89 renix 4.0 need help

i have a 1989 jeep wagoneer limited xj 4.0 auto i can go outside in the morning and it will start up good but after you shut it off once or twice it wont start back up unless you let it set at least a couple hours i put a new cps on it today and the coil and icm arent very old either me and my dad checked the spark and its firing strong but its orange not blue and it seems to have good fuel pressure i really need some help ive been trying to fix this for almost 2 weeks also somebody has removed the ballast resistor and just spliced the wires together

What does the cranking sound like when it won't start?

Orange is not that good.., and something to check out, 'fer 'sho.

The splice job is ok, just makes the fuel pump sound awful.

sounds like normal cranking but it doesnt take very long for it to drain the battery

Sounds kind of like your battery is failing. A weak battery and the starter sucks down all the juice and doesn't leave enough for the ignition to fire right.

A quick test you can make is to crank it and check the volts at the larger yellow wire at the ignition coil. Then hook up a jumper to another battery and check it again.

Severely worn brushes in the starter and it may work, but may suck way more amps than normal and turn over slowly.

The connector between the coil and the Ignition module needs to be clean and tight.

Do Cruisers ground refreshing. I make a jumper for the ground from the battery negative to the chassis. Check the Ignition module ground.

Ohm test the coil to distributor cap wire. Check the distributor cap spark plug wells for corrosion or moisture. Check the inside of the cap for severely worn rotor and cap contacts. I typically use two distributor caps and rotors to each set of spark plugs, my plugs seem to last forever. Check under the sync sensor mounting plate for water inside your distributor. I had the exact same thing going on. I had water in the bottom of the inside of the distributor, the motor and distributor would heat up and the water would turn to vapor and short out the high voltage spark inside the distributor, after the motor cooled down the water would settle to the bottom again (drove me nuts).

Weak spark is usually something simple. But it usually won't cause a no start, it makes for a really bad idle and/or the motor craps out at higher RPM's.

The starter not turning over fast enough can cause a hard start.

A weak CPS signal (new doesn't mean good). Do Cruisers CPS volt test. You my also want to do an ohm test on the CPS, cold and hot. I had two that were under 125 ohms cold but were 180 ohms hot and the motor would seldom start hot. Clean the CPS connector really well, spray and scrub with a good solvent (not WD 40 or any other oil), preferably with a good contact cleaner. Make sure the CPS wires are well away from the exhaust manifold. I found the easiest way is to tie the CPS pigtail wires to the speedometer cable, then you are absolutely sure they aren't going to cook on the exhaust manifold.

You may have more than one issue going on and they add up.

Try turning the key from stop to run a few times then to start and see what happens. You may be loosing prime, but this usually shows up after the motor has sit all night.

You may want to try a start with around 1/8 th gas pedal, if your IAC is sticking shut, this opens the throttle plate enough so you have enough air for a start.

Sounds like a lot of work, but when you get done the reliability really increases for the old Renix.

i just had a guy tell me his did the same thing and it was the coolant temp sensor so im going to try that tommorow and if that doesnt work ill do what you said

worst thing you can do is throw parts at it, go thru cruisers list and find the problem...

It is unlikely to be the coolant temperature sensor on the Renix. There are two, the one on the drivers side of the motor down low is for the ECU. The one on top of the head rear is for the temperature gauges.

Easy to test, do an ohms test (cold motor) on the temperature sender, lower left on the block. Then do the same ohm test on the intake manifold temperature sensor (cold motor), they should have close to the same ohm reading.

Left and right on a motor is always as you are sitting in the drivers seat.

Any part can fail, but a temperature sensor is far down on my list of probabilities. Much more likely to be the harness for the engine temperature sensor, 02 sensor and knock sensor cooking on the exhaust. If your issues have anything at all to do with the temperature sensor. I've been farking around on the Renix for 25 years and never had to change a temperature sensor, but like I said anything is possible, just some things are more likely than others. I've had way more problems with my wiring than with my sensors.

Trying to get that sensor out of the block is going to turn into a large can of worms. I really believe you don't want to open that can unless you have tested and have to open it. It is likely that sensor has been in there for 24 years and it may be pretty stuck in there. IMO you want to use that money to buy an ohm meter and test first.

i just drove it up the road to a buddies house and when i came back out it wouldnt start it was turning over slow it acted like the battery was dead so i went home and got the battery out of my truck and it started it right up and when i got home the battery that was in the jeep started my truck right up

Renix are notorious for not starting with a low battery. Even though it is cranking fine, the voltage is low enough that the ECU does not produce a proper spark, if any. I have fought this several times. I am thinking about adding a circuit that boosts the voltage to the ECU when it is low.

Before throwing a battery at it, have it checked out. You might have an alternator that simply isn't charging enough.

I was leaning towards the starter being bad but if you don't think that's what it is I won't change it the volt guage shows just under 14 volts with it running and with all the lights the radio and heater on it drops to 12 or 13

What you describe is pretty typical for the renix power distribution system.

I think 8mud is probably right here, you're in ohio, it's f'ing cold there, lead acid batteries work very poorly once that temp drops below <40. So if you have an older battery this could very easily be your culprit.

However, before you go out and buy a new battery, check your cable connections, take the battery clamps off and clean the wire ends with a bronze brush and some contact cleaner, do the same thing with the clamps. Besides cold temps, dry air has a tendency to cause your contacts to go bad, this creates resistance that will ruin your day just as much as a dead battery.

The thing to remember is that the starter has a direct line between the battery and the lead on the motor, if the starter isn't cranking the motor over, then the problem exists somewhere in there.

Basics of renix debugging:

1) If the engine doesn't crank, it's either battery or wiring
2) if the engine cranks, but doesn't start, check for spark, if no spark it's your CPS or CPS wiring (usually it's the wiring)
3) If the starts, but idle goes high, your IAC/IAT system is dirty, if not that, your TPS is not working properly.
3a) If it starts, and then dies when you start driving it, your IAC/IAT system is dirty

Also, it is not your coolant temp sensor, the only way this could cause problems is the engine temp affects the timing advance controlled by the ECU. When a car is started (hot or cold) it's running in open-loop mode, until the ecu puts it into closed-loop. What would happen if it was the temp sensor is your car would never go into closed loop (the ECU would think it's too cold).

Given that you swapped the battery, I think this means either you contacts are dirty, or your battery is hosed.

000

the starter does crank over it just turns over slow

Sounds like a bad battery

what size battery would you reccomend the one in it now is 650 cca

ok i went and bought a used starter off of a buddy of mine and put it on and it turns over faster and better than it ever has and it seems like all the electronics are working better the seat belt beeper even sounds better and i put a new set of plugs in it just for the heck of it and it started up and ran better than ever but it is still flooding somehow after i started it i drove it around for a while and when i got home i shut it off and it started right back up but if you wait more than 5 or 10 seconds it wont unless you hold hold the gas wide open and crank it forever or wait a while im starting to think that one of the injectors are sticking open and flooding one of the cylinders

pull the vac hose off the fuel pressure regulator... if it failed thre will be fuel in the vacuum hose

ok ill check it

there wasnt any gas in the fuel regulator vacuum line

Check the TPS adjustment, sounds like it may be going bad.