New 4.6 Stroker Dies When Clutch Engaged - Help!

Performance mods and Advanced Stroker discussion.
retro
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New 4.6 Stroker Dies When Clutch Engaged - Help!

Post by retro »

Appreciate all the information this site has provided me, and encouraged me to build a 4.6L stroker! However after about 450 miles I started experiencing an issue that I have been unable to resolve. Most of my build was guided through information I gleaned from this site, Dino's writings and Russ Pottenger. Almost all of my build parts were sourced through Russ and designed to run off the 99 4.0 fuel injection system I have. He and I have talked quite a bit about the problem below and I appreciate all of his help to date…he has been awesome to work with!

The issue I have is when I depress the clutch to shift out of 2-5 gear, the engine will die almost immediately….acts like I switched the jeep off. At times I have been able to hit the accelerator with it in neutral and get it to stay running, although most times it will still die. I can start it back up right away and continue to drive. It does not do this when in 1rst gear, and only about half the time when in second…..second gear is where I can usually catch it and keep it from dying by hitting the gas pedal. Once in a while it will stay running if in one of the higher gears (3-5), but this is only about 1-3% of the time. After starting the engine again it will stay running even if I shift back into gear and then depress the clutch again to unload the engine from the transmission. It will do this regardless of the amount of acceleration prior to depressing the clutch or if I am coasting beforehand. It has been very frustrating and results in having to start the engine back up after every stop or if I am slowing down to prepare to stop at a light. Again, the mechanism the seems to trigger this issue is depressing the clutch and taking load off the engine this way…..shifting in and out of gear has no correlation.

Build and history: #2 piston skirt came apart in my 99 4.0. Was tempted to 5.3 swap, but wanted to keep it "pure"….besides never messed with a Jeep/Chrysler engine before. The 4.0 engine was "retrofitted" in my 1990 YJ by the prior owner, and was not running well when I bought it….turned out to be a combination of poor wiring practices and a bad crank sensor. The engine is mated to the 1990 AX15 that was in the jeep originally.

Engine build:
• Forged rods, pistons, rings, pump, lifters, timing chain, etc. from Russ.
○ Racetech pistons, dished 26cc's
• Crank is out of a 86 4.2
• Quench set at 0.038"
• Machine work done at my local race shop, Watson-Ruppel and included: rotating assembly balance, 0.030 bore, decking of heads and block, 3 angle valve job and blending, grinding & polish crank, machine spring seats so they were all the same height from the deck, clean and mag block and head (no cracks), install new cam bearings and hone/fit cam…..I am sure I am forgetting a few details at the moment but it was thorough work.
○ Crank centerline to deck = 9.450"
○ Piston deck height = 9.457"
○ Mahle head gasket, 0.40" compressed thickness
○ Quench 0.033" (if my math is right)
○ Is my quench too tight???
• I ported and polished the head including polishing the chambers. Watson-Ruppel touched up a few things and cc'd the head, but the comment was the work was done very well and they didn't really have much to add to improve (luck on my part). Intake slight work to port matched to the heads.
○ Stock valves (I know, I should have went to the larger valves…..big regret lol).
○ Chambers range: 59.8 - 60.6cc (60.2cc average)
○ 26cc dish, 60.6cc chamber, 2.14cc head gasket volume (accounting for piston 0.007" above deck), should be 9.2:1 static CR (again if my math is right).
• Cam was bought from Russ and is a Comp, ground to Russ's specs (see attachment) and nitride surface treated. Harland-Sharp 1.6 rockers from Russ as well.
• New pushrods from Jegs…I cannot recall the exact length but have it written down if someone needs that info to help.
• BBK 62MM throttle body
• McCleod streetpro clutch
• Crank sensor is 3 years old and Mopar brand, less than 15,000 miles on it.
• New Bosch O2 sensor….I am running the upper one only. This is how it was prior to the build and ran fine.
• New intake air sensor…I broke the old one by accident during engine removal.
• Injectors are 24# from fuel injection connection (via Russ).
• NGK Coil Rail
• NGK plugs: ZFR6F (see pics attached, I just pulled them).
○ Not quite sure what to make of them….the markings on the insulator make me think detonation, but I have not had any noise or other anomalies that would indicate that. Have run everything from 93 octane to 87 octane without an apparent issue. No apparent change in performance from either.
○ Also not sure what the deal is with the electrode having that little shelf on the one side.
• Banks Revovler header into 3" stainless welded exhaust, 2.5" Magnaflow muffler and 2.5" tailpipe.
• Flowcooler water pump & new AL radiator.

Things I have checked:
• Fuel pressure 49 - 50# at idle, decreases under hard acceleration to 44-46#, right back up as soon as I let off the accelerator.
• IAC is newer and has the correct amount of supply voltage according to the manual I have.
• TPS checks-out within the range given in my manual.
• MAP has correct supply voltage according to the manual and there do not appear to be any cracks in the boot.
• Fuel injectors all have the correct resistance according to the manual.
• Vacuum at idle is 16-17 inches
• Engine very briefly hesitates when the throttle is rapidly opened, but otherwise runs great at idle, under load and acceleration. Not sure if that brief hesitation is related somehow or not.

Regarding how the fuel injection system is retro'd in the older jeep:
• Fuel pump is electric in-tank and controlled via the ECM and relay.
• Crank & cam sensors are plugged in and function as they did in the 99 vehicle
• Only the upper O2 sensor is installed. I read the lower is only really for emissions.
• Temp sensor installed in the water neck as stock.
• No changes or alterations to those on the throttle body and the intake air temp sensor.

I appreciate any and all thoughts, suggestions and comments. I have run out of ideas on what is going and hope this community can help me resolve so I can enjoy this Jeep/motor. Everything else I have ever owned, modded & played with was GM so this has been a bit of a learning curve….I am weak when it comes to the Jeep/Chrysler ECM logic and programming. I have a whole pile of other improvements I am tripping over as I need to get this fixed before I move on with the rest of the work!
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Re: New 4.6 Stroker Dies When Clutch Engaged - Help!

Post by Cheromaniac »

The 0.033" quench is fine and I also have the static CR at 9.2:1.
The hesitation and random stalling suggest there's a lean air/fuel mixture. Are you still running the original Remix ECU? If so you don't have any scope for adjusting the part throttle fuel curve. You mentioned 24lb injectors but which ones are they?
1992 XJ 4.6 I6 - 5MT - Stroker build-up, Stroker "recipes" Sold
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Re: New 4.6 Stroker Dies When Clutch Engaged - Help!

Post by Torqsplit »

How do you have the speedo connected with your setup, electric sensor or old style mechanical/cable? Reason for asking is that, oddly enough, the speed-sensor is what activates the IAC to open as you slow down. If i unhook mine for any reason, or if the sensor is dying (rare), it will fall flat on its face between gears or coming to a stop. Without a speed-sensor input, I dont know where it's pulling that info on your setup? Basically the iac can handle it when starting and when already at idle, but once underway & under throttle the iac closes fully. It only re-opens to catch the engine when coming down to idle speeds again. So maybe it's not getting the signal it needs from the speed-sensor, or it needs some help with the airflow demand. Part of the issue is that the airflow thru the small passageway in the IAC circuit is very small and doesn't always adjust itself enough to compensate for the bigger engine's airflow needs. I see you have a fairly new IAC motor with appropriate voltage showing. When i put my 68mm TB on i had similar troubles. I found that the iac has the range it needs to manage idle, but it can't respond quickly enough to go from full closed to possibly almost full-open in time to catch the engine before it stalls. If you're BBK TB came "pre-adjusted", you MAY have to do the no-no of "very slightly" adjusting the idle-stop screw for the throttle valve to open it just a hair further. **You'll have to disconnect the battery and force it thru another learning cycle to have this work properly. The idle might run wild if you dont!** Verify your speedo setup 1st, cause that sounds more like the culprit to me at this point. I wouldn't mess with the TB until last. Maybe even shoot some Throttle body cleaner thru it if you haven't already, just to be sure it's not hanging. Hope this helps you narrow it down 👍
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Re: New 4.6 Stroker Dies When Clutch Engaged - Help!

Post by retro »

Cheromaniac wrote: July 10th, 2022, 11:52 pm The 0.033" quench is fine and I also have the static CR at 9.2:1.
The hesitation and random stalling suggest there's a lean air/fuel mixture. Are you still running the original Remix ECU? If so you don't have any scope for adjusting the part throttle fuel curve. You mentioned 24lb injectors but which ones are they?

The ECU is the one that came out of a 99 Jeep Grand Cherokee, which is the donor vehicle for the engine I was told by the prior owner. I checked the numbers on the block and it checks out to a 99 model, so I am assuming it is the same year. It is definitely not the older OBD1 system, but OBD2. I can see about pulling numbers off of the ECU if you can give me a bit of guidance on what to look for.

I'll check the numbers on the injectors...and get back on that.

Sorry been busy with work and finally had a moment to check the post....appreciate your interest and reply!
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Re: New 4.6 Stroker Dies When Clutch Engaged - Help!

Post by retro »

Torqsplit wrote: July 11th, 2022, 7:30 pm How do you have the speedo connected with your setup, electric sensor or old style mechanical/cable? Reason for asking is that, oddly enough, the speed-sensor is what activates the IAC to open as you slow down. If i unhook mine for any reason, or if the sensor is dying (rare), it will fall flat on its face between gears or coming to a stop. Without a speed-sensor input, I dont know where it's pulling that info on your setup? Basically the iac can handle it when starting and when already at idle, but once underway & under throttle the iac closes fully. It only re-opens to catch the engine when coming down to idle speeds again. So maybe it's not getting the signal it needs from the speed-sensor, or it needs some help with the airflow demand. Part of the issue is that the airflow thru the small passageway in the IAC circuit is very small and doesn't always adjust itself enough to compensate for the bigger engine's airflow needs. I see you have a fairly new IAC motor with appropriate voltage showing. When i put my 68mm TB on i had similar troubles. I found that the iac has the range it needs to manage idle, but it can't respond quickly enough to go from full closed to possibly almost full-open in time to catch the engine before it stalls. If you're BBK TB came "pre-adjusted", you MAY have to do the no-no of "very slightly" adjusting the idle-stop screw for the throttle valve to open it just a hair further. **You'll have to disconnect the battery and force it thru another learning cycle to have this work properly. The idle might run wild if you dont!** Verify your speedo setup 1st, cause that sounds more like the culprit to me at this point. I wouldn't mess with the TB until last. Maybe even shoot some Throttle body cleaner thru it if you haven't already, just to be sure it's not hanging. Hope this helps you narrow it down 👍
Old style with a cable. I have a new Glowshift speedo with an electronic adapter from them but not installed. Either way it doesn't give a VSS signal. I have wondered about this myself, and the IAC issue you discussed above...just wasn't sure where to go with it next.

The 4.0 ran fine before without the VSS before I pulled it to make the stroker from it...no issues at all, but maybe with the stroker things are lean enough that it matters now or the smaller stock throttle body had an effect on the IAC being able to compensate??

I would be happy to plug a VSS in somewhere, but not sure where/how to do that. I know there is a sensor in the pumpkin on the 8.8 I have to go in it...not sure if that would work as a location? Thoughts?

I have verified the IAC passages are clean.

I appreciate your thoughts and feedback....this reinforces some suspicions I had, but again, not sure where to go from here.....
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Re: New 4.6 Stroker Dies When Clutch Engaged - Help!

Post by retro »

Injectors are #0 280 155 784. Do you believe they are adequate or should they be larger/smaller? May be difficult to assess with out more data?

On the VSS, saw a few posts on other boards where guys with newer jeeps had similar issues to mine when their VSS went bad.

I looked and it appears as though I could use a SYE for a 95 or newer AX15 as it will have the boss machined in that new tail-housing for the VSS. From there I could plug the VSS into the wiring harness and splice into the signal wire for my new electronic speedo?

I would like to try this theory out first though before trying to return my SYE for the 1990 AX15 I have (for mechanical speedo). I have a mechanical to electronic adapter I bought from Glowshift to make the new electronic speedo work. Pic of it below. I was thinking, since I cannot return it, maybe I go ahead and connect it to the existing tail-housing, use their plug, then retro the three wires into the factory plug/harness. The green wire according to Glowshift is the signal wire, which I found some data that states the wht/orange wire on the harness (going to pin-47 on the ecm) is used by the ECM for VSS signal. Does this sound right and would the device below be able to do that? I am not 100% sure I got the right adapter, GM 16 pulse...it was an educated guess.
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I6FAN
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Re: New 4.6 Stroker Dies When Clutch Engaged - Help!

Post by I6FAN »

The ECU is the one that came out of a 99 Jeep Grand Cherokee, which is the donor vehicle for the engine I was told by the prior owner. I checked the numbers on the block and it checks out to a 99 model, so I am assuming it is the same year. It is definitely not the older OBD1 system, but OBD2. I can see about pulling numbers off of the ECU if you can give me a bit of guidance on what to look for.
Being that this is a retrofit, it would be useful to verify the correct ECU; there is a difference between ECU's equipped with automatics and manuals I believe. If I recall it does do something to how the engine is controlled during deceleration or something. it'd be worth verifying as the previous owner had issues, he could have swapped ECU's or something.

Don't overlook the basics. I knew a guy (me, lol) who threw tons of money on an intermittent engine stumbling/cut-out, convinced that it was EEC related. Turned out to be a pin-hole burned through the rotor that was intermittently shorting on the distributor shaft at a certain rpm. It was the last thing I checked, and should have been among the first.

Good luck my friend, hope you get it sorted out to enjoy!
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Re: New 4.6 Stroker Dies When Clutch Engaged - Help!

Post by Torqsplit »

Looks like you have everything you need to make this work. I6fan is right-on with the Auto vs Manual ECU, as 99 grand Cherokees didn't have a manual option. That may be a wild-card for you in all this. Def verify the easy stuff 1st too. You mention the VSS being on the transmission, is your jeep 2wd? I've seen a few xj's that way, never knew if made YJ's like that. Doesn't really matter, just curious. Most are mounted in the transfer case. The OBD1 sensors are essentially the same as your adapter. They work with a gear in the housing and were adapted from the older mechanical style, but drop right in the housing. $20-$30 on rockauto if you ever need a replacement 👍 Later styles use a reluctor ring, like in your 8.8. I can't verify the wiring colors for you, but sounds right for the signal wire having a tracer mark on it. Mine's the old style w/ only 2-wires. They updated to 3-wire connectors later, like what you have there. Good luck, & hope it all sorts out for ya! Oh,btw. If you get all that hooked up, it may take the ecu a little while to re-learn with that new input. 1st couple drives might still do funny. 🍻
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Re: New 4.6 Stroker Dies When Clutch Engaged - Help!

Post by retro »

Thanks for the input. Sorry I haven't responded yet, I was hiking in Utah with my wife and trying to unplug!

First question, how do I confirm which ECU I have? Is there serial numbers or something like that I can gather off of it and post here to determine? The guy told me it came out of a grand cherokee, but it may have been a regular cherokee....not sure if they had manual transmissions?

Also I need to clarify, there is no VSS on the transmission...the transmission is the original AX15 that came in my 1990 YJ. It has a manual speedo with the mount in the transfer case tail-shaft as you noted. I have the glowshift adapter to go from the manual speedo to the new electronic glowshift gauge.

So to be clear, will the three wire adapter from glowshift work to provide a speed signal to the ECU if I grab the right wire on the VSS plug off the ECU harness? I follow you on the OBD1 versus OBD2 sensor, just clarifying if the setup I proposed would work for OBD2.
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Re: New 4.6 Stroker Dies When Clutch Engaged - Help!

Post by retro »

Also, one follow-up question just out of curiosity.....why did the engine (pre rebuild/stroked) not die like this even though the speed sensor was not hooked up/in place then? Not arguing the theory that it is related to the absence of the speed sensor, just my curiosity as to what the stroker build changed that caused it not to work.
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Re: New 4.6 Stroker Dies When Clutch Engaged - Help!

Post by retro »

I6FAN wrote: July 15th, 2022, 2:16 pm
The ECU is the one that came out of a 99 Jeep Grand Cherokee, which is the donor vehicle for the engine I was told by the prior owner. I checked the numbers on the block and it checks out to a 99 model, so I am assuming it is the same year. It is definitely not the older OBD1 system, but OBD2. I can see about pulling numbers off of the ECU if you can give me a bit of guidance on what to look for.
Being that this is a retrofit, it would be useful to verify the correct ECU; there is a difference between ECU's equipped with automatics and manuals I believe. If I recall it does do something to how the engine is controlled during deceleration or something. it'd be worth verifying as the previous owner had issues, he could have swapped ECU's or something.

Don't overlook the basics. I knew a guy (me, lol) who threw tons of money on an intermittent engine stumbling/cut-out, convinced that it was EEC related. Turned out to be a pin-hole burned through the rotor that was intermittently shorting on the distributor shaft at a certain rpm. It was the last thing I checked, and should have been among the first.

Good luck my friend, hope you get it sorted out to enjoy!
Thanks for the input…I replied with a few questions below but you are right, need to sort out which ECU it is. Picture attached from the ECU. Are you able to decide those numbers and tell what this engine really came out of??
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I6FAN
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Re: New 4.6 Stroker Dies When Clutch Engaged - Help!

Post by I6FAN »

That PN P56041 652AE is showing: 2000 Jeep Wrangler 4.0L 6-242 Mt Electronic Control Module P56041 652Ae

Like Torqsplit mentioned 1999-2004 Jeep GC did not come equipped with a manual option.

I don't know if that ECM you have is for manual Wrangler (intuitively seems likely with Mt in description(?)).

I found this youtube video informative. They are swapping to manual transmission in a GC. That's essentially what you're doing with the exception of the type of vehicle you've transplanted it into. 2000 Jeep Wrangler 4.0L 6-242 Mt Elect ... 6041 652Ae

You might find other videos and such. Did you search this site, as I think I've seen something similar to this before?
I6FAN
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Re: New 4.6 Stroker Dies When Clutch Engaged - Help!

Post by I6FAN »

I posted the wrong url, should be https://www.youtube.com/watch?v=h138NSGFI7o
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Re: New 4.6 Stroker Dies When Clutch Engaged - Help!

Post by retro »

Thanks, I'll check it out. When I tried googling that part number everything that I could find came up with a 2000 wrangler, 4.0 with manual transmission. I am now wondering if the engine actually came out of an early production year 2000 wrangler (99 block, 2000 ECU).....the young man that sold me the wrangler I am not convinced was sure of the swap....someone else had helped him.

I am currently sorting through the wiring based on the pin out drawings for a 2000 wrangler, searching for the signal wire to the ECU.

Does the 16 pulse mech to electronic glowshift adapter correspond correctly to the 2000 wrangler speed sensor signal type that would be delivered if using the original speed sensor for a 2000 TJ, 5 speed manual?
I6FAN
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Re: New 4.6 Stroker Dies When Clutch Engaged - Help!

Post by I6FAN »

Can you confirm the block casting?

From FAQ on this site:
53010449AA : 1999-2001 XJ, 1999 TJ
53010327AB, 53010328AB: 1999-2004 WJ & 2000-2006 TJ

You were told it was a 99 WJ, but it's looking like you have a 2000 TJ ECM and possibly a TJ engine as well. Also, these were pivotal years as TJ's changed from the AX15 for 1999 to the NV3550 for 2000. If you narrow down exactly what you have, hopefully, that'll help figure this out further.
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