Help with injectors...

[1988GTU]

I know I need to add a 1/4 turn valve lash, that is why I am running slighty rich.
Here is a little more added info...
"33- manifold absolute pressure (map sensor signal voltage high
33- mass air flow (maf) sensor or circuit - excessive airflow indicated "
"Check the vacuum hoses from the MAP sensor. Check the electrical connections at the ECM. Replace the MAP sensor"
"Trouble Code 33 indicates that the Mass Air Flow (MAF) sensor is reporting more air is entering the engine than makes sense based on RPM and TPS. The MAF sensor produces a frequency output. The frequency varies proportionally to airflow. The ECM monitors the frequency and thus determines airflow into the engine.

The conditions for setting this code are:

* no Code 21 or 22 (TPS Error) present, and
* the air flow reported is > 40 grams per second, and
* TPS indicates < 10% throttle position, and
* the engine speed is 1400 RPM or less, and
* the above conditions exist for over 5 seconds.


Typical causes for this code include:

1) Faulty MAF-to-ECM connection
2) Exceedingly noisy spark plug wires
3) Poor routing of MAF harness (i.e. near coil packs)
4) Maladjusted TPS sensor
5) Defective MAF sensor
6) Defective ECM"

Now what may be happening is that your car might be stuck in open loop by default since that sensor has failed. You have tried changing the sensor?


Hope that helps!

[ForcedFirebird]

Ahh ha! So am I, but I also changed to 24#ers. So I'm probably getting rich both from the injectors and bigger rockers. I'll hook up the voltimeter to the o2 and see what I get if I have time tonight, might have to wait untill tom afternoon. Want to get it running good for the Wed nite test-n-tune.
Do you know what kind of detrimental effects are a result of code 33? I think the ECM is going into "safe mode".

[1988GTU]

no codes.... as of yet. I do expect a failing O2 soon since it does run rich.

[ForcedFirebird]

Did it throw a 33 code at idle? Vac at the stock location on the throttle body seemed to be low for the AFPR, but I'll try that again and get back. Thanx 1988GTU!

[1988GTU]

Why couldn't you use the vacuum from where the old fpr once connected too?

Yes the rockers would be more than likely giving you a slightly more lope. I know the 1.6's did for mine.

[ForcedFirebird]

Gutted the stock FPR and the car idled today, but it's throwing code 33 (low vac @ MAP). To get the vacuum for the AFPR, I tee'd off the window washer and off the MAP and neither worked (to correct code).
.
Help, please?
.
BTW, could it be because of the lopy idle I'm getting since the rocker swap?

[ForcedFirebird]

Hey dave! Thought I might see you here.
No the Firebird is one of my four vehicles, and would like to get the turbo installed soon. And yes the reason I changed injectors already is because I had the top of the motor apart. I might go back with the stock injectors just so I can go to the track on Wed. and see if there's any difference with the 1.7's

[boostedrs]

hes going turbocharged shortly,thats why he droped the injectors in the motor,while he had the manifold apart to install the rockers. im pretty sure the car isnt his daily driver

[sharkey]

stock computer and 50% bigger injectors is not going to work. i tried running 19lb injectors on my built motor before tuning and it idled very rich, stumbled all the time. when it finaly cleared out around 4500rpm it went like a bat outa hell. it wasnt until i got my megasquirt in that i was able to use these injectors.

[treeZ24]

i'm already using the gold race series rockers, + as other guys said i also have aluminum heads and there's not very much space.

i would be more concerned about the fact the only mods are the rockers, on an iron head 3.1 engine and you have 24# injectors. i'm pushing 200hp and 24# injectors are perfect for my application running 85%

if anything i would be more inclined to go back to the 16# injectors and bump your pressure UP until you get your MS working. the other thing with dropping the base fuel pressure without knowing what it is, when you get the vac reference to drop the pressure further at idle the quality of the fuel pattern coming from the injector will be pretty poor. practically pouring fuel into the intake rather then atomizing the fuel as it is supposed to be.

[boostedrs]

u can use 24#'s but u need to drop the base fp,its not optimal but it does work,i have done it and other ppl on tgo have done it,it will run slightly rich @idle though.
mainly his problem is he installed a afpr in the return line from the fuel rail,the stock fpr is still installed holding the fp @ 42-45 psi.also with i beilve u will see decreased vacum from the 1.7's which will also make the stock fpr increase fp slightly

[XLR8ING]

I used to have the 24# blue tops.
Without proper computer control, I think you're gonna have to go back to stock injectors. 24 is just too big unfortunately.

[bszopi]

They fit on a 3.1 from a Firebird, ie a iron head engine. There are alot of rocker that will fit the non-splayed valve heads. Its the aluminum heads that it is hard to find rockers that will work.

[Azrael]

It's awesome that the ford rockers fit. But the question is, do they match up geometry-wise?

[ForcedFirebird]

what pressure did you turn the injectors down to. because i don't think they are going to like being below 30psi iirc ford rates them at what, 38#?

Haven't checked the pressure yet, got tired after the rocker install. While I was at it, painted the UIM. I turned the stock FPR down as far as it would go. And yes the Ford injectors are underrated in comparison the GM's. I'm surprised you didn't ask about the SBFord 1.7 roller rocker arms I found that work on the pushrod 60*...
They were $69 delivered and bolted on using the stock pivot balls and locking nuts, not to mention they fit under the stocker valve covers.
After some discussion on another site it was suggested to "gut" the factory FPR and rely on the aftermarket one.