Rough idle after new injectors?

[diysv6]

I did the test today and I got around 60psi with the car running. The reading went straight down to 56 after turning the car off. Then after 5 minutes it went down to 50psi and after 10 minutes it went down to 45psi. Anyone know what this would indicate?

To my mind the fuel pressure looks OK. I don't think you have an injector leaking down the pressure.
Mine ran 57 psi. Turned off - After 2 minutes was about 42psi. After 14 minutes was 21psi. I had no injector problems, only the ECU.

 

[Kokentoe]

To my mind the fuel pressure looks OK. I don't think you have an injector leaking down the pressure.
Mine ran 57 psi. Turned off - After 2 minutes was about 42psi. After 14 minutes was 21psi. I had no injector problems, only the ECU.

Hmm, then I wonder what could be causing the weird start up. It starts up fine in the morning, it only seems to do it when I drive the car, then turn it off for about 15 minutes or so, then start it up again.

Note: I recently found out that you're meant to use some type of grease on the injector o-rings which I did not apply when I fitted them, as not doing so means they might not seal properly? Regardless, I have done so now so tomorrow I'll see whether that has fixed the problem. I certainly hope so...

 

[diysv6]

It starts up fine in the morning, it only seems to do it when I drive the car, then turn it off for about 15 minutes or so, then start it up again.

Have you left the fuel pressure gauge on for an extended period, eg. overnight - what is the static pressure then, and does it pump up in eg 1-2 seconds to 60psi? What is the pressure after being started taken up to operating temp and then stopped eg. for 1 hour. Is the time to operating pressure about the same as a cold start?
There might be a lead there.

Is the fuse holder and the present fuse for the fuel pump clean, not overheated looking. It may be excess current through the fuse/holder. Somewhere I think a contributor mentioned the close rating of the fuse when related to the pump's current draw if it is sluggish or starting to fail etc. A check of the connector/s at the petrol tank could be in order. (dirty, loose, corroded etc). Maybe a new fuse as a tryout?

Found a fuse related post about a V8 pump, but the principles may apply in your case.
http://forums.justcommodores.com.au/vz-holden-commodore-2004-2006/164066-vz-fuel-pump-problems.html

The ute has a roll over valve - does that have any inherit problems causing the fuel tank to run under a vacuum?

Digging in my notes the fuel pump normally pulls about 7.4A (V8 9.6amps hence the fuse problem above?) Delivery is 1.7l/min at operational pressure.

 

[ari666]

You could end up with high pressure fuel in your eyes.

LOL!!! i can attest to that. fkn hurts man.

 

[ari666]

Note: I recently found out that you're meant to use some type of grease on the injector o-rings which I did not apply when I fitted them,

just vasalene is fine. any kind of petroleum jelly. its just there to assist install, same as lubing up the rubber ring on a oil filter when you fit it. it just helps to stop the o-rings grabbing, and really should be used on all rubber items that are used to seal. once theyre installed though the lube does 4/5ths of fk all.



id also like to say that diysv6 are worthy of rep. helpful users like that need to be rewarded with more than just "likes"
rep is given with the little "sherrifs star" on the bottom left of his post. chuck a comment in the box and give him + rep.

 

[Kokentoe]

Just got back from holidays. Quick update on the injector situation. I removed them and fitted my old set of injectors to see if the strange start up problem would still occur and it no longer does. So it's definitely something to do with the new set that I bought. They are exactly the same type of injectors which are genuine bosch. After doing some research it seems like they could be some leaky injectors causing those particular symptoms I'm experiencing. There is 12 months warranty for the injectors so I could get a replacement, but should I attempt to have them tested first and is it possible to fix a leaking injector/s?

In regards to "diysv6" and his responses, I certainly appreciate it. It is always good to have helpful members like him on a forum. Having said that, I'm also grateful to everyone else who has given feedback and those who continue to do so. Cheers!

 

[diysv6]

After doing some research it seems like they could be some leaky injectors causing those particular symptoms I'm experiencing. There is 12 months warranty for the injectors so I could get a replacement, but should I attempt to have them tested first and is it possible to fix a leaking injector/s?

https://www.youtube.com/watch?v=VGaL9IbB4AI

This is a Utube video.
At about 2m10sec is a leak down test done with the company's timer/injector pulse box.


The Tech2 will do a similar test on each fuel injector whilst installed on the vehicle.
Can you source the Tech2 access and then you can hopefully identify the bad injector/s.
It will/may give you an argument for replacement under warranty etc. if done on a recognised company letterhead.
http://www.gearchatter.com/viewtopic10640.php
The Tech2 test will show injectors which are under and over delivering the standard volume of fuel. Looks pretty neat to me.



Sitting behind all of this is the "tune" that you mentioned in an earlier post.
The car still runs well on the original injectors. So perhaps the tune is very delicate, and not robust (broad spectrum) like the Holden software.
Did you relocate the original injectors into the original tuned cylinder to get this good idle?

If I may ask, what tune have you got?


Thanks to the members who have mentioned my posts. I remember and appreciate people helping me out on occasions, and I feel that if I can repay the favours, then that is what the Just Commodores fraternity is all about.

 

[Kokentoe]

https://www.youtube.com/watch?v=VGaL9IbB4AI

This is a Utube video.
At about 2m10sec is a leak down test done with the company's timer/injector pulse box.


The Tech2 will do a similar test on each fuel injector whilst installed on the vehicle.
Can you source the Tech2 access and then you can hopefully identify the bad injector/s.
It will/may give you an argument for replacement under warranty etc. if done on a recognised company letterhead.
GearChatter.com :: View topic - Fuel Injector Balance Test with Tech 2
The Tech2 test will show injectors which are under and over delivering the standard volume of fuel. Looks pretty neat to me.



Sitting behind all of this is the "tune" that you mentioned in an earlier post.
The car still runs well on the original injectors. So perhaps the tune is very delicate, and not robust (broad spectrum) like the Holden software.
Did you relocate the original injectors into the original tuned cylinder to get this good idle?

If I may ask, what tune have you got?


Thanks to the members who have mentioned my posts. I remember and appreciate people helping me out on occasions, and I feel that if I can repay the favours, then that is what the Just Commodores fraternity is all about.

I just put the old injectors back on the fuel rail in no specific order. The idle was fine with either set of injectors, the only difference was the struggle to start up after sitting for a period of time with the "new" injectors.

It's just the tune for alloytec motors which was done on the dyno. I don't think it would be causing the problem with the new injectors, but rather there is some issue with the injectors themselves. I'll probably just take them to a mechanic to have them inspected, and then get them replaced if need be.

I went and bought one of those injector service kits which come with new o-rings and filters. Probably won't fix it but I'll give that a go first and see what happens. I heard people spray carb cleaner inside the injectors when changing over the filters to clean them out. Should I do this and could I use something like contact cleaner instead?

 

[diysv6]

If your original injectors are idling and starting without any hesitation then I would leave them be for the time being.

Re the new injector set, I would try for a money back or replacement under the warranty terms. Under consumer law, being the Christmas advice to buyers we hear around the place, a retailer does not have to give the money back under law, unless if stated in the purchase conditions etc. Contact the seller for their returns policy on used goods and restocking policy.

Being unfit for purpose should get a swap over, argue for all 6 of them. If they are eager to please and in the service industry, they may be willing to test the replacements at no cost to keep your goodwill.

I would try to negotiate the money back/total replacement before you spend money on a Tech2 report.

I'd try for a no cost solution initially, (postage costs maybe your end), then decide if the cost of the Tech2 test report will get you the replacements you need. If the Tech2 comes up with a good report for all injectors, then the ball game restarts for the solution.

Many retailers do not take returns on electrical devices as they can be damaged by poor testing techniques or system electrical faults damaging the new device.

Other JustCommodores members may have a different slant on your problem, maybe a mechanic could contribute his testing method and how the return process works for him?

 

[diysv6]

If you consider this method, please undertake all safety precautions prior to the attempt. Fire extinguisher, safety glasses, gloves, location, scrap rags, second person etc.
I'd hook up the fuel pressure gauge prior to this testing to observe pressure variations etc.
I take no responsibility for the outcome.

RE the new injectors which may be leaking.

I have read somewhere that a simple leakdown test is to remove the fuel rail with the injectors still attached.

Place a few sheets of newspaper, white paper etc. on top of the inlet manifold and then lay the complete injector assembly on the paper.
You may have to support the fuel rail to ensure no damage to the outlets of the injectors.

Carefully power up the fuel pump - Do not try to start the car. (remove the fuel injectors' power connector at the fuel rail to stop any triggering).
The symptoms of a leaky injector is a petrol wet spot or pool under the injector which is faulty.

This could save on the Tech2 testing costs and give you photographic evidence about the leaking injector.