Correct injectors?

[XfireZ51]

Originally Posted by Jaap

Fuelpumps have been replaced fuel pressure is as it should be

Are you checking FP while driving and going to WOT?

[Jaap]

Originally Posted by XfireZ51

Are you checking FP while driving and going to WOT?

What do you mean with FP and WOT?

[FU]

FP = Fuel Pressure
WOT = Wide Open Throttle

[Jitse]

He means the fuelpressure, and how the pressuregauge is acting when going wide open trottle. ( under load)
FP at idle 46, and dont go's really lower when driving, with both pumps on testconnector FP is around 52.

[Jaap]

Originally Posted by FU

FP = Fuel Pressure
WOT = Wide Open Throttle

No, we didn`t test Fuel pressure at wide open throttle while driving.
At idle, fuel pressure is 45 psi and on both pumps 52 psi with testconnector.

[Paul Workman]

Originally Posted by Jitse

He means the fuelpressure, and how the pressuregauge is acting when going wide open trottle. ( under load)
FP at idle 46, and dont go's really lower when driving, with both pumps on testconnector FP is around 52.

52 psi at (WOT) too - just to be clear.

[Jitse]

Did nog drove with the test power supply connected, used it only for testing the primairy and secondary fuelpumps by pulling each fuse. Jaap his car is always running on full power. a previous owner lost the power key and they bypassed the powerkey in always on mode.
But when I drove with the car in the street I did not see much deviation in the fuel pressure, it was stable.

[Jaap]

Originally Posted by Jitse

Did nog drove with the test power supply connected, used it only for testing the primairy and secondary fuelpumps by pulling each fuse. Jaap his car is always running on full power. a previous owner lost the power key and they bypassed the powerkey in always on mode.
But when I drove with the car in the street I did not see much deviation in the fuel pressure, it was stable.

Well, i gues you now know who`s my mechanic

Are there some people here who have more suggestions?
Drove the Z this afternoon and the problem is still not fixed.

All help is welcome

[XfireZ51]

Originally Posted by Jaap

Well, i gues you now know who`s my mechanic

Are there some people here who have more suggestions?
Drove the Z this afternoon and the problem is still not fixed.

All help is welcome

If this started after you swapping injectors, I guess I'd pull the plenum again and check everything under there one more time.

[Hib Halverson]

Originally Posted by Jaap

Now we have a new challenge the car runs only good above 4000 rpm when it gets under the 4000 rmp the car starts to shock in every gear when the pedal is put to the mettal.. and it`s way to slow.

Do you guys have any idea what it could be?

I think there might be a little language barrier issue, here...when you say it "shocks" what do you mean by that?

1) Misfire?
2) Throttle response problem?
3) Total engine cut out?

This thread is not exactly clear on fuel pressure, either. Make SURE you are testing it properly. Do not test it with the engine idling. Test it with the key-on/engine-off.

If you have 52 psi fuel pressure key-on/engine-off, it holds when you turn the key off and you have that pressure at WOT 4000 rpm or higher with the secondaries enabled--all of which you should have with two new pumps and a new fuel filter--you likely don't have a problem with fuel pressure.

The images of the injectors on the first page do not show the whole injector but they do not look like OE injectors. We'd have to see the whole injector to know for sure.

There are a lot of crap injectors on the market but there are, also, few good ones, too. The stuff that Marc sells is good. The stuff you buy really cheap on the Internet...maybe not so good.

The best on the market--admittedly somewhat pricey--are RCEngineering's LT5 injectors. I discovered them in 1997 when I did my a project series on my engine for Vette Magazine and, since then, RCEngineering has sold hundreds of sets of them to ZRoners. See www.rceng.com.

Reading all these posts, and assuming your fuel pressure readings are 52 psi key-on/engine-off, has me thinking that the misfire might not be fuel related.

Also, the sensors you are talking about are "oxygen sensors" or "O2 sensors" not "CO2 (carbon dioxide) sensors". You said you replaced them...what sensor did you use to replace them with?

Finally, it's a bit hard for me to tell but it sounds like this problem might be misfire at part throttle not misfire at WOT high rpm. Is that true? If so, I'd sure like to see some scan test data of what the fuel trims and O2S readings are in normal driving.

Part throttle misfire can be lots of different things.
1) Wrong injectors
2) Weak ignition
3) Improper calibration

Good luck!