Wont start... HELP

[Infidel Edition]

OK. The other day, it just cranked... As if not getting any gas.
I checked and swapped a couple fuses and good to go. I figured it was just a bad fuse.

It sat for a couple days waiting to swap the steering pump and today SAME CRANKS BUT NO START.
Rather than dig for issues, I dealt with the steering pump swap.
Tomorrow I'm gonna check the relay.
...fingers crossed!

What else should I be checking ~ if it isn't the relay.
+ if I turn the key to the 'on' position... Should there be juice to the pump? & how much?

Once I get everything good, I do want to add a couple toggle switches to replace the stock ignition. But I'd like to find the issues first.

Help

[Mudderoy]

OK. The other day, it just cranked... As if not getting any gas.
I checked and swapped a couple fuses and good to go. I figured it was just a bad fuse.

It sat for a couple days waiting to swap the steering pump and today SAME CRANKS BUT NO START.
Rather than dig for issues, I dealt with the steering pump swap.
Tomorrow I'm gonna check the relay.
...fingers crossed!

What else should I be checking ~ if it isn't the relay.
+ if I turn the key to the 'on' position... Should there be juice to the pump? & how much?

Once I get everything good, I do want to add a couple toggle switches to replace the stock ignition. But I'd like to find the issues first.

Help

Sounds like the most common no start (and intermittent no start) issue, bad CPS. Of course it could be the connection. Might try disconnecting and connecting first.

[prerunner1982]

Can you hear the fuel pump prime when you turn the key to on?

[Infidel Edition]

I don't remember if I could hear it or not... That'll be the first check when I get home.
If there isn't any noise, should their be current at the plug on the pump when the key is "on" (not start, just on)?

...on the wiring diagram, it looks like the ORG wire runs from the pump relay to a junction (tied to O2 sens relay / ECU Injector feed / & a junction split to the EGR SOL ~ Ballast Resistor / and Fuel Tank Unit - ORG line in)
...on the Fuel Tank Unit, there is ORG line (should be power), BLK (ground), and VIO (fuel gauge).
***so check power at relay ORG larger gauge
***then ORG into pump...
~ otherwise, trace it from the pump to the relay and look for issues? Assuming it's a bad connection that is.

And on the CPS ~ I've been meaning to swap it out since I've noticed it takes a bit more to start from time to time. But I wanted to upgrade the electrical (big 3) first to make sure it wasn't a lack of juice.

:keegirl:
So the gal at work told me to ask her Crazy 8 Ball.
I asked if it was a simple electrical issue.
response, "Outlook Doesn't Look Good"

I then asked it if it was the CPS.
response, "Odds Are"
...WOW! Who knew 8 balls could be used to diagnose jeeps!

[BlueXJ]

OK this is the order of operations for a Renix to start:
1- Turn on key and listen for the fuel pump, once it quits there will be pressure at the rail.
2- Turn key to start position, the engine must turn over 3 full revolutions in order for the computer to recieve 3 signals from the CPS.
3- CPS will send those signals to the computer which will then allow power to be routed through the relay to the injectors and the distributor.
ENGINE STARTS.
Any or all those steps may be at fault or may work fine but any one of them can cause a no start, so you need to check each step. This will allow you to diagnose the problem.

[Infidel Edition]

OK this is the order of operations for a Renix to start:
1- Turn on key and listen for the fuel pump, once it quits there will be pressure at the rail.
2- Turn key to start position, the engine must turn over 3 full revolutions in order for the computer to recieve 3 signals from the CPS.
3- CPS will send those signals to the computer which will then allow power to be routed through the relay to the injectors and the distributor.
ENGINE STARTS.
Any or all those steps may be at fault or may work fine but any one of them can cause a no start, so you need to check each step. This will allow you to diagnose the problem.

Thanks. That gives me a logical flow to work with.
~For clarification, in reviewing info on the CPS, someone said if it's bad, it could tell the pump - not to pump?
...but on a cold engine, turning the key would still engage the pump... Correct?

And if # 1 is a no-go, then, check the wiring path?

[XJ Wheeler]

Sounds like the most common no start (and intermittent no start) issue, bad CPS. Of course it could be the connection. Might try disconnecting and connecting first.

X2. It can be very random as well, like working after you messed with those fuses and not later.

Sent via messenger pigeon - i talk, he types.

[F1Addict]

Thanks. That gives me a logical flow to work with.
~For clarification, in reviewing info on the CPS, someone said if it's bad, it could tell the pump - not to pump?
...but on a cold engine, turning the key would still engage the pump... Correct?

And if # 1 is a no-go, then, check the wiring path?

The CPS isn't tied to the fuel pump at all so if you don't hear the pump priming then that would be caused by the pump/relay/fuse and not your CPS. The CPS does, however, trigger the injectors. Here are a few things for you to check...

1. Renix CPSs can be diagnosed with a multimeter. Disconnect the CPS from the harness and, with your multi-meter in volts AC probe pins B and C on the CPS while someone cranks the engine (it won't start with the CPS disconnected), it should read ~0.35-0.5 VAC (remember, AC, not DC). If it reads lower than 0.35 VAC then the Hall sensor isn't producing enough voltage for your ECU to recognize the signal and you'll have no spark.

2. It's not difficult to produce faulty numbers using a multi-meter so it's a good idea to verify those numbers with a spark test so pull one of the plugs and ground it to something, crank the engine and watch for a sharp blue-white spark at the electrode. If your multi-meter read between 0.35 and 0.5 VAC and you have spark, move on to your fuel system. If your multimeter read less than 0.35 and you have no spark, replace your CPS.

The only problem with the CPS test is that, as XJ Wheeler said, they can be random so it's best to test them when you're experiencing a no-start situation. On the other hand, even if it's running, you're likely to get very low voltage returns on the CPS test (closer to 0.35v), if they're pretty low, replace your CPS.

[Infidel Edition]

Pump engages when key is turned to on.
Crank & crank = no joy

Swapped the relays just in case... And file cleaned the prongs on the relays and CPS plug... Still no joy.

Disconnected the bat (-) while I finished swapping out the steering pump.
Reconnected and she fired up with no hesitation.

In reading up on the CPS I'm sure it's the issue.
Over the last month or 2, I've had some times high idle ~ some times low
My voltage gauge is reading consistently low (just put in new bat & high output apt) & tested it with multimeter and at the parts store as good
And the recent few no start issues...

Worst case, I'll swap it out and simply have a new CPS and rule that out.
~ though it looks like a PITA to swap!

Thanks all for pointing me in the right direction

[Infidel Edition]

Dumb question...
I can see the CPS from under and I have swivel extenders and every thing I need to get it off

But as I can't reach up there to grab it, how do I get it back into position to install it properly?

Chaa Whaaat?

[F1Addict]

The CPS is aligned by the mounting bolts so it's difficult to put it in wrong, just be careful and don't drop the bolts into the bell housing, they're a PITA to get out.

Also, I've found that of you go in feet first from the driver's side it puts you in a much better position to reach the CPS with your left arm but I've got fairly skinny arms so it may not work with everybody.

[XJ Wheeler]

I found it made a huge difference to disconnect the front driveshaft from the axle, its just four bolts and its so much easier. Make sure the u-joints caps don't come off and just tilt it out of the way.

Then i reached up between the axle and trans crossmember to figure out the best assortment of extensions/socket.

Sent via messenger pigeon - i talk, he types.

[Mudderoy]

I found it made a huge difference to disconnect the front driveshaft from the axle, its just four bolts and its so much easier. Make sure the u-joints caps don't come off and just tilt it out of the way.

Then i reached up between the axle and trans crossmember to figure out the best assortment of extensions/socket.

Sent via messenger pigeon - i talk, he types.

Mark the yoke and the drive shaft so you put it back the same way. You can introduce vibrations into the drive line sometimes, just depends on the balance.

[Infidel Edition]

The CPS is aligned by the mounting bolts so it's difficult to put it in wrong, just be careful and don't drop the bolts into the bell housing, they're a PITA to get out.

Also, I've found that of you go in feet first from the driver's side it puts you in a much better position to reach the CPS with your left arm but I've got fairly skinny arms so it may not work with everybody.

Once I went feet 1st... Piece of cake.
I could wiggle my left hand up and into position (couldn't see it... but could feel it)
And a 12" swivel extender to a 6" swivel.
**had to use the 1/2 driver because I couldn't get 1 handed leverage with the little driver...
And it took like 20 min.

Not sure if an automatic would be more PITA, but I could see getting the drive line out of the way to make room.
BUT AS NOTED, "feet first" is the key.

[Infidel Edition]

...didn't resolve my voltage meter error...
Gonna keep digging to find my short and I'm betting that'll resolve other issues too.

Idles smother and starts consistent (same day trials)