ok well i've been chasin a weird *** miss for awhile now. changed and checked everything. and discovered that im not gettin any timing advance at all. all the wires are plugged in. so i was wonderin if i need a new comp or if it could be somethin else.

 

With TPI you should get an error code if the ESC module goes out.
What code/s do you have?

 

o ya its a 92 speed density 350.
but i had no codes unless i unplugged the ESC wire to set the timeing which is code 42. but i just picked up a new comp. and now it sounds like it only wants to run on about 5 cylinders with the ESC plugged in. with it unplugged it runs fine but of course no advance. and code 42. could my prom possibly be shot?

 

this ****ers about to get a damn carb, if i cant figure it out soon. could it possibly be that my PROM is shot. and thats why im not gettin any advance.
and it still wont run right wtih the ESC plugged in. it surges really bad and will not idle to save its life.

 

PROM or distributor? any guesses??

 

I'd make a guess of the pickup coil or ignition module in the dizzy. The coil broadcasts the signal where it's at and the ECU tells the ig mod what to do. One of the three is toast or there's a loose wire. You should be able to have them tested at your local parts store before you spring for a new distributor.

I went ahead and got an MSD for Christmas. Best move I made.

 

its got a new pickup coil and module. and i even had them test the module before i left the store, beucase i've had brand new ones that didnt work right. but what wire would it be because all there is the the ESC control. "which i would believe to be workin due to no code bein thrown" or is it one of the dizzy pulse inputs. i dont feel like rewireing everything there. but if i have to i will.

 

any ideas before i start rewireing everything???

 

???

 

Where is your ESC located? I think I would check that again.
Do some datalogging to see if the ECM is commanding the advance and/or seeing an error.

The distributor doesn't really handle the advancing, the ESC does that per the command of the ECM.

 

Just check continuity on on the 4 wires leaving the distributor back to the ECM to see if one is broken.

Somewhere, I'm remembering if you are in limp mode your spark advance doesn't work... anyone know??

 

Thinking about it... even in limp mode your connections would be good or it would be running very rough. I found a link referring to "service mode" where the A+B of the ALDL port were connected. Maybe yours are shorted to ground?? I dunno...

https://www.thirdgen.org/forums/tpi/...ight=mode+limp

http://www.autozone.com/images/cds/g...3d80163ff1.gif

 

thanks there. gonna look into all that. but i have a TBI harness layin here that i stole the wireing for the dist. so we'll see how that goes. but unfortinantly aint got a scanner to see whats goin on...

o ya and i got another comp and its doin the same thing...

 

ok well all rewired and same ****. i think im gonna put in another module and see how that goes. but when the ESC is unplugged it runs fine just no advance. and when i plug it back in. it surges real bad. like from 500-2000 and thats all itll do.

 

Bout halfway down that link, there is a description from Vader that talks about closed loop operation. If your ESC is good then I would suspect one of your sensors is keeping you in open loop. Could just be the coolant temp switch or something easy. Hopefully you can find it soon... Good Luck!! and please update, I'm curious.

 

Did you try a different memcal too?

 

na not yet. its in a 92 s10. so i have to have one made. to bypass the vats and everything. and right now i aint got the cash to do that, and i dont know anyone that can. but that was one of my first guesses, because doesnt it control the spark tables and everyting?.
and while its in open loop its still gonna give it spark advance. otherwise itd want to detonate like a bitch when its cold.

 

not the chip, just the memcal.

 

so the memcals will be the same? but the prom is what holds the tune?

 

ok well apparently i havent been gettin spark advance for a long time now... cause i just disconnected the EST wire and it drove just like it had been. and i got a code 42. but soon as i plug it in the engine surges real bad. and the SES light goes out. i put a timin light to it with the EST plugged in and while its surgin the timing advances with the rise in the RPMs. but will not idle. i've got to literally floor it to get it to surge from 500 to 2000... i've also gone through and unplugged each sensor one at a time and no change at all, when i unplugged the intake water temp sensor it wouldnt run at all. but when the engines runnin with the EST unplugged and i put it into field service mode, the comp flashes sayin its in closed loop but then the light will just stay on and wont blink anymore. i've got the timing set at 6*. does anyone know how to omh test a module? or how many volts are suppose to come through the EST? i really appreciate the help tryin to figure it out. so lets try to solve this thing!

 

Which model ECM are you running?

 

When my SES light stayed on all the time, I ended up getting a new ECM after a LOT of tail chasing. My injector switch was fried closed but it could be anything that confuses the grounds onto the black/white SES wire, I guess. Makes a difference if it flashes or stays on...

https://www.thirdgen.org/forums/tpi/...?highlight=ses

https://www.thirdgen.org/forums/tpi/...light=stay+ses

 

1227730. you think i should give another one a try?
i mean the trucks driveable now. its just that i wanna get this fixed before i put everything back togethor.

 

Shows correct for a 92 350 L98:
http://wiki.3400z24.com/1227730

If you do swap, pull your ground off the battery FIRST.
You don't, you will fry the new ECM.

 

ya i think im gonna go back to the junkyard and try another one. but i always unplug the battery before i screw with anything, because i have shorted **** out before...

 

aight well i tried two more comps. same numbers of course. and both of them did the same thing. so im guessin its in my prom?

 

I'm thinking your ESC is built into your memcal. That's why I suggested trying another memcal but not changing your chip.
If you know someone with the same model car you could swap the memcals (with chips) just for a quick test so you don't have to pull the chips from the memcals.

Some people may say that it's the module or (EST) in the distributor that controls the timing, but it cannot work without the signal from the ESC.

Here's a pic on this thread:
https://www.thirdgen.org/forums/diy-...ght=esc+memcal

The "chip" is the larger chip on the right hand side. Factory chips will be soldered in place. Aftermarket chips are often just slid into a ZIF socket put in the same location.

 

i honestly have no clue. i found a little black box that is the VATS. hooked up in the truck. dont know if it works or not. but i dont know of anyone around here with a 350 TPI car. or even wtih a TPI car period...but the only person i've found in the area that does tuneing charges 300$ just to put it on the dyno for an hour. and like 125$ and hour after that.

 

ok well i got a comp and prom out of a 91 350 TPI camaro. and it did the same thing with the ES wire plugged in. so i guess im gonna go back after the module again...

 

If all those tests were performed correctly and your timing light is correct you might want to test the ESC & distributor wires for continuity. I'd check the one going back to the ECM plug first. I'd look up the schematic for your ECM & model year to find the right wire position on the ECM plug. If you can't find it someone in the DIY-PROM/ECM sections might post it for you.

Have you already checked to see if your car is going into closed loop when running?

 

i havent checked the closed loop operation with the new comp. but with the old one it was goin into closed just like normal.i know which wires they are goin ito the comp. tan/black. white. red/black. and purple/white one. they've all been replaced. but i guess ill try it anyways to see if one might be broke...
if i still dont find anything wrong then i think im goin to buy a new dizzy just to take that out of question to.

 

Do you have access to a scan tool of sorts? Something to verify what the ECM is seeing? That would help a lot

Also, if you had a chip burned for the swap, you may already have a memcal adapter and chip....

Send me a pic of what you have inside your ECM for a chip to snowyz28@yahoo.com

-jason

 

im pretty sure its a stock chip. theres no adapter. who ever did the swap took enough time to even hook up the VATS. i took a stock chip and comp out of a 91 camaro today and it fired right up. but of course didnt run worth a **** with the EST wire plugged in. so im gonna try to get ahold of a new dizzy. and go from there.

 

Have you checked your timing chain for play?? Also, are you certain your firing order is 1-8-4-3-6-5-7-2 going clockwise on the dizzy with #1 pointed to the drivers headlight? Reason I ask is if you are advancing so far on the wrong spark plug it's going to run horribly like you describe. Just going for something simple. Been bit by worse.

 

o ya i've checked the fireing order more then once... and yes its advanced properly. i just picked up a brand new dizzy so im gonna put that in a few minutes. i cant get chain slap... theres gears baby. so hopefully this new dizzy will do it.

 

well idk what the hell was wrong with the other dizzys. but the new one fixed everything. its runnin great now. Thanks for everything.

 

I thought you said you replaced the coil module and pickup coil

that is a new dissy

how much exp do you have

by the way glad to hear the car is running

 

i replaced the coil pickup and module. with brand new ones. that didnt work so i put in another dizzy wtih an old module that tested good. and a new pickup. neither of the modules were good i guess. i work at a auto machine shop i know what im doin. so dont question my experience. but i am goin back to discount tomrrow and gettin my money back for the damn POS module they sold me and tell them to get a new tester!

 

Glad to hear it's good now.