CapedCadaver

iTrader: (8)

yeah i'm going to look into that. maybe on the FS thread someone's got a TPS for sale. i need the harness too; the boot is ripped open so it's going to corrode again if I don't get another waterproof boot. i want to check for voltage across the variable part of the TPS though, since it happens most at low-part-throttle (maybe 10%-50%), but it has funked up at idle too, i would see it puttering while I was in park.

Max_5gen

iTrader: (2)

Couple more details about my case to confuse you more - my car has O2 sensor dead and it's been dead for a while, it should not cause any trouble except poor gas mileage.
When I was experiencing the trouble idle could go up to 1500 and stay there even without me touching the pedal, in P. I thought, it was engine coolant sensor, replaced it with new - nope, didn't help. This was before I discovered bad contact on TPS. BTW, this TPS was new, I replaced the stock one with TPS from Infinity J30, it seems to be the same thing. I tried to open my old one and broke it - the plastic cover was rivetted to the base. My advice - don't try to open it unless you have a spare or really good skills - you'd need to put it back afterwards to drive the car.
TPS also has one more important sensor - idle switch. It is just two contacts that must be closed when throttle is closed and they have to open as soon as you depress the pedal. My own theory is that CPU consideres TPS value to be zero at that point. So, I couldn't make mine to produce more than .2V (must be .4V) without those contacts opening - so I left it at the position where they just ready to open when I move the throttle. Works like a charm, otherwise my automatic Maxima was going nuts - slamming into 2 at high rpm to the degree that my wheels squeeked. Never thought that improper initial TPS position can have such an adverse effect and it was set at .4V, according to FSM. This is also my own unconfirmed observation - I didn't have time to try it again.
I also had leaky fuel lines before all these troubles - car was driving fine, except the paddle of gasoline under and the smell. No, your original idea doesn't seem right. Fuel pump also doesn't look likely to me - you're saying that it happens more often at low rpm, where pump can produce enough pressure working even partially. If you pull the fuel pump fuse it usually takes few seconds for car to die - at this time with completely stopped pump. OTOH the low rpm part of TPS will be worn the most as it stays below the middle most of its life. Depends on your driving style, though .
I also found this quite useful: http://www.cardomain.com/ride/748507/1

CapedCadaver

iTrader: (8)

the connector = suck anyhow. look at all the green corrosion junk. can't be good. anyhow, i'm going to start to work on my TPS and harness too. I need a good way to redo the harness with a new one, because my current one is teh suck. maybe some of that grease also, like you put on your battery contacts. that way if the "new" [jy] one harness boot rips too, i'll still have that grease on there.

Max_5gen

iTrader: (2)

The link in my previous message belongs to completely defferent guy, I have nothing to do with those write ups. He has very nice pictures and very informative pages but he also expresses his own opinion- use at your own discretion. I didn't put anything in my TPS, just replaced with the one from J30 it was twice as cheap. Just for the record - I've fixed a lot of electronics in my life and I have never succeeded reparing a pot, it came back every time, so I just don't try anymore. The thing the guy is right about is the ohmmeter test - if you unplug TPS socket and connect ohmmeter instead it should at least provide you with smooth resistance change throughout. The key word is 'at least': if it doesn't - it surely has to be replaced if it does - it guarantees nothing . Resistance between side contacts should stay the same regardless of throttle position. One glitch - replace the TPS, it has crack in its resistor plate.

LvR

It sure is a pity Viking left - he may have been opinionated, but usually had very good technical reasons for arriving at that opinion, and more often than not he had the right approach to tackle any problem

Max_5gen

iTrader: (2)

Sorry if it sounded bad - I do praise him for the site and if he was hanging here I'm sorry that I missed a chance to chat with him. Actually, I can't recall any other place with so much relevant information. It just OP sounded like myself few years ago and I hoped that he wouldn't take anybody's advice (mine in the first place) as a fact.

CapedCadaver

iTrader: (8)

OK i got a new vid of it. i'll post it as soon as it's ready to see.

I haven't cleaned anything yet. I wanted you to see/hear it better before I cleaned anything. I know my TB is grimy inside, and I know my hard TPS connector (the waterproof one) is corroded because the rubber boot broke wide open, thus allowing moisture in. Dunno about the other two (MAF and IACV).

CapedCadaver

iTrader: (8)

here is teh video.

coincidentally the hesitation started at THE MOMENT i turned on my blinker, though totally unrelated. i did not increase gas pedal pressure from the time I hit 1200rpm sputtering, to the time I entered 2nd gear.

strangely my warmup idle was just 1500, though I don't think my engine was fully cold because I was only there for like 3 hours if that.

LvR

I was about to comment on the strange effect the indicators getting switched on had on the idle when you changed your post - anyway sure is strange.

IMO the rate at which your idle speed fluctuates in that video cannot be compensated for by the IACV at all - its way to slow for the mechanical valves in there to cause/affect the mixture ................ so to me then its an electrical issue

Time to stop wondering and doing:

1. Start vehicle and have it idle - switch on every conceivable electrical load and see if the batt/alt remains around 13.5V+.

2. While #1 is happening measure the voltage drop over the fat cables running between the alt output terminal and the + batt post - measure on the post itself and not the batt terminal as well as the alt output bolt itself and not the terminal ................. if all is well expect to see no more that about 0.1V over the length of that fat cable and terminal assemblies ............ much more than that is looking for trouble.

3. Do the same as #2 for the earth side of the battery - and especially the short little cable running to the body of the vehicle - lots of problems seen mentioned on the forum there

4. I would check Viking's website again and do a complete once-over of all the earth connections on that vehicle.

5. IF you have a voltmeter that you can mount and watch inside the cabin (try and connect it to the "busbar" inside the fusebox and not on the batt or alt directly - this way you can detect funky wiring connections from the battery if your alt+batt is ok), do that and see if your voltage stays around 13.6V+ at all times - also - See this little personal experience of mine with charge/alt issues

6. Since you have already mentioned you know some of the connectors in the engine-bay are corroded, its time to do them all and clean them properly - again see Viking's for very good details.

Once all of those (including replacing the known bad O2 sensor) have been attended and sorted I feel confident in saying you should have a less funky overall performer

CapedCadaver

iTrader: (8)

just to be sure you saw correctly, the car is in motion basically the whole time the blinker is on. I stopped for maybe half a second, and then continued on (albeit VERY slowly due to the hesitation). so the fluctuation is actually happening at part-throttle, say, 1/16th or 1/10th. by the time the hesitation was done, I was already finished turning, mostly. but the hesitation last time (with the music blaring) was when going dead-straight.

LvR

Sure - but IMO we are now starting a lot of speculation on the possible interaction of various unknowns caused by various known bad connectors etc.

Time to clean it all up and have a decent reference.

Alex_V

+1. Fix the list of small easy stuff and then we can go from there.

Oh one thing you can do is take out the fuel pump and make sure the pre-pump filter isn't clogged.

~Alex

CapedCadaver

iTrader: (8)

i'm getting a 53k mile used TPS and harness pretty soon. Possibly same-day shipped to me tomorrow, to solder onto the old harness. i can do the oxy sensor tomorrow too. I'll do the rest as I can.

I'll look around for the alternator connector stuff. if I may ask, do i access the fat wire on the alternator end from the top or bottom of the car? as far as i can tell the battery light has never come on except during startup when it's normal.

LvR

We don't have the same alts as you guys here in South Africa - we have Bosch units here and in my case I had to do it from the bottom after removing the RH side bottom belt/engine cover with 4 (?) screws. Guess I could have done it from the top but I don't fancy possibly frying the skin off my arms on the hot exhaust manifold.

That battery light tells you about the alternator generating a voltage higher than that of the battery (and that is really all) - depending on the internal design and connections of the alternator, you may find the alt actually producing 14V+ while the batt is sitting at something lower, yet not have the full alt's output reaching the batt terminals ala my experience documented in that link of mine.

CapedCadaver

iTrader: (8)

well, i'm buying a new TPS today, scraping the crud off the old harness connector while waiting for a new one of those from Mr Alex_V, cleaning TB and IACV and possibly the MAF... and possibly seafoaming this bad puppy. If i do seafoam, would I just pour it all into the vaccuum line at once or what?

CapedCadaver

iTrader: (8)

http://btp.mine.nu/Jared/max.org_stu...s/MVI_2130.avi

... cleaning IACV and TB later today I think. after I do my taxes. and replacing 02 sensor if my mom will let me drive her car to the parts store, so that i will not burn myself upon touching the exhaustybits.

maybe seafoam too?

CapedCadaver

iTrader: (8)

yeah our alternators are also basically sitting on the floor of the engine compartment too. so off comes the plastic cover... and in goes the multimeter

LvR

You on your own with Seafoam there - we don't know the stuff here - lots of posts seen on the subject and how to smoke-up the whole neighborhood though

CapedCadaver

iTrader: (8)

i was already told basically how to do it by Mr Alex_V (dunno why I call him mister... he's just 2 weeks older than me). I cleaned TB and IACV mostly yesterday, but it was getting late and I'd already snapped a vaccuum line in half so I called it a night. I'm about to get back out there, and check out the buildup on the IACV's valve seat and the other thing... um.. the air cut valve. I cleaned the TB with a toothbrush so it should be pretty good now. The IACV plug-on-a-hex-nutted-stick thing was absolutely DISGUSTING though. The tip shrunk by like 2mm in diameter when I cleaned it; it had THAT MUCH buildup. After I replace the vaccuum line (i've got some leftover from another job) and actually put the intake back together in a non-OMFG-it's-late-i-give-up manner, I'll see how it runs, and warm it up, and adjust idle. But I will put off the TPS until after I get the new connector from Alex, and I'll just buy another TPS and let that be that.

Then i'll go to my grandparents' house again... and shoot another video. That's the one starting point from which the hesitation almost always happens, is at their house. Sometimes at work, sometimes at my house... but like 70% of the time I leave there.