Renix no start after HO engine install then fire

Jeez what a mess. after about 4 weeks of searching and diagnosing i'll post this hoopla.
Pulled jeep into garage because it ran like crap, thought engine was blown, 200K total miles on the 87 with about 60K of pure high revving offroad shenanigans. Put HO motor in with 77K miles (verified) new distributor, fuel pump, cps, o2, plug wires… Go to start and right as it fires up everything under the hood (driver side) burst into flames. Open header + leaky fuel line = poop in pants.
Lets see if I can remember it all,
Wire loom going to c101 is not burnt but when I opened it (c101) up all the connections looked like it had some 10 year old dirty electric grease all over em. Had no electric cleaner handy so I just plugged it back in as the jeep ran before with it.
New optima yellow top with 12.36 volts:
Solder the cps wires that were burnt (the harness side going to computer), no start…
Put old cps back in still no start. The reading is very incosistant. When putting two different ohmmeters set to 200 ohms it gives me all sorts of readings from 34-230 no pattern in readings.

Spark is clean and white
Plugs got a little wet with fuel after a bunch of cranking, although the fuel rail nipple spit out very little fuel. But the jeep ran with the new fuel pump and you can hear it prime.
Just under 4 volts at the camshaft position sensor.
Just under 5 volts at the tps.
Havent tested the coil but I’m getting good spark so…
Starter solenoid next to battery is getting voltage but I forget how much.


App:
87 cherokee with a 99 ho engine and all renix intake and electronics hooked up to it accept for the temp gauge sensor (I haven’t tapped into the thermo housing yet) But the connectors at the temp sensor in the block got very burnt, to the point where I can’t even disco the temp sensor from the wire harness connector. I just left it connected as I don’t think the temp sensor would effect the startability.

The fire was mild and I put it out very quickly aside from the rag that was sitting on my battery that caught on fire so I threw it over my shoulders when everything was flaming up only for it to land on a 32 gallon trash bag filled with empty oil bottles and such. Then I had a giant ball of burning trash in my garage, I of curse had to pick this ball of inferno up with my bare hands to carry it out to the street to keep it from burning my apts down. Aint lifes screw ups grand.

Help please

Sorry to hear about your fire issue. Coulda been way worse though. Clean the C101 really good with electical cleaner. . The CPS signal runs through there, along with other important stuff, if you haven't had the factory CPS mod done. Grounds clean and tight, no paint, at dipstick tube mount? Ground strap from back of head to firewall installed with paint scraped off under bolt at firewall?

"App:
87 cherokee with a 99 ho engine and all renix intake and electronics hooked up to it accept for the temp gauge sensor (I haven’t tapped into the thermo housing yet) But the connectors at the temp sensor in the block got very burnt, to the point where I can’t even disco the temp sensor from the wire harness connector. I just left it connected as I don’t think the temp sensor would effect the startability.-----"

If I understand what your saying--the highlighted print, above--the temp sensor input to the ECM is missing? Very important for fuel management, especially at cold start up. You say "temp gauge" sensor, but I believe the sensor near the rear of the block is the gauge sensor, and the one on the thermo housing is for the ECM.

thoughts, (guesses)

-CPS wiring shorted during.. took out a fuse or 5 volt (?)supply to sensor?
-heat weakened connection to CPS or flowed plastic into pins? (bad or intermittent connection)
-took out a relay, fuse?
-below area-O2 and wiring?
-battery volts staying up during crank?
-fix leak! try again with about 1/8-1/4 throttle while cranking.

--Good Luck--

cruiser54 said:

Sorry to hear about your fire issue. Coulda been way worse though. Clean the C101 really good with electical cleaner. . The CPS signal runs through there, along with other important stuff, if you haven't had the factory CPS mod done. Grounds clean and tight, no paint, at dipstick tube mount? Ground strap from back of head to firewall installed with paint scraped off under bolt at firewall?

Click to expand...

Whats the factory cps mod? bending it closer to the flywheel? I've tried a new cps and the old one. Grounds are all good with VERY thick welding wire used for all cables. Their John Kelley's cables.

The leak was fixed

sends around 4 volts to the cps when cranking

bubba i was referring to the temp sender that sends the temp to the guage cluster. I was planning on incorporating that into the thermo housing as the 99 cyl head i have has no hole tapped for this as my 87 did. The temp sender that pulses the injectors is in the block, the connecter to that is quite melted. I'm going to pick up a new block temp sensor and solder a new wire harness side connecter to the female end.

cps plastice wire connectors are fine and un-burnt, o2 sensor connecters are fine and un-burnt, knock sensor connecter and the temp sensor next to it are the only two connecters that got burnt. A couple injector connecters at the wire harness side had some heat damage, the wire's going into them look ok but a couple of the connecters have some slight meltage, very little.

Won't start.

You have consistent spark--CPS/CKP is good, B Latch relay is good.

So, cranks, spark, a**uming compression. Missing element--air/fuel mixture?

Grab a NOID light and check for an injector pulse; grab a fuel pressure gauge and check the pressure; pull a couple spark plugs and see if they are wet; hold the throttle to the floor and then crank the engine to see if it is flooded.

CPS mod was a factory TSB running the CPS wiring right to the ECM, bypassing the C101 connector.

Has it ran, at all, with new engine and parts?

-thinking of distributor 180* out.

(TDC,153624 CW) (#1 @ 5 o'clock viewed from passenger side looking in on HO)

oops! never mind re-read OP.

The volts to the cps really shouldn't drop when cranking, since it is regulated down from the 12v by the ECU unless the battery voltage when cranking is low. I would try and charge the battery. I've had multiple problems with Renix not starting even though the engine turned over well due to the addition of big cables.

CPS generates it's own voltage.

Did you use a fire extinguisher? What type? I've heard/ seen it happen before. The powder gets sucked in and since it kills the oxygen in the air maybe you have the stuff in the cylinders causing it? Or it has fouled a sensor. Long shot, but it could happen...