. It doesn't seem to run lean or rich. No ping. Chevy LT1 injectors (24 lb). The CPS, coil and ignition module are new. No spark at the coil wire after it starts acting up.

Plenty of other issues over the years, stuck injectors, replaced fuel pump, IAC, TPS, MAP, ECM etc... Its old and gets hard used.

 

[cruiser54]

Test the CPS and make sure it's wires are not touching the exhaust manifold.

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

 

[cruiser54]

And, since you have an 88, there's a heck of a good chance the CPS signal is getting lost in the C101 connector.

Click on the link below and go to Tips 2 and 27.

http://www.naxja.org/forum/showthread.php?t=1115935

 

[bigdaddyjlove]

Oddly I don't have the C101. I have always assumed that I have a late 88 and they had already made the correction. In any case, it isn't there.

I'll check the cps per the write up this evening (rain permitting) and report back.

 

[cruiser54]

What's the 10th digit of your VIN?

 

[bigdaddyjlove]

I'll have to check when I get home. I drove one of the other XJs today.

 

[bigdaddyjlove]

10th digit is J
full is
1JCMT7898JT212244

 

[cruiser54]

It's an 88 then.

 

[bigdaddyjlove]

Yep, that's what the title says , but thankfully still no C101 connector.

 

[cruiser54]

Yep, that's what the title says , but thankfully still no C101 connector.

Just for fun, I'd like to see a photo of the area near your brake booster.....

 

[bigdaddyjlove]

http://i.imgur.com/2leHAir.jpg

Hope this works. ..

 

[bigdaddyjlove]

If you can see the pic, no c101. The harness is a mess because I've been tugging at it the last week or so trying to check everything.

Also, that stay yellow wire is to the ac compressor for on board air. I pulled it free of the harness so I wouldn't confuse it with the other yellow wires I'm after.

 

[cruiser54]

http://i.imgur.com/2leHAir.jpg

Hope this works. ..

It did!!

No evidence of C101 removal and no C101 bracket on the firewall.

 

[bigdaddyjlove]

Yep. I know 88s are suppressed to have it. But this one never did. The production date is faded beyond legibility, so I have always guessed it was very late 88 production.

 

[cruiser54]

Would have to be....

 

[87manche]

looks just like my 90 did.

You never know what was going on in the 88-89 years. So much turmoil.

So where are we at on this thing?
you've got fuel, so the CPS is good. You've got spark, until hot?
Have you put a light on the trigger wire from the ECM to the ICM when it dies? i'd think a noid light would do it.
At least then you can figure out if it's ECM or ignition component related.

 

[bigdaddyjlove]

Gonna try that tomorrow. waiting on a buddy to come by and being a second set of hands. Hopefully tomorrow after work.

 

[AIbandit]

I had a problem with hot starts during my stroker break in last week, after adjusting the TPS it was fine. Not sure if that's a legitimate solution but it seemed to solve it for me. :dunno:

I was thinking it was injectors since fuel and spark seemed to be present.

 

[bigdaddyjlove]

Ill check tps too while im there

 

[bigdaddyjlove]

Wanted to thank everyone for their help. I managed a few minutes at the junkyard Sunday and picked up a stock ECM from a '90. Plugged it in and ran it for two hours. all seems to be well.