Are these injectors toast?

Josh Harder

Josh Harder

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Joined
Dec 15, 2019
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Alberta
I pulled my injectors as 3 out of 6 had a slow leak, as I was cleaning and inspecting them I noticed 3 have hairline cracks. I believe it was these three that were leaking.
The resistance ratings are decently even across all 6. Check out the pics for more info.

Also could this be the culprit to my long crank issue?
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The plastic housing does not hold fuel and will not cause a fuel leak. If they were leaking it was at the tip and sure, it could cause a long crank because it bleeds pressure out of the system.
 
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At least eliminate one possible issue. How many miles on your Jeep?
 
Cracked injectors is a common problem on the TJ. 4/6 of mine were cracked. The cracks aren't really a problem. I swapped them out and it fix a rough start issue, but injectors do not commonly go bad on TJ's. If you are seeing a long start and a lack of fuel pressure at the rail, the fuel drainback valve is a much more common issue than leaking injectors.

If you do plan to replace injectors, do not go with new mopar ones. I spent $500+ on them and they were garbage. I sent them back to rock auto and paid $50 for 9 used injectors from Davey's Jeeps. Those have been close to flawless. I'm going to swap some new O-rings on them soon since my idle did get a bit rougher after swapping them in.

EDIT: I swapped the O-rings and cleaned the injector seats. Idle is still poor to the point I have ordered 6 Bosch injectors. The Davey's seem hit or miss.
 
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jodomcfrodo said:
Cracked injectors is a common problem on the TJ. 4/6 of mine were cracked. The cracks aren't really a problem. I swapped them out and it fix a rough start issue, but injectors do not commonly go bad on TJ's. If you are seeing a long start and a lack of fuel pressure at the rail, the fuel drainback valve is a much more common issue than leaking injectors.

If you do plan to replace injectors, do not go with new mopar ones. I spent $500+ on them and they were garbage. I sent them back to rock auto and paid $50 for 9 used injectors from Davey's Jeeps. Those have been close to flawless. I'm going to swap some new O-rings on them soon since my idle did get a bit rougher after swapping them in.
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I'm thinking leaking injectors are the issue as it fires up instantly when is been sitting a few days and cranks a few seconds when it's hot or been running within the last 24 hours.
Its seems to me like 3/6 are leaking until there's no fuel pressure when it sits. It takes a while for the gas to run off or evaporate and then starts fine. And when i crank when it's been running within a day it cranks for 3 seconds and then runs rough for another 5 and then runs fine. Almost like a flooded engine.

I'm also not a professional here so keep that in mind
 
When I first purchased the '01 Sport 4.0L I replaced the factory original 1 hole fuel injectors with 12 hole fuel injectors. IF you are considering replacing your leaking fuel injectors; check out the K Suspension fuel injectors.
The second link is for reference only. DO NOT purchase the Chinese fuel injectors off of Amazon; I tried the Amazon injectors and the engine felt like it had lost power over the factory injectors and the engine idled rough.

K Suspension
12 hole Fuel Injectors
 
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CharlesHS said:
When I first purchased the '01 Sport 4.0L I replaced the factory original 1 hole fuel injectors with 12 hole fuel injectors. IF you are considering replacing your leaking fuel injectors; check out the K Suspension fuel injectors.
The second link is for reference only. DO NOT purchase the Chinese fuel injectors off of Amazon; I tried the Amazon injectors and the engine felt like it had lost power over the factory injectors and the engine idled rough.

K Suspension
12 hole Fuel Injectors
Click to expand...
I've read anything from "stick to oem mopar injectors" to 4 or 12 hole after market injectors. It's hard to know which path to take
 
I installed a set of the K Suspension 12 fuel injectors and have had good results. I know several members that have gone to the 12 hole fuel injectors and are pleased with the results.
Years ago I upgraded from 1 hole to 4 hole injectors on a '98 XJ 4.0L which lowered the emissions, increased MPG and performance.
Not trying to convince you to buy them; just informing you of what I observed.
 
CharlesHS said:
I installed a set of the K Suspension 12 fuel injectors and have had good results. I know several members that have gone to the 12 hole fuel injectors and are pleased with the results.
Years ago I upgraded from 1 hole to 4 hole injectors on a '98 XJ 4.0L which lowered the emissions, increased MPG and performance.
Not trying to convince you to buy them; just informing you of what I observed.
Click to expand...
Did you find the there was a difference between 4 and 12 hole?
Also what brands should I stick to?
 
CharlesHS said:
I installed a set of the K Suspension 12 fuel injectors and have had good results. I know several members that have gone to the 12 hole fuel injectors and are pleased with the results.
Years ago I upgraded from 1 hole to 4 hole injectors on a '98 XJ 4.0L which lowered the emissions, increased MPG and performance.
Not trying to convince you to buy them; just informing you of what I observed.
Click to expand...
Pulled the trigger on a set of remanufactured 4 hole injectors. Seems like a quality company/ product. I'll let you know how it turns out.
Thanks for the help!
 
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Previously installed the 4 hole injectors from Five O Motorsports, but their prices have gone up some since I purchased mine for the 98 XJ 4.0L. Those injectors worked VERY well...
So far the K Suspension injectors are working well for the '01 TJ 4.0L.
 
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Josh Harder said:
I'm thinking leaking injectors are the issue as it fires up instantly when is been sitting a few days and cranks a few seconds when it's hot or been running within the last 24 hours.
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Oooh, following this; I have the exact same problem.

Interestingly I had the opposite problem (not wanting to start after sitting overnight) until I changed my fuel pump. Now I believe I have a leaky injector due to maintaining pressure in the line instead of draining back into the tank.

Additionally, I'm picking up a hint of raw fuel smell right after starting it too. The other day I had my airbox apart and could smell fuel in there so I feel like I had an injector that was leaking and evaporating through an open intake back into the airbox.
 
samobius said:
Oooh, following this; I have the exact same problem.

Interestingly I had the opposite problem (not wanting to start after sitting overnight) until I changed my fuel pump. Now I believe I have a leaky injector due to maintaining pressure in the line instead of draining back into the tank.

Additionally, I'm picking up a hint of raw fuel smell right after starting it too. The other day I had my airbox apart and could smell fuel in there so I feel like I had an injector that was leaking and evaporating through an open intake back into the airbox.
Click to expand...
You'd probably be able to differentiate on your own but just to mention it - I smelled gas from the cabin when I'd start the Jeep and it was the round regulator on the fuel rail. You'll probably see some wetness under the regulator if it's leaking.
 
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