full power problem

[janozr1]

OK , tomorrow will drive Z first with one than with second fuel pump, I will
remove 10a fuses and see what will be ...
thanks for now,Jano

[janozr1]

Here are results...if I take out fuel pump fuze 1 car die , reply with pump fuze 2 (it is near fuze-pump 1 or somewhere else?????) car work normall so my
conclusion is that second fuel pump dont work...???

[Jagdpanzer]

If you have access to a fuel pressure test gauge you can check the engine fuel rail pressure with the ignition key on and the engine not running. Both pumps should be running in this condition. Rail pressure should be at around 40-45 psi. Now pull the fuse for primary pump and see what happens. If the pressure stays up then the secoundary pump is OK. You can can also check the primary pump out this way to.

[Aurora40]

If your car is cold, coolant temp is close to ambient, and you pull the fuel pump 1 fuse and it won't run, then yeah, it sounds to me like your secondary fuel pump doesn't work.

[janozr1]

No, I cant messure fuel pressure, i dont have tool , but If every pump have own fuse, car run or not when Im put in-out fuses , am I right , so in my case car not run when I remove first pump fuse.......that mean to me ...second pump is bad . Correct or no ???
If Im gonna check and replacement pumps which one is first and second ...lower or higher on the fuel holder.
regards,Jano

[janozr1]

so , last news...
both pumps runs good under 176 F , than secondary pump
go off so reason for that isnt fuel-pump problems , problem is somewhere else
( code 61 ) .....Im waiting for any suggestions

jano

[tomtom72]

Jano,

Both of the pumps are the same part number, identical pumps mechanically. The ECM calls the second pump on line when the conditions say the pump is needed.

In my 90 FSM the listing for DTC # 61 is Secondary port throttle system fault. Usually, by not exclusively, this means the the Secondary Port solenoid switch is/or has failed. OR that the vacuum leak is bigger than the system can tolerate and still work properly(this is most unlikely).

Sorry I do not have a reliable source for DTC's for any other yr ZR-1. I have a 90 so I have a 90 FSM. I would say a quickie way to see if the secondary solenoid will not hold vacuum is to disconnect the vacuum line from the vacuum pump at the line splice over by the right side water tube on the Injector housing. Connect a hand vacuum pump to the end of the line that goes under the plenum by the the tube & alternator ( that's where it is on a 90). Apply vacuum to the line up to about 10 to 12 inches of Hg and see if the vacuum gauge stays or if it drops quickly or drops slowly....that means a leak. If it holds vacuum for at least 2 mins. then there usually are no leaks.

Just as an appendix to all my ramblings: Over at the NetRegistry site, in the maintenance section, under the common issues(?) or How To section there is a very well written explaination of the workings of the secondary port throttle system along with all the vacuum parts needed to make the system work.


Tom

[janozr1]

Tomtom ,
first would like to thank you for great answer , after many readings
on this forum and members answers I learned that is my problem under the plenum as you thinking too , so my suspect is sec. air inlet valve which is I
think clogged because I dont find any vac.leak. (this happened after long hot ride when I stop and take fuel on the gass station ) I never pull off plenum before so Im thinking now how can test- check it =D>=D>=D>
I also learn that sec fuel pump goes out at 176 F to protect my engine.

regards,Jano

[tomtom72]

Jano, Glad to be able to help out, albit in a small way.

It's been a long time since I went thru the secondary vacuum system, parts and functions. I did mine over when I did my injectors a few yrs ago.

A small, but important point to remember about Electronic Engine Control systems, EEC systems, is that the only way a DTC can be set is if a sensor or a control device that is monitored by and or controlled by the ECM is not functioniong correctly. Usually if the sensors fail they send no data to the ECM and /or do not acknowledge the reference signal or emit a reference signal. The devices that are controlled by the ECM set DTC's if they do not function, either mechanically or electrically and in some devices they also have a reference signal. All that said, I'm a long way from being smart in EEC operation and theory and functionality. Sooooo, I would suspect that if you can do the vacuum test on the secondary control solenoid and it passes the vacuum test then that solenoid & the check valve before it are okay from a vacuum aspect. The control solenoid may have a fault on it's electrical side. That may be an avenue to explore further. The rest of the parts in the secondary control system take their orders (so to speak ) from that control device. The rest of the system can only respond to the solenoid's commands: the tank, the hose, the actuator diaphrams are all just mechanical parts with no direct connection to the ECM.

In any event please read up over at the NetReg site because my knowledge is far from the whole story. I would say that it is likely you will have to pull the plenum to properly diagnoise and correct the issue.


Tom

PS I'm leaving to go watch F1, be back later!

[Jagdpanzer]

Originally Posted by janozr1

Tomtom ,
first would like to thank you for great answer , after many readings
on this forum and members answers I learned that is my problem under the plenum as you thinking too , so my suspect is sec. air inlet valve which is I think clogged because I dont find any vac.leak. (this happened after long hot ride when I stop and take fuel on the gass station ) I never pull off plenum before so Im thinking now how can test- check it =D>=D>=D>
I also learn that sec fuel pump goes out at 176 F to protect my engine.
regards,Jano

Here is a great post over at the Corvette Action Center ZR-1 forum on LT5 Secondary Port Operation & Vacuum Diagnosis:
http://corvetteactioncenter.com/foru...ad.php?t=14272