Duffdog

hey guys

oh ya, about the hard starting, i dont have that problem at all, never have-- I have a 98 tacoma, i was wondering what would cause the problem in the first place.

gadget, the in & out settings are the same as yours-- 15 and 15 i believe, right? anyways-- the low throttle is set at -12% all the way across except at the lowest point ( 1000rpm ) its at -15% and the hi throttle is set at -6% all the way across. Strange, but since it was set this way ive had no pinging at all and no check engine lights either . I have a question for ya gadget, i watched your dyno run and you revved the engine way above 5500 rpm, how did you manage that one?? My comp. kills the spark when you get to rev limit....

Tim

ravencr

Thanks for the response Duffdog! I can't wait to hear Gadget's response.

Chris

Gadget

The theory on the hard starting with the Maxx Autoworks 330cc injectors is this. When the ECU is in its initial starting mode it will inject a predetermined amount of fuel that is programmed into the ECU. It does this because none of the sensors are online at that time and won’t start generating signals until there the engine is running and there is sufficient flow through the MAF to generate an accurate reading. So it just shoots in a present amount of fuel to get the engine started.

Here is where the problem comes in. The ECU has no idea that you have installed oversized injectors, and as far as it knows it has the stock injectors installed. So when it gives the engine the initial start up squirt with the oversized injectors it just dumps to much fuel and floods the engine. This is more of a problem when the engine is hot then cold.

A cold engine will start in pig rich conditions, but a hot engine will have trouble starting when it is to rich. This is why engines that have had this starting problem with the MAW 330 injectors do finally start when hot a cloud of black smoke comes out of the tail pipe.

All of the people that have had this hot start problem with the 330 injectors have cured it when they installed the 305cc injectors that I am using. Also for some reason this seems to be more of a problem with the older trucks and less of a problem with the newer ones.

Adjustment of the AFC to affect this hot start problem has proven ineffective. The reason for this is that the AFC and like devices are signal conditioners and modify the signal from the sensor to the ECU in order to “trick” the ECU into doing something you want it to do. Since this hot start problem is during the starting mode of the ECU and does not look at the sensor signals for initial starting the AFC adjustments have no affect until the engine starts.

I do not know if anyone running the Supra MAF and 330 injectors have ever had a hot starting problem, but it should not make any difference as the engine does not look at the MAF signal for initial starting.

Well, that is the theory anyway.

I am glad to hear that you are having good luck with 370cc injectors and that confirms a friend of mine told me. I was the third guy to use the AFC on a 3.4 and the second to use the Supra MAF.

The first guy is a guy in PR (www.JigServers.com). He was drag racing his 4Runner and developed an intercooler for the TRD supercharger. He was running oversized injectors, the Supra MAF and the AFC. I was keeping in close contact with him when he was developing his setup and I was following it closely. He told me that if you run 360cc injectors with the Supra MAF then you could do so without an AFC or any other signal modifier. With you running the 370cc injectors and needing to lean slightly that pretty much confirms what he told me.

The second guy to run the AFC was my good friend Charlie in PA. I did his connection guide for him to install his AFC and he got his delivered before I got mine so he beat me and was the second guy to run an AFC on a 3.4.

This is all good news as I have been worried for a while now. The engine I am building is should be making a bit more power then the one I am currently running and I have been worried about needing to increase my injector size. I am at a perfect 80% duty cycle now with the 305cc injectors, but if I make more power then the injectors will need to be larger to stay within the 80% duty cycle target. It is nice to have other options while staying with a slightly modified stock engine control system.

Gadget

www.GadgetOnline.com

ravencr

Gadget,

My main concern is if I could or would have any problems going with the RC engineering 370cc injectors versus having to spend the extra money to buy the Toyota 305cc's? I thought what Dr. Z said about the -10 setting he runs versus your +40 that you run, make sense to me, but did I miss your response to that part? Maybe you explained it.

I'm pretty ready to make a got of all this, and my main two concerns I have is:

1) Toyota 305cc or RC engineering 370cc injectors
2) Perfect Power SMT-6 or Split Second FTC1-E

If I could get your vast knowledge on these two subjects, I'll be good to go, and will greatly appreciate it. Thanks!

Chris

FattyCBR

I've got a set of 305cc injectors for sale if anyone is interested.

Ravencr I sent you an email.