Hard Cold Starts ( Engine Temp)

[big66440]

Ok guys I've been struggling with trying to get my Manche to start easier when the engine is cold (ie first morning startup) I've replaced the crankshaft position sensor with a mopar piece and did the whole bypass trick the factory would sell the kits for back in the day, cleaned the $#!& of the TB and IAC valve passages, next on my list is a timing chain replacement, indexing my distributor and a new coolant temp sensor, any input will be welcome, thanks in advance.

[cruiser54]

How hard is it to start? How many seconds does it crank over?

 

I have NEVER found a Renix 4.0 dizzy to be indexed correctly BTW.

[big66440]

IT TAKES LITERALLY ABOUT A FULL MINUTE OF CRANKING (I PAUSE SO I won't KILL MY STARTER) once the engine gets to operating temp it fires up the way a renix usually does

[cruiser54]

Have you checked the fuel pressure? Cold?

[big66440]

Yup checked out at a solid 35psi, I've even "primed"the system and pinched the return line to no avail.

[cruiser54]

How about this? And, have you checked for spark when this happens? Is it blue? Have you done a ground and connector refreshing? Sensor ground test?

 

Renix Jeep ICU/Coil contact refreshing

 

The contacts between the coil and the ICU on your Renix Jeep can become corroded and loose causing a complete or intermittent no-start condition. I recommend the following procedure as a maintenance precaution to insure this is eliminated as a possible cause now and in the future.

The coil is attached to the ICU by two T20 Torx bolts. Remove these two bolts and lift the coil up off the ICU. You will see 2 pins and 2 sets of contacts. Clean both the pins and springy contact pieces with a good electronics cleaner.
Squeeze the springy contacts closer together with some needlenose pliers. Apply some dielectric grease to the contacts and bolt the coil back on to the ICU.
While you’re right there unplug the connectors from the ICU and inspect the pins in the harness connector. Make sure the pins are not retracted into the connector. Spray out the connector and the receptacle of the ICU with the same good electronics cleaner you used earlier. Apply dielectric grease to the connectors and plug them back in.

I feel this procedure should be performed at least once in the lifetime of a Renix Jeep.

Revised 11-29-2011

[MJCARENA]

I had almost the same problem with mine. Would only start cold with a shot of starting fluid, and then start normal with the engine warm. Had spark and good fuel pressure while cranking, The exhaust pipe smelled like raw fuel, like it was flooded.  Turned out to be my Temp sensor for the ECU (on the block by the motor mount drivers side) You said you changed the temp sensor. But which one?  Hope this helps.

[cruiser54]

Easy to test the IAT and CTS. Could also be a bad ground in the sensor circuit.

[big66440]

I'm thinking of replacing my coolant temp sensor.

[cruiser54]

Easily checked with a meter.

 

Have you ever done this?

 

Cruiser’s Renix Sensor Ground Test

This sensor ground circuit affects the CTS, TPS, IAT, MAP, ECU and diagnostic connector grounds. It’s very important and not something to overlook in diagnosing your Renix Jeep as it is common for the harnesses to have poor crimps causing poor grounds. If any or all of the sensors do not have a good ground, the signal the ECU receives from these sensors is inaccurate.

Set your meter to measure Ohms. Be sure the key is in the OFF position.  Using the positive (red) lead of your ohmmeter, probe the B terminal of the flat 3 wire connector of the TPS . The letters are embossed on the connector itself.
Touch the black lead of your meter to the negative battery post. Wiggle the wiring harness where it runs parallel to the valve cover and also near the MAP sensor mounted on the firewall. If you have an 87 or 88 with the C101 connector mounted on the firewall above the brake booster, wiggle it, too.

You want to see as close to 0 ohms of resistance as possible. And when wiggling the harnesses/connectors the resistance value should stay low. If there is a variance in the values when wiggling the wires, you have a poor crimp/connection in the wiring harness or a poor ground at the engine dipstick tube stud. On 87 and 88 models, you could have a poor connection at the C101 connector as well.

Revised 06/12/2012