I replaced the '87 IROC 305 TPI with the 350 HO 330 crate engine. Now I don't have timing advance. Do I need to replace the PROM or have it burned? or is there other tuning under the hood or in the electrical circut that .....HELP.

Stan

 

Of course you need a new eprom. You have changed the entire charateristics of the engine and you need to let the ECM know about it. If you had an "old fashion" carb/dissy, you wouldn't be able to bolt the old carb and dissy EXACTLY as they came off you 305 and have it run optimally. With EFI, it's even more critical.

This Board is to learn how to burn your own eproms. If you wish to learn more, go here

https://www.thirdgen.org/newdesign/tech/promintro.shtml

As for buying an eprom, you MIGHT get one that runs "half okay". People that sell eproms will always tell you "no problem", but in all honesty, there is NO WAY someone can burn you an "optimal eprom" without having hands-on access to your car. Doing "eproms by mail" just doesn't work.

Lastly, there are scum suckers that cruise this board looking for fools that want a "cheap eprom". Don't even CONSIDER one of these guys. The only thing that will get burned is your wallet.

Lastly, we are not a referral service for "who can burn you an eprom". Go to the "AFTERMARKET BOARD" if you want to make that kind of post. But don't be surprised if a bunch of guys respond "the best eprom is the one your burn yourself" and suggest you come back to this board.

I've been playing with cars for over 30 years and the guys that always seemed to have the "fastest car", even when it was virtually identical to another car was all because he could "tune his engine".

If you want to have a fast car, you MUST learn how to tune your engine. When you get into it deep enough, you will learn that even things like temperature, humidity and elevation all affect the tune, and what worked GREAT at sea level @ 60*F runs poorly when the elevation changes or the temp changes. Over time, if you get into burning your own eproms, you can even develop an eprom that will work optimally in virtually ALL elevations and ALL temperatures...but it takes time and experimentation.

Lastly, NO ONE will be able to burn that kind of an eprom for you. If they say they can, they are lying. You only get that kind of an eprom with a LOT of testing and experimentation.

I suggest scoping out some of the posts on this boards, especially "newbie" posts. I generally recommend starting by reading all the old posts (up to last year) and reading forward. The guys that do that generally turn out to be the best "students". The guys that are lazy and won't read any of the old posts tend to find people answer their posts "less and less" as most questions have been asked a gizillion times.

 

Well, Glenn; Thanks, I think for the lesson. I sure didn't know I was getting into all of this. I'm not sure how much I can handle...I'm not a mechanic...I'm a psychotherapist. Before 12-23-01, the most i had ever done on a vehichle was change the oil. I needed a challenge....

Stan

 

Well, don't be quite so quick to write yourself off. Few of us were born "all knowing" about cars, let alone the eprom.

I think EVERYONE that has gotten into eprom burning will agree that they have learnt MORE about their car and engine than they every thought they knew. Unlike a lot of people that THINK they understand what's happening inside their engine and start to make a bunch of useless changes - the people here do have a good knowledge (though we are ALL learning still) what is REALLy happening.

I am sure a lot of the MAF guys would recommend that the BEST place to start is using the "ARAP" Bin as a base and converting your TPI to an 89 type system (i.e. disable the Cold Start Injector").

FYI, many of the "custom eproms" that I have "looked inside" tend to use the ARAP BIN as a base for MAF cars - regardless of year.

So rather than spend the $350-500 for a "custom eprom" just buy the equipment and use the "base" that all the "custom eprom writers" use. Then as you learn more, you can make further "tweaks" to improve performance, driveability and gas mileage.

Oh, yeah - you will also learn a LOT about your car/engine in the process. Ask any psychotherapist and they'd say you'd be crazy not to try it.

 

Just wondered how and where your base timing is set. Did you set your distributor to 6*? Was the brown/black striped wire next to the heater box disconected as the distributor timing was set at 6*? Is it reconnected? Everything Glenn said is true, your best off getting set up to do your own tuning, anything else is just a band aid at best. But your question seemed more aimed at something missed during the swap than a mismatched bin. oh well, hope this helps, Bob

 

Hey Glenn: The brn/blk wire at the heater box was d/c when timed "Timing for the engine is 10 BTDC". The brn/blk wire was then reconnected. engine won't start with it reconnected but will start when it is d/c. Engine won't advance time during increased HP or retard timing .... puter is not working right even though i replaced the ECM. Lower row of dash lights which is where the engine light is doesn't come on at any time....not sure if this is related but it seems like i read somewhere that the engine light, if not working (burned bulb or blown fuse) won't allow a scanner to read the ECM? Thus preventing the ECM from engaging....Not sure how the Blk/Brn connect or D/C could be related to this though. Does this make sense.???

Stan

 

Oops, a little dislexic (sp) Bob. Now Glenn, about that "ARAP". I just learned what an ECM, ESC and MAF was....ha

Stan

 

Well, if the ECM is not even operating at all and you can't link to it, you may have a problem with it's power or ground or one or more of its sensors, or possibley a PROM issue. Check the fuses first and maybe the grounds if the fuses are OK. Is the PROM fully seated in the new ECM you put in? Did you remember to swap your PROM out of the old ECM and put it in the new one? I would also give all of the sensors a quick once over and make sure they are all connected.... It is easy to miss one on a full engine swap. I'm just stating the obvious at this point, so no offense.... Your problems seem to be much more 'hardware' oriented at this point. That tan wire with the black stripe is the ignition bypass for the ESC system and basically disables the ECM froming changing the timing. That is why you disconnect it to set the base timing and reconnect it after that. The ECM assumes (as long as the PROM is stock) that you have 6* base timing and adjusts it from there depending on what the timing tables demand for the situation. You can change that base timing parameter in the PROM later if you so choose.......

Sounds like you haven't even gotten the car into closed loop so who knows how that PROM you have is going to react with your combo. But if you have a MAF system - ARAP is the way to go for a base. ARAP refers to a four character label that GM put on all of the PROMs it created. The ARAP one happens to be the most refined (AFAIAC) and most aggressive one out there for the MAF cars. It has extremely high timing figures along with more performance oriented MAF scaler table figures. It is rumored that it was created for test cars that GM gave to magazines so those cars would perform extremely well and sell more cars for GM. Hard to say if that is true.... I have also heard that it only came in vettes and still others say that it was made for factory supported racing teams for things like the SCCA.... Whatever the origin, it is the place to start with a MAF system. A lot of it doesn't even require changing to get the car running quite well, IMO.

Well, gotta run... good luck though,
Matt

 

Thanks Matt, Bob and Glenn; You have all provided a good amt of info to check and follow up on....More will be revealed. BTW; what is an AFAIAC? I don't remember reading this in https://www.thirdgen.org/newdesign/tech/promintro.shtml ...but I lost my memory in the war........the war on drugs that is... :lala:

Stan

 

I think AFAIAC stands for As Far As I Am Concerned.

 

AFAIAC stands for As Far As I Am Concerned.


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:lala: :lala: :lala: :lala: :lala: :lala: :lala: :lala:

Man, anyone know of a good psychotherapist?