Started up the car. Idled pretty well. O2's seemed ok until the car went into closed loop (still parked) then the BLM's started rising quickly to 160 and the car stumbled for a bit and then died. The only things I changed in TC from the stock AUJP bin was inj constant. to 28#, and the knock attack rate below 1200 to 0 because I get some valvetrain noise at idle. Fuel pressure is set at 47 with FMS Injectors I believe they are rated at 25.3# @43.5 PSI. I had raised the Inj. constant to 28 because it was idling very rich at idle before (in open loop) with inj. constant at 26. I have the logged file in Moates software if someone would look at it.

 

When you say it was rich at idle in open loop-rich based on???? Did you have a wide band on it?
Wait until it goes closed loop....try lowering the inj. constant and see what the blms are when in closed loop......at blm of 160 it's tried to compensate as much as it can and then it's way lean.

 

Rich like burn your eyes rich and all I have is a heated O2, no wideband so I don't know exactly how rich. What are typical O2 mv. on a cold start (35-45 F) in open loop? I had a set of cold champion race plugs and it fouled them in a few minutes of running.

 

Set the injector constant to correspond with the injectors you have.

Set the fuel pressure to spec.

If you need fuel at idle then go to the VE fuel table and start adding fuel.

Lieing to the ecm will bite you.
Tell it as many truths as possible, only and only if you have done something really outrageous, maybe fib to it. Just jacking numbers around til it runs isn't the way to get it running CORRECTLY.

 

I will set inj. constant to 25.3 and set my fuel pressure back to 43.5 or so since that is what the injectors are calibrated to. Should that be with vac. hose off? Seems like that would throw off the whole thing if I set it with vac. line off and then plugged it in. Won't it change the set pressure (as tested by inj)? What is average O2 on a cold startup so I can have some sort of idea what to look for?

 

the problem with setting your fp that low will be that you will be real lean at wot. did everyone see your running a s/c 406. your asking the ecm to make guesses after the map maxxes out and ideling most likely is the least of your problems keepin it together under boost at wot will be a big problem if you get too lean.we need more info on your setup to help but be very careful without a wb02 making wot passes as i feel that 24's are already too small for your setup.
pete

 

I have a Cartech FMU on it now, and some 32 lb. injectors to install after I get some road miles on it. I just want to get it driveable for now. Not going to be doing any full throttle stuff yet as the whole setup only has 160 miles on it because I haven't been able to drive it very much due to not having any prom burning equipment unil recently and it p****d me off to much to try to drive it before. I have the diy-wb hardware just need he sensor. What is a good recommened fuel pressure to run?

 

FMUs are crutches for folks that don't use the right injectors.
I'd use 41 vac off.

 

not to get into a debate but you should be pushing more hp than me and i'm running 30 lb svo;s and the fp set at 50psi no vac and you have a bigger moter than me.and as for the fmu they are very hard on your fuel pump make sure it's up to the task or can we say boom! thats why i ditched mine.before the 30's i ran55 psi and a fmu but the stock pump seemed weak over 70psi.so i'd definatly not go under 45 no vac,but like grumpy says tune to what the moter wants not what you think it wants
pete

 

Why do you set the injector constant when the vac. line is unplugged when it changes the sec. you plug it in?

 

because thats how the factory service manual says to check pressure with vac line off

 

With the engine running at idle and you disconnect the vacuum line to the FPR (and plugging both open ends), the fuel pressure rises about 6 to 10psi, this simulates the WOT fuel pressure.
Because the ECM is in a non-learn mode when it is in PE mode, you want to tune knowing the PE (WOT) mode fuel pressure.
When the engine is idling or you are driving around at part throotle, the ECM is in the learn mode.

You can also simmulate WOT fuel pressure by simply turning the key to the on position (do not start engine) and immediately reading the fuel pressure.

Also, shutting off the engine, the fuel pressure should fall off very slowly. If it falls off quickly, like to 0psi in only 1 minute or so, you have at least one leaking fuel injector.

 

Or a bad regulator, or a bad check valve in the pump.
To check for which is leaking, take a pair of vice grips and find a section of the return line that is rubber, and crip it together (do not make it so tight that the hose is damaged).
Energize the pump by turning on the key....if pressure still drops quickly, then its not the regulator.
Find a section of the supply line thats rubber, energize the pump and quickly crip the supply line with another pair of vice grips, if pressure continues to drop quickly after cripping supply line, then you have a stuck/leaking injector.
If cripping the supply line stops the pressure, then its the check valve in the pump allowing fuel to flow backwards when under pressure, usually not a big deal if its able to maintain the required pressure with the line off (or WOT).

 

justme

did you ever find the problem? and if so what was it?

 

I ended up sticking a set of 42 lb injectors in it, ditching the FMU, leaving the fuel pressure at 47 psi and setting the injector constant accordingly. That got it to idle fairly decent, (a tad rich) played with the VE tables at idle to get it dialed in.

 

This has been discussed a few times, you noted that the car idles well until it hits closed loop.

When the car goes into closed loop it uses the O2 to adjust. Any decent sized cam is going to reak havoc with the O2 at idle, the extra air is going to fool the O2 into thinking your running lean when your not.

This is exactly what is happening in your case... the ecm sees the air and tries to add fuel which doesn't help(hence the 160blms). From the sounds of it, the car is flooding itself out and stalling.

Rbob went over changing the O2 toggle voltages in a older post.

 

One more thing I just noticed.. Your running the 749 ecm.. which by changing the injector constant will not have any effect.

You need to change pulse width tables. I don't remember the exact formula that is used to scale the table, its been posted before though..

 

This is an old post. I have solved my problems. I was merely stating what I ended up doing that corrected my problems. The post was back when I was running the 730 still.

 

Is this happening to other people?
As my car hits closed loop it takes about 2 minutes for the BLMs to hit 160.
While it's idling at 160 I can give it some gas and BLMs come right back to 128s.
I've been banging my head looking for intake leaks.
I thought I solved it when I fixed a cracked vacuum hose and replaced the O2.
It hasn't changed anything.
I'm using 24 lb Accel injectors.
I've dropped my injector constant to 23.5lbs in an attempt to richen my mixture.

I went as far as putting in the original 305 MEMCAL with the 19lb inj. constant and it still got lean.

Can anyone help me here?
I'm running MAF.

 

What is your fuel pressure set at? What FP are the Accell injectors rated at?

 

24lb injectors.
I'm running them with the fuel pressure @ 50psi.

She should be running rich.
I've spent my time looking for a leak on the topside of the engine.
I need to get her up on jacks and slide under her and look for exhaust leaks.