Chriskaw440

success. First try. took about 20 minutes. I did my best to set the new sensor to the same position the old one was in with a flat head screwdriver (turning the mechanism the throttle plate shaft goes into on the sensor) attached to the throttle body in as close to the same position as old one was in also...set idle speed, shut off engine, reconnected everything, started up, test drove for a few miles, drives great....got my idle just a tad higher than 750....more like about 760 but I can live with that. Checked ECU for codes..."55" (all normal) Truck seems happy so I'm happy. Now I'm going to go do yard work.... Oh and the new sensor was only $11.65 (beck arnley) on closeout at Rock Auto parts. (for 5 speed manual)

thanks! found both my volt meters finally and did more research on replacing the TPS....hopefully it will go well. Mine doesn't have a check engine light...its the old school red and green flashing lights on the module under the passenger seat...but thankfully all is normal.

I finally got my new TPS in the mail today......now to see if I have the patience to deal with it. Guess I need to go buy an Ohm Meter too.....

I've heard all the octane banter here also....but my 1990 always runs much better on premium. Even with the new knock sensor and no error codes....everything in good shape etc etc. 87 or 89.....under load....mine knocks still/runs noisier. So I just pay the extra few cents and live with it. with 250,000+ miles on it....she keeps on going and I just changed all the spark plugs last month when I replaced my lifters....they all had perfect "wear" on them. About 350 miles to a tank of gas give or take driving conditions. As I understood it on these rides, the timing is electronically controlled so I never mess with it.... Need to replace my TPS sometime but I hear it's a bitch to get it adjusted right...and I've heard that its easy....which is it? I've never replaced one. -Chris

Just did mine on my '90 SE about 2 months ago or so.....not too difficult....getting the BOTTOM bolt back onto the steering box lined up with the washer on it was a bit of a bitch (there is an upper and a lower bolt fitting since there are two lines going to it). I was having a bear of a time trying to wrestle the old line out of the engine compartment since most of it is all metal and wouldn't slide out too easily, so I just cut it up into pieces. My NEW assembly of course was NOT exactly like what the original was....but it still worked fine. Just couldn't use some of the original metal line spacers along the way anymore so in some places I just zip-tied the two lines together (they run side by side pretty much) to keep them snug. The bleeding part is easy once you refill the resevoir. The book says lift front end off ground, crank steering wheel all the way over in both directions a few times...etc etc.. My jacks wont go high enough to lift my front end LOL so I just topped it off, and went driving around my street looking like the indy cars keeping their tires warm during pit laps LOL and my steering has been just fine. ps....eat some wheaties or use a long handle wrench for breaking those banjo fitting nuts loose....they are pretty tight...and you MUST use the washers on them otherwise they will leak.

yep, and thats what the AAC (Iac) is suppose to do...adjust the idle speed up a notch to compensate for the extra load placed on the engine by the accessories. it should adjust up just a few rpm's though.....not nearly 1000 rpms LOL My AC is not even working or connected (no belt either) maybe one day I will test it with my special tool...........the sledge hammer in the back shed.

Mine never acts like it wants to stall.....either always about 800 rpm....or sputtering just over 1000...and the usual sometimes almost 2000 steady, then after a minute or two or three.....gradually falls back down to normal. Its been better since all my work....but still something not quite right.

UPDATE: damnit....tonight it started idling high again......gggrrrrrrrrrrrrrrr.....still not as often but....enough to piss me off

Since spraying the carb/intake cleaner into the air intake tube while engine running (pretty much a full can worth)....Mine has NOT gotten stuck on high idle since. (I just used off the shelf carb/intake cleaner...not seafoam or any other 'specialty' product)

Helllll no I'm not putting any more seafoam in my engine LOL. The throttle body cleaning I sprayed in seems to have helped quite a bit...drove around today and it barely wanted to do the erratic idling. BUT, Im pretty sure it has to do with the throttle body or TPS, because when it would start acting up, I would just barely tap the gas pedal, kind of like when I just tapped on the throttle linkage with my hand, and it would immediatly drop down to normal idle. Not 100% positive but just saying....those are my reports so far! -Chris

Well I just went out to check for any codes and I got "55" which means no malfunctions (at least as far as this old type system can detect LOL) and then let it warm up and sure enough it started acting funky again with the idle....speeding up erratically and such....when I put my hand on the throttle cable linkage and reved it just a tad it would settle down....then act up....etc etc. I removed the small vacuum line from the intake tube and shot about half a can of carb/intake cleaner while working the throttle some so it wouldn't konk out and then let it run for a little bit....seemed to be normal again so I am hoping it is just build up on the throttle plate/intake stuff. TPS is what I am looking into since everything else checks out and all vacuum lines and such are good and in the right places. We'll see how it runs today when I head out later -Chris

Well honestly I haven't gotten to check for any codes yet ....been a very busy week. I plan on checking this weekend. Since then though it has on occasion gotten stuck on high idle again but for shorter length of time.....darnit!!!!! Still much better than it was before...but....still more checking to do I guess. New IAC, new hoses(vaccum), plenum gasket, spark plugs, lifters.. Do these have "neutral switches" ?? mechanic told me once I need a new one but I have no clue where it would be or even if a 1990 5 speed has one.... -Chris

Pipe Dope patch crap wont last. Midas tried that shortcut on me and I busted them for it because they lied and said they installed new gaskets when all they did was shove new ones in and then covered them with pipe dope. Never even bothered to unbolt the flanges. I dont care if they say its "tough to work on old exhasts".....its what they say they SPECIALIZE in right? standard exhaust work is not rocket science. They are just being lazy.

wouldn't it be cheaper and less-headache involved to just find a 4x4 body/set up and transfer engine and what not to that? Seems like trying to turn a standard into a 4x4 is an aweful lot of work involved and parts and customization and such. just my 2 cents

My 1990 SE has the same issue...sometimes its normal temp reading, sometimes way low...and it seems like my mileage is worse when the temp gauge is reading low. Mechanic friend that worked on my vehicle a while back says my temp sensor connector/wiring is the culprit (the sensor that is on the coolant neck above the fan area) and sometimes I wiggle it around, make sure its firmly connected and the temp does read more normal for a while. The connector is so oil and dry rotted (plastic) that it just doesnt seem to want to stay tightly in contact. I ordered a new sensor and will probably just hardwire it direct since I doubt I can find a new connector anywhere.

If anyone is planning on replacing their hydraulic lifters, I suggest following these steps/details...which were left out on other peoples posts from what I remember. -definitly clean the lifter block thoroughly as their are oil passages that weave through it and through a small hole in two of the bolt-thread areas (one on each end). I used carb cleaner since it shoots out a good strong shot of cleaner and air to blow out any gunk or crud...and mine had some that could not be seen just by looking at the lifter block. I second guessed my work on the passenger side and removed the assembly again to do a better job of cleaning and and sure enough blew out more gunk. -with new lifters, do not just shove them into the lifter holes in the block....as I found that some fit better in some lifter holes than others. so I had to test fit each one--with plenty of oil, until they all moved freely with just barely any finger pressure. If they feel too tight, try a different one. I soaked the whole block after cleaning in oil also so there were no 'dry' areas in them. Oil is a good thing....use plenty of it (I did NOT buy new lifter blocks....did not feel this was necessary) -thoroughly coat the cam lobes and lifters with clean oil before replacing the lifter assembly. I used an oil can (the old fashion kind with the hand trigger and flexible spout) to squirt ample amounts on everything -medium sized ZIP TIES are a life saver for keeping the old and new lifters in place when removing and reinstalling the assembly...this is also mentioned and shown in photos in other posts here regarding the same topic. -soak the new lifters in lightweight oil like 5w-30 or 5w-20 before installing and stand them upright in the oil bath...you will most likely see the tiny air bubbles escaping from the tips. I occasionally tapped them or banged my oil container with the lifters in it on the table to help losen any air bubbles. DO NOT turn the lifters upside down at any time. -I drove the first few miles gently to make sure they would seat properly and get fully lubed before putting any serious load on them. Maybe thats a bit much but I felt safer doing this, just like you would with a rebuilt engine....to break it in. This was my first time doing this and the first time I just did the passenger side and was NOT as thorough as I was the second time around which is probably why the #5 lifter got fried after just a few miles and I luckily caught it going bad before it was too late. Apparently it was not moving as freely as is should and the pad got severly worn down. I know it wore my cam lobe a little also but oh well replacing the cam is not in the books so it stays as it is Now with all new lifters, IAC valve, spark plugs, all vacuum lines and a cracked air intake tube fixed...and power steering restored (high pressure line replaced) she purrs like a kitten. Never run this good before. Hope it stays that way for a looong time. 1990 SE 5 speed with over 250,000 miles God knows how much I saved in LABOR costs had I had to take it to a shop for this much work. Special thanks to ROB (alkorahil) at Nissan in Texas for helping me with the parts and expertise. Highly recommended. -Chris

Just finished my project with replacing all the hydraulic lifters and the IAC (also called AAC) valve, and a whole bunch of vacuum lines, and while I had the plenum off I also replaced all the spark plugs because it was SO EASY with the plenum out of the way. My air intake tube also had a big split in it near the air filter end of it and I just cleaned it really good and used silicone sealant around it and let it sit for 24+ hours to dry. Made a nice flexible seal on it. Since this thing is rubber, and over 20 years old, I wasn't surprised to find the big split and I am sure it was letting in air. Cranked it up.....smooth as a kitten purring. Drove to the gas station to fill up....my Pathy has never run this smooth before and I have had it since 2001. Keeping my fingers crossed that it stays this way!!!

Sure enough I did find a crack in the vaccume line right where it slips onto the egr (dry rotted).....I just wrapped it tightly in electrical tape until I can get to the parts store to buy more vaccum tubing...seems to be a little better but I'm also still replacing the original IAC valve because I DO NOT want to have to take the plenum off again anytime soon LOL. I can tell it is still not operating quite right anyway. thanks for that tip

I replaced a fuel line connection at the filter on my wifes '97 Ford Aerostar van....checked some other things while I was under the vehicle to make sure all was good. Went back into the house to tell her "it's all good now...we can go...." Hopped in, bragged about how easy the fix was, cranked it up, put it in reverse.....then came a pretty serious sounding "KAACHUNK!!" noise and the van rocked a bit... Dumbass me forgot to take out the floor jack it was still jacked up on. (luckily no damage was done...other than my pride.)

I just ignored my lifter noises for years, finally got around to replacing them just because it was getting on my nerves.....and since I found two that had damaged tips on them (pieces missing) where they meet the rocker arms (rocker arms are fine by the way), I decided to go ahead and just replace all of them. I already did the passenger side where the damaged ones were, one NEW lifter failed so I had to put one the old ones back in for now (defective part...thank you rock auto! and yes they are refunding me the $) and I'm about to order 7 more from akorahill along with a new plenum gasket and IAC valve. My lifter noise started out as just initial cold start up tapping, but has since gotten to where I can hear them tapping even long after full warm up and while cruising down the road when I get on the gas. Yes there was some sludge but nothing unexpected....all looked normal from normal wear and tear. I also watched them operate while the valve cover was removed to check for good oil flow through all the lifters and soforth. You can do this (passenger side at least) for a short while as some oil will spatter out into the engine bay....) 250,000+ miles and stiiiiiiill going!

I'm about to order a new IAC and the rest of the lifters need to finish replacing all the hydraulic noisy 250,000+ miles on 'em lifters. Will let you know how it turns out idle-wise. -Chris

Hi all, Sometimes when I come to a stop, or just coasting along like through a parking lot, out of gear, my idle will jump to about 2,000 rpm.....then gradually creep back down to normal (650-700'ish rop) I know the valve is there to kick in when additional load is placed on the engine such as AC on, or power steering load....to feed more air to the intake. So I'm thinking its cutting on when it doesn't need to...my ac doesn't work anyway LOL. Doesn't do it all the time, just occasionally...which of course is a waste of gas, and makes it harder to shift into first gear. Tapping the gas pedal or riding the clutch a little doesn't lower it....it's always gone back down just on its own..... Is that typically the Idle Air Control Valve going wacky? (and for all I know its the original one) I hear they can get carbon filled with age. Everything else related to idle operation seems to work fine. No vacuum leaks that I can find anywhere either. I want to go ahead and order a new one but since they are about 140 to 150 bucks, I wanted to get some opinions first. I want to replace it if thats the general consensus when I do my drivers side lifters since I have to take the plenum off anyway...and the stupid thing is under the plenum. thanks! -Chris

Here is a comparison shot..... one of the original lifters on the left, the NEW lifter, with only a few miles on it, on the right.... the toothpick is there to show how much was worn off the pad. Hmmm...should I try to get my money back??? Maybe next time I will spring for the high dollar ones. (remember, everything else associated with the operation of the lifters works fine) bad new lifter...

either two things, exhaust manifold leak (as the manifold heats up, the metal expands and closes the leak....) or, the typical hydraulic valves showing their age and ticking until the oil fully circulates. As they age and wear, they start to loose the ability to retain oil in them and they can then tick/tap some at cold start up for a moment or two. Not a huge thing really, more annoying than anything. I just replaced half of mine because I was getting tired of the noise. but I did find two damaged ones in the process.

reassembled, ran for a couple minutes without rocker arm cover on to visually see....quiet as church now, saw great oil flow around all lifters and such. Time to go to wal mart for my test ride (I'm out of printing paper for my work/computer!!) so keeping my fingers crossed. I noticed this time when it cranked it....no tapping whatsoever. Friday night after putting all the new lifters in...there was some tapping like crazy for about 5 minutes until it pretty much stopped...... I'm wondering if it was that one lifter I removed tonight. (remember I replaced it with one of the old ones now) We'll what happens over the next couple days