I just completed a SDPC Vortec 350 TPI swap into my 305 TPI 91 Z28. Now that everything is in, I'm running into one main problem:

When the car slows down to a stop, it shuts off. I installed a new knock sensor for a 350 cid engine. I bought a new ESC module as well, but I wasn't able to find out wherethe ESC module was located in the car. My dealership service manual says its near the brake booster but I don't see it. I'm thinking that this is the main problem and that the knock sensor is retarding my timing back. Right now its set at 6 degrees. I'm running a PCMforless piggyback chip that I just ordered for the engine swap. I'm running 24# SVO injectors which the tune was supposed to compensate for. I'm not sure if maybe its something to do with the tune itself.

Here is a list of mods:

Mods before swap:
High-Flow Cat
K&N air filters
Hotchkis Strut Tower Brace
KYB AGX adjustable shocks/struts
Eibach Pro Kit Lowering Springs
Flowmaster American Thunder Catback
Accel Distributor Cap and Rotor
PST Polygraphite Front End Kit
Energy Suspension polyurethane transmission mount
180* T-stat
Hypertech Cool-Fan Switch
Gutted Airbox


Mods added during swap:

Vortec TPI 350 Crate Motor (2 bolt main, LT4 Hot Cam, 1.6 roller rockers, Vortec 64cc heads)
SLP 1 ¾ “ headers and y-pipe (Fel-Pro gaskets, catalyst adapter)
24lb SVO fuel injectors
Custom Prom by PCMforless
Ram air boxes
TB Coolant Bypass
Boxed LCA’s
MSD Superconductor 8.8mm wires
NGK-T55R spark plugs
DEI hi-temp heat boots
Made-for-you vertical wire loom separators
Made-for-you aluminum brackets
Powermaster 140 Amp Alternator
Thermo-Tec Starter Heat Shield

I went through the search and could only find mention that the ESC module was located behind the brake booster and relays on the drivers side in the engine bay. I also saw a comment that the TPI equipped cars came with the ESC module built into the ECM.

I checked both locations and didn't see anything. I even checked under the dash on the drivers side and still found nothing. Can anyone help me out by telling me where the ESC is located in a '91 TPI?

 

You don't have an external one...it's inside the computer.
Part of the memcal.

 

so there isnt an actual module?, its part of the so called "motherboard"?

 

No...it's part of the memcal ...the thingy that has the chip (PROM)in it.

 

Ok, well part of my problem is that I have the wrong part. I have part number #16128261 ESC Module, which is for an '87 to '89 according to the local dealership.

The guy at the parts counter says there was no ESC module listed for a 5.7 '91 Camaro.

Does anyone have even a picture of this thing?

 

Get a new memcal then... There isn't an esc module, as people have said.. I doubt that is your problem though... Does the car run with the stock tune?? I'm thinking problem with the chip...

 

Hmmm I haven't tried it without the piggyback chip from PCMforless. A buddy of mine seems to think that (the new tune) might have been the problem, too.

I did find a part number for an ESC module on autozone's website, but its a special order item and there are no pics of it, which makes me wonder why they'd even have one listed for a 1991 5.7

 

its part of the memcal circuitry (the little deal that plugs into your ecm)..

 

Tomorrow I'm going to see if taking out the piggy back chip makes a difference. I'm still not sure it would have any effect since the knock sensor has been changed out to the newer one for a 350 engine. I would think it would still retard the timing.

 

Ordered the memcal for the ECM and it should be here by the end of the week. Hopefully that will fix my main problem I've been having.

 

Just got the new ESC module / memcal in for my car today from gmpartsdirect.com and it fixed the problem I was experiencing with the car shutting off at stops.

Also, I got the 3.73's in today with a TA girdle and stud kit and let me tell you, going from 2.73's to 3.73's is a night and day difference! (Feels like a new car!)

I can't wait to get some dyno numbers and track times down.

 

Ok this is strange. Left last night from my buddy's shop after installing gears and the memcal. Drove GREAT all the way home, never shutting off once on my 40 minute trip back to my place. Get home, park the car, post on here that the problem was fixed, shower, and go to pick up a friend to cruise around in the car....

The moment I get to the end of my driveway, the car shuts off like it had been doing with the old memcal.

So I guess my problem didn't get fixed after all. It's strange that it was fine all the way home and then it decided to just start all over again. I tried pulling the codes off the engine and it only flashed code 12.

I'm not sure what it could be--my first thought that maybe the fuel filter was having trash slosh around in it when I came to stops, but that seems unlikely that it wouldn't have a terrible miss all the time. Maybe it is my throttle position sensor or a vacum leak? Fuel pump relay?

Anyone have any ideas?

 

How about taking the ignition module to get it tested?

 

ignition module was swapped out last august so I don't know if it would be that, but you never know. I have a new one that I could try on it.

 

In my 91 RS i had that module, and it was right next to the brake booster... but i have TBI, not TPI, so i dont know if its different...

 

Just a little update:

After reading through a ton of threads I narrowed my problem down to the IAC and replaced it. At the time I replaced it, I hadn't seen the tech article on how to actually adjust the idle, so it idles a little high right now, but that should be taken care of tonight. Otherwise, problem with cutting off at stoplights fixed! Weeeeee

Thanks to everyone who helped shed some light.

 

Too bad I didn't see this earlier I would have said IAC right off the bat. So how does it feel next to the old 305TPI. Was your 305 an auto or 5 speed and do you recommend the swap? How does it idle?
I've been considering this motor for some time now.

Thanks for any info man!

Steve

 

Rev, any additional news on this engine swap? Are you happy with it? Get any power dyno numbers or track times?

 

Well, unfortunately I lost 3rd gear in my transmission on my way to the drag strip 2 weeks ago. (Riding home in 2nd gear at almost 40mph is not fun!) I will be headed there either this coming thursday or saturday, depending on if I get everything set up by then. Here is the newest round of mods to go in this week:

Spohn LCA relocation brackets
Pro-Built Automatics Street/Strip rebuild kit
Transgo shift kit (included in rebuild kit)
"The Beast" Reaction Sunshell
B&M Supercooler Tranny cooler
Precision Industries 2800 stall "Vigilante" torque converter

...and I also had the car stall out at stops again, after adjusting the idle air screw. A friend of mine suggested cleaning out the IAC housing, channel, whatever you wanna call it. So I plan on doing that this week once the tranny is back in. It did have a lot of carbon buildup in there when I put in the new IAC control valve. Hopefully that will FINALLY cure that problem. lol

I will be running on nitto drag radials at the track. I really don't even want to guess at what time I might run. I'm hoping for low 13's. (Maybe a 12.9 if I'm lucky?) I'm going to get a few vids of my runs that night, so I'll post them on here.

All in all I'm happy with the swap. I think this torque converter is gonna wake this car up quite a bit. As far as dyno numbers, I was hoping to get it dyno tuned at Carolina Auto Masters by Jeff Creech sometime in the next couple of months when I have $400 to put towards it. That way, I get dyno #'s and a tune, which will hopefully pull some more horsepower out of it. There is a dyno about an hour away from me, but its 4 pulls for $60 usually. I'd rather just hold out for the tune.

I'm thinking of adding an SLP loudmouth in place of the Flowmaster American Thunder catback sometime soon. I've dropped so much money into this thing in the past 3 months that its crazy. Didn't think I'd get it this modded this quick, but speed is an addiction. Anyway, I'll keep ya updated man.

What mods do you have on your car right now? Feel free to PM me sometime and talk cars.

 

LOL i know what you mean. Its happened to me late last july.

Hows that TPI and the hotcam? And the 373 gears? They aint too much for the car is it? What TPI runners you have. I am considering the same motor but dont like the hot cam in it. Sure it runs good but think that cam is too big for TPI.