1989 Gen 1 with High idle

Steve-O

New member
Hi everyone,

First post... Well, after buying this thing almost two years ago for $800 and driving it an hour home and parking it, I am finally ready to start getting it going. First off, it's a 1989 with 211k on the odometer. Silver with very straight body, 6 cyl, auto, sunroof, OEM alloys, Etc. Seems to be a bit of a premium model compared to others I've seen online. LS perhaps??? Bought to take the three boys light wheeling in desert and SoCal mountains. Plan to pull a small 4' box trailer full of firewood, etc. Want to go straight Safari for some fun overlanding. My dream vehicle is a defender 110, and this seems as close as I'll get. Love the style.

I got online a year ago and ordered all the FSM's as well as a Chilton's and Haynes's manual. Had many years exp wrenching my old veh's in younger days (Vw's of all kinds-air and watercooled , Jeep CJ7, '69 Fiat spider, Scout II, MBZ 190) but now that I'm 46 y/o having had a driveway full of newer Vehs over last 20 years, three screaming kids and a crazy wife, I really have lost many of my wrenching and diagnostic skills. Perishable skills to say the least. Went to Harbor Freight and bought a larger low profile floor jack and several heavy duty stands. I'm ready to go.

So here is where I am at. Seems to run pretty good. Shifts smooth, no smoke, knocks, etc. does have a gnarly "ticking" I keep reading about on these engines that seems fixable. Before I can do anything though, need to get it smogged and I haven't even tried b/c the idle is penned at 1500 plus/minus rpm no matter what I do. Starts right up and stays about 2000, then eventually gets down to 1500, maybe 1300 lowest. Then consistent. No ups or downs.

Cleaned the TB and IAC. IAC does not hum or make any noise when key turned to first click as I've read elsewhere, however seems like most IAC problems I've read about are irregular idles at stop lights, etc. Adj Screw is backed all way out. Not even sure if this is supposed to be an actual idle adjustment?? Tried spraying wd40 on connections looking for vacuum leaks. Thinking of goofing around with the timing to see if perhaps it is advanced. Runs great though driving down the street. Anyone know what it would feel like if advanced too far? Thought about ordering a new IAC, but thought I'd give this forum a chance first. Been admiring the veh's here for several years. Love the whole idea of Expedition Portal. May just take this Montero on a trip as far South as I can go someday. Bucket list.

Once I get it smogged and drivable, pretty sure I'll start going crazy as my 13 y/o wants to learn to drive and use it in couple years when he starts driving. Also need a driver's side seatbelt (male connector that bolts to floor)if anyone has a line in Southern Cal or online source ideas. Grey would be nice. Photos soon as I figure out all this high tech stuff.

Thanks in advance,

Steve
 

Dereksd

Adventurer
Welcome to the ExPo! Post some pics of the ole Monty, 211k and still running smooth is a feat in itself! Can't wait to see the build.
 

Steve-O

New member
Mass Airflow???

Been tinkering around while doing internet searches....

Found a post elsewhere where the guy had the same problem and disconnected the Mass Airflow sensor and took the "coils" out of the idle air control valve. He was able to control the idle by then using the adjustment screw...

Tried this and, wow, able to hear the engine purr for first time since we bought it two summers ago down from the usual 1500- 2000rpm's. Adjusted to 800 rpm's give or take and drove around the neighborhood for 30 mins. Great acceleration, power, etc. Boys love this thing! Wasn't exactly sure what the poster above meant by "coils." Removed three screws on the IAC and discovered a small 5-6 coil gold colored spring and washer. Took this out and replaced cover. Put it back and noticed no difference. Not sure what this is all about.

Of course, now the check engine light is on. Googled the Mits style MAF and seems they are not "cleanable" like the ones with the wire that heats up. Sprayed some non-chlorinated brake cleaner throughout and let it dry thoroughly. No difference. Plugged MAF back in and the idle went thru the roof. Of course these sensors are too expensive to just buy to try. Really want to ensure this is the prob before I purchase. Saw a used one on eBay $185. Will try the pick a part method, however, time is limited and finding one of these Gen 1's seems few and far between. Wondering how I would figure out which other Mits vehicles might use a similar MAF? Any cool parts charts or sites online would be great.

Getting closer.

Steve
 

Steve-O

New member
Here is a driveway pic... Bone stock. Outside is a nice patina silver with just a bit of surface rust around windows where the original black accent paint was. Gonna clean up the rust and repaint matte black around windows and give the body a good scrub and wax.

Plan is some 31" Bfg all terrains, full safari style rack, snorkel, and custom bumpers front and rear with rear holding the usual cans, etc. Like a small winch up front as well with some sand recovery gear on top.
 

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Steve-O

New member
Alright, borrowed a friend's air filter lid with MAF attached. Connected the wire and the rpm's shot up to 2000 just like mine does. This leads me to believe something other than MAF???

Totally lost now... Really hoping for some folks to start chiming in.
 

1morebike

Adventurer
If I were you I would try the guys over at 4x4wire the site is awful but a bunch of knowledgeable guys. I think most of them are also on here but they seem quicker to respond over there. I have a 1990 lwb but the idle has been perfect since a tune up so I'm no help.
 

Steve-O

New member
If I were you I would try the guys over at 4x4wire the site is awful but a bunch of knowledgeable guys. I think most of them are also on here but they seem quicker to respond over there. I have a 1990 lwb but the idle has been perfect since a tune up so I'm no help.


yeah, kinda looking that way.. thanks for the tip. Gonna do that tonight if time.

Just changed out the IAC and no change. Thinking perhaps the throttle position sensor.

Thanks again,

Steve
 

justcuz

Explorer
Have you tried putting a vacuum gauge on it and checking for vacuum leaks? Most modern FI cars will compensate for a big vacuum leak by going to high idle. Try disconnecting your vacuum booster for your power brakes on any new car and watch your idle go to 1500 or 2000 rpm.
Check all your vacuum lines, maybe your power brake booster diaphragm is shot. Pull the vacuum line and plug it and see how it runs.
 

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