Newbie w/ Questions

1st off I gotta say, Love this site! Very Informative! That said, here's the deal. 1987 XJ pioneer, 4.0L, auto. I was having problems with a high (1200 rpm) idle when starting up cold. Cleaned out the IAC and that helped. Alot of times after I'd stop to fill up on the way home, when restarting the engine, it would crank fine, fire for a second or two, then go back to cranking, then firing, then cranking, etc. Usually after about 20 to 30 secs. it finally caught but the idle would be high for about 10 seconds then drop back down to normal. Also the fuel pump was sounding like a hair dryer (at all times) but especially loud when the weather was warm. Yes, I changed the fuel filter. I finally got around to changing the fuel pump. This seemed to help,or so I thought (at least it don't sound likre a hair dryer!) It still does the cranking thing but only once in a while,but the motor catches faster.(like in 10 seconds) And it occaisonally does the high idle. What else should I check ?
A few more questions. What's the difference between my 4.0L and the HO 4.0L ?(My wife has a 96 XJ country w/a HO 4.0 and it seems way more powerful) Would it be easy to put a HO 4.0L in my XJ ? What is a Renix and do I have one? Sorry for the novel. TIA for any advise/info.
Steve

Cal-XJ said:

1st off I gotta say, Love this site! Very Informative! That said, here's the deal. 1987 XJ pioneer, 4.0L, auto. I was having problems with a high (1200 rpm) idle when starting up cold. Cleaned out the IAC and that helped. Alot of times after I'd stop to fill up on the way home, when restarting the engine, it would crank fine, fire for a second or two, then go back to cranking, then firing, then cranking, etc. Usually after about 20 to 30 secs. it finally caught but the idle would be high for about 10 seconds then drop back down to normal. Also the fuel pump was sounding like a hair dryer (at all times) but especially loud when the weather was warm. Yes, I changed the fuel filter. I finally got around to changing the fuel pump. This seemed to help,or so I thought (at least it don't sound likre a hair dryer!) It still does the cranking thing but only once in a while,but the motor catches faster.(like in 10 seconds) And it occaisonally does the high idle. What else should I check ?

Click to expand...

Here's a link you might want to read on the intermitent high idle. There are more, just use the search feature in the Advanced form and have it look through the threads for you.

http://www.naxja.org/forum/showthread.php?t=22176&highlight=intermitent+high+idle

A few more questions. What's the difference between my 4.0L and the HO 4.0L ?(My wife has a 96 XJ country w/a HO 4.0 and it seems way more powerful) Would it be easy to put a HO 4.0L in my XJ ? What is a Renix and do I have one? Sorry for the novel. TIA for any advise/info.
Steve

Click to expand...

Cam and injection system is very different, leading to more HP and Torque. Again, search the modified section and you'll see the swap has been done before. May be that the 87 is a little on the tired side too, that's why you're noticing the difference in power. Yes, you have the Renix injection system. Some people love them, some hate them.

Thanx Grizz. The link was helpful. I'll try the search also.