i am baffled 2001 dodge 3.3

[wvcab]

2001 dodge caravan, 3.3, 270k miles. Incoming day driver had no complaints, nite driver drove 12 miles and returned saying van was running like crap, quick drive test confirmed it seemed to be missing, and did not want to idle, check engine lamp on, battery lamp was on, idled real rough.

got it in the shop, it was throwing codes for oxygen sensor high, tps voltage low, tps voltage high and a 1748.

data  showed oxygen sensor 1 was stuck at 99%. tps ohmed out ok, and 1748 is an internal code for the computer.


pulled the plugs and the plugs are sooty black, and smell of raw gas.

replaced plugs and wires (they had 90 k on them), did a compression check  the high was 185lbs low was178lbs.  the van has had computer issues in the past so i swapped computers with a know good one, and no change.

put a fuel pressure guage on the van and it has 50lbs steady pressure, i wanted to look at the fuel so i pressed the fuel bleed valve on the guage, to bleed so fuel into a clear jar, and the van started running great, no misses, smooth, would accelerate, as long as i was bleeding the pressure off, as soon as i released the bleeder valve, it starts missing.

[wayne petty]

just curious...  which scan tool did you end up with..


the harbor freight 98614 unit???

that unit displays live data on these so you don't have to ohm things..

just get to the live data stream..  

something else...  post the model info..

i did send you a complete 2001 voyager service manual...

look for the RGEP section..

it would be a really big help with the code numbers.. not descriptions..

does that model have a fuel pressure regulator that could have failed and is leaking gasoline through the vacuum hose???

can you slowly bring the engine rpms up while looking at a vacuum gauge hooked to manifold vacuum .. does the vacuum increase?? or stay the same.. or does it drop the faster you go indicating a blocked exhaust .. either a crushed pipe.. a collapsed internal pipe..  melted cat... blocked cat..


P1748 is a TCC short to ground.... a serious code that needs to be looked into... that is more than likely in the valve body bolted to the front of the transmission..

do you have a spare wiring harness connector for that automatic transmission.. so you can ohm the individual circuits..  i am taking that is the overdrive transmission...

the transmission diagnostics is in the rget section..

i can write out the valve body testing.. its not hard...   you will have to pull the battery. battery tray.. the cruise control bracket. and the radiator cooling fan to really get down to test the valve body in place... takes about  
10 minutes to do all of that...

[wvcab]

wayne, you sent me a copy for the 2000....
the 2001, was the first year for the engine and transmission computer to be encased in the same box...

scan tool? i have the otc, the same one as i have always had...  and it does have a data stream.

the cat, ummm the hollow cat?  the exhaust pipe has pressure.

i will have to post the codes... they are out in the shop, and i am relaxing as frank mows his lawn....

[wayne petty]

will a moderator please remove this text and the cat info above..

not the whole thread...  just the hollow info ..

[wvcab]

Sorry I was thinking of the cat screaming down in the hollow.

Codes;
P0202D , P0122A, P0123A, P0118, P0108A, P1478, P1496

[wayne petty]

P0202-INJECTOR #2 CONTROL CIRCUIT
When Monitored: With battery voltage greater than 10 volts. Auto Shutdown Relay
energized. Engine speed less than 3000 rpm.
Set Condition: No inductive spike is detected after injector turn off.



~~~~~~~~


P0122-THROTTLE POSITION SENSOR VOLTAGE LOW
When Monitored: With the ignition on. Battery voltage greater than 10 volts.
Set Condition: Throttle Position Sensor voltage at the PCM is less than 0.16 volt for 0.7
seconds.
POSSIBLE CAUSES
THROTTLE POSITION SENSOR SWEEP
INTERMITTENT CONDITION
5 VOLT SUPPLY CIRCUIT SHORTED TO GROUND
5 VOLT SUPPLY CIRCUIT OPEN
TP SENSOR INTERNAL FAILURE
THROTTLE POSITION SENSOR SIGNAL CIRCUIT SHORTED TO GROUND
THROTTLE POSITION SENSOR SIGNAL CIRCUIT SHORTED TO SENSOR GROUND CIRCUIT
TCM INTERNALLY SHORTED TP SIGNAL CIRCUIT
PCM 5 VOLT SUPPLY CIRCUIT
PCM TP SENSOR SIGNAL


~~~~~~~~

P0123-THROTTLE POSITION SENSOR VOLTAGE HIGH
When Monitored and Set Condition:
P0123-THROTTLE POSITION SENSOR VOLTAGE HIGH
When Monitored: With the ignition on. Battery voltage greater than 10 volts.
Set Condition: Throttle Position Sensor voltage at the PCM is greater than 4.5 volts for
0.7 seconds.
POSSIBLE CAUSES
THROTTLE POSITION SENSOR SWEEP
INTERMITTENT CONDITION
TP SENSOR SIGNAL CIRCUIT SHORTED TO 5 VOLT SUPPLY CIRCUIT
TP SENSOR SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
TP SENSOR INTERNAL FAILURE
SENSOR GROUND CIRCUIT OPEN
TP SENSOR SIGNAL CIRCUIT OPEN
PCM

~~~~~~~~~~~~~~~~~~~~~~

P0118-ECT SENSOR VOLTAGE TOO HIGH
When Monitored and Set Condition:
P0118-ECT SENSOR VOLTAGE TOO HIGH
When Monitored: With the ignition on. Battery voltage greater than 10 volts.
Set Condition: The Engine Coolant Temperature (ECT) sensor circuit voltage at the PCM
is greater than 4.96 volts for more than 2.6 seconds.
POSSIBLE CAUSES
INTERMITTENT CONDITION
ECT SENSOR SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
ECT SENSOR INTERNAL FAILURE
ECT SENSOR SIGNAL CIRCUIT OPEN
SENSOR GROUND CIRCUIT OPEN
PCM

~~~~~~~~~~~~~~~~~~~~~


P0108-MAP SENSOR VOLTAGE TOO HIGH
When Monitored: Engine speed between 600 to 3500 RPM. TP sensor voltage less than
1.2 volts for greater than 1.7 seconds. Battery voltage greater than 10 volts
Set Condition: The MAP sensor signal voltage is greater than 4.96 volts.
POSSIBLE CAUSES
INTERMITTENT CONDITION
MAP SENSOR SIGNAL CIRCUIT SHORTED TO 5 VOLT SUPPLY CIRCUIT
MAP SENSOR SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
MAP SENSOR INTERNAL FAILURE
MAP SENSOR SIGNAL CIRCUIT OPEN
SENSOR GROUND CIRCUIT OPEN
PCM


~~~~~~~~~~~~~~~~~~~~

P1478-BATTERY TEMP SENSOR VOLTS OUT OF LIMIT
When Monitored and Set Condition:
P1478-BATTERY TEMP SENSOR VOLTS OUT OF LIMIT
When Monitored: Ignition on.
Set Condition: The Battery Temperature Sensor, internal to the PCM, goes above 4.9
volts or below 0.1 volt for more than 3.2 seconds.


~~~~~~~~~~~~~~~~~~~~~~~~


P1496-5 VOLT SUPPLY, OUTPUT TOO LOW
When Monitored and Set Condition:
P1496-5 VOLT SUPPLY, OUTPUT TOO LOW
When Monitored: With the ignition on.
Set Condition: The 5-volt supply to the sensors is below 3.5 volts for 4 seconds.
POSSIBLE CAUSES
INTERMITTENT CONDITION
THROTTLE POSITION SENSOR
MAP SENSOR
A/C PRESSURE SENSOR
EGR SOLENOID
5 VOLT SUPPLY SHORTED TO GROUND
PCM



~~~~~~~~~~~~~

what a rats nest of trouble codes....

did you pick up your private message above?

do you have the ability to save the data stream info and snap shot info and paste it into a PC ?

check your new private message with my cell phone number...

wayne...

[wayne petty]

after i posted the info above...

i would like you to drag out your handy digital volt meter...

set it to 20 volts DC....   get the hood open...

get the van started...  turn on the headlights..   if you have to have somebody help keep it running while you do this..   you should be able to do this in under 2 minutes...

copy and paste this and print it out large,  please post results..

1.   test between the positive and negative battery POSTS...  14.1 to 14.8 volts is expected...

2.  test between the Negative battery POST and the engine block.. 0.04 volts is expected..

3.  test between the Negative battery POST and the body .. 0.02 volts DC is expected..

4.  test between the engine block and the body...  0.02 volts is expected..

if you get 0.00 on tests 2, 3, 4,... change the meter setting to 2 volts DC.. and do test 2, 3, and 4 again...    looking for the small voltages posted..

the 0.04 and 0.02 voltages are correct for ground to ground with the engine running and the headlights on..

if you get much more than the tiny readings.. you have a bad ground... and that needs to be fixed first...


this test can be done in under 2 minutes...  has to be done with the engine running..  and the headlights on...

will find all kinds of gremlins that will trip you up....

remember...   electrons flow from Negative to positive...  if you have a bad ground between parts.. you may not have enough electrons to do the job...     if you have a bad ground...  when the alternator is charging..  there might be way too many electrons trapped on the engine... causing weird voltage problems.... like you are having..

this is really the first test i do on EVERY CAR that comes in.. and usually i do it before it leaves just to verify...

i measured 8.5 volts one day on a chevy pickup that was having problems..  this was between the engine block and the body .. both probes on the negative side..  when i fixed the ground. many of the Multiple problems this truck had vanished..

[wvcab]

:cry:  came home at 830 am and reran the scan tool to pull the codes .. van started but ran rough... came home after reading you last post and attempted to do the voltage checks, the #@$# wont start now, i pulled the #2 plug and it is swimming in gas, pulled the rest of the plugs, and they are all swimming in gas.

will give you a call after 5 if thats cool?


i am fustrated at this point.

[wvcab]

used your 4 step voltage drop check, the frame ground, under the battery tray was corroded, and the drip/drain tube was missing on the battery tray. The drain/drip outlet from the tray is 3" above the ground wires/lug, and in direct line.  So cleaned the grounds, and wire ends, and installed a 5" rubber hose on the battery tray. I also removed the plenum, and the injectors,  drained the fuel rail ( the fuel was clear) and replaced the orings and blew out all the excess fuel. I then noticed the insulation on a wire going into the cam sensor was cracked, so i pulled the cam sensor and some of the strands of wire were broken, so i replaced the cam sensor. Put it all back together, and the van runs.

so bad ground, coupled with a bad cam sensor?

the only thing not working at this point is the radiator fans.... will tackle that tomorrow evening.

wayne thank you for the help.