I posted this issue on forum.pgmfi.org, but I did not receive any reply. I really DON'T want to spam all forums, but I'm out of ideas what could cause this If anyone has any idea, please post it....

I have a really strange problem. I bought a set of " 450cc" injectors on Ebay( I wish I haven't done that, but I was a real noob when I did so), they are BLACK TOPS.

I installed them on my D16A6 project with PM6 ECU, using NG55/60 ROM and turboedit, first stock, then 2,5 bar MAP, same trouble.


The problem is that when I scale the map for 450cc injectors and try to use it in the car, the AFR is unbelieveably lean( idle or partial throttle, I never tried to do WOT with such lean conditions).

I enriched the whole table by approx. 30%, now it seems to be much better, but still when it goes to boost, AFR jumps to 15-16:1 for a second or two( seems like the moment before turbo gives full boost), then the AFR is constant about 13:1 on WOT( cus I tuned it).

According to this, I thought these injectors are smaller, but hell they are not ! They have resistance of 2,7 ohms, that means they ARE Peak&Hold, and they have " MDL 450" written on their side, so they really ARE 450cc.


Can anyone give me a hint where I should start to search for the problem?

The basemap tells me my injectors should be open for 11-12 ms on 10 PSI - full boost of my small turbo, but I'm using 15ms of time on my 10 PSI right now

The same with idle - basemap idles at about 1,4-1,7 ms of injector open time, but I need about 2,3 ms of time to have the AFR ok ...

heeeelp

 

You are correct, they make black top 450cc, and those era Denso's did tell you what they flow on the side:



Also, make sure you have no exhaust leaks between the engine and wideband sensor, and within 3 feet after the wideband sensor, as this will cause false lean readings. Ignition misfires will also cause false lean readings.

Three things to check, IMO:

1) fuel pressure

2) ignition system (cap, plugs, wires, etc)

3) exhaust leaks

BTW, out of curiousity, how lean were you reading off the 450cc scaled basemap, that you found it unbelievable? How was idle quality at that point?

 

Hi, thanx for the reply.

1) no leaks in the exhaust system - doublechecked before first engine start. The whole exhaust system is new just like the whole turbo-project.
2) I am curently unable to check the fuel pressure, but my suspicion is the fuel pump simply isn't able to maintain the pressure that these 450cc injectors need, but noone else seems to post such trouble with them either here on HMT or on pgmfi.org .
3) Well, with the basemap made for 450cc injectors, stock map sensor and stock fuel pressure( setup before installing the 2.5 bar MAP) the idle quality was terribble, car sounded really bad, and AFR was 18-21:1 . When I saw that AFR and heard the engine sound, I immediately shut it off to avoid any damage. Then I added about 30% more fuel to the ROM into the fields where idle is read from, and all was OK, AFR was about 13:1, engine idled like with the stock 240cc inj.

I checked the ignition&wiring as well, all is fine.

You know, the strange thing is that if I add about 30-40% more fuel to the whole map, the car runs fine. But I don't really like that, I want to find out WHY do I have to add that much fuel to my fuel map just to make the car run OK, when other ppl use the same fuel map with original values for 450cc without any trouble.

... not to mention the problem with a short-time lean condition before going to full boost altough the map seems not to have any "fuel holes"....

 

2) Stock fuel pumps are good for close to 300 whp. You'll only run out of pump when pushing power aka WOT and/or under boost at some point if it's weak.

Do you have any way to increase TPS-based aka tip-in fuelling? I did a lot of work with Ghettodyne which TurboEdit is based on (and changed radically since) but I've never used TurboEdit itself. Sorry for the n00b Q when I'm supposed to be helpful If no, then I'm going to guess that the tip-in fuel is set up for stock injectors and should be safe-rich. Why you are going lean is

Anyway to lower the AFRs WOT down to 12:1?

Can you get pics of your plugs?

 

Sounds like you didn't get 450's. Is there a number on the side of the injector?

 

Yeah, I thought too that these injectors are smaller, because scaling the basemap not to 450cc but to 330cc(xenocron's basemap helper :-) ) gives me quite similar fuel map to what I have done by enrichening the 450cc basemap according to AFR.. so I thought" ok, they are smaller".

But the injectors have " MDL 450 " on their side, and they do have 2 spray nozzles on their bottom, so I really think they are 450cc

Also, when I enrich the fuel table to have the AFR@about 13:1, car idles and runs fine, so I don't really think they are broken as well.

This whole problem is a big mystery to me ... I just wanna find out WHY do I have to enrich these 450cc that much, and WHY when I do a WOT, the car is lean for about 1-2 seconds and then is stoich, but MAP sensor reading says that it reads from the same tables like 2 seconds before, when the AFR was lean

 

i dont suppose you had your old, used, injectors cleaned and balanced? just a thought. I know my first set of supra 440's were not flowing 440cc. swapped them out for another and was alot better. not as drastic as yours, but like i said, could be something to conisder.