3.6 Engine - Now I understand the power issue

[ShadowsPapa]

And lubrication is the exact issue with them.
Not sure if it is metallurgy or something else, but CP4 pumps installed in Chevys and Fords mostly failed the scar test when examined. 15ppm sulfur is not enough to provide sufficient lubrication. The diesel shops (3ea.) near me had shelves of CP4s they pulled due to issues, mainly in the Chevrolet and Ford platforms. In the Duramax community, the -4 pumps do not have a good reputation at all.
I added a quart of automatic transmission fluid to each fill-up, and I also strained and poured oil from the recent oil changes into the fuel tank. I drove my Duramax for a little over 10 years but most of the time it had a CP3 pump doing the heavy lifting.

Sulfur isn't necessary - EU has a much lower sulfur content by law and has for quite a while. However, they do require it lubricate via other means.

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[biodiesel]

The aftermarket has been fitting 5.7s, 6.4s, hellcat 6.2s, LT4s, and even 1100hp hellephants in that same engine bay. Even Stellantis fits the 392 in the same bay in the JL. It's not a size limitation period. You can easily fit 2 times the displacement and 4 times the power with ease.

That's true, but Jeep initially said the reason why they didn't offer a V8 in the Wrangler/Gladiator was due to space limitations. One of the concerns was passing the crash safety test. Perhaps Jeep was making excuses since they found a way to make the 392 work.

 

[Lost1wing]

Keep using a fuel additive and the CP4 pump will last a very long time. They have been shown to last 900,000+ miles with proper lubrication.

I wish it worked like that. Plenty of horror stories about those that use additives still end up with failed cp4s. I can't say I religiously use an additive, but I can say that I fill my fuel filter with it. I believe, never run low on fuel and be sure to prime the filter head after a filter change. One bad batch of fuel is almost a sure way to cause early cp4 failures and that is out of our control. Even at a reputable station.

 

[biodiesel]

I wish it worked like that. Plenty of horror stories about those that use additives still end up with failed cp4s. I can't say I religiously use an additive, but I can say that I fill my fuel filter with it. I believe, never run low on fuel and be sure to prime the filter head after a filter change. One bad batch of fuel is almost a sure way to cause early cp4 failures and that is out of our control. Even at a reputable station.

I think the horror stories are mostly on the GM and Fords. The EcoDiesel got the Bosch wear package (best in class). We have lots of EcoDiesel guys on the forum/facebook groups with 300,000+ miles without any CP4 pump failures. It's fairly rare to hear of a CP4 pump failure on the Ram 1500 diesel forum. Lubricity is the biggest issue. CP4 pumps don't fail in Europe.

 

[OldButStillJeeping]

I'll be the odd man out; I think the 3.6 is a good engine for the JT.

It's a small Jeep truck. If you want a full size 1/2 ton buy a Ford F150, RAM or GMC/Chevy 1500.

So many folks are pushing these little trucks to the limit. And then complaining.

If you want a V8 1/2 ton, RAM and GMC have them. If you want a turbo V6, Ford has the ecobooms.

Be well. Jeep on.

Eric

 

[biodiesel]

I'll be the odd man out; I think the 3.6 is a good engine for the JT.

I agree with you. Generally speaking, the Pentastar is a reliable long-lasting engine.

 

[Stan H]

I wish it worked like that. Plenty of horror stories about those that use additives still end up with failed cp4s. I can't say I religiously use an additive, but I can say that I fill my fuel filter with it. I believe, never run low on fuel and be sure to prime the filter head after a filter change. One bad batch of fuel is almost a sure way to cause early cp4 failures and that is out of our control. Even at a reputable station.

Diesel fuel in US is very dirty .

 

[ShadowsPapa]

Lubricity is the biggest issue. CP4 pumps don't fail in Europe.

EU requires it over there.

I know for a while people were saying - even in these forums - that the EU didn't have failures because our EPA cut sulfur out and our regs were more restrictive. I wondered and did some research. Turns out the EU is more restrictive, but, they require the fuel be lubricative. They even have requirements for that. We allow more sulfur, but don't give a rip if the fuel lubricates.

 

[Hootbro]

Had a new 6G 2024 Ford Ranger with the 2.3L EcoBoost for a hot minute and I will not lie, I like the power delivery in it better than the 3.6L Pentastar.

 

[Coltron_Actual]

I'll be the odd man out; I think the 3.6 is a good engine for the JT.

It's a small Jeep truck. If you want a full size 1/2 ton buy a Ford F150, RAM or GMC/Chevy 1500.

So many folks are pushing these little trucks to the limit. And then complaining.

If you want a V8 1/2 ton, RAM and GMC have them. If you want a turbo V6, Ford has the ecobooms.

Be well. Jeep on.

Eric

Same same. I knew exactly what it was and what it wasn’t. We loved our JL but even a lowly 5’ bed was a great addition for our daily lives and chores. Oh manure compost is on sale at the hardware? Great, we can take a dozen bags right now without running home for the 10’ trailer or driving with literal bags of sh*t inside the vehicle with us.

The real knock against it is my one piece fishing rods that fit perfect in a JL aren’t fitting inside the cab or bed without the back window open or sticking out over the tailgate. Guess I’ll just have to buy more two piece rods.

 

[Coltron_Actual]

Yeah, I love our LJR, but am finally going to swap or a performance rebuild on the 4.0 for traveling around Montana+. Flat is fine, but there is no pulling hills here.

I haven’t done it yet, but I’m really curious to have WranglerFix do the tune he’s offering on the ECU’s. Not sure about yours but my original ECU died quite spectacularly one day. His ECU replacement saved the whole vehicle.

 

[DanW]

If you think the 3.6 has enough power, you've never driven the 3.0 diesel...

It has more power than the diesel with a fuel pump failure.

 

[DylanM]

I get the impression a lot of people here never had to daily drive a vehicle with a 0-60 time in excess of twenty seconds.

 

[ShadowsPapa]

If you think the 3.6 has enough power, you've never driven the 3.0 diesel...

It does have enough power. The diesel would be more that needed
You are defining "enough" by your want, not need, and your own perspective.
The 3.6 has plenty for my towing, hauling, and other NEEDS.
My 4.0 powered Eagle has plenty. My dual quad 73 has more than enough, more than plenty

 

[Teqsand]

It does have enough power. The diesel would be more that needed
You are defining "enough" by your want, not need, and your own perspective.
The 3.6 has plenty for my towing, hauling, and other NEEDS.
My 4.0 powered Eagle has plenty. My dual quad 73 has more than enough, more than plenty

Ok, ill play.... you take your 3.6 rubicon, ill take my 3.0 rubicon.... we are allowed the same two modifications, say a 4" lift and 37's .... then we drive 500 miles to go wheeling in even an easy trail in Moab..
which of us will complain about power?

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