jht3

symptoms:
-i can hear and feel an intermittent miss at idle and throughout the rev range
-at 25% or more throttle the pinging begins
-no smoke from tailpipe
-no oil in coolant or vice versa

for years now, my 146k mile 3vze seems to ping under medium to heavy load, so i've been giving it 89 octane since that helps it out. i say it pings, but it sounds like ball bearings being shaken in a metal can, so that may or may not be the proper diagnosis. FWIW, it sailed through emissions just two months ago

well a month ago i was running low on fuel, so i stopped by a local Sunoco and filled up with 89. after pulling onto the freeway a few minutes later, the engine pinged like never before and was way down on power. i chalked it up to a bad tank of gas, and limped home, but after many more tanks of 89 and 93 octane the engine is acting the same and is misfiring.

what i've replaced:
-spark plugs (NGK u-grooves)
-plug wires (NGK blues...i broke the OE #3 removing it)
-battery (not related but added it here anyways)
-catalytic convertor because someone cut mine off

the problem got even worse after changing plugs and wires over the weekend, and i am sure the wires are not swapped. i disconnected the EGR vacuum line and plugged it, with no change. i've also cleaned the intake with throttle body cleaner and a 1/2 bottle of seafoam, with no improvement.

over the next few days i plan on testing the ECT, EGR (if i can get a vacuum pump and gauge), VAFM. i don't have a throttle body gasket or i'd pull it and test the TPS. i'm quite frustrated right now and hope i'm going down the right path. i really hate going under the hood on this truck as everything is so crammed and tight.

jht3

today i tested my EGR. at idle i applied vacuum to the valve itself and my engine sputtered even worse. not so much that it died, and i cranked in 20in of vacuum, but it makes me believe my valve is OK. i don't have a vacuum gauge, so i was unable to run through the other EGR related tests. is it possible my EGR is leaking just a little bit? i'm not convinced but just bringing it up

another possibility i didn't think of is my fuel filter could be clogged. it is the original filter so it needs changing anyways. the pressure gauge i have doesn't have a banjo fitting, so i can't test the pressure. i did unplug and block off the pressure regulator, which audibly raised the idle, but didn't cure the misfire or whatever it is.

blue_CA_yota

if it started after you were low on fuel, its possible your fuel filter is clogged with some junk that was on the bottom of your tank..

Pinging is likely to be a timing or fuel problem, so you're at least looking in the right direction.

you don't need an intake gasket to test the TPS.. Don't have to take it off, just measuring the resistance across the pin connectors.. recent thread on here, TPS Adjustmen and Idle adjustment, good link in there.. you can test the tps in about 2 mins with a multimeter..

Thelast83inNJ

Can you scan for codes? Look for lean code? 25? Check the distributor for wear/slop between shaft[rotor] and gear. Spark timing could be changing due to play. Ignitors go wacky. Code 14? EGR problems most of the time are vacuum control solenoid/modulator. Need vacuum gauge teed-in to vacuum hose of EGR and drive, only needs 5-10 inches to open.

sb5walker

You mentioned plugs & wires, did you also replace cap & rotor? My cap gets pitted even before my plugs are done.

Have you run a compression test? It's a good idea with a missing veezy.

pb4ugotobed

Save yourself all the work of checking this, measuring the tps resistance, testing vacuum, etc. Spend 5 minutes and do a quick compression test. I'd almost bet money you've got valve issues... especially if you've never adjusted valve lash is how many hundred thousand miles... The owners manual even recommends resetting valve lash every 60 or 75k miles IIRC...

jht3

thanks for the tips

no codes in the ECU, so nothing to check there

i don't have a compression tester but it's on my list of things to test when i can borrow a friend's. i know the valve's need attention i just haven't had the time to pull the top covers and order shims since this is my only vehicle right now. i'm still putting my other car together after getting it painted

the last time i tried to check the TPS, i couldn't get a reliable reading with my test leads. i'll give it another go

also on my list is a look at the cap and rotor but i'm not expecting to find anything major there

pb4ugotobed

If you got a ball bearings in metal can kind of noise, then you've probably got bigger problems than an out of adjustment TPS or dirty cap/rotor. Start with a compression test and see where you're missing out. I'll be willing bet you dropped one or more cyl's.

jht3

sure, but it has sounded like this for YEARS and only with the throttle buried. and the sound is worse with 87 octane than with 93. shouldn't it sound like that all the time?

regardless, a compression check is long overdue

EDIT: oh yea, the engine only sounds rattles like that when under load. it is rattle free while revving it in neutral

blue_CA_yota

check your ignition timing.. it's possible that your distributor rotated..

the increased octane in 93 grade gas, increases its resistance to detonation. You've got a terrible detonation problem by the sound of it..

jht3

my fuel filter fittings are corroded fairly badly, so i hit them with PB blaster and was able to crack the input fitting loose, as well as the mounting bolts. i ran out of time and didn't get to free the output fitting.

checked my timing and discovered it set at ~50 BTDC. last time the timing was set was maybe 5 years ago by my local dealer, so i'm wondering what sort of damage that may have done, if any

my distributor cap and rotor have seen better days, so those are on the list for replacement


set my timing back to spec and adjusted the idle. i had to rotate the distributor CCW nearly to its max to set it. the timing mark jumps around a few degrees...that is normal right? the misfire feeling has nearly gone away, but i'm not convinced it is completely gone. regardless the pinging is GONE and it pulls to redline better than i can remember. a little less power off the red lights until the rpm's climb but i can deal with that

pb4ugotobed

If you have to set your distributor at its max setting to get the timing set right, then chances are you're overdue to have your timing belt replaced. I'd be willing to bet it's stretched pretty badly...

jht3

hmm....good point. if i pull my upper cover, is there a way to measure that. or tell if my belt slipped a tooth?

jht3

it is still missing slightly. i know it because i'm looking for it, but it is barely noticable

new parts:
plugs
wires
cap
rotor

checked:
timing
engine coolant temp sensor (ECT)
EGR valve

todo:
replace fuel filter
test TPS on-car
check compression

sb5walker

Its not normal to have to rotate the distrib full CCW to set it - should be near the middle. Did you set the jumper in the check connector before checking timing?

If you did set the jumper, timing belt could be a tooth off, so could the distributor gear.

If its still missing, you need to check that compression. Also, what was the appearance of the plugs? All the same? Flat black with carbon? White deposits & worn, rounded electrodes? Or the normal tan/light gray deposits on all plugs? You could have a clogged injector or two.

jht3

yes, i jumpered the connector. and it advances as it should when un-jumpered. i'm thinking something is definitely wrong but not sure what yet. this was all put together last by the dealer when my headgasket went in '03. i find it hard to believe the belt stretched this much and with such a dramatic effect on retarding the timing

i don't have a compression gauge yet, but i'll get one soon

when i pulled my plugs, all were the same except #5 was visibly a little leaner. i would say all looked a bit rich and the electrodes were rounded off. they have been in there for ~50k miles so i was expecting them to look worse. if i can remember, i'll take a photo of them

sb5walker

Unfortunately, having the dealer do the work is FAR from a guarantee that it will be done correctly. VERY FAR.

Autozone or another parts store might have one to lend.

Maybe the #5 injector is a bit fouled - that could certainly account for missing. Try a bottle of Red Line SI-1 Complete Fuel System Cleaner - it has the most polyether amine of any in-the-tank injector cleaner. CRCs Guaranteed to Pass Emissions Test Formula is next best, and at the moment, those two appear to be the only two that still contain PEA.

Good luck.

pb4ugotobed

The best injector cleaner is the EFI cleaner that comes in the pressurized can... that plugs directly into your fuel rail (make sure you get it before the rail so it gets the cold start injector also). that stuff works wonders... I've seen it make cars that could barely hold an idle purr like a kitten after you run a can or two of that stuff through.

pb4ugotobed

And yes (although condition dependant) a timing belt can stretch significantly in 6 years... Toyota recommends replacement every 72 months

sb5walker

The concentrated, in-the-fuel-rail type injector cleaner does work better than the in-the-tank stuff. Sending the injectors to witchhunter is best of all.

It's the miles that get the timing belts, not the months so much. Toyota recommends replacement every 60k miles; but many of us replace them at 70k with no problems. Most of the ones you hear of breaking do so over 90k miles.