Beginners Guide

As a complete novice I have been struggling to put all the TBI EFI pieces in place.
I have begun to construct a document for my own use based on my finding so far.
I know i have probably made some mistakes and this is where you can help.

Please feel free to e-mail me any additions / amendments on andrew@doschalmers.fsnet.co.uk

I am always looking for actual facts eg formulas that the ECU will use and handy info like injector sizing etc.

Hopefully I can build it up as my knowledge grows and then other newbies can benefit.

 

As a fellow newbie, I would be interested in something like this as well. In fact, I already have some stuff to contribute if I may. I have some stuff on basic wiring, circuit tracing, adaptation of GM TBI/EFI to other engines and ignition systems, etc that may help others like ourselves.

 

EXPAND THIS!

Great idea. When I first started messing with '80's GM, I was absolutely lost!

I'm sure several folks gave me good answers....but the terminology was Greek to me, so the answers were useless.

I like the detailed explainations of what they are, what they are called in the vernacular, and what they do! Man....I sure could have used that info about 2 years ago!!!!!(To be honest...still can in some areas! )

NM

 

Thank you for your positive comments.

I am doing a fair bit of research on injectors - sizings, whys and why nots, BPC/BPW constants etc.
I am trying to put it all into an excel sheet which asks the basics like engine CC and fuel PSI then works out as much as possible for you. Max HP, BPW/C etc. Once I have the info I will update,

The strange problem is that i get a lot conflicting info so i need to find out whats actually correct first.

I didnt really think anyone would take notice of this post but i am heartened you did.
If you liked that then you might like this fictitious race....

EFI in a Drag Race

Again I made this to help me understand whats going on inside that evil little metal brain and I update it as I learn.
I need more info on what the engine sensors would read at the various points so if anyone can help i will be happy to update.

 

some minor corrections. The O2 volts are mixed up, around .8 or so indicates the engines mixture is around 13:1 and the .2 indicates a lean mixture of around 17:1(?) or so. Another thing is that not all ecms completly ignore the O2 in PE. Mine doesnt seem to. If the mixture appears to be richer then whats called for the blms will fall slightly to correct for it. Doesnt have the same scope as in non-pe but non the less I think that some ecms can somewhat correct for fueling at WOT. I think another reason that there is so much different data is the calibrations in the ecms vary so youll see alot of different info for each. Heck, i noticed that even between my ecm and the later one in the tbi f-bodies there are alot of differences in the way everything is set up.

 

at WOT the computer should correct for a lean condition (BLM's above 128), i am not aware of it correct if the BLM's are below 128

 

Hmm... Ive seen mine fall below 128 to around 125 at WOT but im not sure exactly how much control it really has over fueling.

 

I thought that it would have had to ignore the oxygen sensor as at WOT the air fuel ratio would be in an area where the stock O2 is inaccurate ? hence wide band..

I have reversed the readings to correct - 0.8 is rich 0.3 is lean.

I Just took delivery of 10 2732a chips and as soon as the Romulator/PP2 get across the pond i am diving in - My first burn still awaits...

On a sobering note i just did my first g-tech'd 1/4 miles and my best ET is 85, the 60 fts are terrible - near 3secs but it was raining and wet.

Thanks to all who have sent e-mails, I am still on the Injector path of truth !!!

 

Well, it is... I think the software engineers probably incorporated that as a saftey measure in case anything goes wrong. I dont think it has total control over the fueling because everything takes place so fast but it probably can at least in part correct for lean conditions. In my ecm there are no thresholds on the BLM. Its set to be active up to 104 kpa and 6000+ rpms. I wouldnt rely on it too much, though.

I wouldnt get to worried yet, try it when the roads are dry. I suspect that youll find your times and possibly trapspeed are better. I know i can spin first, second, and third when its wet out so id probably have similar results.