JustaValiantguy Posted March 13, 2019 Share Posted March 13, 2019 I recently picked up an 86 Renix 2.5 TBI MJ from a local farmers, who said he couldn't get it to run right. Almost instantly, I noticed that there were a few connectors not connected to anything, a lot of butt connectors, and that Haynes/Chilton made a terrible diagram for this specific engine. I was wondering if anybody had any pictures of the wiring/ could help to ID some of these stragglers. Link to comment Share on other sites More sharing options...
Ωhm Posted March 13, 2019 Share Posted March 13, 2019 Welcome to CC. This 88 manual could help with most of your questions. 88 Electrical Manual Link to comment Share on other sites More sharing options...
JustaValiantguy Posted March 14, 2019 Author Share Posted March 14, 2019 Okay, that explains a few of the connectors, but there's one, by the ignition module, and I don't know if it is supposed to connect to the male spade terminal on the coil or if it is an unused connector like some of the others. I've tried attaining spark with and without this wire connected to the coil, and have had no luck. Link to comment Share on other sites More sharing options...
Ωhm Posted March 14, 2019 Share Posted March 14, 2019 Ignition module only has two connectors. One is a 3 pin and the other is a 2 pin. Loss of spark can be caused by a faulty Crank Position Sensor (CPS). Link to comment Share on other sites More sharing options...
eaglescout526 Posted March 14, 2019 Share Posted March 14, 2019 7 minutes ago, JustaValiantguy said: Okay, that explains a few of the connectors, but there's one, by the ignition module, and I don't know if it is supposed to connect to the male spade terminal on the coil or if it is an unused connector like some of the others. I've tried attaining spark with and without this wire connected to the coil, and have had no luck. Does the wire have a flat connector and is a red wire? If so that for the optional under hood light. It does not plug into that spade on the coil. Don't know what that's for. For no spark / start I would check the Crankshaft Position Sensor on top of the transmission bell housing on the drivers side. See if the sensor is dirty and putting out the right voltage. Link to comment Share on other sites More sharing options...
JustaValiantguy Posted March 14, 2019 Author Share Posted March 14, 2019 That was one of the first things that I checked, and, even finding that it looked okay, still replaced it under warranty (because that's what having friends at a parts store can do, apparently), and I still don't have spark. Good grounds, new coil, tested module, and confirmed good wires via ohming them out. And the two pin connector is depinned on the "a" side. Link to comment Share on other sites More sharing options...
Ωhm Posted March 14, 2019 Share Posted March 14, 2019 If CPS is assumed good, the injector within the throttle body should spray fuel. Does it? Two pin (C214_A) should be empty. C214_B goes to the ECU for timing control. Link to comment Share on other sites More sharing options...
eaglescout526 Posted March 14, 2019 Share Posted March 14, 2019 59 minutes ago, JustaValiantguy said: Okay, that explains a few of the connectors, but there's one, by the ignition module, and I don't know if it is supposed to connect to the male spade terminal on the coil or if it is an unused connector like some of the others. I've tried attaining spark with and without this wire connected to the coil, and have had no luck. That green wire needs to go to the starter relay. Does the relay have an open spade? Link to comment Share on other sites More sharing options...
JustaValiantguy Posted March 14, 2019 Author Share Posted March 14, 2019 All spades are filled on the relay, and this wire is in the loom going the other direction. It comes from what I assume is C103_B. Haven't tested for fuel yet, have to drive into town and grab some so I can test that Link to comment Share on other sites More sharing options...
Ωhm Posted March 14, 2019 Share Posted March 14, 2019 C103 is a inline connector (Engine harness to Engine Control harness) and C103_B (RED) goes to fuse link G. Link to comment Share on other sites More sharing options...
eaglescout526 Posted March 15, 2019 Share Posted March 15, 2019 10 hours ago, JustaValiantguy said: All spades are filled on the relay, and this wire is in the loom going the other direction. It comes from what I assume is C103_B. Haven't tested for fuel yet, have to drive into town and grab some so I can test that I put some thought into it and I think that plug is for the oil pressure switch or sensor. Link to comment Share on other sites More sharing options...
JustaValiantguy Posted March 16, 2019 Author Share Posted March 16, 2019 That makes sense, it looks like the previous owner put in an oil pressure gauge, and had the line run directly into the sending unit's spot. Link to comment Share on other sites More sharing options...
JustaValiantguy Posted July 4, 2019 Author Share Posted July 4, 2019 Alright guys, after putting this off for months, I decided that I should maybe try again. I've done my digging in the wires and wire C213, which is the timing input to the ICM, is not receiving any power, cranking or not. I was wondering if the PCM is the issue or if there was something else that could be preventing the PCM from putting out the power. The PCM has been replaced prior, as there is a reman sticker on it. Link to comment Share on other sites More sharing options...
Ωhm Posted July 4, 2019 Share Posted July 4, 2019 15 minutes ago, JustaValiantguy said: wire C213, which is the timing input to the ICM Do you mean C214_B? Link to comment Share on other sites More sharing options...
cruiser54 Posted July 5, 2019 Share Posted July 5, 2019 Have you tested the CPS output? CRUISER'S MOSTLY RENIX TIPS RENIX CPS TESTING AND ADJUSTING OCTOBER 30, 2015 SALAD 92 COMMENTS 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 itself as shown in Figure 2 as Connector A, 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. Another little tip to save tons of aggravation is to stick a bit of electrical tape to your 11mm socket and then shove the bolt in after it. This reduces the chances of dropping that special bolt into the bell housing. Link to comment Share on other sites More sharing options...
omega_rugal Posted July 6, 2019 Share Posted July 6, 2019 on carburated 2.5l is there an ECU controlling the spark? i have seen diaghrams where the CPS plugs directly to the ignition coil... Link to comment Share on other sites More sharing options...
JustaValiantguy Posted July 19, 2019 Author Share Posted July 19, 2019 On 7/4/2019 at 5:28 PM, Ωhm said: Do you mean C214_B? Yes, my bad, but I don't see the ckp on that diagram, unless they are referring to it as the engine speed sensor? Link to comment Share on other sites More sharing options...
Ωhm Posted July 19, 2019 Share Posted July 19, 2019 3 minutes ago, JustaValiantguy said: I don't see the ckp on that diagram, unless they are referring to it as the engine speed sensor? Engine Speed Sensor = Crank Position Sensor (CPS). Link to comment Share on other sites More sharing options...
cruiser54 Posted July 19, 2019 Share Posted July 19, 2019 2 hours ago, Ωhm said: Engine Speed Sensor = Crank Position Sensor (CPS). Test it. Link to comment Share on other sites More sharing options...
JustaValiantguy Posted July 25, 2019 Author Share Posted July 25, 2019 Testing the sensors, I've been through 6 so far, kinda getting tired of crawling under there and getting rust in the eyes😅 but I was wondering if there was something else wrong. I've cleaned the mounting surface for the sensor, and verified tester connection, but have not gotten a sensor to even register ANY amps. Ohms test is spot on, for all sensors, but like Cruiser mentioned, the ohms aren't definitive. Link to comment Share on other sites More sharing options...
kazam Posted July 29, 2019 Share Posted July 29, 2019 It seems like you are testing components appropriately. If you have not already since starting into the Jeep you might check the wiring harness connection at the firewall, open that up and make sure everything is clean and correct then put it back together with some dialectric grease. I had a no spark issue resolved with some cleaning and pin straightening there. Link to comment Share on other sites More sharing options...
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