Baffling no-start on new stroker

Performance mods and Advanced Stroker discussion.
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OneOverZero
Posts: 1
Joined: July 23rd, 2012, 4:29 pm
Vehicle Year: 1990
Vehicle Make: Jeep
Vehicle Model: Comanche

Baffling no-start on new stroker

Post by OneOverZero »

Hi all,

I've recently wrapped up a stroker for a 1994 XJ and am completely at a loss as to why it won't start. It cranks, fuels, and sparks, but won't even pretend to fire - sounds like a classic timing issue, but I could use some input! Unfortunately, I've moved 2800mi in the meantime, but a trusted friend has it for the time being, and we're both stumped now.

Relevant details:
  • 1994 XJ, AW4
  • 1994 block/head/flexplate with ~560k (the only items reused)
  • Icon 944 +0.020" pistons on resized OEM rods
  • Scat crank
  • CompCams 232 (I think - don't have the order form in front of me)
  • New Bosch injectors
  • Champion RC9YC4s gapped to 0.035"
Things I've done in the meantime:
Ignition
  • Confirmed timing (rotor is just past 5 o'clock with #1 at TDC on compression stroke, confirmed with old cut-down cap)
  • New coil & wires; each plug sparks beautifully
  • Confirmed that the distributor drive gear isn't pinned 180deg out
  • New cap and rotor...
  • ...and when that didn't work, threw in a new distributor altogether to eliminate the possibility of a bad pickup
  • ...and when none of that worked, a new computer!
  • Checked NSS and swapped out CPS, but since the engine cranks/sparks/fuels, no surprise there.
Electrical
  • TPS voltage endpoints test out fine.
  • Cleaned, reseated, and OxGarded all grounds; added additional grounds for redundancy; checked resistance across all of 'em
    Fuel
  • Threw new O-rings on FPR and confirmed appropriate rail pressure
  • Threw OE injectors back in out of desperation
  • Confirmed that all injectors are pulsing and providing fuel
Mechanical
  • Trusted machine shop built the shortblock, but I've confirmed that #1 is at TDC with valves closed when the balancer mark is at 0deg.
  • There's no way the flexplate can be misassembled... right? Bolt spacing is asymmetric and the CPS output appears to be registering with the ECU.
  • Flexplate is absolutely the original one as my others are all manual flywheels.
  • All vacuum lines are present and intact.
What incredibly simple error am I missing here? I'd rather not pay to get this thing shipped from NC to Seattle, but I'm out of brainpower. My Renix and OBDII COP knowledge is irrelevant here.

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Mike B
Making Progress
Making Progress
Posts: 65
Joined: September 15th, 2019, 11:05 am
Stroker Displacement: 4.7L
Vehicle Year: 1995
Vehicle Make: Jeep
Vehicle Model: Xj

Re: Baffling no-start on new stroker

Post by Mike B »

I'd recommend confirming that you are on compression stroke for cyl #1 by using a compression tester while cranking the engine over by hand. I just finished my build for my 95 xj and had a crank but no start situation. I verified by looking at the rocker arms, both appeared to be closed, but I was in between each phase. At that point, I checked everything else first, fuel, spark, compression, double checked timing of the distributor and I had nothing, not even an attempt to start. I guarantee that you're 180° off with your distributor, so put the compression tester on and double check that, then look back at your rotor to see when it ends up, probably will be at 11 o'clock like mine ended up. It was a humbling experience, but im glad it was simple solution rather than having the camshaft timing completely scrouged up.
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Cheromaniac
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Posts: 3180
Joined: March 8th, 2008, 12:58 pm
Stroker Displacement: 4563cc
Vehicle Year: 1992
Vehicle Make: Jeep
Vehicle Model: Cherokee
Location: Cyprus
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Re: Baffling no-start on new stroker

Post by Cheromaniac »

The first thought that came into my head was that the distributor is off 180*.
1992 XJ 4.6 I6 - 5MT - Stroker build-up, Stroker "recipes" Sold
1995 Mustang GT - 4AT - Modded Sold
2006 Mustang GT - 5MT - Modded Midlife Crisis Car :mrgreen:
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