Rustydog555

Starts cold idles fine will restart over and over idling in drive way but take her for a drive and it takes starting fluid to restart
Have replaced idle air control, CPS and tps cleaned throttle body refreshed grounds have good fule presser while running at start up and doesn't leek down when shut off
It stumbles when trying to restart like its flooded but that doesnt seem right if it takes starting fulid to start.
Could the 02 sensor be causing this?
She has got me stumped any help or other angle to look at

tjwalker

Have you verified fuel pressure with a fuel pressure GAUGE? No shortcuts allowed.

For a RENIX, you should have 31 psi at idle. Then disconnect the vacuum line leading to the fuel pressure regulator (be sure the vacuum line leading to the FPR is pulling good vacuum) and the pressure should jump to approximately 39 psi.

If fuel pressure checks out, I would start suspecting engine management sensors like the coolant temp sensor and the map sensor. How many miles on your oxygen sensor? If over 80k, I'd install a new one they have a finite lifespan. Bosch is a good choice for oxygen sensors for Renix engines. I don't think the oxygen sensor is the root cause of your issue though.

Here is a link to testing many things RENIX. Just need a meter and the ability to use it. Start testing sensors one at a time. It often is a process of elimination.

Good luck!

http://www.lunghd.com/Tech_Articles/...iagnostics.htm

highmileage

EGR could be stuck in the open (either the valve itself or the solinoid), or MAP sensor. But a good run through on the sensors wouldn't be a bad idea.

Rustydog555

Yes with a fuel presser gauge
Got that link and have been testing sensors
Not sure about the 02 but question if it would cause the hot restart problem
Coolant temp and intake air are also on my hit list but seem to test ok

Rustydog555

Na egr closed and eliminated

highmileage

Could be in your dizzy, or coil? Where's Cruiser, this is up his alley?

Rustydog555

Have checked dizzy is indexed to #1 and have fire at no start
The need for starting fluid makes me think the injectors aren't firing

DFlintstone

Since I have baby alligator clips on my meter, I can verify I have over .35 ACV from my unplugged cps cranking in less than three minutes.

RRRR Quick start does it. It DOES happen that a weak spark will fire one mix, and not another. I might also check for a crisp blue spark when it's not starting.

Not to disagree with the above! U get a squirt from that schrader valve when it won't start?

Not the 02. Highly doubt it.

Floorboarded, it will cut fuel to the injectors cranking. You might try that.

Rustydog555

This was helping which led me to think its flooded
Even thought an injector was leaking

DFlintstone

The stock injectors on the 87-90 are without question, crap. Yea. I guess they programed the ECU to cut the fuel floorboarded, (Max air), to help start when flooded. Just a guess. I wouldn't EXPECT quick start would help there though. Maybe the ether ignites, where over rich won't ????Doubt it! You can always unplug your pump power from the back of the resistor, or pull the second relay and see if cutting the fuel pump power causes it to fire for a second.

cruiser54

How long does the fuel rail hold pressure?

Will it start on it's own after a period of time if you cycle the key on and off, priming the system before actually turning the key to Start?

And yes, those injectors are junk. Upgrade. Programbo here on CF has them.

Rustydog555

Holds 31lb for at least 30 min
Injectors were replaced when I swapped motors I know I didn't know about the 4 hole upgrade at the time but I know they were for a newer 4.0 HO
I have no idea if that's good or bad but is been running on them for 4 years

First off got wet ran 6 hours died got towed home
Replaced cps cuz no spark
my coil brain(under coil) and dizzy all worked on my known running test jeep and the new CPS old CPS and the one I got from junkyard all worked on buddy's jeep
Replaced the ecm with one from 89 as per cruiser
Jeep started yea
Course is starts running like crap and stalling then the hot hard start so I did the basic tun up plugs wires cap rotor
I cleaned all the connections (there all dielectric greased from the get go but dirty joust the same) checked temp sending units
Cleaned all the grounds bat, dipstick, firewall
Tuned the tps and she starts and idles good was cycling a little but cleaning grounds and vacuum helped
Just once she is hot not over heating just good n hot it takes starting fluid holding it to the floor and quite a bit of cranking but once she starts all good runs fine
Turn off let sit hour or so starts Ritchie up

cruiser54

Check the vacuum hose from your throttle body to MAP sensor. No kinks, splits, melted spots, loose connections etc.

Have you ever done my sensor ground test BTW?

Rustydog555

Yes but am going back through all the grounds and connections some of my plugs were old n brittle
Gonna pull the engine harness and redo the grounds or at least check em over again
Gonna get my hands on a good volt ohm meter the cheep $9 digital is now telling me I got 16.5 volts at the batt and a 9v I checked got 13v
Gonna put everything back together and see if adj the tps with a good meter helps

Rustydog555

So now I get no volts on b leg to tps good ground and good volts on A but nothing on b
Going to get a new tps