Fuel problems

[FireKraka]

Hey Gary how are you going with the issue.
Early Commodores don't run OBD1 system but ALDL I think it is called, I have looked for a diagnostic tool for some time and never found one so I rely on the method I detailed above, jumping ports 'A' & 'B' on the diagnostic connector and counting the code.
Let's know how you get on I'm interested to hear what the fix is.
Neil

[gazza]

Hi all problem not solved yet don't know what to do. Thanks Gary.

[Blacky]

so you have rectified the pressure issue and its still doing the same thing ???

[gazza]

sorry blacky haven't fix the problem but you are right about the fuel pressure i will be looking for a forty psi pump and see how that works . If that dont fix the problem I will have a look at something else. worst case will be to fit commodore fuel tank and pump. Will see what happens will keep you all up to date. Cheers Gary.

[gazza]

Just spoke to the guys at EFI hardware and they said it doesn't matter what psi pump i use its the fuel pressure regulator that controls the fuel pressure the pump only sends the fuel to the motor. I have changed two fuel regulators and one adjustable regulator . I dont know what to do now. cheers Gary

[Blacky]

What pressure do you have at the fuel rails ???

[gazza]

Hi all Blacky i have spoken to mechanics about this fuel pressure in the line thingy what it does i dont known can someone please tell me what is does or what will it tell me. Does it tell me what the problem is. This car is starting to make me climb the walls not knowing what the problem is. cheers Gary

[FireKraka]

Sorry Gary I thought you had the commo tank and in tank pump as well as the external.
My Ute runs commo internal and an external pump and I don't have the problem you are talking about at least it is not caused by the fuel pressure. You also don't want to go down too far in fuel pump[ pressure 40 psi is only approx. 2.6 Bar and you really want to be around the 4 Bar which is approx. 60 psi which is why I didn't think you pump was much of an issue to start with.
The reason I asked you about K's on the engine and if you had done a compression test my engine was second hand, it originally had roller rockers but they had been sold before I got the rest of the engine.
When I fist started running the engine it developed the same issue as yours, before I got the first dyno tune done it got tot he point that it wouldn't start, it was running extremely rich, got some advise, told to change plugs and it started straight up.
Took it for first dyno, they got a basic tune into it before finding a couple of issues, exhaust scatter all over the place, compression test found #1 cylinder with Zero compression and some other minor stuff.
I found one of #1 cyl valves being held open slightly, this can also be carbon on seats, wear in valves, bad lifters etc.
Second dyno, more timing into it and running heaps better but scatter still out, this was because I still had the second set of plugs in it and they had fowled up, new set of plugs and it has come good, mind you I did find another cylinder that was down 50 psi same problem as #1 cyl.

I tell you all of this and did ask earlier if you had done a compression test, go back to basic fault finding, old saying in my business "don't strip down the engine just because you have a bad spark plug" (actually I just made that up ) I'm in the marine diesel business so the saying goes a little different

So waht I'm suggesting mate is change your plugs run the engine, take a set of cylinder temps at the exhaust outlet if you have a big scatter take all the plugs out, pull the fuse for the fuel pump and do a compression test, also change the oxy sensor, those basic diagnostic checks that are easy to do my light on the problem, if you don't know how many K's are o the engine it can't hurt to do this easy stuff.

You can give me a ring if you like 0423 827 973 I may be able to help
Neil

[FireKraka]

Gary the fuel rail pressure regulator is there to maintain a constant pressure in the fuel rail so that when the computer tells the injector to open there is ample pressure there to supply the cylinder, the regulator has a small vacuum line to the inlet manifold and the manifold vacuum opens and closes the regulator maintaining pressure.
When you turn the car off the regulator is shut (no vacuum) and the fuel rail is pressurized so the next time you start the car there is pressure there for the injectors/cylinders before the pump kicks in again.

Is you fuel pump controlled by the computer or does it just come on when you turn the key and it continually runs all the time??
Neil

[gazza]

Hi all i know what you are saying Blacky but what i was referring to is i have been asked about the pressure in the fuel line i was told i need a gauge to test it . Thats what i dont understand like what will the gauge tell me will it tell me what the problem is. yeah neil might have to do a compression test on each cylinder. And change the 02 sensor The fuel pump is wired into the v6 conversion loom so when the ignition is turned on the pump starts. I hope this helps. Cheers Gary.

[ehsv6]

Hi Gazza

What suburb are you in. If your close I may be able to help once where out of lockdown.
Had a V6 in my EH for nearly 10 years, also owner of a VS and VX.

Regards Keith

[gazza]

No problems Keith i am i Melton will sort something out after lock down is over . Cheers Gary.

[ehsv6]

OK I'm near Ringwood so we couldn't be further apart.

[Harv]

Hi all i know what you are saying Blacky but what i was referring to is i have been asked about the pressure in the fuel line i was told i need a gauge to test it . Thats what i dont understand like what will the gauge tell me will it tell me what the problem is.

The gauge will tell you the pressure in the fuel rail. You should not have to buy one - most mechanics should have one. It will show you one of a couple of things:
a) the fuel pressure with the car off is OK, and stays that way when the car is started. This means fuel pressure (pump or reg) is not your problem.
b) the fuel pressure with the car off is OK, but is waaaaaay too high when the car is started. This means the fuel pressure reg is too small to keep up with whatever pump is installed. Put in a smaller pump, or put in a bigger reg.
c) the fuel presssure drops down too low with the car off, but is OK when the car is started. This means the fuel pressure reg has a leak, and is wetting your plugs when the car is off. Replace the fuel pressure reg.

Cheers,
Harv

[gazza]

Hi all. I had a talk with Neil ( FireKraka ) on Friday very nice guy. Done a comp test and i have high and low numbers #1 150 #2 145 #3 165 #4 160 #5 175 #6 150 . i done the test about 5 times and they are the numbers i got on every test i done. I dont know if i done the test right i brought one of the supercheap comp tester Will be ordering a 02 sensor during the week and hope to have it on by the weekend. Cheers Gary.