1991 geo tracker doesn't usually start in colder weather.

[wildfire]

This problem has been plaguing me for years...and I have been storing it on my driveway for years, rarely driving it off the lot. ( I've been saving it to take to my gulf island cabin) I've replaced the fuel pump many years ago when it originally wouldn't start, and since then have checked everything suggested online over the years (even sent my ecu in twice 2 yrs ago to have it checked over or repaired. When it runs, it purrs like a kitten. But other times the pump just won't kick-in, usually in colder weather. I'm not going to spend much more time on it, going over and over the same routine. I am just wondering if there is something that might affect the fuel pump in colder weather. As was usual, it stopped starting last year in the colder fall, winter and early spring. It still didn't start 2 weeks ago on a mild day, but today, on a hot day, it started right up and ran perfectly. Any thoughts.? thankz

[fixkick]

the pump is bad
or the 2 wires feeding it , end to end are bad. (that means all connectors on those 2 wires are bad, can be, and is common on very old cars like this)
the wires exposed to the elements of nature are prime SUSPECTS.

[wildfire]

thankz for quick reply fixkick...My 91 geo tracker is a 2-door convertible (have hardtop) automatic 4x4 1.6 L 8 valve engine. I bought it here in Canada, and have owned it for 20 yrs. I have done all those tests you speak of over the years. It has little or no rust, and rarely been off road in past. Last time I checked the wiring behind the taillight a few years ago when it wasn't running, was good. So I was getting power to that point. I was going to drop the gas tank again this summer, and check the wiring, and replace the fuel pump again just as a last resort, ( I was thinking a loose or bad connection or faulty fuel pump) but then yesterday it started up again and ran perfectly. So, I was just wondering if this was a common problem, or if there was something I missed in regards to hot/cold weather starting. And like I said, I also sent my ecu in a few years ago to have it checked by the pros twice, and they said they fixed some minor things and rebuilt it the first time, and it also checked out fine the second time after that.

[wildfire]

Yes, engine lights glow aokay.
Yes...engine cranks over all the time when I turn the key on.
When I hear the buzzing in the back when I turn key on, the engine will always start.
When I don't hear the buzzing...the engine will never start.
I've trained my ear to recognize the 3-second buzz.
All Last summer, when I turned the key on about once a week, and got a buzz it started...then the cold weather came it didn't buzz and start.
Since it's not reliable yet, I don't insure it and don't drive it off the lot...just back and forth on the driveway.

[fixkick]

the pump is bad or the 2 wires supplying power it is bad, connectors top list
you can swap the Main relay with the fuel pump relay
below the ECU are 2 identical relays.
one is green socket with pink wires , other is main, for ecu
you can swap this at any time, they are identical.
if the ECU goes dead after we now know (and CEL lamp dead too) then the main relay is now known to be bad.
when the pump is dead.
go back to the tank, get a nice rubber mallet or 18 " 2x4 board and hit the tank bam, if that makes the pump wake , the pump is bad or the 2 wires to it are bad. (on top would be it)

here are the 2 relays,



this can be tested with a voltmeter when dead.
see that pink wire there,?''

i like to cheat (US navy ways) we go to the middle first , making the job 1/2 less. see?
the tail light left SIDE is that place but takes 2 people, (the 3 second rule , makes that so)
same wire pink
as seen on my pump page and here , largest pink wire with black strip is the wire.





the wire runs from the relay,
under the drivers sill plate, to the Leftrear tail lamp then from there down to the bumper, jack then up and forward center to tank and one more connector to fail.
that is the actual path, (in my 91 inspected every inches of it looking for hacks ,damage , and all connectors in the path at least 4 there are and all connectors were bright shinny brass, and no green rust on them (corrosion not allowed) all the way to the tank.
if it failed I use voltmeter to find it.
but it is a fact, takes 2 people you and kid or any one safe at the key, 10 year old kid? put 4dw lever in Neutral, chock wheels, car can not move and is safe.
i then ground the meter black test lead to the body. or (battery neg lug)
with meter on DC volts, prob the large pink wire, end to end, obviously the most easy points first, and the relay tops that list.
if it goes to 11.5 to 12.5 volts key to start, then its good. (will be lower cranking, but that is only if it cranks, its not, 10v is possible cranking.,
Then to tail, lamp huge plug pink 12v key on, each time. (11 to 12v range, in truth no less than 0.5v below actual battery volts is spec)
here



make sure G402 is not bad , 0v key on each time its ground there. to the pump ,clean it . (all 2 door cars LOVE TO FAIL here G402 and the pink connector pins on the left ) water gets up here and well, fails.
http://www.fixkick.com/INJECTORS/PUMP/Pump-Ground1.jpg
Next is center here of bumper bundle of pump wires.

here is the real drawing,

see this. see c403 is where the huge pink wire is.
see rear brace here and this bundle of wires it too can fail.



then last the pump. connectors. this connector too can fail., and is super hard to reach.



all this is on my pump page, lots of info there and tons of causes. i think not one failure mode missing.

Fuel pump relay bad, (rare) do the swap
wires bad
connectors bad
pump bad (smack it hard, keep this in you head so if stranded, pump dead, smack it , no tow truck. )
G402 bad.

http://www.fixkick.com/INJECTORS/PUMP/dead-pump.html

[wildfire]

thanks fixkick for the all the diagrams etc....I already switched the relays before, and they were okay.
I cleaned up the connectors and ground wire behind the tail light...they were pretty clean.
I have tapped the gas tank before when it wouldn't start while my wife turned the key on, and it would start to sputter sometimes, and sometimes not.
Since it is a fairly new pump, I think your suspicion that the wires or connectors may be bad is correct, but it will be hard to detect which ones while the car is still starting.

[fixkick]

facts so far.
1: the failure is intermittant.
2: the voltage is near 12vdc at the tail lamp, pink wire, key on, 3 seconds on, and this point in the chain is good. so is the ground wire seen there for the pump is not rusty.
3: so we now know the problem is at the rear of car. not in side the cab wiring,
1/2 the battle is over, with just one voltemeter test and visual inspection of those 2 wire connections at the tail lamp.

[wildfire]

Yes, it certainly helps to know all that beforehand. The weather has warmed up now, and so far my tracker has started up each time, so I can't test it for faults. But I know it will eventually fail sooner or later, just like it has over the past number of years. In the meantime, if I drop the tank, is it possible to change a few connectors and/or just bypass the wiring between the left rear taillight and the pump? Since I know I had power going to the taillight when I checked it in the past, when I first started having this problem occur. So I suspect a poor connection somewhere there, that's somehow affected by the change in temperature.

[fixkick]

AS the nice drawing on my pump page clearly shows, the wiring harness DRAWING
shows you the 2 wires (Plus/minus and PINK/black) go to a connector at the center rear of the rear bumper, and is 100% visually inspectable and the voltmeter works that too.
this is the wire part on the way to the thank

here is top of tank views, a real 2door.

[fixkick]

if the connectors are all good, and 12vdc makes it to the top of the tank ,then it can fail here too. (and side the tank too)




the rack (pump hanger)