ImportsRsloths

Set base timing at 6*
as you rev the engine, it retards instead of advancing...
was an 88 305 TPI, now working out bugs on new motor-
355 TPI, Ed Wright Chip, Bunch of mods......... Why would it retard though??????

RB83L69

Is the connector hooked back up?

ImportsRsloths

Yes its hooked back up!

1986redbird

could it be the knock sensor, and the computer is retarding timming to try to eliminate knock.

ImportsRsloths

The knock sensor is a used one off of a 85 TPI vette??? Could that be? or maybe the sensor doesnt even work.... but you think that would set off a code!!!

Grim Reaper

Your answer is above. I told you the ONLY way to get a good chip is to burn one yourself. Guess you learned a $350 lesson.

ImportsRsloths

Glenn WTF is your deal???? Just for your info... the timing retards with the 305 5 speed chip ALSO.... Its not the chip thats wrong with it but rather something else like: Computer, ingition module, coil, maybe knock sensor, but its not the chip!!!!!! THINK!!!

Grim Reaper

I am thinking. Now swallow your pride a little and listen; or you are not going to resolve the problem and spend a lot of time and money. Or be slower than you should be.

Controlling spark knock is the KEY to power. These engines are HIGHLY prone to knock and you have to play a lot with the timing to find the "magic spot" where you have max timing advance with minimal knock.

FYI, I burnt over 200 different combos for my eprom last year. Over 75% was spark related. The difference between stock and modified (and this was when my engine was still basically stock) was night and day. I shaved over .5 seconds.

But, you have to do this yourself. You can't just order one from Ed Wright and expect this to work. This is what I have been trying to tell people all the time on the DIY Prom Board and those the DO get into eprom burning discover EXACTLY what I am saying.

Those that don't, discover what you find out...the modified eprom doesn't have the right spark curve, triggers the knock sensor and then pulls all their timing out. That is why you MUST do it yourself, because to get Ed to do it the proper way is going to cost you a fortune.

Lastly, before you go the next route (disable the knock sensor because you'll find a new knock sensor does the same thing), you will find that "inaudible knock" quickly becomes "audible" once you cross that threshold.

Sorry to hear that you didn't heed my advice and now you are learning your lesson the hard way. The money you spent would have paid for all the equipment and I could have made suggestions on how to control the knock retard to find that "magic spot".

I was where you are over 2 years ago, and ulitimately, it was the "tuning" of the eprom. Bite the bullet, get the eprom burning equipment and learn to burn your own eprom so you can fix the tuning. Else, you are about to waste a lot of money and never really fixing it.

Scan tools tell no lies and almost EVERYONE that gets a scan tool and hooks one to their TPI engine for the first time find the same thing. I don't know how many times I have seen this type of post. And they all have exhausted all their options except altering the tuning.

On these cars, the "magic spot" is a narrow window of about 2*. Go below that, an your car becomes sluggish and slow. Exceed it, and you encounter detonation. I finally found my "magic spot" where only .4* of more advance anywhere in the power band would trigger knock. That is how tight I finally got it. But you only get to that spot with a lot of time and testing. There are no quick fixes or simple solutions. Just tuning and testing, and testing and tuning. Eventually it all comes together. It requires work, but the results are well worth it.

Ultimatley, you too will realize why the ONLY way to get an optimum eprom is "do-it-yourself".

ImportsRsloths

Alright Glennie-poo, the guy helping me brought home a $3000 scanner from his work and hooked it up to the computer and it was throwing codes left and right..... when the car was OFF it said it was idling at 3200 RPM....... even set a VATS code and the car doesnt have Vats set a lean exhaust code and the car is running rich as hell.......... theres your prom problem JK i need a new computer!!!!
Thats cool and all that you shaved .5 seconds from your prom mad prom burning skillz....... but ill save .3 and only spent about 5 minutes installing it...... while you spent half of your life the last couple years burning proms..... WHATS YOUR GOAL????? get .6 seconds off? Also its just a car man.... DONT MAKE IT YOUR LIFE!!!!

Grim Reaper

Could be...a bad eprom (or poorly seated eprom) can do the same thing. Generally when the ECM goes, you can't pull a code 12 when you check the ALDL with a paper clip. Install your original eprom and see if it does the same thing. That will narrow it down between the two.


My car was bone stock when I shaved the 1/2 sec AND I get US 30 MPGs on the highway. I MADE money from my eprom burning equipment from all the gas I saved in just one year. I never had to turn a wrench or get dirty to do any of this.

I see a lot of guys with cams and heads and their cars are slower than mine. The difference, mine is finely tuned.

As for the time spent, that actual time is not all that much spent on the actual prom burning. Cars are a hobby for me and it's a labour of love. I take pride in doing this all myself and knowing every nut and bolt on my car. Better than getting drunk all the time and doing drugs. Now that is a complete waste of time.

F-BIRD'88

A loose distributor hold down clamp will cause the timing to retard
when you rev it also.