Chriskaw440

yeah I thought about that....of course AFTER I did the fix but I can take the tape off and get a shot when I get some time away from my work here soon. there are two coolant sensors on the neck/pipe, I'm referring to the larger one closer to the engine, typically has a YELLOW connector on the sensor and yellow connector on the electrical line(s) running to it. (this is on a 1990 year se by the way so similar years would probably be about the same)

FINALLY figured it out. This weekend I finally took care of the coolant temp. sensor connection/harness...it was dryrotted/brittle/broken up for years and would never stay firmly connected to the sensor and finding a new one is near to impossible so I simply took my dremel tool to the connector end and broke apart the remaining 'plastic' encasing the two wires, cut off the old female ends and attached new female connectors, put heat-shrink wrap around one of them so it would not accidently come in contact with the other one causing a short (since this a fabrication), installed the new temp sensor, attached the new wire leads and wrapped in electrical tape. Engine temperature reads normally now on the instrument panel gage (always read real cool even if it was over 100 deg outside) AND my random excessive high idle problem is gone. Normal idle is much smoother too. that's all I did and the engine purrs like a kitten now. ....ok aside from some random rattle caused by a heat shield that's driving me nuts now!!!!

faulty coolant temperature sensor can make system think the engine is running too cool so it thinks it has to add more fuel to the system thus making it run rich and causing black smoke. Been there done that myself. Just a suggestion on something to check that's all.

black smoke can also be caused by faulty coolant temp sensor as I had experienced in the past. Engine thinks it is running "too cool" so it dumps more fuel into the cylinders..thus causing black smoke. My temp sensor just had a lose connection caused by the plastic housing being so brittle from age and broken up. Once it was fixed, no more black smoke.

yeah your symptoms sound similar to mine. I'm just a bit frustrated because I replaced so much stuff and now its "complaining to me" with it's warm up period LOL. I'm trying to remember if it was doing this stumbling BEFORE I cleaned the MAF or if it started after I cleaned it. Part of me things I should not have even messed with it. thanks for your thoughts! -Chris

1990 SE 5 speed....first start of the day....for the first 20 seconds or so, it idles normally, a little fast...then it drops to sputtering...like it struggling to stay idling....once warmed up, it idles normally. Does that sound like a MAF sensor going bad? I did remove it to clean it like described elsewhere here...very carefully....and I think that made it worse. With engine running, I just disconnected the MAF and the engine died immediately....so it must be either working right or somewhat correctly. Everything else has been replaced sensor and vacuum line-wise over the last year. My other 'guess' is the EGR valve..... ECU says "55" (all good) thanks, Chris

I'm having the same sort of issue with my 1990 SE 5 spd. I posted under the 1990 year trucks "crappy idle..." after replacing most EVERYTHING one can think of...and until the engine is fully warmed up....it idles like crap...like it is struggling. Only thing I have not yet replaced is the EGR valve. -Chris

Ok, here's all the new stuff: (1990 SE) spark plugs, cap & rotor, ignition coil, knock sensor, plenum and intake manifold gaskets, lifters, TPS sensor, IAC valve, cleaned MAF sensor, all vacuum lines (and appear to be all connected correctly), seafoamed intake system (via brake booster line), etc etc.... No ECU codes....flashes "55" which is 'all good' engine seems to struggle during warm-up....I can hear it suckin air in through the air filter (K&N cone style) every time it misses. gas mileage still seems about right. Engine still pulls good and strong under load. response is instant when playing with the throttle either at the throttle body or gas pedal. idles at normal RPM for the most part, better when fully warm of course. while it was idling I pulled the vacuum line off the EGR valve and it made no difference, and I felt no suction either at idle or while giving it gas. I'm wondering if that's the culprit? Fuel injectors all sound good and clean. After all this work, I really figured it would be better than it is.....I think I am missing something but cant quite put my finger on it. I have not yet replaced the plug wires but they really don't have a ton of miles on them...maybe 30,000 or so...if even that much. after most all of the major work was done (like the lifters) and such, of course I had the battery disconnected. When I reconnected everything and fired it up...she purred like a kitten. Then eventually...after a day or so....started the sputtering and missing, I am assuming after the ECU had fully reset everything/parameters? any ideas are welcome thanks, Chris

I don't think WD40 is flammable any more.....thought they changed that a few years ago.

not having that vacuum hose attached WILL make the engine run/idle pretty crappy too as I had learned from experience of accidently knocking it off when changing the #6 spark plug LOL.

woot!

yeah like a faint rapid zapping sound...steady. The plastic cover split and broke off years ago so its just the coil. lately when the engine is cold...during warm up, it sounds like it is struggling to idle smoothly (missing a lot). on FIRST START...sounds great..smooth, then starts to stumble/struggle to idle smooth... Once its warmed up fully, idles beautifully. everything is new except for plug wires and coil. (new IAC, TPS, plugs, cap, rotor, lifters, vacuum lines, Oxygen sensor) its like the 'in between time' from initial start to full operating temp that is stumbles quite a bit. Oh and once in a while, the cranking sounds a bit weak when starting...most of the time its the usual FIRES RIGHT UP though (and the battery is still pretty new/ok)

well so far, 20w 50 VR1 is my new best friend... definitly quieter running, will never be like new again, but I'm happier for now.

Last night I was listening to my engine as I changed oil and soforth and could hear sound, kinda like if you are standing near high tension power lines...that static/electric buzz kind of noise, and it seems like its coming from the ignition coil which is of course located right next to the plenum. Is that normal? Just seemed a bit loud to me. Do ignition coils start to show any signs of pending failure or do they just up and quit working when they go bad. Never changed mine...its the original for all I know. Just put new dist cap and rotor on, new plug wires are next when pay day rolls around.

eeewwwwwwww......makes the pathfinders knock sensor job look like cake work compared to that mess! lol

yeah it was some work to get to it but overall, with some patience and good planning...it wasn't that bad. I took my time as I was replacing other items along the way once I had the plenum and intake manifold all out. Used to have a '95 chevy blazer for a short while and its knock sensors were on the sides of the engine, one on each side of the block...so easy to get to, but of course, two of them instead of one. Sold it anyway....then it was t-boned at an intersection and destroyed. RIP Blazer lol

Well even though its a little after the fact, I changed the oil to Valvoline VR1 20w 50 as this has ZDDP in it, probably not as much as it USED too but its all I could find at the moment. Autozone used to carry a Rislone oil additive that had ZDDP in it for about 12 bucks but the store says they had to pull it from the shelves, even though their web site says they still sell it. Took it for a spin for a while and its definitely quieter. I was also starting to have a slight rear main seal leak so the heavier weight oil may slow that down a tad also. With the high mileage on my engine, the extra protection can't hurt anything.

yep...located under the intake manifold...on top of the engine valley. such a perfect location!

yep....and did my knock sensor a couple years ago. that was fun...and easier than I had envisioned.

Nope...I didn't see any mention of that anywhere before. I've only used Lucas oil treatment recently. They were quiet as a church mouse for a while but I've noticed now they have gradually gotten noisier. Probably about 400 to 600 miles since I did the replacement...I'll have to look in my maintenance book where I record everything. Only use the truck around town once in a while since I work from home...and not driven hard. (my wife's car is more comfortable!) edit: just checked mileage, its been about 560 miles since doing the lifters. Had I known about the oil deal I would have taken those steps. I've also done some reading now regarding LUCAS OIL STABILIZER and how it is junk along with other so called 'oil stabilizers'...just thickens up and can cause aeration in the oil (trapped air bubbles). Apparantly LUCAS OIL STABILIZER used to contain ZDDP but I saw where THAT one is no longer available in stores. Using diesel oils is also kind of frowned upon for use in regular gas engines for various reasons I won't go into here...well because they are designed for DIESELS and their high compression and blah blah blah... Since I am past my break in period with my new lifters and I'm sure the cam lobes are slightly worn anyway both from the wear of the new lifters and just from being over 20 years old now...I am considering changing to 20w-50 as classic car engine builders and soforth say this is fine to use in older engines with the only negative thing being a slight reduction in gas mileage. Basically all I ever heard before I did the lifter job was "just replace them like the manual says and you're good to go". No mention of the oil issue. If by some miracle a chunk of cash lands in my lap....I'd do the replacement again. The engine still runs awesome and does not blow smoke or consume oil...for having 252,722 miles on it. Gotta keep it running for as long as it can.

TIP: always replace them ONE AT A TIME.....otherwise you may not connect them to the right places

I miss my rotaries!!! had 3 RX-7s....all first generations. God those engines ran soooo smooth and quiet (except for the racing exhaust I had on them!) and now back to the lifters....all new, all installed beautifully...checked and double checked, rocker arms nice and tight upon installation, oil flow good...Don't see how things could go back together any better without replacing EVERYTHING like the cams, lifter block(s), rocker arms and shafts, lifters...etc etc......... and now they are back to being just about as noisy as the old ones were. Don't have the bucks to get all the parts mentioned above to do it all again so I guess I'll just have to be the unfortunate one in town to have the stupid "sounds like a sewing machine" engine.

agreed....and I did!

ah interesting to know...thanks. (obviously I don't have that same manual LOL!)

I was just saying to myself...."oh please oh please just work ...." Drive around a lot early today and it seemed ok. sometimes it pauses at 1000 rpms as it drops from driving speed, and then settles right at about 760 rms nice and smooth. With 252,000+ miles on the engine...I know it will never be pefect again but at least it seems like the wild rpm days are behind me now....finally. so this spring I replaced: all hydraulic lifters, new plenum gasket (of course), all new vacuum lines, new spark plugs, new power steering high pressure line, new IAC valve, new distributor cap & rotor (today), seafoamed intake system (via brake booster vacuum....lots of pretty white smoke!) I may replace the EGR stuff since I believe its all original.....next pay day