I think she was running a little lean.....

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Dec 19, 2013
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Fort Worth, Texas
2011 Jeep Wrangler 3.8L/42RLE with 131,xxx miles. Customer complaint......Misfire & a Squeaking noise.

*DTC P0303 (Misfire Cylinder #3), Using my Low Amp Clamp & Scope.....Verified one cylinder has low compression.
*Performed Leak Down test on Cylinder #3 at TDC with Bank 1 Rocker Shaft removed, 75% leak down.....With no air escaping the Intake or Exhaust valves.
*Removed Bank 1 Cylinder Head (Which is quite easy) & found the Piston had a broken Crown/Ring Land, Galled the Cylinder wall, And had been VERY hot (Has a charcoaled look to it)
*Flowed all 6 injectors & found #3 to be severely restricted.

Boy.....The wrecking yards want a king's ransom for these engines, It's not much more to completely rebuild this one, Will be Hot Tanked, Bored & Honed, Decked, New Cam bearings & Core Plugs installed. Heads will get a Valve Job, Surfaced, & new Guide Seals.
Crank looks perfect as did the Rod & Main Bearings....But will get new Inserts, Timing Chain was a little loose so it will get a new one along with new Lifters & Oil Pump.
Both Exhaust Manifolds are cracked & will be replaced. Still had the original copper Champion plugs in it!!!

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That is a real mess. I would like to see what happened to that injector. Are those Bosch or Deka? If Deka it would be no surprise, it is very common to see them fail in the 3 ms range then come back once the time is increased but the Bosch are usually pretty sturdy.
 
That's really unfortunate, those are usually very long lived engines. At least it's not a complicated DOHC getup, the OHV valvetrain makes that repair a whole lot easier!

I would have thought that'd be a common junkyard engine, must be the minivan engines don't swap over due to the different orientation.
 
That is a real mess. I would like to see what happened to that injector. Are those Bosch or Deka? If Deka it would be no surprise, it is very common to see them fail in the 3 ms range then come back once the time is increased but the Bosch are usually pretty sturdy.

It's got Deka's
 
That's really unfortunate, those are usually very long lived engines. At least it's not a complicated DOHC getup, the OHV valvetrain makes that repair a whole lot easier!

I would have thought that'd be a common junkyard engine, must be the minivan engines don't swap over due to the different orientation.

Never cared for the Chrysler 3.3L or 3.8L.....I've seen a lot of weird failures with them over the years, But it's nowhere near 2.7L bad though. I think the 3.5L/4.0L SOHC are better engines all around & what should have been used in the Wrangler before the 3.6L became standard.

The Transverse 3.8L's are not machined & tapped for the Longitudinal engine mounts, The Minivan engines are very cheap.
 
It's got Deka's

It might be a good idea to swap them out for some Bosch units. It is common to have a 25% failure rate with the Deka and it is usually always the same 3ms range fail (or they stick for a second or two when first started which causes other issues), it drives the bad one(s) lean under flat land cruise conditions.

The Bosch number is 0280158119, they may be hard to find new but I can probably hook you up with a supplier if you want some.
 
Never cared for the Chrysler 3.3L or 3.8L.....I've seen a lot of weird failures with them over the years, But it's nowhere near 2.7L bad though. I think the 3.5L/4.0L SOHC are better engines all around & what should have been used in the Wrangler before the 3.6L became standard.

The Transverse 3.8L's are not machined & tapped for the Longitudinal engine mounts, The Minivan engines are very cheap.
You answered my question before I asked about a van engine. Same weirdness with the 03-06 2.4 in the wranglers. Those are very scarce
 
It's too bad they didn't put the Pentastar out in 2011 in all the cars like they did the Grand Caravan.
 
Love seeing engine teardown / rebuilds-- thanks for the photos, looks great so far. Looks like a pricey repair.

I think the 3.5L would be a poor fit for this application, those are fairly high strung engines, lacking torque down low. The 4.0L ameliorated that to a fair degree though. I'm genuinely curious why they chose the 3.8L. The 3.5L/4.0L had already been set up for longitudinal orientation (LX platform and Nitro); I'm not aware of any 3.8L mounted that way prior to the Wrangler, except for the old LH cars. Cost is the only thing I can think of.
 
The 3.3/3.8 are pretty solid pushrod motors.

I'm more surprised they didn't use the 3.7 in this application.
 
The 3.7L being a 90° V6 might have posed some packaging concerns, I've swapped 90° OHV Chevrolet engines into Wranglers before, But they are not as wide as a 3.7L SOHC engine.

Swapped a Chevrolet 4.3L V6 into a 2006 Wrangler once.....Liked it better than any of the V8 swapped ones!
 
2011 Jeep Wrangler 3.8L/42RLE with 131,xxx miles. Customer complaint......Misfire & a Squeaking noise.

*DTC P0303 (Misfire Cylinder #3), Using my Low Amp Clamp & Scope.....Verified one cylinder has low compression.
*Performed Leak Down test on Cylinder #3 at TDC with Bank 1 Rocker Shaft removed, 75% leak down.....With no air escaping the Intake or Exhaust valves.
*Removed Bank 1 Cylinder Head (Which is quite easy) & found the Piston had a broken Crown/Ring Land, Galled the Cylinder wall, And had been VERY hot (Has a charcoaled look to it)
*Flowed all 6 injectors & found #3 to be severely restricted.

Boy.....The wrecking yards want a king's ransom for these engines, It's not much more to completely rebuild this one, Will be Hot Tanked, Bored & Honed, Decked, New Cam bearings & Core Plugs installed. Heads will get a Valve Job, Surfaced, & new Guide Seals.
Crank looks perfect as did the Rod & Main Bearings....But will get new Inserts, Timing Chain was a little loose so it will get a new one along with new Lifters & Oil Pump.
Both Exhaust Manifolds are cracked & will be replaced. Still had the original copper Champion plugs in it!!!

e7ni4Su.jpg

bks3km4.jpg

e2ihe3G.jpg
This kind of work is what separates the true automotive techs from the parts replacers. Most are afraid to go into an engine these days.
 
This kind of work is what separates the true automotive techs from the parts replacers. Most are afraid to go into an engine these days.

Not necessarily, it's just that engine work (especially good engine work) is not cheap. For most cases, customers opt to replace the engine with a used one because it's cheaper and will get them back on the road quicker.
 
So what would the symptoms be of a clogged injector? I guess on a 4 cyl it would harder to ignore, but would it even throw an engine code?
 
Misfire, or lean fuel trims. Lean cylinders run hotter , so an IR temp gun on the manifolds can also be a useful tool
 
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