90 gp 3.1 issues

[pontiac3100]

okay my cousin has a 90 grand prix se 3.1 w/ 220k miles.
for quite sometime when you drive the car ,shut it off, and go to start it back up it does'nt want to.

as if the battery is dead.

i checked the volts while someone cranked it...it only goes down to like 10v-11v.

and most of the time it works when you jump it.
or if you let it sit for more than an hour...please help me.
thanks

[pontiac3100]

anyone??

[RWK]

Maybe a bad battery? Maybe not enough amps to turn the starter.

Maybe the starter is going bad?

[pontiac3100]

no the battery is fine.
it's from my old car and the battery is somewhat new....

iut's fine when cold as i said in a previous post i hooked my dvom up to it and checked the volts when starting.
it goes down to 10volts....

[pontiac3100]

?????

[IanSzgatti]

just be a little more specific with the symptoms and you'll have a billion answers... i.e

how does it sound starting cold?
does it crank every time cold?

how does it sound when it does crank after driving?
is it only after the car has been drivenshort trips?
does it only happen when car has been at operating temp for a while?
does the car ever stall/run rough?

Voltage means squat... you can have 12v and 150A, or 12v and 650A.
Before condeming things and guessing, we need more precise info on the symptoms... so tell more and we'll be more helpful... if you already found the prolem, great... post up your findings!!!

[pontiac3100]

just be a little more specific with the symptoms and you'll have a billion answers... i.e

how does it sound starting cold?
fine
does it crank every time cold?
yep
how does it sound when it does crank after driving?
the same
is it only after the car has been drivenshort trips?
no
does it only happen when car has been at operating temp for a while?
yes
does the car ever stall/run rough?
thats the weird thing. it does'nt stall with me.
but with him it does (and he kinda drives like miss daisy)

and it idles high too.

but when i have the car it depends where ever i go i leave it running.
i take the key out though and lock the door

Voltage means squat... you can have 12v and 150A, or 12v and 650A.
Before condeming things and guessing, we need more precise info on the symptoms... so tell more and we'll be more helpful... if you already found the prolem, great... post up your findings!!!

but i still have'nt found the problem though

[IanSzgatti]

ok, when this happens again, you need to be prepared, and I'll tell you how. Print this... it's gold.

First, get an ohm meter and set it to measure 1-200 ohms... check the resistance of each injectors. You want them all above 12 ideally, Heres how to see whats going on....

example #1 cyl#1 -11.8 ohms
cyl#2 -3.4 ohms
cyl#3 -12.2 ohms
cyl#4 -12.6 ohms
cyl#5 -11.4 ohms

in this case, injector number 3 has much too low resistance, causing a high enough draw in the circuit for the PCM shut down injector power, causing a full no start.


example #2

in this example, your car is cold, and can be started. if you checked the resistance of injector three now you might get 11 or 12 ohms, but as the injector heats up it expands, allowing it to become "open".

check all your injectors after you've warmed up the car. if you find some low numbers... replace them.


Now, if they are all within range when the car is hot, you'll want to lean toward getting some used known good coil packs, and ignition modual, and a crank sensor.
at the time when the car stalls, have a spark tester in the car and while it is "no-starting", check to see if you have no spark... if no, take some water (keep in the car, a big jug) and pour it on the coils to cool down the ICM quickly... if it cools down enough and your car fires up, replace ICM... if it doesnt, replace crank sensor.

intermittents are a bitch just check your injectors first, because i think your hunting will end with them. take your meter to a U-pick-it yard and try to grab a shit load of 12+ ohm injectors, so that if they do fail when heated you'll have lots and chances are you'll be good to go.

let me know what happens.....

[pontiac3100]

thanks for the advice i'll make note of it; but i meant the starter does'nt do nothing when it's hot under the hood.

but i told my cousin that when the car keeps shutting off it has to b ethe injectors.

becuase on my maxima se when the engine is cold she gets up with no problems.

but like 20minutes later it acts up.
one of my injectors had 26 ohms.

i told him that has to be the problem.
and to replace the starter too.

also we replaced the coil pack and icm so thats ruled out.

as for the idle hiogh thats another issue according to the code there's like a short in the idle system thats making the iac motor open more.

i removed the connector but it idled @800rpms and crappy then then slowly raises up.

does the pcm have to be for a 90-93 3.1 mpfi pontiac?

becuase he grabbed one form a 3.1 lumina.

[IanSzgatti]

i dont get why an injector would have above stock resistance??? I've never seen internal corrosion in an injector... oh well.

as far as your PCM question, ask in the computer threads on this site.

[SHOoff]

but i told my cousin that when the car keeps shutting off it has to b ethe injectors.

Wait, it's shutting off on it's own when it's running? I thought you said it just wouldn't re-start after shutting it off?

as for the idle hiogh thats another issue according to the code there's like a short in the idle system thats making the iac motor open more.

i removed the connector but it idled @800rpms and crappy then then slowly raises up.

Bad IAC?