ECU connundrum

[EagleMark]

Actually before you try the stuffed towel test make sure you have enough fuel pressure. Low pressure also can cause the pinging, as well as other ignition issues.

Also set timing to 0* bypass disconnected. Re connect and clear error 42 from setting timing. Check timing with a timing light and should be around 15 degress at idle and go up when reved to 20's depending on RPM and MAP. Basically just see if timing is working correctly and in ball park.

Another ignition pinging issue common on these but usually comes with other poor running characteristics is the distributor cap! Inside cap at coil button which is spring loaded fails, spring does not keep button pushed down. Happens on fairly new caps as well. Can usually see arcing on rotor as well.

You may have 2 issues? Pinging and error 32.

[70chevrolet]

Actually before you try the stuffed towel test make sure you have enough fuel pressure. Low pressure also can cause the pinging, as well as other ignition issues.

Also set timing to 0* bypass disconnected. Re connect and clear error 42 from setting timing. Check timing with a timing light and should be around 15 degress at idle and go up when reved to 20's depending on RPM and MAP. Basically just see if timing is working correctly and in ball park.

Another ignition pinging issue common on these but usually comes with other poor running characteristics is the distributor cap! Inside cap at coil button which is spring loaded fails, spring does not keep button pushed down. Happens on fairly new caps as well. Can usually see arcing on rotor as well.

You may have 2 issues? Pinging and error 32.

Ill check the cap and wires. 14psi fuel pressure and timing dead on at 0 degrees. I've been through the throttle body and bumped the fuel pressure to 14. The new exhaust has been ordered and is gonna happen. If that doesn't fix my code 32 where would I get a stock like chip that just eliminates the data for the highway check of the EGR?

[EagleMark]

There is no stock chip that would not have EGR tests...

[70chevrolet]

Nice truck!

Thank you. And your right. It's not a bandaid. I shouldn't have said that. What I meant was. I would like to make the truck run like stock, if possible. I'm old school and I know nothing about chips and data logging. In my naive frame of mind I can only compare it to carb jetting and advance curve.

[70chevrolet]

There is no stock chip that would not have EGR tests...

Understood. What I meant to say was a custom tune emulating the stock chip with the exception of
leaving out the EGR programming. Please pardon my ignorance to exactly what is involved in writing a chip

[EagleMark]

Well if I understand correctly yes. Whether you want to adjust the test to pass or if you want the EGR system completely disabled, yes, both can be done properly. There's many so called custom chips out there that have EGR turned off wrong! Or just the CEL error code 32 disabled and the EGR system is still operating, which is a bad thing obviously.

[EagleMark]

Please pardon my ignorance to exactly what is involved in writing a chip

First you read the chip, then make changes to the bin file you read off chip, then burn new chip.

This will help you understand some of our terminoligy.

http://www.gearhead-efi.com/Fuel-Inj...-a-must-read!-)

[70chevrolet]

just an update on this... I replaced the cap and ran a tank of high 91 octane through it.. This severly decreased the EGR incideces. however, the problem still persists but much less often. This is unexpected too because my old cap appeared fine. .. So, ive narrowed it down to a poltergeist, exhast backpressure, carbon in the intake, or possible ignition problem (hence the new cap made the occurences less). I intend to replace the chinese module with a GM module and new wires first. Then I plan to replace the edel-junk performer with a factory GM and at that time clean out any existing carbon. I have all the parts to go from my true duals with no cats to a stock catback setup with a walker cat (however, i ran into another chevy owner running true duals/no cats/ cherry bombs and they have no egr issues) I will post back as I complete these. if all else fails, i will succumb to the poltergeist theory.

[1BadAction]

I intend to replace the chinese module with a GM module and new wires first.

Those modules are finicky, and I wouldn't trust one of the crap chinese ones driving more than walking distance away from my garage... Also, if someone installed it without using the heatsink compound that's included in the package, all kinds of weird ignition issues will happen when it gets warm. Personally I use "Arctic Silver" when installing modules in my TBI trucks, it's one of the best heat transferring compounds you can get.

[70chevrolet]

Those modules are finicky, and I wouldn't trust one of the crap chinese ones driving more than walking distance away from my garage... Also, if someone installed it without using the heatsink compound that's included in the package, all kinds of weird ignition issues will happen when it gets warm. Personally I use "Arctic Silver" when installing modules in my TBI trucks, it's one of the best heat transferring compounds you can get.

i pesonally have never had one act up but have heard it can happen. After reading an interesting piece titled "hot rodding the EFI". Located here : http://www.crankshaftcoalition.com/w...EI_distributor

the author references that the way the genuine GM vs china modules control dwell is different internally to the module between the two. I cannot attest to the accuracy of this statement but I'm going to try anyway and see if the truck runs/performs any different.
Please keep in mind when I say "china" I am not disrespecting the Chinese in any way. A lot of good products are made there. I personally love Chinese food.

[1BadAction]

i pesonally have never had one act up but have heard it can happen. After reading an interesting piece titled "hot rodding the EFI". Located here : http://www.crankshaftcoalition.com/w...EI_distributor

the author references that the way the genuine GM vs china modules control dwell is different internally to the module between the two. I cannot attest to the accuracy of this statement but I'm going to try anyway and see if the truck runs/performs any different.
Please keep in mind when I say "china" I am not disrespecting the Chinese in any way. A lot of good products are made there. I personally love Chinese food.

Interesting article, and I have no way of knowing about the dwell time, but it wouldn't surprise me. The problem is that the chinese electronics are many times reverse engineered from the originals, then they use inferior internal parts which has an effect on durability and the operation of said part.

Chinese food =
Most Chinese automotive parts =

[EagleMark]

There was some testing done on Thirdgen.org that proved even 2 differant numbered GM modules have differant timing curves. I furthered the testing and can guarantee that you never know what timing will be at any RPM with aftermarket modules...

[70chevrolet]

There was some testing done on Thirdgen.org that proved even 2 differant numbered GM modules have differant timing curves. I furthered the testing and can guarantee that you never know what timing will be at any RPM with aftermarket modules...

UPDATE!! after driving around for two days with the GM ignition module over the china, I am overwhemingly astonished of how much difference a module can make.. I wouldve never imagined as I always assumed the module just converted pulses to the ECM and the ECM advanced/retarded time. My truck ran pretty darned decent with the china, but it never ran as good as my old 1994 that I had a few years back, so I just assumed the motor was tired. I was wrong. I'm not claiming an additional 20 horse or anything, but I can tell im getting more advance all over. The whole band feels much crisper and more awake. My truck is a 5-speed which makes it especially noticable. To the average schmuck I could see maybe not noticing any change at all, however I am at one with the truck and the truck is at one with me, so I notice everything. I havent seen a code 32 (which is what I am chasing) since I swapped it out, however its only been two days. When I dropped the cash on this I was actually thinking that I was wasting $60 on swapping out a new part for a part that isnt faulty and I could not have been more wrong. I definately feel like it was worth the $60 bucks... Again, dont anyone run out and expect that a module is going to add a second to your quarter mile or anything like that.
FYI my part number is 10482827..

[70chevrolet]

Happy to report resolution. After driving around for 30 days and many hundreds of miles, I havenet had seen my SES at all. The code 32 is gone.. I chased this light for damn near a year
SOLUTION: Put the factory Y-pipe back on. I tried everything short of burning a new chip eliminating the higway EGR test and nothing worked. I even tried creating backpressure using homemade adjustable baffles. Still a no go! I put the factory Y-pipe back on and a walker cat with a Flowmaster single in/dual out muffler. and 2.25 tails and the SES light hasnt been on one time since. Prior to that with 2.25 true duals, no cats and dual dynomax super turbos, I was getting the light just about every day but only on the highway. It made me so mad, the color orange still raises my blood pressure.
In addition, The truck has more grunt under 1500 rpm and I was rewarded with a 1-2 mpg increase in fuel economy.. To me the truck drives nicer. On the highway at 70 It doesnt rev like it did with the duals but hell, the speedo only goes to 80mph. I dont spend much time up top.
Conclusion. True duals on a TBI is usesless, just go with a cat back for the look. Unless you are running oval track :). To each his own though.
Also, With respect to the pinging issue. I thing I must have combustion chamber deposits because I switched to 93 octane and the noise is almost gone (i.e. detonation). I plan on doing a cylinder flush through the spark plug holes at my next oil change.

Thanks to everyone who contributed ideas and pointing me in the right direction. And for helping me understand what the ECU was thinking

[EagleMark]

Thanks for updating the thread with the fix and outcome!

You do know I can adjust the chip properly to still use EGR and adjust the Code 32 test to pass! Not a trick or cheat, just change the parameters for the test to pass with new exhaust system.