H4Inf

I posted this in the 1st gen area but got no response, and since my engine is from a second gen, I thought I'd give it a go here:

My engine is the 6 port 13B with EFI. Secondary injectors start running at about 3000rpm just after secondary butterflies start to open. Fuel comes straight into the secondary fuel rail, then around into the primary and back to the tank.

Basically the problem is that if revs are under 3000 and I put any load on the engine, it bogs down and nearly stalls - the second any load is put on it - instant death. If the revs are over 3000 then it will run fine. The problem is intermittent however... I can't pick what is causing it.

So basically to drive right now, I have to keep the accelerator pushed to the point where the secondaries are running.

Any ideas on this at all?

assman20a

the primarys are bad or going bad or there dirty. my motor is doing the same thing and i have a check light but it runs poorly above 3k rpm

H4Inf

Might try running some injector cleaner thru the fuel system then...

I think mine isn't running as well as it did above 3000 too... I'm not sure though.

H4Inf

Just thought I'd also mention that with load on the engine, just as you push your foot past the secondaries opening bit, it backfires.

I don't quite understand though - how with no load on the engine, it brings up the revs fine, and then with load, it is no good?

Thoughts?

assman20a

mine backfires to but it continues to do it

im in the midst of trying to figure it out

Kahren

iTrader: (13)

the fuel should go into teh primary rail then around the back and then exit at the front of the secondary rail. and i hope you have a FI fuel pump in that FB

H4Inf

Hmm my fuel goes into the back (near the firewall) of the sec rail, then theres a hose from the front of the secondary rail down to the front of the primary rail. Then at the back of the primary rail the rubber hose hooks upto the metal line running back to the tank.

Theres the stock pump into surge tank, then between surge tank and the sec rail is an EFI pump.

A bit off topic, but wondering if you know any drawbacks of running fuel thru the secondary fuel rail first?

Cheers

Adam

maybe a kangaroo took a **** in the tank? just a possability

Kahren

iTrader: (13)

the fuel pressure regulator must be the last thing before the fuel comes out. that is also how the factory lines are ran. swap your lines.

H4Inf

Here are a couple of pictures, I don't know what the pressure regulator looks like, perhaps someone can tell me!

Fuel comes in here:


Then goes from the secondary rail up top front, down to the primary rail at the front:


Then comes out the rear end of the primary rail to go back to the tank:


How does that look?

Thanks!

Kahren

iTrader: (13)

i dont remmber the s4 setup off top of my head. but i dont think you have it right.
the fuel pressure regulator is the hat looking thing on the secondary rail.

88IntegraLS

Speaking for my own S4 NA engine, fuel goes in to the primary rail first through the pulsation damper, then exits the primary rail and goes into the secondary rail from the back, then exits the secondary rail through the fuel pressure regulator at the front of the secondary rail.

It appears to me that your current hose setup does not supply pressurized fuel to the primary fuel rail at all because it has to come out of the fuel pressure regulator to do so. the fuel pressure regulator should be the last thing the fuel goes through after goign through the rails. It is the piece that bolts on the end of the secondary rail in the front with two bolts, and has a vacuum line on top and fuel line on bottom.

H4Inf

Ouch! Thank for your assessment! I'll look at changing the way it's setup. I don't know who did the work on this or why they did it this way... Thanks again,

Have a great new year

RotaryEvolution

iTrader: (30)

S4 or S5 AFM? if it is a flapper S4 AFM make sure that the door is not sticky on initial break. you may want to get some readings from it at the ECU also and compare them to specs to be sure your AFM readings are accurate. if it tests ok then i would proceed to think it is a fuel injector problem as you have been checking.

H4Inf

I have no AFM heh...

Kahren

iTrader: (13)

:O where did the afm go, mayeb u need to go find it? or is this an aftermarket efi car?

H4Inf

Microtech Digi Series 1 (not exactly the best ecu)... No AFM or O2 sensors.

Kahren

iTrader: (13)

digi series one? never heard of that one? is this somethign for australia only?

H4Inf

This is 10+ years old. "For racing use only".. it works... enough.

I've read the main problems are that it is pretty course - Not good for controlling large injectors as it cant get the timing down fine enough.

Kahren

iTrader: (13)

ah i c, does it control timign also? have you been at the dyno?

H4Inf

The ECU controls fuel only.. Ignition is electric dizzy. Havent dynoed because no money and I probably want to finalise my exhaust system before that.

Kahren

iTrader: (13)

cool, good luck with that, let us know the results!

H4Inf

It is quite an intermittent problem, so I'll do a few things and get back to you all.

Also here is what the Microtech Digi Series 1 Pro ECU looks like, for future reference