(11-28-2020, 02:34 PM)1995 toad Wrote: I have a 95 tracker that I think has a lean miss after warm up new plugs wires cap rotor air filter fuel filter 150 ish all cylinders belt is good bolt is tight fuel is 35 start 31 run no cel tps tests all good does same miss with o2 disconnected idles great and runs good until it warms up then it has an intermittent sporadic miss. when it misses the injectors make a clattering sound instead of the crisp click at idle when listened to with a stethoscope. cant figure this one out will be pulling the ecu to check caps.. I need some advice. thanks in advance95 16valve + misfiring.
is idle at 800rpm hot? and car have full power on hills?
if spark is good and timing for spark at spec, (others messing with cam belt can get this set all wrong (cam and distrib)
first prove spark is ok
and spark tips are not , black,green,oil wet, or fuel wet dripping, or other odd things there)
the gap is 0.028" not ever out of box ignored and set to 0.045" as NGK sets them (their wild guess is wrong) this car is not high energy spark thus narrow gap.
spark not bad above then it must be fueling.
next is engine, good.
150psi is low is that on all 4 jugs(cylinders)? my guess done on dead cold engine, compression test here.
warm or hot engine sea level and throttle must be blocked 1/2 to full WOT open and let the needle peak do not count engine turns ever. peak it.
of low and 150 is, warm to hot, try the wet test, if it shoots up to 190 or so, the rings are very worn. always log all 4 cylinders, to see them all equal.
The 16v is [b]195 PSI. Seen in FSM chapter 6-6 (not 6A1) Facts. <<< true spec, not my car.[/b]
my data:
My 1996 Geo Tracker 1.6Liter 16valve. , pulls 183-185 PSI on all 4 cylinders. (warm )
My 97' pulls 185 PSI min. dead cold. (a new head) later and hot it does 195 PSI. Old 100k mile engine, now with new oil rings, new crank and new head.
Valve lash not at spec, if set too tight a hot engine can misfire or burn those valves up.
vacuum gauge test shows 19" vacuum hot 800 RPM idle but never BOUNCING VAC, ever.
fuel pressure at spec and , 6 PSI change from keyon to hot idle? must be, or FPR is bad. 36PSi keyon then 30psi at idle is common , 6psi must be seen difference.
Lots of FPR this old fail, or even leak fuel out the VAC nipple. oops bad FPR.
injector leak down test passes, then balance test can be done.
and the more difficult injector, balance test pass? all four do the PSI drop down test equally timed.?
----------------------------------------next is EFI--------------------------------------------------------
those 4 injectors are PWM modulated, fast, to keep them cool so the 3.2MS pulse at idle , there chopper driving that pulse, ive never heard that sound.
Ive scoped it for sure, and chopped. (the chopper is injector cooling and but the injector never reacts to the chop only the slow 3.2mS hot idle pulse.
those cooling pulses are 33kHz, only dogs can hear that, not me for sure,see that on my scope but hear no, the 3.2mS sure as a click only.
Chattering to me smacks of ECU crashing, (bad caps do that) bad caps can also make VSV valves on car go nuts and chatter, and more,
95 has no oBD2 scan tools that work 96+
so is much harder to diagnose.
fuel is 35 start 31 ? what are these number, and how obtained?
O2 pulled only causes, better running if ,hot engine, the cracked exhaust at #4 tube (classic) makes good O2 read 0v and if you unplug o2 it goes to 0.45v
and now engine runs better hot, or o2 is fully dead, pulling it can make fuel mix go better.
if the injectors actually really chatter, at the actually pintle,, true, that smacks of bad caps in ECU , but PWM cooling pulse could be heard. IDK.
hit list on EFI is all sensors , input wrong;
- bad caps is not a sensor but top of all old ECU never upgraded CAPS list. (the big corner cap loves to fail)
- ECT does not read 300 ohms on fully hot engine (pull plug ohm meter to 2 pins read) DMM set to resistor range'
- IAT is not it. but can be tested same as ECT using chart for that, but why bother? the 92 has no IAT, so...
- O2 tells lies, dead, or erratic or old 100,000 miles rated, and or the #4 exhaust header is cracked. sucking in air making O2 read dead wrong.
- MAF bad. (or china $17 clone here, a good maf marks are 58BOO , suzuki marked, if not the maf is clone or refurb. clean the maf from 8 " distance <cleaner.
- TPS bad. if the ohms readings are smooth ,it is good, if TP pin varies from say 1v and 3.5v smoothly key on , no start, and hand moved throttle it is good.
- bad ECU but #1 gets most cured.
Good luck to you and hope all this pans out. good.
cheers and happy holidays
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