weird tps signal

[thecrew2999]

i got a MS2 version 3 and ive been having weird issues where tomorrow im gonna reflash the MS completely because i made the mistake of calb the thermo sensors while running and i think it is causing the issues anyways the issue im having is this.

the tps signal when watching the datalogs and all is jumpy between negative numbers and 30 it appears even tho i am not hitting the throttle, but when i do it does not read any changes (this is only with engine running) once its off tho its reading just fine.. that dont make any sense to me im not sure what may be causing this.

as for the thermo sensor not reading right it is reading very low where the factory temp gauge in the cluster will go almost to the red zone before i shut it off. where its not letting the fan kick on like i had it before (fan kicks on when grounded).

when i hear coolant bubbling the MS is reading about 180 - 190 degrees. the IAT seems to be reading fine as its very very close to the outside temp but the CLT saying at least 20 degree colder which i think is why the fan isnt kicking on being influenced by the MS reading ( i have the fan kick on with the factory setting from the factory computer )

hope this all made sense since its getting late and i need to get some rest

[Matt Cramer]

Where are all your sensors grounded?

[thecrew2999]

all threw the factory grounds. see the factory had the grounds all on the same wire which all fed right back to the factory computer, it works a lot like the MS does but i did add another sensor ground since i have a LC-1 wideband i wanted a good reading there also and so i wired in another ground to it. basicly just splicing off of it. this is located inside the dash but im thinking about removing it now since it dont seem to make a difference if its connected or not readings are the same.

i think i should mention one thing tho..

i have my wiring harness connected to the pins in the factory computer ( i had this working perfect before so i cant say its the fact i am using the factory and MS ) i have some wires off the megasquirt running together with the factory computer for example the CLT and IAT sensors both run into both computers as well as the TPS but the ignition and injectors i removed them from the factory computer so it does nothing only the MS runs them.

also i had a different issue earlier where the CLT would go with the TPS movement and it turns out i had a wire touching and that cause the whole problem. the TPS worked then...


im gonna reflash and also gonna check all my connections for the 30th time make sure i dont have anything touching..

reason i posted this is because it sounds like a weird issue with the CLT sensor

[trakkies]

How did you share the TPS? It has 5 volts across it. If you wired both 5 volt supplies from the two ECUs I'm not sure what would happen.

[thecrew2999]

they both just read the same voltage. i didnt add tps to one and then the other they both read from the same source

[thecrew2999]

ok i just reflashed then i imported the saved msq i had saved of it before the flash and also checked all the wires... nothing it touching anywhere that is remotely related and i even double checked the resistors i have installed on the MS mother board both are reading perfectly to each other yet the CLT still does not read right.. when i turn the key to on before attempting to start the car the IAT reads outside temp and the clt reads about 20 degrees colder or more.

when the car is started it climbs pretty fast (coolant temp) then it slows down when the factory cluster is climbing, it keeps climbing yet the MS reading for temp is slowing to almost a hault.
by the time the MS reads 180-190 the coolant is bubbling in the overflow. IAT dont seem to climb much but it does move and it is a cold garage so just ignore that.

the TPS still does not work when running yet it reads when the key is on and not running..

i have not checked batt volts on the MS but the block on the bottom says good so i havent thought to check it till now.

ill include my MSQ and mind you i have not really done much to it at this point since im having other problems. i even done a datalog to prove the MS isnt reading tps but still the car revs ok dont seem to be effected by the fact its not reading almost like it is reading just not showing up on the dashboard.

another thing i feel i need to mention i was messing around with a ground a few days back and i hit a power source with it by mistake and seen a spark ark off lights dimmed but it happened fast and i didnt think there was any damage, just funny readings now is all...
it was either the ground to sensors or O2 wire.

do you think there is a chance i might have done some sort of weird damage?

to try and explain more i had spliced the sensor ground where it goes into the factory sensor ground and it was connected where it should have been, the other end i was gonna connect to my wideband ground to try and keep a clean signal when this mistake happened

[thecrew2999]

anyone?

[Matt Cramer]

Are you sharing temperature sensors with the factory ECU, or does the MS have its own set of sensors there?

[thecrew2999]

everything is shared with both ECUs only difference is MS has control over injectors and spark

i had to in order to keep the fan control setting and cruise control i needed to keep the use of sensors to the factory computer

the factory fan control is used by speed sensor and temp sensor it kicks on for temp but also is over ride by speed if the car exceeds 40mph i believe it is the fan is shut off so it dont burn it up.

the cruise is the big reason i kept the factory computer at all without it the cruise cant work.

[thecrew2999]

i can understand i guess the sharing of sensors you guys keep mentioning but the thing is it never had a issue before and if its being a issue why isnt it messing with the IAT and why do i lose TPS when the engine starts? but not before with just key on.

i guess ill get my hands on another spare computer and ruin that as well see if maybe just something happened to this one i got in there....

see when i put it back to factory it runs flawless

[trakkies]

i can understand i guess the sharing of sensors you guys keep mentioning but the thing is it never had a issue before and if its being a issue why isnt it messing with the IAT and why do i lose TPS when the engine starts? but not before with just key on.

i guess ill get my hands on another spare computer and ruin that as well see if maybe just something happened to this one i got in there....

see when i put it back to factory it runs flawless

How are you actually piggy backing the sensors? I've never done this, but my thoughts are that simply paralleling the various inputs might not work properly without some form of buffering.

[Matt Cramer]

everything is shared with both ECUs only difference is MS has control over injectors and spark

What is the value of the factory ECU's bias resistors for the coolant and IAT sensors, and does it use a constant bias resistance or does it switch bias resistors at different temperatures?

[thecrew2999]

i got everything connected in the factory computer, i got the wiring for MS either touching the pins that come into the factory computer or i have the pins in the factory computer completely remove from the factory computer and only touching the MS wiring.

if you know what a ford computer looks like without the case you would understand what im saying

like one side had the solder points for the pins and if i shared those pins i would just solder the wires for the MS to them and if i wired the injectors for example i would unsolder the pin and pull it threw to its own wire going to MS.
its nice because the factory computer has its own sensor grounds for ref and its own case grounds and 2 other ground points as well as several power pins.

i ran it this way because i wanted to keep it clean and be able to switch back to factory if i felt the urge. was also kinda the idea so i could get more SHO guys into the MS since all we have is the junky tweecer






i forgot to mention that.. before i messed up and used the MS bias resistors that came with it for GM but then i was having a issue with the fan not kicking on and then removed ( i believe r4 and r7 ) and replaced with ford ones and it was dead on everything read the same and everything functioned

[Matt Cramer]

If you do not know what temperature sensor bias resistors are inside the factory ECU and whether the ECU uses a single set of bias resistors or switches them at different temperatures, DO NOT SHARE TEMPERATURE SENORS WITH THE ECU UNTIL YOU DO.

[thecrew2999]

umm ok .. yeah it uses the ford ones sold on the DIY website i cant recall the exact value of them off hand but yeah its the right ones plus is a single one no switching.

like i said it worked fine before fan functioned and it read the right temp

but how about the TPS?
when i checked battery voltage it read 12+ not running and 14+ running so its correct (on the MS screen)

i am having one problem with my alt tho when i start its not charging right till i give a quick rev and it starts to charge. i will be fixing that asap i gotta get another but its not everytime so i doubt thats the issue

[Matt Cramer]

I am not asking about the bias resistors in the MS. I am talking about the bias resistors inside the EEC-IV. If you don't know THEIR value, don't share temperature sensors.

[thecrew2999]

got it figured out... turns out i had a strand of wire touching inside the db37 connector i soldered it back in place on the pin slipped tape in between the pins so no more problems and its working again..

it was hard to see the strand as it was touching behind the pin..

everything working good again.
just need to get my tune down now, pig rich

thanks everyone for the help