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Slow to Start? - Don't know what you don't know

BIG1RED9

NAXJA Forum User
Location
Coarsegold CA
Recently got a few miles on the Jeep. In all about 200 since I began to rebuild things, was on jack stands for 7 years. Making progress on the mechanical front. Want to make sure the 4.0 is starting as it should. My goal is a complete restoration not for show but to have as a solid, clean, sharp looking machine. Pretty will come later. I'm in my 60's and live in the mountains where snow can hit. Priorities are now it operating properly and reliability. Looks will come later. Funny how things changed since I was 20. :eeks1:
My starer is new and quick. To me the when turning over, there are 2 major sounds/tones. I get about 8 to 10 of these cycles in about 5 seconds before I hear any attempt to fire. It then comes to life. Typical? If not where do I look.

Enjoy the weekend, thank you!
Don
 
Not sure what you mean by tones. Slow starts can be a number of things. Most common is the fuel pump check valve, it allows the fuel lines to partially empty. I turn my key to run, then back to off, then again to run and start. When the key goes from off through run to start, the computer primes the system. Sometimes the prime isn't enough and cycling it to run then off and then to start gives it two prime cycles.

Weak spark you can check by pulling a plug, grounding it well and having someone turn the motor over, Sharp blue/white spark. Be careful or you will shock yourself.

Weak CPS signal can cause hard starts. Cruiser has a write up on testing the CPS.
 
The Renix era Jeeps don't wick right off like most folks are used to.

The ECU must see a strong enough signal for so many revolutions before it provides spark and fuel.

Have you visited my website and performed any of the Tips there?

If so, which ones?
 
what year? leaky check valve is the most common source of slow firing, but there are others

Post 3. It's a 1987.

On the REnix Jeeps, great strides can be made by completing Tips 1 through 5 FIRST, before getting off on any other tangents.

Known issues and it's preventative maintenance.
 
I am not saying it is hard or slow to start as I have no frame of reference. I shared the crank cycles and amount of time it takes to ask those that have that vintage to chime if it is normal or there is an issue.
 
The Renix era Jeeps don't wick right off like most folks are used to.

The ECU must see a strong enough signal for so many revolutions before it provides spark and fuel.

Have you visited my website and performed any of the Tips there?
Yes

If so, which ones?
I have so far done 1 through 3 and plan to continue as time permits.

How many revolutions do you think is typical and about how many seconds before it begins to fire?
 
My 87 has to crank a while before it starts. But if it cranks, it starts; always does, always has. Been this way for the last 13 years.
 
Well, that's good to hear!!

Clean the throttle body and Idle air controller along with snugging up the intake manifold bolts sometime soon.

Did this today. I also checked the TPS and it is out of spec. I have an automatic and the most I can get is 1.35 volts. Have a new one coming.

Thanks
 
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