3500, 7730 ecm, code 33...cant figure it out

[merlot566jka]

ok well a little explination first, the car has been running and idling on its own for a while now. ive been trying to datalog, but cant get a connection. so today i thought id do somethings to make the engine bay look better and take care of my exhaust. heres what i did today..

moved coil packs into trunk
moved the cts, tcc and reverse switch's wiring to under the exhaust.
put a new connection on the positive terminal (everything flickerd when i started the engine today)
ran new pipe from the collector to the tips.

when i got done with the exhaust i went to start the car and its started like normal, ran rich and then idles right at 950. then the lights on the dash went out and the car died. i went back and found the positive terminal was loose so i tightened it again and started the car. it died imediatly. i started it again, revved it up to clean off the plugs and took my foot off the gas...it died again. i checked the codes, 33 was the only code. thats for map sensor voltage high. i checked the map, vaccum and wiring. all was ok. reset the ecm and tried it again....same thing.
thinking it was a vacuum leak, i smoked the engine (leak detector from redline, good tool to have) and i found the throttle body adaptor was leaking. so i replaced the gaskets, added some rtv and waited about 45mins and started it again. same thing, died imediatly. i tried again this time holding the rpms around 1200, it surges like it has a vacuum leak. so i smoked it agian. no leaks. now im puzzled. i swapped map sensors...nada.
i pulled off the tb and adaptor, cleaned then up made new gaskets again, rtv again and let it sit for about an hr. still same exact thing. i smoked it again and took off the oil cap to see if there was anything coming from inside of the engine....nothing.

where do i go from here? i have no vacuum leaks, the wiring isnt grounded, map is good, and it ran fine before.

did the batt cable that came loose screw things up in the ecm? it did flicker and shut off while the car was running...

i dont think there is anyway me putting new exhaust on can affect the map....can it?

is there a way that the coilpack relocation cause this problem?

how can i test the map wiring ( its got the 5v reference, but i cant tell what its supposed to be, voltage wise, at teh other terminals. i know the other is ground.)

what frustrates me the most is the car ran fine into the shop, and i really didnt do anything that would cause a problem with the map. i cant get the damn aldl cables to work so im screwed there.

im really not liking the fiero today.

[IsaacHayes]

What ALDL cable are you using, what laptop, and are you using a USB adapter? Are you sure the ALDL connections are solid on the port?

Maybe un hook the ground and let it sit for a while to clear the ECM, then try it again after it has cleared.

[merlot566jka]

usb obd1 cable from aldlcable.com

acer aspire 4520 laptop from wal-mart

connections are very good. ive checked everything over and over. been trying to get it to data log for about 3 weeks now. no success. ive tried tunerpro rt, freescan, winaldl, tunercat, and datamaster. ive tried every com port up to com10. tunerpro says my cable is found and functional on com3...yet com3 is my modem and my cable is installed on com8. if i move the cable to com3 i get nothing from the aldl cable test. its just very frusterating. with my vettes id use a home made interface witha $50 laptop and it worked great....now i dont get shit with an $80 cable and $600 laptop. what gives?

[1988GTU]

I would try using a Serial cable (non USB) if your laptop/pc contains a 9pin serial port.

[Joseph Upson]

I would try using a Serial cable (non USB) if your laptop/pc contains a 9pin serial port.

I believe it depends on whether he is running Win XP or an earlier version. 98 should work but a newer model laptop with XP may require the USB to 9 pin serial adaptor. That's what I ended up using with my laptop manufactured in 03.

Can someone provide a link to the other programs aside from Tunerpro that can datalog 8F code from the 730 ECM. I'd like to try the free examples since I'm already registered for Tunerpro.

[merlot566jka]

aside from the data logging, anyone ever had map problems?

usually with a vacuum leak you have a higher than normal idle, in my case i do not.

is there a way to test the map while its connected to a voltameter to verify its function?

im going to swap ecms in the morn and see if that helps

[merlot566jka]

and i just replaced the plugs.....maybe ill give them a check to make sure they didnt back off...i used nuclear grade anti-sieze i 'got' from my ship. maybe i didnt get them snug?

only other thing i can think is wiring, grounds, or lim.

illl check the cts too

[IsaacHayes]

Yeah, check the ECM pins and the MAP connection if you put the new pigtail on. You soldered it on right? Check to make sure the connection hasn't failed from a cold solder joint or something. Make sure all your grounds are good. Did you isolate the ECM case from chassis ground?

[merlot566jka]

no the ecm is grounded to the chasis..is it not supposed to be?

the map connector never came off the fiero's wiring harness, i used the old style map, just tee off the brake booster line. helps when you hit the brakes and the engine would lower in rpm....makes it less dramatic.

ill double check the grounds all 1 million of them from the ecm and batt

[IsaacHayes]

Well if the grounds fails on the engine to chassis or to battery high current could go through the ECM. Just a precaution safety measure. GM keeps the ECM's isolated for this reason.

[merlot566jka]

didnt realize that.

that sux. good thing i have a backup ecm

[Joseph Upson]

Well if the grounds fails on the engine to chassis or to battery high current could go through the ECM. Just a precaution safety measure. GM keeps the ECM's isolated for this reason.

Definately makes a difference, I destroyed my first twin turbo 3.4 motor after having forgotten to connect the ground. The engine repeatedly went into severe detonation at little to no boost on take off. I didn't find the problem until I pulled the engine to make the setup single turbo cluelessly thinking that had something to do with it and didn't discover the damaged pistons until after that was finished and driven on for about 2 months. My guess is the missing ground caused excessive timing advance from the ECM.

It was a nightmare because an exhaust rocker backed off at the beginning of the new cam break in which occured after the turbo change and the cylinder amazingly used the intake valve for intake and exhaust resulting in a tapping noise in the intake that sounded like the previous detonation episode causing me to interrupt break-in rpm several times. By the time I figured it out the cam had been damaged and that manifested as a miss after about 30 miles of driving and an engine full of glitter after 60 miles.

It also stopped up the oil filter because I plugged the bypass, discovered while flushing the engine at home and noticing the oil pressure bottoming out to 0.

You definately have to succeed at datalinking, it wouldn't be so bad if you were dealing with a few adjustments to the stock engine with its designated code. Remember my MAP sensor was bad causing most of my headaches and I didn't discover it until I finally got an ALDL link because no codes set for it.

[merlot566jka]

well crap.

i guess ill gab a new map too

[merlot566jka]

it was the ecm

[IsaacHayes]

Make sure to isolate it this time.