map and vss codes

[rtcabal]

hey there,
recently got my van up and running after a rebuild. its getting close...

after the first time i really got on it (an entrance ramp 10psi run), the check engine light immediately came on and the car went into limp mode. it gave me 'map 13' and 'vss 14'. i replaced both (a new map and a used vss) and it didn't do doodle squat. i can't find a vacuum leak, though i'm not ready to rule that out, as we've all seen some sneaky vacuum leaks.

any ideas? wiring?
thanks for all the help. i'm pretty ready to be done ironing out the kinks, and get on with the front wheel burnouts.
-taylor

[NAJ]

Is that a code 13 and 14? If so they are both Map codes.
13 is Map Pneumatic (Vacuum) Circuit
14 is Map Electrical Circuit
Code 13 is set if Map Voltage does not match Throttle Position or Vac/Pressure do not match Voltage. Voltage is directly related to Vacuum/Pressure.
Do not forget that the Map Vacuum Supply is from the Baro Read Solenoid.
Tee a Vacuum/Pressure Gauge into the line before the Baro Solenoid and see what your Vac/Pressure reading is when the problem occurs then Tee into the line between the Baro Solenoid and Map Sensor,they should read the same.You may want to Tee into a Known Good Manifold Source first so you have a Good Baseline to compare to.
If everything checks OK you will need to compare MAP Voltage to Vacuum/Pressure.
Post back your Vacuum/Pressure results and we will go from there.

[rtcabal]

ok. got myself a fancy new vacuum guage; 18" at the map and 18" between the map and the baro.

also, my otc 2000 its giving me 'map 13' and 'vss 15'. sorry, but i messed up earlier and said 'vss 14'. so, yes, 13 and 15.

thanks,
-t

[NAJ]

You have a Scanner,that makes things a lot easier.I assume everything is Stock? You will have to run the Scanner into the Vehicle and and with a Helper drive the Vehicle until the Problem occurs.You will want to record MAP Voltage and Vacuum/Pressure at the time the Problem occurs. Tee your Vacuum Gauge into the Line between the Baro and Map so your reading is straight from the source.

[rtcabal]

yes it's stock, but there is a grainger valve. and gnarly 3-inch straight exhaust that's soon to be replaced (i bought the van with this on it). it ran fine before, maybe a little rich. and of course, boost creep.

the scan tool will tell me the voltage reading, huh? i have not explored it's capabilities outside of reading codes.

also, check engine light comes on at idle, about 6 seconds after start-up. do i need to drive it to get a reading?

[rtcabal]

i just did the sensor test with the otc. i think i performed it correctly. i did not drive the car, however, and the manual it came with leaves much to be desired.

anyhow, car idling, 18" vacuum between baro and map, press '5-sensor test', then '08' for the map, and it gives me this: 'KNOK0.0V08'. (note the first 'o' is a letter, the last 3 numbers.)

did i do this correctly?

[NAJ]

Read Map Voltage from Datastream

[rtcabal]

datastream? is that a function on the otc? sorry, i haven't had much time to mess with it today...

[NAJ]

Data Stream allows you to look at Sensor Values, Map Output, Coolant Temp,
Air Charge Temp, TPS Voltage,O2 Voltage,Idle Speed,MPH, etc.
My Monitor 2000 died many years ago.I have been using Chrysler Scanners since 1995 but the Monitor should allow you to see all Data and perform all Tests as the Chrysler DRB 2. There were earlier years where you were not able to read "Live" Data, I just do not remember the year it changed,I was able to read "Live" Data on my 90.
Data and Actuator Test Mode are the 2 you will use the most.
Learning your Monitor will be like playing a new Video Game,the more you use it the more you will learn about it and it will become easier.

[rtcabal]

my otc calls it 'dataline'. anyhow, i'm glad at least that i'm getting to explore the scantool...

map voltage started at .08, then climbed by.02 increments every second or so. i turned the motor off around 3.4, the highest i saw it climb. also, did the test with 2 map sensors and it gave the same reading.

what do you think? should i poke around with a multimeter?

[NAJ]

If I understand correctly Map Voltage is climbing by itself at idle?
This is a Turbo Vehicle Correct?

[rtcabal]

yup. 1990 plymouth voyager with a t1. has the decals; its factory. and, yes, the check engine light comes on after about 5 seconds of run time, then the van goes into limp mode. as i said, i got this reading with 2 different map sensors, so i'm pretty confident this is correct. the voltage doesn't change (except for that incremental climb) when i rev, either. just adds .02 every second.
???

[NAJ]

When it goes into failure the controller is putting in a substitue value.
Connect a Voltmeter between the Signal Return and Ground and see what Map voltage truely is.While you are doing this Tee a Vacuum Gauge between the Baro and Map so we can see what Vacuum to the Map is.
Also with the Key On/Engine Off and the Map Connector unplugged Connect your Voltmeter between the 5 Volt Reference Line and Sensor Ground.
If you do not have 5 Volts connect the Ground Side to a Good Engine Ground and see if 5 Volts are present.

[rtcabal]

i just got a reading by doing a 'sensor test'. don't know why i didn't do it right yesterday...

the map volatge is .8. it changes when i rev it a little, up to 1.2.

map pressure is 11.311"

baro pressure is 28.

pressure between the map and baro is 18" at idle, goes up accordingly when revved. i've had a gaue spliced in the whole time.

sorry i'm a novice with the scan tool. the readings i just got from the 'sensor test' mode seem to be good. don't know why when i check it through the dataline it increases like that... going to poke around with a multimeter and let you know what i see.
thanks, alot.

[rtcabal]

multimeter says:

5v reference good with respect to map harness ground.

.85v from map at idle.