ASE doc

It's Mikey, I'm sorry. i haven't been very thoughtful on helping you with this issue. We started by looking for a wiring issue, then went to the ECM, now were looking at bad sensors and I haven't been giving you very good guidance. I never even mentioned using a scan tool to verify what is actually happening when this problem occurs. This is generally the first think I suggest. Why I have not guided you back to testing I don't know. Sometimes we get so lost in the forest, we can no longer see the trees.

You are getting to a place where you are putting alot of money into this problem. I would like to see you step back and take a deeper look at what is causing this issue. There are several types and brands of scanners available that will read your ECM. Tuner Pro is a PC based system that has many capabilities, including data acquisition and recording. You cvan do a Google search to find where to buy it. Another option is a generic scan tool. I just used my old Snap On MT2500 "Brick" yesterday diagnosing a 93 Olds. The "Brick" was the tool to have 20 years ago. They sold for $2,500 new. Now I see them floating around for $300. Most Techs wont bother with them because all of the scanning capability of the MT2500 is available in either of the newer and much cooler Snap On machines. But for $300, they're a great value for the DIYer. And they will work on many vehicles, including OBDII even Europian and Asian with the right software. And over several model years.

Get a scan tool of some kind that will read OBDI GM. Use it to look for any clue as to what is causing your system to behave the way it is. Every component I can think of that should cause this poroblem has been replaced. We need to look at the system as the ECM sees it to see what is out of place. This will point to wiring or other issues in some part of the system that's causing this set of symptoms.

itsMikey

so i ended up taking it back to the shop...they couldnt get the new ecm to communicate with there scanning tools, so i took the stock ecm back and its running great.

the maf, was in fact, bad. but since the ecm wasnt compatible, it showed no change to me.

in the end:
bad mass air flow sensor (maf)
dirty idle air control (iac)
HUGE vaccum leaks



big thanks ASE Doc and everyone else that contributed to helping me

ASE doc

This is one more of several cases where I've seen ECMs replaced due to misdiagnosis. Don't feel bad. I've done it myself with some fairly expensive units, like the ABS module in a 2004 F-250 Ford P/U. $650 and alot of hair pulling later, I found a shorted connector in the harness. BTW, once powered up, or in some cases once the sealed package is opened, ECMs are not returnable. This is one more painful reminder to us all to think twice or even three times before replacing an ECM.

ASE doc

Good job Mikey, and happy motoring!

bungo78

iTrader: (1)

Congrats! Back on the road and 1 day closer to an LS1 swap during a BBQ wink wink. lol!

itsMikey

thanks
it was a used one but yeah, i tend to jump and just start changing stuff...

shhhh...you might upset the trolls

itsMikey

aaaaaaallllllrrrriiighhttttt -__-

so its doing it YET AGAIN!

now tho...ive replaced
the fan switch (drivers side head)
alternator
coolant temp switch

the codes still wont flash...not even the 12 that its supposed to.

when i turn the igniton ON the primary (drivers side) fan comes on and the ses light stays on and stays solid.

when it was running (without ses light on) the ses light would blink twice on igniton then stay on until i started the car and it ran great.

blows my mind...its gotta be the ECM right??
i think tpis sent me either a bad ECM or a non-compatible one. sent it back already.

HALP?? lol

james.gould150

sux man...i had mine in the shop and had injectors replaced and cts replaced,tps set,iac replaced...worked great for about a day now i think the fuel pump is shot but idk ive discovered too many to count bad grounds and i am not financially able to keep up with it im gonna see if the fuel pump does the trick and get a new fuel filter...im also gonna go to a jy and replace ecm in hopes there is an issue in there

itsMikey

mines gotta be the ecm cuz i cant even attempt to pull codes.. >.<

bobbyk3lly

wow, it sounds like you both are having a huge amount of problems here, if you find out let me know cause my 86 L98 camaro vert is doing the same thing

itsMikey

put a new ecm in and its running great (for now) will let u guys know

ASE doc

Oh man! I dropped this thread because I thought you were all done fixing this car?! I hope it's all good now.

itsMikey

it seems to be atm haha..the ses light still blinks when i turn the ignition on tho..made a new thread for that...

zride91

Wow, I had a season that sounded a lot like this, but injectors finally resolved it, sounds like you've been down that road already and it sounds like you've got a lot more going on...

I hope the new ECM helps, if you still have problems, you need to start going through wiring, maybe a mouse made shop under the hood somewhere and went to work... I had a nest right on top of the intake, under the plenum (made a nice little home), and they made my injector harness a main course. Those little f'ers can make one heck of an electrical nightmare. You may want to pull your passenger side inner fender to get access to the ECM harness inside the fender and make sure it looks OK. I believe the ECM harness also winds up by the blower motor (which will make a nice little rodent home too).

itsMikey

i doubt theres any rodents in there..the cars daily driven

i need to know what the flashing ses means!!! ahhhhh!! haha

itsMikey

uhhh sooo wtf is this??? O.o and how come it doesnt go to anything?

fireburdluvr85

thats your vapor canister and it should hook up to a metal line from the tank.....

itsMikey

as in the gas tank? O.o where would the line have gone???

ASE doc

Hey Mikey, Look for the metal vapor line to be grouped with the fuel lines as they come up into the engine compartment. The vapor line should end right close to the canister.

itsMikey

got that all hooked back up...

was running good with the new ecm and now its doing the same thing again...

really ready to craigslist it at this point...

ill explain it again...

i turn the ignition on, the ses light comes on, stays solid and the primary fan comes on.

when i start it, it idles weird and when i put it in gear, it wants to stall out and idles really low.

im really at a loss here guys. ive spent so much money and time trying to figure this out

StrahlZ28

Hm... Kinda sounded like an ECM issue... you try replacing the coolant temp sensor?

itsMikey

which ever is the one on the passanger side..i couldnt get too...i think that ones the sensor

i replaced the switch tho (drivers side)

its a brand new ecm...it worked for a week of daily driving..went to go to class earlier and it started doing it again

i was thinking..MAYBE..my aldl plug got messed up in my feeble attempts to get the codes and is grounding itself out? long shot i think tho...

ASE doc

The ALDL would be a good place to start. You have an intermittent electrical issue somewhere in the ECM harness. Start wiggling wires.

itsMikey

so start at the ALDL and follow it too the ECM then from the ecm to the engine bay?
just wiggle stuff and see if it changes anything?

this is really starting to stress me out! lol..only stress ive ever had (given, im only 18) has been with this car

ASE doc

I know it seems like it's been having issues for a while but I am quite sure that all of this stalling and strangeness is probably due to a single short or open some where in the harness. When you find it, you'll laugh at all the trouble it's caused you.

itsMikey

prolly wanna punch something when i find out its something small

hope thats what it is...im in graphic design right now so thats how im replying but class doesnt end until 2..so ill get on it as soon as i get back home and report back

fireburdluvr85

the coolant temp sensor is on the front of the plenum under the throttle body. the ones on the sides of the head are for the gauge and fan switch. i noticed someone asked you recently in this thread and you said the ones on the sides of the heads. what data is the ect providing? is the booster leaking vacuum when you hit the brakes? just something i wondered yesterday as i read this.


the sensor on the pass head is the fan switch and the one on the drivers side is the gauge sensor

itsMikey

ohh..yeah i replaceed the one on the manifold below the TB too...

its gotta be something grounding out the ecm cuz its like its going into service check mode but not flashing any codes..

gonna check soon

itsMikey

attached a wiring diagram for 5.7 TPI FI for 89 Trans Am (incase anyone else needs it)

ASE doc

I am currently uploading diagrams from the Helms factory Service Manual Electrical Diagnosis Suppliment. Unfortunately for your purposes, my book is for the 87 Camaro. The diagrams in the Helms book are very detailed and precise. They show all ground locations and routing. Unlike the pencil drawings that you find on Mitchell. Having really good diagams to work with makes things much easier. I'm assuming you love your TA and plan on keeping it. Look at Helm's webstie for availability of the books for your car. It's a very good investment.

itsMikey

will do i think i got it..the negative battery ground wasnt very tight

ASE doc

I was just thinking. I know that sounds dangerous. But your issue could very well be loss of continuous battery power to the ECM. that would explain the lack of DTC memory and the poor idle.

Still, whenever a car runs poorly after its adaptives have been reset, I always watch for Block Learn to go lean or rich and then try to find the cause. In fact, the way an engine runs after reset is one of the indicators I use in verifying proper operation.

Jpl87t/a

Hi I have a 87 trans am 305 tpi and I want to ohm check the the injectors. I checked them hot and they read 17 to 18. I also checked them cold and they read 30 to 33. What does that mean? Thanks for the answers in advance!

Jpl87t/a

Hi I have a 87 trans am 305 tpi and I want to ohm check the the injectors. I checked them hot and they read 17 to 18. I also checked them cold and they read 30 to 33. What does that mean? Thanks for the answers in advance!

92purplehaze

iTrader: (8)

everybody wants some help on mikeys thread lol

itsMikey

lol..i know

so..guess what guys

it was a bad ground...from the negative cable to the body i couldnt help but to laugh...will admit, was kinda mad too.

fireburdluvr85

ive heard from other owners that that little ground to body wire off the battery terminal can screw up alot of stuff. i have 4 main grounds just in case. might not be a bad idea for the future? i have one to front of block, one to alternator case, one to back of head, and one to trans case. call it over kill but i got excellent ground points when looking.

ASE doc

Jpl87, You really need to start your own thread in order to recieve proper attention. 30-33 ohms is way off the charts. I have to wonder if your ohmmeter is functioning properly. Be sure to verify zero with the test leads held together before you test.