I would like and could use something better, but the $5 HF ones actually seem to work. I bought 2 Chinese off Ebay for < $8. Not as good! Who would have thought that possible. Bought a nicer $25 meter at HD, but it took a crap and the Harbor Freight one still works.

 

tested the coil and if i read the mutli meter correctly it looked good..low voltage came to .3 and the high voltage test was 5.53..

gonna test the other items mentioned already..

 

I cut the "probes" off my meter leads and soldered little alligator clips. I can always clip it on to something to probe with. The downside is it's not so handy with house current.

Anyway that CPS is crucial. I just this minute went out and checked the Napa "premium" I put in two weeks ago at just over 1/2 a volt. (.56).

The coil resistance is checked in "Ohms" of resistance. (has the Greek symbol that looks like headphones). I have yet to find specs for the Renix coils.

At my ICU the first yellow gets about battery voltage, and the rear gets about 5 volts. If you're reading 3, you might be on to something, I don't know what thou. I believe it does go thru the c101. If I had one, I'd clean it for sure as per cruisers instructions.

 

i'm on a bigger learning curve with the new tool than i was without it LOL...when i get home i'll check the others..

i did check the coil on the ohm selection..not sure what the repair manual meant by less than infinity??

 

Did you in fact clean the coil to ICU connections yet?

 

might be some testing info here that may be help full alsohttp://jeep.zerok.ru/index.php?page=134

 

yes they are cleaner than a whistle and all greased up...rechecked the coil and on the low end test it was.3 and the high end test was 15.38 with the meter set on ohms..

i took the C101 apart and cleaned it all out relubed and bolted it back on..checked the CPS and when i was cranking it ranged from .5 up to .68 with the meter set on volts..

tomorrow i will check all the ground straps to see if something is wrong there.. probably stick a new cap, rotor, plugs and wires in it just to rule it out..

the injector pulse will be checked out as well...

any other ideas what it could be?

 

"""not sure what the repair manual meant by less than infinity??"""
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Yea, isn't that sweet? Reading that coil test gives me a headache. Since resistance is in ohms, the higher the number, the higher the resistance. What they mean I think is it's not an open circuit, but still a very high number.

Primary are the wires to your ICM/battery. Secondary is the wire to your little brother. (I only had a big sister )


I found these #s posted somewhere for a 92 (non-Renix) Jeep
The primary maybe should be in the realm of ohm 1(one)ohm +,--, not much resistance, hence it passes a bit of current. (this would be on the 200 scale)
The secondary, to ether side of the primary, 6000 to 30,000 ohm's. (so might be on the 20,000 (20K) scale.

This is neither here nor there but I took a couple readings off my 90, (Renix), that I could do easy just pulling some wires. Secondary to Battery Neg.(--), read just under 20 on the 20K scale. Secondary to the pin where the first yellow 12V wire plugs in, 6.4 on the 20K scale. The coil was still mated to the ICM so make of that what you will! (and Pete, no, haven't cleaned it this century!)(but I will)

Brian, two more things. I've been at this stuff awhile. (started wrenching on my training wheels,). I've never seen an engine that will refuse to start with a weak battery, like one of these. I have a number of rigs, and sometimes run the old Jeep battery for another year in a normal car. A good hot battery is a must.

Also if you have spark, compression and fuel, and no start, being flooded is possible. If you floorboard it it will cut the fuel and allow maximum air. Also the little tube from the inside of your throttle-body up to the MAP sensor there on the firewall can get brittle and delicate. Any little crack, or if it's plugged, the MAP without good vacuum will dump extra fuel.

I'm learning from these guys as well. Freedgr, injector pulse. Do you mean like connecting a taillight bulb to the injector connector?

 

injector pulse is best checked with a noid light its a low voltage bulb that in serts into injector plug ,

 

Since you have an 88, you have the dreaded C101 connector on the firewall above the brake booster. This crappy connector carries almost every signal to and from the ECM, including the CPS. Try this. Can't hurt and can only help.

Renix Jeep C101 Connector Refreshing
　
The C101 connector on 1987 and 1988 Renix Jeeps was a source of electrical resistance when the vehicles were new. So much so that the factory eliminated this connector in the 1989 and 1990 models. The factory recommended cleaning this connector to insure the proper voltage and ground signals between the ECU and the fuel injection sensors. We can only imagine how this connector has become a larger source of voltage loss and increased resistance over a period of almost 25 years. The C101 connector needs to be cleaned at least once in the lifetime of your vehicle. Chances are it’s never been done before.

Almost every critical signal between the engine sensors, injectors, and the ECU travel the path through the C101.
The C101 is located on the driver’s side firewall above and behind the brake booster. It is held together with a single bolt in it’s center. To get the connectors apart, simply remove the bolt and pull the halves apart. You will find the connector is packed with a black tar like substance which has hardened over time.
Take a pocket screwdriver or the like and scrape out all the tar crap you can. Follow up by spraying out both connector halves with brake cleaner and then swabbing out the remainder of the tar. Repeat this procedure until the tar is totally removed. This may require 3 or more repetitions. Wipe out the connectors after spraying with a soft cloth.
If you have a small pick or dental tool tweak the female connectors on the one side so they grab the pins on the opposite side a bit tighter. Apply a true dielectric grease, not the stuff that came with your brake pads, to the connection and bolt it back together.
　
　
Revised 11-29-2011

 

all this talk about weak spark have you ever sprayed starting fluid in it and see if it trys to start at all

 

Heck, couldn't hurt.

 

right fuel pressures never been verified correct

 

Yea, or hearing the pump run a second after the key is turned to on, or checking for voltage at the ceramic ballast resistor for the fuel pump there on the fender by the air cleaner. (cranking)
(battery voltage to the front, a few less volts out the rear wire directly to the pump). I guess that resistor was added when people complained about noise. By-pass it, or can it if you like. I changed mine when it simply fell apart.

 

i dismantled and cleaned the C101..the tar is really neat stuff.

i have not tryed starter fluid yet..i might tonight if the jeep doesn't end up in the pond..i can definately here the fuel pump come on...injectir pulse and fuel pressure has not been checked..only reason is i'm still getting weak spark so first things first.

i'm a little baffled, it ran perfect, drove it 50 feet and it died..it has over 400k, just recently put a rebuilt head on, belts, hoses, rad. tune up stuff, alternator battery etc. i'm wonderin if i didn't break a wire somewhere. gonna also check for something really simple like did the negative battery terminal come loose on the other end of the battery, or if i yell at it will it start.