Idle slows and stops after revving

[CliveElliott]

I have a Canadian 1990 Geo Tracker, 1.6 L 8V TBI, with 3-speed auto transmission and 4WD with 143K miles (220K km). Engine was swapped about 3 years ago and has about 120K km on it.

It starts fine and idles at about 800 rpm consistently, until I speed it up to 1500 or 2000 rpm; then it won't hold the idle speed after that - gradually slows down to 500 rpm, sputters a few times and stops. (I can easily keep it going using the throttle.) Then it won't start - just cranks, and unflood mode doesn't help (i.e. throttle pressed to floor). Is this a fuel problem (e.g. pump or filter or bad fuel?), or could the ISC be dirty?

I should mention that it coughs occasionally when I rev it - bad gas?? (It sat for months so we added some Seafoam and 2-3 gal more gas.)

Another quirk I should mention is that the throttle doesn't seem to control the engine as accurately as I would expect - engine speed sometimes changes without my moving the throttle, and is sometime slow to respond to throttle.

It has new NGK cap/rotor/spark plugs and wires, new air filter and new ECT sensor. Compression is about 130 psi (cold, WOT) on all cylinders. (We are at 3500 ft altitude so it should be 135 psi hot).

[fixkick]

I have a Canadian 1990 Geo Tracker, 1.6 L 8V TBI, with 3-speed auto transmission and 4WD with 143K miles (220K km). Engine was swapped about 3 years ago and has about 120K km on it.

It starts fine and idles at about 800 rpm consistently, until I speed it up to 1500 or 2000 rpm; then it won't hold the idle speed after that - gradually slows down to 500 rpm, sputters a few times and stops. (I can easily keep it going using the throttle.) Sounds like eGR sticking open to me this.

Then it won't start - just cranks, and unflood mode doesn't help (i.e. throttle pressed to floor). Is this a fuel problem (e.g. pump or filter or bad fuel?), or could the ISC be dirty?
if it dont start check spark, if sparks gone check the VR gap i the distributor, this dizzy makes its own spark and timing.
the isc will not cause sputtering but would cause idle regulation to end. if it sticks.

I should mention that it coughs occasionally when I rev it - bad gas?? (It sat for months so we added some Seafoam and 2-3 gal more gas.)
how many months, 12 ,24?


Another quirk I should mention is that the throttle doesn't seem to control the engine as accurately as I would expect - engine speed sometimes changes without my moving the throttle, and is sometime slow to respond to throttle.
correct not normal, hot idle is regulated at 800 rpm (AC off)


It has new NGK cap/rotor/spark plugs and wires, new air filter and new ECT sensor. Compression is about 130 psi (cold, WOT) on all cylinders. (We are at 3500 ft altitude so it should be 135 psi hot).
correct 139, or as you said is ok at 3500'
map hose not clogged
, fuel filter ok?

check engine light on , key on, then off running?
then use the diagnostic jumper clip and see if ECU flashes out 12s? code? for ok.

if spark is not lost, usually as stall is, EGR stuck open. I see if the egr closes every time, you cut the throttle.
or fuel pressure lost
or engine is flood,

good luck !

[CliveElliott]

Thank you very much for your reply!!
I have a Canadian 1990 Geo Tracker, 1.6 L 8V TBI, with 3-speed auto transmission and 4WD with 143K miles (220K km). Engine was swapped about 3 years ago and has about 120K km on it.

It starts fine and idles at about 800 rpm consistently, until I speed it up to 1500 or 2000 rpm; then it won't hold the idle speed after that - gradually slows down to 500 rpm, sputters a few times and stops. (I can easily keep it going using the throttle.) Sounds like eGR sticking open to me this.

Then it won't start - just cranks, and unflood mode doesn't help (i.e. throttle pressed to floor). Is this a fuel problem (e.g. pump or filter or bad fuel?), or could the ISC be dirty?
if it dont start check spark, if sparks gone check the VR gap i the distributor, this dizzy makes its own spark and timing.
the isc will not cause sputtering but would cause idle regulation to end. if it sticks.

I should mention that it coughs occasionally when I rev it - bad gas?? (It sat for months so we added some Seafoam and 2-3 gal more gas.)
how many months, 12 ,24? 12 months


Another quirk I should mention is that the throttle doesn't seem to control the engine as accurately as I would expect - engine speed sometimes changes without my moving the throttle, and is sometime slow to respond to throttle.
correct not normal, hot idle is regulated at 800 rpm (AC off)
It does IDLE steadily at about 800 until I start playing with the throttle. What I mean is that when I move the gas peddle the engine speed doesn't respond accurately.

It has new NGK cap/rotor/spark plugs and wires, new air filter and new ECT sensor. Compression is about 130 psi (cold, WOT) on all cylinders. (We are at 3500 ft altitude so it should be 135 psi hot).
correct 139, or as you said is ok at 3500'
map hose not clogged Will look at your site to see how to check this.
, fuel filter ok? Not sure. My husband could check that; he's been too busy working on our other cars.

check engine light on , key on, then off running? yes
then use the diagnostic jumper clip and see if ECU flashes out 12s? code? for ok. yes, 12s and nothing else

if spark is not lost, usually as stall is, EGR stuck open. I see if the egr closes every time, you cut the throttle. ]I'll check your website re checking EGR. I hadn't done that yet because it looked a bit complicated for us non-mechanics.

or fuel pressure lost
or engine is flood, If it was flooded, wouldn't the "unflood mode" have an effect - causing it to at least try to fire? Unflood does nothing at all.

good luck ! thanks again!

[fixkick]

the 8v EGR
is in easy plain site below throttle body
just push the diaphram metal ring in buy hand, that ring there , just push it and the valve opens (key off) and it then retracts under internal spring pressure.
all suz, are noted for sticking EGR, its there THING.
The EGR flexs about 1/4" or 5mm .
i push it like 5 time to make sure it moves, and dose not hang. a new one makes thud sound as it seats closed.
the non responsive throttle will be, bogging lack of fuel issue or misfire, the former is a smooth lack of power the latter is misfire loss of power, and is violent, heard, felt and see engine shake.
this fact above is key to diagnosis
as is pulling a spark plug and see if its white or black. or oil soaked. ready spark plugs sill works on today's gas engines.
12 codes means ECU is happy. good.

yes flooding will clear just like you said. (for sure the least try to fire statement) all accurate
not drivable is it
power lacks wide open throttle, parked and driven. right, if can be driven.
gas dont go bad in 12months, most dont....
does engine reach 180f coolant temp, and hold there? too hot to hold hand on upper rad hose? this is normal, less is bad. 150f very bad.


if the DIZZy Misfires, see the real dizzy page here, and the VR gap
http://www.fixkick.com/IGN_timing/89-timing.html

its noted for wild failures and heat soak failures. the VR and the ignition inside, can go bad, or worse , intermittent or wild results.

cheers to you from texas

[CliveElliott]

the 8v EGR
is in easy plain site below throttle body
just push the diaphragm metal ring in buy hand, that ring there , just push it and the valve opens (key off) and it then retracts under internal spring pressure.
Does the engine need to be up to operating temperature when performing this test? We did it while cold (60oF).
Do you mean the ring on the outside of the diaphragm? It doesn't budge. When we push the rubber diaphragm it moves about 1/16". But none of the metal parts around it move at all. Guess it needs cleaning!? If so, we'll follow the directions on your website. We've ordered a new gasket for it.

all suz, are noted for sticking EGR, its there THING.
The EGR flexs about 1/4" or 5mm .
i push it like 5 time to make sure it moves, and dose not hang. a new one makes thud sound as it seats closed.

the non responsive throttle will be, bogging lack of fuel issue or misfire, the former is a smooth lack of power the latter is misfire loss of power, and is violent, heard, felt and see engine shake. It's just slow in responding the to gas pedal, and sometimes smoothly slows down when I haven't moved the gas pedal at all. Nothing violent. Time to check fuel filter?
this fact above is key to diagnosis
as is pulling a spark plug and see if its white or black. or oil soaked. ready spark plugs sill works on today's gas engines.

12 codes means ECU is happy. good.

yes flooding will clear just like you said. (for sure the least try to fire statement) all accurate
not drivable is it. No. We can back it out the driveway and then it stalls and we have to wait for it to cool before we can restart it and drive it back into the driveway.
power lacks wide open throttle, parked and driven. right, if can be driven. Not sure what this sentence means
gas dont go bad in 12months, most dont....
does engine reach 180f coolant temp, and hold there? too hot to hold hand on upper rad hose? this is normal, less is bad. 150f very bad. Will check this. I understand from your website that the EGR doesn't work if engine is not hot enough.


if the DIZZy Misfires, see the real dizzy page here, and the VR gap http://www.fixkick.com/IGN_timing/89-timing.html
I don't think it's misfiring. Just occasionally missing when I add throttle (once or twice a minute) - perhaps a bit of water in the gas? Cap and rotor are new and good quality.

its noted for wild failures and heat soak failures. the VR and the ignition inside, can go bad, or worse , intermittent or wild results.

cheers to you from texas
Thanks again for your very valuable help. It's an honor to be talking to the author of your amazing website.

[fixkick]

the 8v EGR
is in easy plain site below throttle body
just push the diaphragm metal ring in buy hand, that ring there , just push it and the valve opens (key off) and it then retracts under internal spring pressure.

Does the engine need to be up to operating temperature when performing this test? We did it while cold (60oF).
Do you mean the ring on the outside of the diaphragm? yes, It doesn't budge. When we push the rubber diaphragm it moves about 1/16". do not push rubber, push only the ring, (center part) there is a skeltonized frame there.
But none of the metal parts around it move at all. Guess it needs cleaning!? If so, we'll follow the directions on your website. We've ordered a new gasket for it.
this EGR can stick hot or cold, open and if it does, idle drops (hot) below 800rpm.,even as low a 400. or stalls.

all suz, are noted for sticking EGR, its there THING.
The EGR flexs about 1/4" or 5mm .
i push it like 5 time to make sure it moves, and dose not hang. a new one makes thud sound as it seats closed.

the non responsive throttle will be, bogging lack of fuel issue or misfire, the former is a smooth lack of power the latter is misfire loss of power, and is violent, heard, felt and see engine shake. It's just slow in responding the to gas pedal, and sometimes smoothly slows down when I haven't moved the gas pedal at all. Nothing violent. Time to check fuel filter? sure, if the filter is clogged, it may only idle and not be drivable.
this fact above is key to diagnosis
as is pulling a spark plug and see if its white or black. or oil soaked. ready spark plugs sill works on today's gas engines.

12 codes means ECU is happy. good.

yes flooding will clear just like you said. (for sure the least try to fire statement) all accurate
not drivable is it. No. We can back it out the driveway and then it stalls and we have to wait for it to cool before we can restart it and drive it back into the driveway. ,ok got you, not enough power to drive car.



power lacks wide open throttle, parked and driven. right, if can be driven. Not sure what this sentence means
sorry, was hoping you can gun the throttle parked, in and get full throttle rpms... 3500 or more. just for a second, hot.




gas dont go bad in 12months, most dont....
does engine reach 180f coolant temp, and hold there? too hot to hold hand on upper rad hose? this is normal, less is bad. 150f very bad. Will check this. I understand from your website that the EGR doesn't work if engine is not hot enough.
nor does the IAC close ,nor does ECU go to hot engine fuel mix. if coolant does not get hot, .


if the DIZZy Misfires, see the real dizzy page here, and the VR gap http://www.fixkick.com/IGN_timing/89-timing.html
I don't think it's misfiring. Just occasionally missing when I add throttle (once or twice a minute) - perhaps a bit of water in the gas? Cap and rotor are new and good quality.

its noted for wild failures and heat soak failures. the VR and the ignition inside, can go bad, or worse , intermittent or wild results.

cheers to you from texas
Thanks again for your very valuable help. It's an honor to be talking to the author of your amazing website.



my honor, ! to help you.

[CliveElliott]

the 8v EGR
is in easy plain site below throttle body
just push the diaphragm metal ring in buy hand, that ring there , just push it and the valve opens (key off) and it then retracts under internal spring pressure.

Does the engine need to be up to operating temperature when performing this test? We did it while cold (60oF).
Do you mean the ring on the outside of the diaphragm? yes, It doesn't budge. When we push the rubber diaphragm it moves about 1/16". do not push rubber, push only the ring, (center part) there is a skeltonized frame there.
But none of the metal parts around it move at all. Guess it needs cleaning!? If so, we'll follow the directions on your website. We've ordered a new gasket for it.
this EGR can stick hot or cold, open and if it does, idle drops (hot) below 800rpm.,even as low a 400. or stalls.

all suz, are noted for sticking EGR, its there THING.
The EGR flexs about 1/4" or 5mm .
i push it like 5 time to make sure it moves, and dose not hang. a new one makes thud sound as it seats closed.

the non responsive throttle will be, bogging lack of fuel issue or misfire, the former is a smooth lack of power the latter is misfire loss of power, and is violent, heard, felt and see engine shake. It's just slow in responding the to gas pedal, and sometimes smoothly slows down when I haven't moved the gas pedal at all. Nothing violent. Time to check fuel filter? sure, if the filter is clogged, it may only idle and not be drivable.
this fact above is key to diagnosis
as is pulling a spark plug and see if its white or black. or oil soaked. ready spark plugs sill works on today's gas engines.

12 codes means ECU is happy. good.

yes flooding will clear just like you said. (for sure the least try to fire statement) all accurate
not drivable is it. No. We can back it out the driveway and then it stalls and we have to wait for it to cool before we can restart it and drive it back into the driveway. ,ok got you, not enough power to drive car.



power lacks wide open throttle, parked and driven. right, if can be driven. Not sure what this sentence means
sorry, was hoping you can gun the throttle parked, in and get full throttle rpms... 3500 or more. just for a second, hot.




gas dont go bad in 12months, most dont....
does engine reach 180f coolant temp, and hold there? too hot to hold hand on upper rad hose? this is normal, less is bad. 150f very bad. Will check this. I understand from your website that the EGR doesn't work if engine is not hot enough.
nor does the IAC close ,nor does ECU go to hot engine fuel mix. if coolant does not get hot, .
[/b][/color]

if the DIZZy Misfires, see the real dizzy page here, and the VR gap http://www.fixkick.com/IGN_timing/89-timing.html
I don't think it's misfiring. Just occasionally missing when I add throttle (once or twice a minute) - perhaps a bit of water in the gas? Cap and rotor are new and good quality.

its noted for wild failures and heat soak failures. the VR and the ignition inside, can go bad, or worse , intermittent or wild results.

cheers to you from texas
Thanks again for your very valuable help. It's an honor to be talking to the author of your amazing website.

I spent half and hour writing a reply, then saved it as a draft, and now I can't find my draft.

Sure enough, the ring on the inboard side of the diaphragm snaps in an out, but only about 1/16". So I guess it needs cleaning.

my honor, ! to help you.

[fixkick]

Sure bad fuel, or water, but was gas cap missing? and parked in rain" there should not be water in gas,
symptoms;:
lack of power.
" for it to cool before we can restart "( at this time I'd check spark plug 1 for flooding, if not soaked in fuel cranked dead, then now check spark. (wide open TV, cranking cuts fuel and this failed, so suggests big time lost spark) (TV is throttle valve) in the TB, is throttle body.
if spark is gone, the DISTRIBUTOR NEEDS WORK. (even the VR gap can be wrong , or ignitor bad.)

EGR valve is stuck, (main, valve below TB) IF IT sticks open, engine will want to stall. it can not be allowed to stick open. (very very common)
The EGR is only on line driving, (on very old cars it even works parked hot)
when running it coughs, (this is lean ) and not backfiring BOOM from end of tail pipe,so the lean sign and or timing off.
Just the lean sign, can be bad clogged filter.
my question on engine heat, are kinda moot if car cant be driven , to see if engine has full power, and the risk of getting stranded doing so...attempting.
sure. but you can idle it until it gets to 180F, 180F is normal temp or 195 is using a 195F thermostat.
the test is easy lacking an IR gun, see dash engine heat meter go past center, then touch the top RAD hose, if it gets hot, so hot the hand flies off this is
normal 180F, too hot to handle the hose, long. say for 1min, ouch., that is test that works on all cars, made.
if say the thermostat is (missing or bad, or some horrid 160fput there) it will flood, due to being locked in ECU cold start mode, rich as pig.
this turns the spark tips black, (telling you, Im too rich big time)
now the filter, it can be bad, if bad, the car will not want to have power, the pressure up where you are will be like 34psi, (low end of spec)
This is the job of the FPR, it lowers pressure at 3500 feet. for the injector to flow correctly at the Low pressure altitude.
FPR is on front side of TB, Fuel pressure regulator, they can go bad, if the vacuum hose removed show gas dripping its bad. or fails pressure tests.
The filter is next to the tank.
http://www.fixkick.com/INJECTORS/TBI-conn-1w.jpg


ON cars like this is check spark timing first, on this car, 2 check
is the spark timing correct? if not? the cam belt slipped. takes me 5min work and oops, RETARDED timing, the 60k mile tune up was skipped.

if that is correct, then I race the engine fast to see if those hidden advancing weights are working in the base of that old rusty distributor.
these distribs can advance out to 30 to 40 degrees' (left side of scale , and way off it to the left) left is ADVANCED timing, to the right of 0 is retarded and
when retarded that means the cam belt slipped as all do past 60k and maybe to 100k,, bam, slips.
our store harbor Freight sells a fuel pressure gauge, see hose on right that fits your car, at the filter test port.
http://www.fixkick.com/tools/fuel_pressure_18usd.jpg

I always check spark first. then fuel pressure.
and for sure, when engines dies, spark, test pronto and spark tip colors. (is it dry, is it wet, is it soaked in fuel is it black,oil soaked?)

this is the EGR main, its revolutionized, and the ring is there.
http://www.fixkick.com/sensors/EGR/egr-main2.jpg

the EGR tests are all on a hot engine, but that does not mean at all that we ignore it on a cold engine.
the EGR must not stick open, on a cold engine or hot. if it sticks open it sucks exhaust gases into the induction and engine stalls or run like crap.
this is a linear function, it can stick a tiny bit, more, , 1/2 stuck or stuck fully out 5mm.
the push test only shows that it is free, and when you release the ring, there, it slams shut, (spring inside) and thunk sound happens
EGR love to stick, its there THING. (last bad one I had stuck only while arriving to a stop sign, engine stalls.) Loves to fail driving, sticks....

on a hot engine you push it , it stalls the engine, , on cold engine same.
the hot test is done, all EGR tests because the EGR is off line cold , at idle (VSV valve is dead) . for same reason, but the push test is always a valid test. to see if its OK, not messed up. (in its own right)
once the EGR is ok, we can see it move, as you gun the throttle by hand,, on some newer USA cars, the car must be moving to allow it to move at all.
but not this old canada car, and most real canada cars , (hood stickers show it is) do not have the ECU DTC errors of 51, weak EGR.
Up in canada the car can be, USA fed,USA CALIF. or Canada, or gray market, the hood stickers tell you what car you really own.


Bad gas, sure, only a sample of fuel needs be taken. (doing so is tricky on this very secure and tight system. 60psi it can be under pressure.
but the test is easy. after its put in glass jar ( tank cap off ,siphon out gas method can work)
sniff sniff, does it smell ok? like fresh gas? the sniff test, passing
then let gas sit in jar for 15min,. (it settles out)
do you see water balls floating on the bottom? , yes, oops water in fuel.
if you park a car put that gas protection in the tank, 1year , needs this.
STABIL gas treatment.


you did a tune up with
No new fuel filter (air too?)
no new belt? CAM>?
no spark timing check, ive seen many cars like that with timing wrong after the belt change, this is because the previous owner found timing wrong
set the distributor to wrong timing, on wrong timed cam, then fixed the cam belt and bingo spark timing is now wrong again.
the Distributor is run off the rear of the cam. so,, the CAM is first always. check timing if retarded, the belt did slip, or even a belt put in wrongs
using the false marks.
i think the 90 has no false marks, unless engine was swapped to newer, G16 and bingo cam cog marks are wrong. (1/2 of them) per my page on same.

On the USA car the engine, block left rear has serial number
G16L12345 "L" means 1990 block.

how is this? cheers.

PS:

Id be all over the engine at stall, to see if spark is good. (using even a fresh new test spark plug out of my glove box. classic spark tests)
best time to diagnose, is the moment of failure. bar none.
in fact , keeping timing light with me, at all times. when I suspect spark issues.
one car I had the timing light duct taped to the windshield wiper, passenger side, pointed to my mug, and me driving around the block, trigger taped too.
the bam, spark ended as engine to hot, bad distrib. hates hot engines.
In fact ive even removed the hood to do that, (no rain) I find testing saves money, but others sees spark go dead, and buy a new DISTRIB and end this.
not my call, but do test spark when engines die, and Secret unflood test fails. (WOT cranking)
$20
http://www.fixkick.com/tools/strobe.jpg


make sure spark gaps is .028" this is spec, NGK gaps them for HEI spark systems, .045" that you dont have.

[fixkick]

on any high altitude car, this one is 80hp and now. hp, and now has low compression (90% of normal)
needs all the best fuel and best spark, it can get.
the compression is low up there.
The FPR must work or it will flood. at sea level we run more PSI fuel, so if the FPR is bad, and runs high pressure engine will flood.
This car the FPR is altitude only device. unlike the MPI engine.
when you gun the engine, TBI , fuel pressure holds. (unlike the MPI engine)
there is a pump stall test. or shunt tests, this shows a weak fuel pump.
there are other tests. the fuel pressure leak, down test. injector leaks.

i do fuel tests last (unless i have hard proof now its bad)
1: engine first, compressing, and vacuum check for steady 20"HG vacuum pull, not bouncing at idle./
2: spark tests, and timing, for sure at stall. for sure.
3: last fueling,, this is the big job, lots of tests. but I must discount the above,first, with tests. cant burn fuel with bad spark or a bad engine. cant. will , not and make full power.


say the spark test passes stalled.
and you see sparks dry
we remove the air horn from top TBI
and person 2 , cranks, you look at injector, its in plane site, and see it spray or not. ? if not, fuel pump off line. or ECU sees code 41, or 42 and cuts fuel, as they ALL DO.

here is what TBI looks, like even cranking , does the same thing.
this is double TBI
https://www.youtube.com/watch?feature=pl...eHgh8#t=30

[fixkick]

watch scotty
see 2.07 in to vid

https://www.youtube.com/watch?v=064Ilsz8...ature=fvwp

got spark?

there are other causes.
one is lost compression only hot.
due to not changing timing belt and reading that book and it tell you to set lash last.

the lash set (or is) too tight (or is or was not set) the engine gets hot and the lash now to tight goes to zero clearance or even neGATIVE CLEARANCE
THE VALVES NOW LEAK, AND BURN UP, BUT ENGINE STALLS, SAVING THEMSELFS.

COMplete the 60k by the book, its best in all cases. (100km service points, in metric, meter distance)

all 8v engines, have 8valves and have special complex cam belt tensioning , step rules. its done with loose lash .
all are.
done wrong, (new belt)
The tension will be wrong, and if done right the engine is NOW, set to spec. so is not part of any problems you see.

Its wise not to run an engine out to 100k and not check lash. valve lash.