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Unread 06-25-2014, 06:34 PM   #1
87MJTim
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CJ7 wont start when hot

84 CJ7 258 T5

I got it last fall and have been driving it on the weekends mostly. The last few weeks I have driven it during the day to run some errands. After a quick stop, I get in and try to start it, but I get two problems. First, some times the starter just makes a grinding noise and wont turn the engine. I will begin by replacing it.

Second, when the starter does turn the engine, it just cranks and cranks but will not fire. Sometimes it sounds like it want to fire but just doesn't.

After several tries, it finally turns over. It runs just fine after this.

I have read several threads on JF with similar issues, but the OP does not give a final resolution that fixed the issue.

Some of the possible causes: engine heat effecting the starter (but the starter will turn the engine), heat effecting the solinoid, or vapor lock. Are there other issues to look for?

Have others had this problem? What did you do to fix it?

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Unread 06-25-2014, 07:50 PM   #2
RenoF250
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Mine did the same. Not sure what it is put I would just push the pedal to the floor while cranking and it would start. New starter should fix the other problem.
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Unread 06-25-2014, 07:55 PM   #3
lucdog
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I would start by cleaning all the electrical connections from the battery, to the solenoid, starter and block. Start with the positive on the battery, then leave that one disconnected until done, then reconnect it.

With a carburetor , I normally hold the gas pedal down a 1/8th to a 1/4 of its travel when starting hot.
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Unread 06-25-2014, 07:59 PM   #4
LumpyGrits
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Try another battery
Have the starter ck'd out and make sure ALL ele. connections are clean and TIGHT.
LG
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Unread 06-26-2014, 06:43 AM   #5
Matt1981CJ7
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Too much timing can also cause hard hot starts.

Matt
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Unread 06-26-2014, 09:21 PM   #6
carnuck
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It will also do this when the 12 volt pickup on the solenoid wears off. To test, put a testlight on the "I" terminal of the solenoid and it should light while the motor is cranking. If not, then it's worn off. Voltage drops too much while cranking (because it passes through an ignition resistor wire) leaving you with not enough spark when the starter is turning slow from heat soak.
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Unread 06-26-2014, 10:04 PM   #7
87MJTim
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Quote:
Originally Posted by Matt1981CJ7 View Post
Too much timing can also cause hard hot starts.

Matt
What timing marks should I set it to?
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Unread 06-27-2014, 04:21 AM   #8
86cj74.2L
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With the engine warm and idling look into the carb throat for fuel dripping out if the upward turned brass tubes in the Venturi cluster.
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Unread 06-27-2014, 05:25 AM   #9
Mike Romain
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Quote:
Originally Posted by 87MJTim View Post

What timing marks should I set it to?
Mine likes 9°. The numbers are hard to see, the lines are 2° each starting with +2 on the far right.
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Unread 06-27-2014, 06:17 AM   #10
Matt1981CJ7
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Quote:
Originally Posted by 87MJTim View Post
What timing marks should I set it to?
If your engine is Nuttered, 6-8 degrees BTDC, with the vac advance hose disconnected and plugged, should be about right for your elevation.

Matt
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Unread 06-27-2014, 07:05 AM   #11
87MJTim
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Quote:
Originally Posted by Matt1981CJ7 View Post
If your engine is Nuttered, 6-8 degrees BTDC, with the vac advance hose disconnected and plugged, should be about right for your elevation.

Matt
I don't know if it was Nuttered. The PO did put on a MC2150 and a diff dizzy. He removed alot to the vac system/hoses. Nutter?
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Unread 06-27-2014, 07:44 AM   #12
Mike Romain
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Quote:
Originally Posted by 87MJTim View Post

I don't know if it was Nuttered. The PO did put on a MC2150 and a diff dizzy. He removed alot to the vac system/hoses. Nutter?
What kind of dizzy? Nuttered just means the emissions computer is no longer controlling the timing.
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89 YJ Renegade. BBD Carbed 4.0 HO. Locked front and rear with 33x9.5 BFG AT's
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Unread 06-27-2014, 12:08 PM   #13
86cj74.2L
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Quote:
Originally Posted by 86cj74.2L
With the engine warm and idling look into the carb throat for fuel dripping out if the upward turned brass tubes in the Venturi cluster.
With a MC forget the above. I wondered if you had fuel drip causing a flood condition
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Unread 07-20-2014, 05:24 PM   #14
87MJTim
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I want to give a follow up. I have not worked on the CJ since I last posted - work, life and vacation interupted what's important.

I dropped the oil pan today to fix the oil leak it has had since I picked it up last Sept. I pulled off the starter to examine it. The "drive gear" (if that is what it's called) was loose. It could move side to side a little and back and forth approx. 1/8". When I shook it, I could hear parts rattling inside. I got a new (reman) from NAPA. No loose parts! Also got a new solenoid.

I have not finished the oil pan gasket change. I will post results when I complete the work.

Thanks for all your suggestions and comments.
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Unread 08-20-2014, 08:01 PM   #15
BinTinBoynio
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Tim, what happened? My CJ7 is also not starting when hot and was wondering if your problem had been solved and with what fix.
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