94 Tracker EGR stall test fail and . . .

[tbb10785]

Hello,

Specs; 1994 Geo Tracker, 2dr conv, 1.6, 8v, 2wd, mileage unknown. Neglected by the previous owner(s) and trying to fix as I have time and money.

To date, fixed the distributor oil leak and got timing close. I couldn't fix the timing with the jumper wire (also couldn't read the codes). Got a used power steering pump and got it functional. Lots of of other little things and reading the fixkick documents.

I cleaned EGR valve about 8 weeks ago, completely filled with carbon. passages clogged but ran out of time so just got those clean this week. I got the passages clean (used old speedo cable) and started the motor to confirm. Revved to the moon when started but quickly stuck my fingers over the holes, motor stalled. Re-installed the EGR tried the stall test and nothing or very little rpm change. I replaced some vacuum lines today and checked the line from the EGR to the bark valve (circular directly above EGR) it was clogged, the line. Cleaned clogged vacuum line and re-tried stall test with vacuum pump. Oh, the EGR valve will hold a vacuum so diaphragm is good?. Anyway, no joy the stall test still didn't cause a stall. Ideas?

Driving. Since day one April 2015 (about 2,500 miles ago) it stumbles or surges on light throttle. Example flat highway at 60mph it surges horrible and worse going down slight grades. However going uphill it drives perfect, good throttle response and decent power for what it is.

Any suggestions? Oh, I can take pictures or video if needed. I better with a computer but working on my mechanic skills :-)

Thank you,
Bruce

[fixkick]

Welcome BRUCE.
did car sit unused for a year>?
the main must open with about 8inches HG vacuum pull, it has a valve there, that open wide, can be done in hand to be sure it repeats and dont stick open as they love to do (and stall car at every stop light)
if the stall test fails, then the exh path is locked,
this car my guess is the horrible quad port EGR, deep hidding intake x4 EGR injection point.
if the input exh path to egr and the output paths are clear , the stall works. (400 on robust engines)

stumble and surge.
defeat the EGR, make sure its closed and see if it stumbles now,,, (just pull EGR main hose , and plug it with say a golf tee)
now if it runs bad. its not EGR, caused.
1;seems that is RPM surge, not misfiring?
when you are driving, and it surges where is your right foot doing, off pedal?
but at 60mph the pedal is depressed and the idle switch can not close , at 60mph so its not a maladjusted idle switch that causes the ISC to go nuts.
must be pure injection rates wrong.
and air leak , only makes power on this engine pure strong power.... same as right foot does. (speed density systems)

i wonder if :
fuel pressure is surging?, (if is bingo) FPR bad? or worse the FPR, vacuum nipple leaks fuel, (bad FPR and most are now, this old)
8v TBI single injector , o-rings cracked. do the key off am i dribbling test , air horn removed? find both failures, o-rings or injector leaks.

more.
does the ECU flash code 12? on demand?
or flash 12s driving and surging.

the surge might be pure air. related. if injection looks ok. the EFI matches fuel to air , actual flowing. so....
vacuum booster leaks. (vacuum pipe)
or some other vacuum line or device leaks air. and varies by time. /heat /virbration, etc.


cheers kick

[tbb10785]

Thank you Kick,

Oh, missed a spec on the car - 5-speed.

I'll continue to work on it as time permits. Sorry, I don't have any history on this tracker. It was a $1,500 beater with a new soft top and tires, it ran so I decided why not. Hard to engage clutch was an easy fix with a new cable. The speedo needed a new cable and a new (used) instrument cluster. I only drive this tracker within about 15 miles of my house. I can walk to work so it doesn't have to be perfect but eventually I'd like to get to to run properly. Annual mileage will probably be 4,000 to 5,000 miles tops. Oh, I had the dreaded stripped fill plugs on the diff and tranny. Diff drained and refilled but will need to weld a bolt onto the tranny plug. Lots of future projects on this one :-)

Stumble and surge. At highway speeds, flat or downhill, with my foot just ever so slightly depressing the gas pedal surging/stumble happens. If I accelerate to half throttle or more NO surge, or if I completely remove my foot from the throttle pedal NO surge. Trying to hold a steady 55mph (or 60mph, etc) causes the surging, if you are completely in the throttle or completely off throttle all OK.

No idle or stall issues when stopping at a light (engine hot or cold ok). Cold idle is good too, starts up with a little extra rpm's and dies back after about 10 seconds.

CEL. Comes on with key at startup and goes off. No burning/or flashing CEL while driving. However, I cannot check the codes with the jumper wire, nothing happens. Also, can't fix timing with the jumper wire. I remember reading something in your posts about why I can't do this because of something else wrong with the tracker.

FPR = fuel pump regulator, correct?

Thank you very much for your reply,
Bruce

[fixkick]

you sir are very welcome and will be glad to walk you to the problem with the least work (assuming EGR must work, laws, tests, smog etc)

yes the 3/8" usa ratchet wrenches just wreck 10mm plugs, its a pain, that..... suzuki still sells them due to still on newer cars.

that surge is bogging, lean out. (it not misfire, to me)
might be 02 sensor issues, (unplug the front sensor , ignore DTCs ) and see if surge is gone. easy check.and defeat EGR too, for testing.
when you WOT it , the 02 is not used, and the MAF rules the fueling 100% (air + fuel = what you get, no trim)
off throttle is cut fuel mode, injectors shut down. so , cant surge.

out side usa, say in canada, there is no CEL when DTC code 51 trip, in usa , it will turn on the CEL running... the CEL trips very by country but all other errors trip it. that is all non 12 errors set the CEL running, on all vitara's EFI.


ok, cruise bogging.
its lean.
why is it lean, FPR (fuel press, reg yes) is stuck open causing low fuel pressure, but why would WOT work at low pressure, seems not FPR.
that brings me to induction air leaks
at low throttle, air leaks are huge campared to total air. flow.
but at WOT or near any air leak would be small, and thus not matter.
on OBD2 cars, we see fuel trim go way off, +40% can happen, -4 normal.
we dont have scan tools for OBD1 so is harder nut to crack. like Brazil nuts. LOL.

the MAF needs to be cleaned first, keep spray at least 6 inches away from the delicate parts inside the maf.
i use CRC maf cleaner, safe for plastics is why. (and sensors)
if its clean it will not under report air flows, under reporting causes lean fueling.
then no air leaks from MAF rear all the way to the intake valves in the head,
even injector cushions can leak air. all plenum points that leak and are not MAF metered will cause lean. (02 can correct small errors sure)
that huge air pipe on mine, omg, i looked behind it and the alum. mound to it was busted off, and there was this huge hole there,.. sucking air
as did a cracked PCV hose sucking unmetered air..

---

i agree , EGR is last , to me its always last.
find bog first.
when running right you will be amazed, at 95hp peppy engine.