Hoping this is the correct forum to post in. I've taken on my father's project 76 stingray. The car is equipped with an 87 iroc-z tuned port fuel injection system and an Accel DFI standalone PCM. He's running a remote-mounted turbo (which is incidentally way too small for the application) and an iroc-z 5-speed transmission.

I continually get error code 72 (cam/crank signal error) about 5 minutes after startup. The system is using a stock-style GM HEI distributor for a cam signal. There is no crank signal/trigger wheel in use. The car will start up and run fine, but after 3-5 minutes this error code will present itself. Rather than just shutting off immediately upon loss of signal, the PCM will continue to run by forcing it's own cam/crank position value. That's nice, except it's probably about 15-20* advanced from the actual/original position. As a result, timing is way off and the car isn't even able to idle properly because it can't pull enough timing to slow it down.

As a band-aid I've adjusted timing tables to be correct after this value is forced as it accounts for 95% of the drive cycle. But, it would be nice to actually fix the issue and not idle at 400rpm until the error code presents itself. I've already tried replacing the module and then the entire distributor. I've also confirmed the wiring in correct (it won't start at all without that signal). Do I just need to upgrade to a dual-sync distributor and get it over with? Or, is there something else I don't know that I could check? Thanks in advance for any and all responses!

 

since this system was not used on the C3 generation recommend you post your question in the C4 generation.

 

Thanks, will do. If a moderator could please delete this thread?

 

I'd be willing to bet there are as many Gen 7 DFI's in C3's as C4's. As it sounds as though You know what You are doing tuning wise I would recommend a Call to Accel and ask them. I have a Gen 7 and did all the install but did not do the Tuning, They have a Dealer network and finding there local installer might not be a bad idea. When I did the install either the system came with a Distributor or I used the one they recommended. I believe its a MSD. For Tuning I use Blood Enterprises in Auburn Washington. If Your car was sitting in front of them they would have the correct answer to Your question in a bout 30 seconds. It sounds as though this project is bit old I would bet there have been many updates to the ECM and it probably needs to be sent to Accel for them.

 

Good suggestions. It seems like every time I try to call Accel the line is busy. I do have the most up-to-date software. That fixed issues I was having with the wideband sensor. I know the guy who works with this software package around here but unfortunately he's kind of a jerk and won't help me without having to pay him exuberant amounts of money for his time/advice.

I'm guessing you're onto something by using an aftermarket distributor. I'm thinking that's going to end up being the answer, I'd just like to know for sure before I blow more money on this car. Maybe I can give those guys a call in Auburn and see if they can offer any advice. Thanks for the response!

 

Up till I went with the Gen 7 I used the HEI. It was the Gen 7 that Prompted the new Distributor an HEI was never used in my application with the Gen 7.

 

From all of the searching I've done regarding this it seems like that is the conclusion everyone came to. Almost every thread ended with "I bought a dual sync and now everything is good."