Diagnose Rough Start

PRNDL

guess we'll never know
Supporting Member
Joined
Sep 25, 2021
Messages
874
Location
North Texas
4.0l, 5spd, no CEL codes, runs completely without issue once started
Battery is a cheaper everstart, unsure of age
Terminals/connectors could use a good cleaning, but don't look terrible

I've had the Jeep for about a year now. The Jeep consistently starts on the first key turn but seems to struggle on the first turn over. Some cranks it struggles once then starts fine. Other times it cranks for a few seconds before starting. Doesn't matter if the engine is cold or running temp, the issue is consistently present.

I plan to clean the IAC, but before I start testing fuel pressure, replacing sensors and/or the battery, I wanted to get feedback.

Videos:
Cold start back to back. First start you hear the struggle on the first turn but it fires up. Second start cranks for a few seconds and then starts.



This is just a few minutes later. First turn still struggles/coughs, but starts/runs fine.

 
Before you look into fuel/IAC/Sensors etc, I think you should remove any doubt that its caused by the "possibly" poor battery, and then ensuring all grounds are removed and cleaned. Most part stores will test your battery for you, and there are several threads on here that point out the location of each ground connection.
It sounds like a bad ground to me. Good luck.
 
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TL;DR
It was the starter dying slowly

It fully died today in the QT parking lot. No clicks, no noises, dead. Swapped it in about 10 minutes and it fired right up.
 
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