87tunedport

have a check engine light on a Trans Am i just got for o2 sensor. i found out all the wiring is gone and i wanna put it back in so i can get the light off my dash and also for the electric choke on the carb. can anyone tell me do i have a single wire o2 sensor or the 3 wire? mines an 86 5.0 with carburetor. also any sources to get replacement wiring?

OrangeBird

iTrader: (1)

That's an easy one to answer ; with the possible exception of the V6 Turbo "TTA" , every third gen left the factory with a single wire O2 sensor . For all I know the TTA very well could be a single wire or three wire since I have no wiring diagram for that car , but I'm 100% certain that all the "regular" (non turbo) cars had the single wire .

PS , the wire your looking for will be a small diameter purple wire , as per this diagram .

87tunedport

where is the ECM located? is it possible to just run a wire from the C1 pin to the o2 sensor and wire in a connector?

OrangeBird

iTrader: (1)

If that one wire only is missing , sure , as long as the 02 sensor's input gets to the ECM it don't matter what color the wire is , or even if it's in the harness all pretty with the others , you get that signal to the correct terminal on the ECM and it will function as an 02 sensor should . If you are looking for the original wire I believe it will be in the large harness that runs from the passenger's side and goes behind the engine . Of course there are at least two purple wires that I know of in that area , one small gauge one for the 02 sensor and one large gauge one for the starter solenoid .

Oh , and your ECM is located in the dashboard on the passenger's side and is mounted where most cars would have a glovebox . You get to it by removing the lower plastic pieces under the dashboard and a couple of screws (bolts?) will allow it to lower down and out of the dashboard .

It will look like the big silver box on the passenger's side in this pic , thankfully you'll not need to take any of the dash apart other than the lower plastics to get to it (I was replacing my entire dashboard in the pic) .

87tunedport

alright i finally got some time to get back over to the car since i got her and the o2 sensor is there and the wiring it is the single wire. however i noticed the piping for the EGR is chopped off and some cut wires around the carburetor. is there a way to pull codes like on OBDII? ill have to find out what the reason check engine light is on

what i do know is the previous owner told me alot of the emissions was removed but from what i have seen it was done poorly. the car does run and drive great, however im suspecting the choke is not working right since when i depress the gas pedal to start it takes a few tries and feathering gas. and probably getting bad gas mileage

should i just leave it the way it is? like i said she runs and drives great and look very nice

OrangeBird

iTrader: (1)

Honestly , were this mine , I'd restore the functioning of each and every system connected to the ECM such that the ECM sees no open connections to any of it's input and output devices . This system was designed to operate with ALL of it's equipment in place , as things get removed the ECM has to use "default values" to replace the missing inputs and this results in the infamous "limp home mode" that is really just the ECM being partially blinded to what the engine is doing . Jerkoffs who just cut and hack ; "ayup , gotta get rid of all them thar EEemissions crap the evil guberment has put under my hood" should be removed from the gene pool and forever banned from even holding a set of wirecutters . CAN the emissions equipment be removed and still have an engine that produces all the power it possibly can ? Of course , but only if some SERIOUS ECM tuning goes hand in hand with any and all modifications . To just remove stuff , and leave the ECM looking for that missing stuff , is the height of poor form and shows your car's previous owner was one of the clueless dolts who butcher these poor cars , rather than anyone with an actual plan for making meaningful modifications . The very fact of the check engine light being on after this clod's supposed "improvement" shows the guy hadn't a clue .

Now , as to codes , if you type "paperclip" into the search bar here you will find that two terminals on the ALDL when jumped together with a paperclip will cause the check engine light to flash out the codes stored . I'm pretty sure it's the top righthand two terminals that when jumpered puts it into diagnostic mode . It'll flash code 12 three times as a system check , followed by flashing out any actual stored codes .

A few pictures of whats actually gone on under the hood will be helpful in determining whats been hacked by the previous owner ....

87tunedport

alright i plan on returning to the car later today to replace a fuse that has blown. i will try that paper clip and see if i can get any stored codes and get some pics of the chopped stuff

87tunedport

Ok when I jumped the pins on the aldl I got code 12 three times which I think is for entering diagnostics then I got a code 15 and 23

OrangeBird

iTrader: (1)

Im not 100% sure but I think 15 is the coolant temp sender for the ECM (separate from the one that operates the temp gauge in the dashboard) and 23 is the intake air temp sender that tells the ECM how warm or cold the air is the engine is pulling in .

Since you already know you've got cut wires and hacked out components , the best thing to do would be to attempt to buy replacements for the missing/damaged pieces from the "parts for sale" listings here and restore it to it's factory state . There are several people who specialize in third gen parts so it's not like any of it is unobtainable , it's just a matter of spending the cash and doing the legwork to track it all down and put it all back together right .

87tunedport

Is the sender for the ECM on the thermostat housing? I have one there hooked up and something that looks as if it was broken off

Also where is the IAT on a carb engine? I thought that was on fuel injection?

OrangeBird

iTrader: (1)

Interesting , I just looked at my code list and that's what it said code 15 is , the IAT , although I do know some of the codes were different whether a car was a MAP or MAF car so maybe something like that is the reason here ?

Anyway I don't offhand know where the ECM's temp sender is on your car since mine doesn't have a carb . I know the search feature around here is a bit difficult but maybe if you get lucky and search out some threads the locations of what's what can be found .

gearhead141

Yes, that temp sensor that is on the thermostat housing is what sends the signal to the ECM. The one that is broken was also a temp switch for the EFE system. Check the wiring for that temp sensor that is still in place. The sensor itself could be damaged and will need to be checked.

The code 23 is for the M/C solenoid on a carbureted engine. I replied to that in your other post.

I agree that the fool that removed all of the emissions equipment only created more problems. You are doing the right thing in getting these problems sorted out.

87tunedport

thanks for your replies on both posts it helps alot.

if all the wiring is ok on the M/C solenoid what else could i do to troubleshoot? just replace?

ill try to see if i can get that broken sensor out tomorrow. what colors are the wires? so i can look for them and see if i can save them

87tunedport

are they both on top of the thermostat housing for gauge and ECM? icannot find much info on the broken one only the one hooked up. my gauge works

87tunedport

is it possible one of the sensors is for the electric fans?

would this one be the replacement for the broken one?

gearhead141

If your car has electric fans now, I assure you it didn't come that way. The broken piece in your thermostat housing is a vacuum temperature switch that was used for the EFE system. You can search on the forum for that. The temp sensor for your instrument gauge is located in the driver side cylinder head. That looks like the photo in your last post. The ECM input is shown in the schematic given earlier. The wires are black and the other is yellow. These are connected to the sensor in your T-stat housing that is not broken; then again, it might be.

87tunedport

i noticed the fans are wired to a aftermarket temp sensor mounted in the radiator fins. but i may remove that crap cause i had bad experience with that stuff. i did discover by turning on the AC the fans turn on too

i checked the wiring on that sensor and they look intact so im probably looking at replacing that sensor then right?

most of the stuff for the EFE system is gone but i still have the heat riser and vacuum servo that stuff looks badly rusted though. the original air cleaner is also gone. probably looking at big bucks to put that back in working order for now ill focus on the 2 codes i have first and see if i can get the CEL off

what do i do to trouble shoot the MC solenoid? i did turn the key to on and heard no clicking

gearhead141

what do i do to trouble shoot the MC solenoid? i did turn the key to on and heard no clicking

There is either an open in the circuit, i.e. blown fuse, or the circuit is grounded. A grounded circuit would cause a full lean condition and an open circuit would cause a full rich condition which would be noted by odor and/or a smoky exhaust. Either way, the car isn't going to perform very well. Other causes of an open circuit would be a cut wire on either the ground or the power. First thing to check is if there is a complete circuit at the connector to the solenoid. With the connector removed from the solenoid and the ignition circuit on, check with a meter for voltage across the leads. If no voltage is found, keep the positive lead on the light blue wire terminal and put the black lead of the meter to frame ground. If voltage is showing, there is an open in the ground circuit. If no voltage is shown, then there is an open in the power circuit.

This will give you a good starting point to trouble-shoot.

87tunedport

Ok I'll try that today, off hand do you know what the voltage should be at?

gearhead141

At this point, I would say you have no voltage. But once you get it working, it should be in the 10-14Vdc range.

I also wanted to mention that your concern about the air cleaner is valid but because you aren't using the car a s a daily driver, I don't think it will matter much. You see, the temperatures under the hood get pretty hot and the factory came up with the cold air intake to make sure the engine wasn't sucking in hot air.

GeneralDisorder

iTrader: (1)

Has anyone verified this even has a CCC carb on it? Doesn't look like it to me. None of those sensors will matter with an aftermarket carb.

Rick

87tunedport

Just got back from testing the solenoid, there is 10.6 volts with key on at the connector.


The car is gonna be summer cruise/ car show car so I won't be driving her on cold days

gearhead141

That is a good solid reading. No need to check the circuit any further, as it is good. Now, you need to check the resistance across the solenoid itself. I just checked mine, and it read 22.7 ohms. After you check yours, which should be more than 10 ohms, we can proceed from there.

87tunedport

just got back from checking that. in case anyone is wondering she is at a storage unit and the manager there is very strict on the "no working on cars" policy, so im trying to secretly do what i can little at a time without arising suspicion.

anyway i was getting a reading of 0 ohms but i also noticed my battery was dying. i took the battery out and have it home on the charger and ill try another attempt tonight after the manager leaves for the day but as of now my reading was 0.

i did have some voltage left as the dome lights were still on but not enough to turn the motor over

gearhead141

Really no need to have voltage. With the connector removed from the M/C solenoid, check resistance across the terminals/posts. Until I got my meter leads in the right position, I wasn't getting any resistance either. My first thoughts on your condition are this: you may have a bad M/C solenoid, it's not unheard of on a new part but very rare. The other possibility is that the solenoid is not adjusted right, i.e. so tight there is no audible clicking heard.

If in fact you don't have any resistance across the solenoid, then it is failed. At this point you are left with a decision; take the carburetor off and replace the solenoid yourself, or take it to a shop and have the work done there, and last choice, leave it as is. However, you will still have the check engine light (CEL). The whole purpose of the M/C solenoid is to ensure that the engine is getting the proper fuel ratio at part throttle condition. If you want to tackle this on your own then I would suggest searching the forum for E4ME rebuild or E4ME M/C solenoid.

87tunedport

how hard is it to remove the carb and replace this solenoid? it is a replacement carb last year but is a stock replacement

87tunedport

ok i unplugged the connector and checked the MC solenoid and still got 0 i had my meter set to ohms and checked 3 times and it was always 0. what else can i do?

how does the solenoid come out? i know you said i have to pull the carb

GeneralDisorder

iTrader: (1)

Have you considered a drop-in, self tuning EFI? These are getting pretty cheap these days. The FiTech stuff is amazing:

http://fitechefi.com/products/30003/

You already have the aftermarket air cleaner, etc....
Just saying....

Rick

87tunedport

by the looks of some videos i have watched and searching the forum i think im calling it quits on the MCS looks like its too much for my measly skill. ill have to take her to my mechanic who knows carbs inside and out, see what he can do

any advice on the CTS code? all i did was verify the wiring condition. should i just replace the sensor?

as of right now its too rich for my blood, i just ordered the stock replacement wheels for the car at a cost of 500 with new tires so its a little out of my range for now

GeneralDisorder

iTrader: (1)

Versus taking the car/carb to a mechanic + parts? The EFI is self tuning so you could do it yourself. I understand the budgetary concerns though. With adding the high pressure fuel pump, and misc. other parts it's easily $1500. Still, that's SOOOO cheap compared to what it's been in the past.

Rick

87tunedport

he is our trusted family mechanic i have gone to for years when ever i run into something i cant handle. hes always good to me on price and if something is more then expected i can make payments to him while still enjoying my car to me seems more reasonable for my budget.

i bookmarked the link you posted as a future project though

87tunedport

Should I just replace the coolant temp sensor?

87tunedport

i have tried every search i can think of on this site and just yahoo to get some info on the MC solenoid and i have not found much of anything. spent last 2 days searching. ran across some threads but most touched base on them but just petered out with no resolution. IDK why but even this thread seemed to have died out

UPDATE:https://www.thirdgen.org/forums/carb...-ccc-qjet.html
i found this thread which i believe will help me. looks like all i need to do is remove carb from car, remove air horn, and i should be able to access the MCS to replace it?

anybody have any links to get the exact part? tried ebay and everytime i put the vehicle in it tells me its not compatible. might be because most of the sellers didnt list Pontiac on the chart but i need to know for sure if im gonna spend 60+ on this part

five7kid

iTrader: (14)

And I assure you that you are 100% wrong. '86 LG4s had a single electric fan, energized with a thermal switch in the passenger side head.

five7kid

iTrader: (14)

http://www.ebay.com/itm/Mixture-Cont...NSRuhh&vxp=mtr

Another source I regularly reference says it's discontinued.

87tunedport

I'll have to check see if I have that switch. I have a single electric fan and then only way to activate it is by turning on the AC
Thanks I just ordered it I'll keep my fingers crossed that this goes ok

five7kid

iTrader: (14)

It has a pretty high "on" point, like 238 degrees. The switch grounds a relay to energize the relay and power the fan.



Just make sure you remove those two screws inside the choke tower when you go to remove the air horn.

87tunedport

Will do thanks I'll keep you guys updated once I get the part and pull the carb

Something tells my she's gonna wanna run hot just like my 87 did lol

gearhead141

Sorry about the Snafu on the electric fan on an '86. My reference point is an '85 with a clutch fan.

five7kid

iTrader: (14)

87tunedport

so, i think i can see why my CTS is not working. the sensor connector also spins

http://www.autozone.com/engine-manag...2_245578_18589

im gonna grab this tonight and put it in when i get the MCS

gearhead141

Such a deal! And you get the pigtail as well. I suppose that might be because the sensor connector may not be the exact same as the original; just a guess on my part. Did you try the multimeter across the sensor leads? If there was an open, then it was definitely broken. It should have given a resistance reading that would correlate to the coolant temp.

87tunedport

I'll try the multimeter today but either way I'm probably gonna just replace it. With the connector broken like that it won't snap into place so anytime driving it can just come off. The female connector on the sensor itself also spins around so leads me to believe connection is disrupted. I'll check and report back

In regards to MCS, can i remove the solenoid with the carb still on the car? I was just wondering cause I saw a guy working on a G-body with the same carb and he replaced the tps that way

87tunedport

good news. i was able to acquire the original Rochester Quadrajet carburetor that originally came on the car.

he said he replaced the carb because the electric choke was not working on the old one. he just gave me the old one along with the original air cleaner, and repair manual.

i got my multimeter out and i was getting 23.4 ohms at the MC solenoid on the old carburetor

gearhead141

I suppose anything is possible, but I'll give you a little food for thought. Do you really want to be tearing a carb apart still bolted to the engine? The possibilities of dropping a small part are very good and the chances of finding said small part are astronomical.

Save yourself a lot of frustration. It just takes a few more minutes to separate the linkage/cables and then you have the carb out and can work on it in a brighter, clutter free environment. I'm closer to 60 than 30 and my aching back just would not be able to take that kind of punishment. Once again, food for thought....

87tunedport

i uploaded some pics of the old carb showing the current state plus the ohm reading. does anything look out of place? can this one be saved?

p.s. excuse my kitty, he didnt want to move. he wants to learn how to work on carbs too lol

gearhead141

It doesn't look that bad, as 30 year old carburetors go. The choke looks like it is original. I say that because it is riveted on. I would say that between the two carbs you have, one good one can be made.

87tunedport

could it be as simple as adjusting the choke? those rivets can be drilled out right?

BTW im still waiting on the MCS so i have not gotten any further on the new carb

87tunedport

thanks for the insight gearhead ill pull the carb and work on it at home
ok i got the new CTS installed along with the new pigtail. i capped off the open vacuum ports on the carburetor and replaced the PCV valve.

now the car idles at 400 any suggestions? when i remove one of the vacuum caps that tees off for the choke pull off the car goes back to normal idle

i just made another thread for that problem because i reinstalled the original air cleaner and a whole new can of worms was opened :/

at least i got the new CTS installed, still waiting on MCS

gearhead141

I believe the "Tee" you are referring to goes to the stock air cleaner and the choke pull off. The port facing forward connects to a hose off the bottom of the air cleaner. You are getting closer to getting the carb dialed in. Once the MCS is corrected, there shouldn't be any more codes.