Extremely Rough Idle After New Alternator

[ZG MN]

Howdy!

Just followed the steps outlined in this thread:

Thread '100 series / lx470 alternator replacement quick tips no pictures'

Nov 13, 2016

Just did this on my 98 LC so it is fresh in my mind took exactly 3hrs and I'm slow, If anyone has basic tips to add please do... I've done this before but not often enough to "do it without thinking" I should add it helps to have a milk crate to stand on...

1. remove plastic engine cover (10mm socket)
1a. remove wires from your battery 10mm
2. remove airbox complete from throttle body to filter cover you can do this in one piece(10mm socket)
2a. remove serpentine belt 14mm wrench on tension pulley
3. remove front skid pan (Deep 12mm socket)
4. remove right/pass side radiator hose (catch...

• ponytl
• Replies: 84
• Forum: 100-Series Cruisers

• 

Got the old one in and new one out in about 2 hours. Lucky for me, old one died as I was pulling into my work lot and the local NAPA had a reman one in stock.

Now, after putting everything back together, the rig has an EXTREMELY rough idle, as if I had a super hot cam in it.

Tried looking for a soloution, but to no avail....any ideas?

 

[GTV]

Check your electrical connections.

 

[Aracobuilt]

Yes, check electrical connections. Also check the vacuum hoses on the passenger side, even though that shouldn't cause an "extremely rough idle".

 

[drmwvr]

Do you have a check engine light on? Have you checked for any codes?

 

[Jack90210]

Is the MAP sensor plugged back in?

 

[ZG MN]

Check your electrical connections.

It was this- the 3-hole plug had become unseated slightly while i was manhandling into place. I put a little dielectric grease in the plug and bingo it seated correctly. Whomever did the previous alternator had broken the tab off of the plug. After that, the idle was still rough, but ECU-learning rough.

Wish I had taken a video of just how rough it was initially.