Idles but won't go

I have a 95 SL1, 120,00m. The problem has gotten worse. I bought the car very
cheaply because it had an "unknown" problem. Which was this... The car would
start and it would idle for as long as you let it idle. But as soon as you put
your foot on the gas pedal it would die. I've replaced fuel filter and pump,
and replaced the Bosch Platinums that the previous owner had in there. He had
replaced the EGR valve as well.
At this point it takes many attempts to get it started, but then it only runs
for about 3 seconds then shuts off. Initially i was not getting service engine
light, but now i am. However, when i use a jumper to get codes, all i get is
the standard 12code.
Suggestions please?

Glen in Maine

 

IIRC, ODB-II started with the 95 model year. You can't read the code
off an ODB-II system with a jumper like you could with the ODB-I. Many
people have said that you can go to Autozone-like places and get the
code read for free.

-rj
98SL2

 

IIRC, ODB-II started with the 95 model year. You can't read the code

ODB-II didn't start till 96, which is why he CAN and did read the codes with a
paperclip.

 

Did you wait after code 12 was done to see if you got more? It should
flash 3 times then goto the next code(s).

http://www.differentracing.com/tech_articles/diag_info.html

My random thoughts at this time, TPS, Vacuum leak, Fuel pump 2 second
prime but never signaled to stay on, inspecting all previous work, Crank
sensor, ignition module... To much left to look at, not enough
discription given for the problem, this will take some time for sure.
Did it ever build oil pressure? When it did run was it rough or smooth
idling?

 

..>ODB-II didn't start till 96, which is why he CAN and did read the codes with

thank-you Bandit. Yes, i can use a paper clip, and did. I finally got some
codes. 22, 23, and 34. According to the haynes manual there is no 22,23, or 34
problem. So i'm back to scratching my head, unless someone has a better list of
codes/problems

 

My random thoughts at this time, TPS, Vacuum leak, Fuel pump 2 second

When It does run, it runs smoothly. I can hear the pump do it's 2 second prime
and if i continue cranking i can hear it running to supply more fuel. The pump
is still a possibility but doesnt seem to be the problem at this point. Could
it be the MAP sensor? I replaced the IAC valve, no luck there.
At this point, when it does start, it will ramp up to 3k rpms and come back
down to about 1k rpms. once it hits 1k it drops right off to 0. Also getting a
lot of white smoky exhaust.

Glen (going bald from scratching his head)

 

here is what i have for your codes:
22 - Throttle Position Sensor-Voltage low
23 - IAT Cicuit low
32 - MAP Sensor - Voltage out of range low

hope that helps
Good luck

Jeremiah

 

I cant remember on a saturn but a lot of those codes are items, on some
cars, that can be plugged into the wrong place since they're all usually
grouped around the throttle body. Also those codes could of been set
from someone forgetting to hook them back up after playing around and
then cranking it. Since they are all low voltage that would be likely if
they werent hooked up. Even unplugging them while the key is on might
set the code.(clear the codes and see if they come back)

The white smoke could be water that has been collecting in the exhaust
or a sign of a blown head gasket. A pressure test of the cooling system
would probably be a good idea. It will tell you if a head is cracked or
a gasket is blown. Another idea to keep in mind is the timing chain may
have jumped. Its very very rare but can happen. Fuel pressure regulator
is another thing you might look at. There is a bunch of stuff to
eliminate thats for sure.

Keep us informed and good luck.

 

This makes it more clear. Those 3 sensors all depend on a +5V power
from the computer. Check them all with a voltmeter - I bet you have no
+5V signal. The bad news - if there's none at the computer itself, then
the computer's shot

The good news - if there *is* +5V at the computer (And I bet there is),
then it's just a wire broken in the harness.

Using a Chiltons or such, you need to find which pins on the sensors
connectors are the +5V supply and which are the return (on the TPS and
MAP - IAT is 2 wire).

I'd forget about IAT for now - the car can run without it. It needs MAP
and TPS, though.

BTW, as an experiment, I once unplugged:

O2
IAT
MAP

And found the car idled just dandy (in fact, a bit better, I thought).
The check engine light came on, but it idled. Revving it wasn't very
sucessful, though.

 

Thats a good observation. I didnt even think about the 5v sourse being
shot. The cars probably trying to run by looking at what few sensors it
has left and its trying to run off of its programing. Letting off the
gas quickly just chokes it down so fast its not able compensate, same
with trying to get above 3000 rpm. If he's slow on and off the gas it
might stay running.

 

PAUL's SUGGESTION: Follow the process to get "transmission codes" to
read out, when you place the computer in diagnostic mode.

The Haynes manual explains how to do it, and has a full list of codes.

There is good chance, at 120,000, that you have some kind of tranny
problem that is killing the engine.


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