hot mess

[torq455]

if you open the tps manually it will max out at 4.99v. mine goes to about 4.34v at 100%. make sure idle voltage is close to .54v and reads 0%. map need to also be checked at wot and engine off, key on too. and find out what your alt is and factor that in. map should be around 4.5v at wot depending your alt. and rpm.

[Superdave]

my TPS goes nuts once in a while.. i usually unplug it with the key on (engine not running) and plug it back in.. then freescan reports it back to 0%

[pontiac3100]

no i thats the volts it reads when I HAVE my foot on the gas all the way.
um key on/engine off the mapp stays around 2.--volts?


i also noticed that when the t/c locks and/or a/c is on she "missfires"....

[torq455]

sounds like the map is bad. low voltage means high vac so little fuel is needed. more voltage means low vac so more fuel is needed. so, with key on engine off vac is low, so i'm thinking that with your reading of only 2 volts, it's telling the ecm to lean out the a/f, since it's suppose to be 4+ volts, thus causing the misfire especially under load. how do your plugs look? lean looks like a heavy frost on the plugs. rich will blacken them sometimes to the point of causing a misfire.

[pontiac3100]

OH NO...i think the last time on looked on the fronts they looked like that.

wait you said with the KEY ON/ENGINE OFF/ WOT...
so i have to have the engine running to check this??

oh yea a couple people told me useing a 95 pcm in a 94 l82 is not a good idea, what do you think??

[torq455]

key on engine off, engine hot at idle, and engine hot at wot are the 3 ways to check.

personally not sure about using a 95 pcm in a 94, might be a obd 1 and 1.5 thing, however i'd never use a different year pcm in my car. sometimes GM will make a change in the engine that requires different programming.

[pontiac3100]

so check all 3 then right??

also i only wanted the 95 pcm becuase it was for a gt...i figured if i got a 94 pcm for base model 3100 then it won't be right......

[pontiac3100]

okay now i checked again...when the temp gauge is 100-180*F the map key on/engine off & WOT it's 2.--.
215*F or when i've been driving for awhile key on/engine off & WOT the volts read 4.--.

i was looking in my chiltons and it said with keyon engine off the volts should be .5 with the engine running at idle should be 1.5v more (*meaning 2.--v)
which is not.

i also noticed when the engine is hot under there and running the map reads 1.8-volts....

plus for some reason she seem to be using alot of gas....i'm useing regular shell.

[kill_them_all]

okay now i checked again...when the temp gauge is 100-180*F the map key on/engine off & WOT it's 2.--.
215*F or when i've been driving for awhile key on/engine off & WOT the volts read 4.--.
i was looking in my chiltons and it said with keyon engine off the volts should be .5 with the engine running at idle should be 1.5v more (*meaning 2.--v)
which is not.
i also noticed when the engine is hot under there and running the map reads 1.8-volts....
plus for some reason she seem to be using alot of gas....i'm useing regular shell.

Map at idle - 1-2 volts
- 18-22 pom = not pulling diaphram, less voltage = sub fuel.

WOT - roughly 4.5 volt
- 0 pom = pull diaphram, more voltage = add fuel.

Check the hose on the bottom of the sensor and also check your manifold pressure at idle.

[pontiac3100]

okay another update, today the outside temp was 90*F engine temp was 99*F , key on engine off map was @4.84v started her up, the "missfire" .
then i drove off floored her ....and no "bogging"!

when i got home and checked after i had shut her off the reading was 3.--volts.

it seems like when the volts read 2.--volts when it's really cold out.

so now the missfire seems to be separate from the "bogging"....


wait am i missing something....
at idle 1.8-volts when engine is running.
at WOT when in drive the volts reads 4.--volts when hot under there....

[torq455]

it's best to check voltage when engine hot so that the idle is at the lowest programed RPM--which will affect vac or map voltage. it it's cold the map will read differently simply because the idle is higher. just change the map for a new delco.

[pontiac3100]

well remember i only have this rpbelm when the engine is cold-warm so....
i think it is the map sensor.
so i'll swap it out

but another problem is when the t/c lock the engine like...stumbles..or missfire.
till the rpms raise past 2k....

[pontiac3100]

okay i got a pcm...from a 94 achieva sc 3100 "dual" exhaust.
and replaced the map sensor.

seems not only the engine "missfires" when cold.
it seems to be under 2k rpms.

and it's really noticeable when her t/c locks.

the map reads 2.--volts, the o2 stays in between.

and it seems that when under 2k @ 50-60mph only egr1 stays open.

oh yea when i was at the gas station letting the pcm relearn she was running a lil rich.


thats all i have.

[pontiac3100]

okay i can say now no cold missfire and i could floor her while in open loop with no "bogging".....
but there's still this engine issue....

[pontiac3100]

bump..