New Chains but Now Running Poorly | Ford Explorer Forums

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New Chains but Now Running Poorly

UrbanXplorerTrek

New Member
Joined
October 23, 2024
Messages
7
Reaction score
3
City, State
North Bend, OR
Year, Model & Trim Level
2003 Ford Explorer XLT
Hello.

I just finished redoing the entire timing chain set on a 4.0L. Startup and still heard chain noise, so I tore it down again and fixed the front hydraulic tension by blowing out the oil channel, which resolved that. Then, I noticed a lifter noise, so I replaced the lifters on the driver's side. No more noise, and it idles well, but there's a jerky spot around 1000 RPM before smoothing out again.

I replaced the fuel filter, which helped but didn’t fully fix the issue. Transmission fluid level is good. The compression is good across all cylinders. Also replaced the blown cat, but now the driver's side is glowing red hot shortly after starting. I used the OTC 6488 tool set for the timing, which was checked and confirmed twice. The car ran fine (except for the noise) before the chain replacement. No check engine lights. Any ideas on what could be causing this? The car is clean and is rust free. I don't really want to get rid of it if possible.

What's been done:

- Complete timing chain set
- Front hydraulic tension oil channel
- Lifters (driver's side)
- Fuel filter
- hydraulic tension (Front & Back)
- Catalytic converter (driver's side)
- Fuel injectors (cleaned and checked spray)
- All O2 sensors
- Spark plugs
- Water pump
- Oil pump
- Intake manifold gasket
- Ignition Coil
- New battery

I'm new to the forum, so let me know if you need further information. Thanks!
 



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Welcome!!!! What are your fuel trims? Is your fuel pressure strong? The glowing cat doesn't sound ideal to me, and since you had a blown cat, my guess is the EGT is sky high.
 






A glowing cat indicates a lot of unburned fuel. Everything in the ignition system good?
 






A glowing cat indicates a lot of unburned fuel. Everything in the ignition system good?
I tested each spark plug outside of the block and by cranking, and they all seem to spark. I also replaced the Ignition Coil (Motorcraft). Any further ideas?
 






Welcome!!!! What are your fuel trims? Is your fuel pressure strong? The glowing cat doesn't sound ideal to me, and since you had a blown cat, my guess is the EGT is sky high.
I'll have to get back out to you once I have a fuel pressure gauge and the OB2 reader set up. Thanks! Please stay tuned.
 






Been busy with other things but got the car into a place that had a ford scanner. It wasn't throwing many codes except for the cat. They were able to show that cylinder 5 and 6 aren't firing correctly (misfiring) though the fuel injectors are firing correctly and compression all looked good. When I got the spark plugs out the 4th is clean like the rest, but the 5th and 6th are black.

Wires seem to all check out with a multimeter and each bank seems correct with timing. I've attached some photos of the timing marks.

Any ideas?

Thanks again for the help!
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20250403_171754.jpg
 






And compression test shows?

Why did you re do the timing? If it jumped time before then the piston may have smacked the valves, these are interference engines
Looks to Me Like cyl 5 and 6 having issues firing
All plugs wires and injectors good new timing set
Glowing cat and black plugs =
Unburnt fuel
Re check compression and write down the numbers
 






Compression was the following:
1: 115
2: 110
3: 109
4: 140
5: 142
6: 140

Does the TDC look correct on the harmonic balancer?
 






It looks close, but is that on compression stroke? The balancer will hit the 0 mark twice during the 4 strokes

Not sure if it’s critical with the sohc engine since it is not a synchronizer it’s just a cam sensor

Could it be the cat converter on that side is plugged? Glowing orange is usually unburnt fuel and that kills a converter quickly
 






It looks close, but is that on compression stroke? The balancer will hit the 0 mark twice during the 4 strokes

Not sure if it’s critical with the sohc engine since it is not a synchronizer it’s just a cam sensor

Could it be the cat converter on that side is plugged? Glowing orange is usually unburnt fuel and that kills a converter quickly
That's at TPC for cams with the ford tool locked in as shown in the other photos.

The cat was blocked but I gutted out both sides to narrowel down the issue and keep things even before putting in a new cat.

If it helps, it runs smooth above 35 mph in the current state. Before I replaced the chains the car ran fine but with the rattle on startup.
 






This is a tough one
You bench tested the injectors
You have all new ignition parts
Compression is good

You have a miss on cyl 5 and 6 as evident by the plugs

Check all wiring and work, this is a big one

Watch it run in the dark see if any ignition leaks

Check fuel pressure
Get scanner to watch real time data fuel trims

Why isn’t the pointer directly at the 0?
It seems a little off?
 






I'd swap the injectors on 5 and 6 with 1 and 2. See if the miss follows the injectors.
 






Thank you for the help. I switched out Injector 5, put in a new sparkplug for 5 and the truck started up smooth. After the cat replacement, I'll be down the road and running.
 






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