jxx

Hello fellow gm enthusiasts.

I have a bit of a problem with an imported 88 c4 corvette, being from australia i have plenty of experience with holden ecu's and tuning but i'm a bit lost with the poor old corvette.

ran diagnostic mode and came out with fault 51 (buggered memcal)
it was running ABTS 4767 and i've been able to read the eprom but i have nothing to compared it with to confirm it is corrupted... any chance someone has a copy of this bin? tried searching the interwebs and can find plenty of other bins but not this 1 in particular.....

Now if it was a holden i'd simply burn any of the numerous bins i have collected over the years as i know what is compatible and will work, if anyone can confirm another bin that will work in place of the ABTS then i'd be very thankful, the car is to heavy to be pushing around...

i have attached the bin rip if anyone can check it and tell me if it is actually faulty, thanks

Tuned Performance

iTrader: (92)

The address 05DD looks like it might be a bit flip and I believe it's correlated with fueling, You do not need to use The ABTS broadcast code you can go to $6e. I do not have the ABTS you can use a $32b ABTT or the $6E ARAR.
The ARAR is a better tune but you need to unplug your ninth injector as well

Tuned Performance

iTrader: (92)

The code 51 can be caused Bye a bad ecm as well The 1227808 should work with your memcal and if the memcal is bad you can make a VN,VP,VQ memcal work.

jxx

Thank you for the quick reply, i was planning on taking an 808 in tomorrow with me in case it was an ecu problem.

Tried erasing and re-writing the abts memcal and my suspicions seem correct, it fails write/verify... seems the eprom is fragged, the initial issue with the car was it wouldn't start easily and there was a strong smell of fuel as it turned over without firing, so the error in fueling would seem to be a correct assumption.

Tuned Performance

iTrader: (92)

Instead of soldering in a new eprom and acdelco used alot of 27c256 eprom on the tpi maf but just used the upper section of the eprom you can use a adapter like this.

http://www.ebay.com.au/itm/Holden-Mo...#ht_3594wt_824

jxx

I don't have alot of 27c128's, was planning on stacking the bin on an eeprom, if it wasn't for the lhm resistor pack i'd just use a v6 memcal, only a 5 minute job replacing it anyway, as i said the car is to heavy to push around :P main aim is to get it running asap

Tuned Performance

iTrader: (92)

You can use the i/o buffer and netress from a v6 just solder in a jumper from pin 56 to 62 on the memcal to set the cylinder select.

jxx

Well a small update, didn't have much time to spend on it but the ABTT tune showed some better signs of life, at least it tried to start (even better with a new set of plugs) but was still running very rich and would stop soon after starting...... the memcal was fine in a commodore 808 ecu diag mode just left the cel illuminated, the 165 seems fine as and have had it running in a vn commodore without fault.

Still a fairly strong fuel smell, lots of black smoke when it actually fires.... will get back into it on monday.

How common is it for the cold start injector to fail and leak fuel? unplugged some of the normal injectors and when it fired it ran a bit rough so assuming they're ok

Tuned Performance

iTrader: (92)

the cold start injector can be held open if there is contaminants in the fuel system. You might check communication with the 808 just bye entering into field service mode. The running rich with the 165 the ecm was in limp home mode. Pull off the fuel pressure regulator hose and check for signs of fuel and ohm out the injectors. I thought the 808 can be a direct replacement with a 32, 32b or 6e calibration but it might not be.

jxx

the 808 should be, it's pretty much the same except for the sxr chip, a 16183082 ecu would be a good replacement but they're fairly rare and sought after as they were only used in manual VR v6/v8 and VS v8 manual, not familiar with the corvette's wiring and haven't looked for a schematic yet, is it like a VR commodore and onwards that uses the 8192 aldl line for more than just diagnostics? anti theft etc etc?

contaminated fuel system is a possibility, i believe the car was sitting around for about 5 years.

Six_Shooter

iTrader: (2)

You can find many bin files on gearhead-efi.com.

I looked but didn't see ABTS in the organized threads, I did see ABTZ that lists as being for possible export.

jxx

thanks six-shooter, i'd already looked through gearhead-efi and diy-efi before originally posting, but both seem to have most bin's except ABTS, all good though, i atleast have a working memcal now so hopefully when i get back to it on monday it'll give me something apart from 12, 51.... big if that the corrupt memcal was screwing with the fault code output but fingers crossed it was.

TORN

iTrader: (17)

ABTD 1987 31565 16070729 1227165 731 7761 L98 5.7 MD8 700 R4 GM1 2.59 RATIO

ABTS 1988 31796 16074766 1227165 4767 7861 L98 5.7 MD8 700 R4 GM1 2.59 RATIO

Looks like these two are the same.

RBob

iTrader: (1)

Possibly, wasn't '88 the first year of aluminum heads on the y-body cars? Or was it '87 with a different head design for '88?

RBob.

jxx

thanks for all the replies, got the thing running although it's not great, ended up unplugging the csi and she fired to life....
seems it's been neglected over the years and suffers from some vac leaks around the egr system.... once warmed up it's hunting, drops to about 500 rpm and shoots back up to about 1200..... still running rich but not as bad so will be looking at removing the csi and plugging the lose ends in the near future.

Had the laptop hooked up and noticed the tps voltage is at 0.51V @ idle/closed throttle, should this be around 0.45V and no higher than 0.50V like the holdens? still getting a grasp on the 165's tuning, leaning towards converting it to map and just running the VR commodore $12 code...

TORN

iTrader: (17)

I wouldn't worry about the TPS voltage its close enough. I would concentrate on the vacuum leaks.

TORN

iTrader: (17)

https://www.thirdgen.org/tpimod2

Idle Air Control

Tools needed:

1. Torx bit # T-20 2. Paper Clip 3. Small Punch

Take the paper clip and open it up and form it into a big "U" shape. Insert the clip ends into the ALDL in the 'A' and 'B' pins.

Turn on the ignition, but don't start the engine. Wait 30 seconds. Now, go remove the connector from the IAC.

Start engine. You are now going to adjust "minimum air". There is a Torx screw on the side of the throttle body. This is what needs to be turned to adjust minimum air, or more commonly known as "idle speed". It comes from the factory with a protective metal cap over it. If the cap is still there, use a small punch to knock it out. Set the idle speed to 450 rpm, rotating the Torx screw clockwise to raise rpm, and counter-clockwise to lower rpm. Once the idle rpm is set, turn off the engine.

Re-connect the connector onto the IAC. Start engine. Idle speed is now once again governed by the ECM, but your idle should be smooth and steady, approximately 600 rpm in Drive (for unmodified cars).

If you set an SES light by having the IAC disconnected, then after shutting down the engine disconnect the negative battery terminal. Wait 5 minutes. This will clear the ECM of all trouble codes. Re-connect the battery and drive the car for 20 minutes to allow the ECM to relearn your driving style.

Throttle Position Switch (TPS)

Tools needed:

1. Digital Volt-Ohm-Meter (VOM) 2. Jumper Wires (make your own) 3. Auto Xray Scanner (if available) will eliminate the need for VOM and jumper wires.

Turn on ignition, but don't start the engine.

With a scanner: plug in the scanner and read the TPS voltage. It should be 0.54Volts +/- 0.075Volts

With VOM and jumper wires: disconnect the connector from the TPS. Using your jumper wires, make a connection allowing some room for the VOM terminals to contact the jumper leads and read the TPS voltage.

If out of spec, loosen the two screws holding the TPS to the throttle body, and slightly rotate the TPS up or down, reading the voltage until it comes into specification. Tighten screws. Using the throttle lever, rotate the throttle to WOT (wide open throttle). The TPS voltage should be over 4.0 volts. Close the throttle again, and then slowly open it to WOT, observing the voltage reading. It should increase progressively and in a linear fashion. If it sticks or jumps or falls off at all while doing this check, that could mean a bad TPS switch and could be a cause of stumbling and driveability problems.

After setting the correct voltage, turn off ignition switch. Remove jumpers/scanner and reconnect the TPS connector as required.