Hi all.

Just wanted to run something by you guy's before I hand over the car to an EFI shop and open my wallet. Now I'm just only starting to get my head around EFI, so that's why I'm telling you everything I have checked and so on.

I have a miss that's been bugging me for a while. I have a old style engine Analyser that I hooked it up to and traced the problem down to Cyl 5. When I isolated that lead from firing it made no difference to the car. After cheeking there is heaps of spark. So I looked to the Injector. If I remove the wiring connector is makes no change to the running quality at all. So I tested it with a Node Light, and it's pulsing fine. That leaves me to assume that only the Injector is faulty.


Now I have never had to remove an injector before so I'm not sure if it's something I should tackle or something I should let an EFI guy do. The only problem there is I ordered a set of near new injectors a few weeks ago to have a spare item, but they wont be here for about 6 weeks (slow shipping) and I don't really want to go spending a heap on these ones if I can avoid it.

Just wondering if anyone has any ideas or advise in what the think the problem might be, if I should look at getting the injector out and so on. Can you try and clean them yourself with Carby cleaner? Is it a big risk getting one out if you have never done it before?

Thanks heaps.
Francis.

 

How did this analyser narrow it down to the number 5 cylinder?
What does the # 5 plug look like...any carbon on it?
Check that cylinders compression?
Also you can omh out the injector(15-17 ohms is pretty good)...low ohms mean that it is not opening right.
also put a fuel pressure guage on,prime the fuel line and then turn off and see if the fuel bleeds off quickl(leaking injector)....these are a few things you can do yet...
if they are the original injectors they just may need to be cleaned/serviced..a good place is Rich @ cruisingperforamnce....he does great work on injectors..if you have a new set coming then I would just have them installed if you fully determine it is the injectors. as a side note you can actually remove several/injectors/wires and not notice much in the running of the car(at idle)

 

Hi mate, sorry for taking so long to get back to you. I ended up getting stuck in to removing the injectors as after you said measuring the ohms the one I thought was the trouble one was open circuit.

I have a big old Engine Analyser. (Scope) It has primary, secondary and power checking tests. Great for older points and early electronic ignition. But still served a purpose with this EFI HEI set up! I did a power check isolating each cylinder from firing and saw that 5 made no change when I stoped it. I placed an in line spark tester and saw a big spark, so guessed that it was not lack of spark.

After the Ohms test I removed it and found an EFI guy had a second hand unit so I bought it and it ran like it has never ran before!

The thing I wanted to run by you and all that care to help, is I found another injector had 28 ohms. I was wondering what is the side effects of high ohms in injectors? Should I change this one as well?

Once I got the car out on the road and warmed up it has developed a little miss. Sort of like cutting in and out on 7 Cylinders. Nothing like removing the EFI harness altogether, but small kicks at idle and constant RPM's.

Secondly I wanted to check something that might sound really basic and silly, but with the injector wirings, do they have to go to a certain injector or can they inter swap between each other? If they are meant to be on a certain injector how would I check they are all right and not crossed over?

Thanks heaps again. Looking foward to hearing from you.

Francis.

 

The 28 ohm injector is also bad. All injectors fire at the same time, so which plug goes on which injector is not important.

RBob.

 

Don't 4 of them fire once then the other four ? Not all at the same time ?

 

Nope. On a TPI they all fire at the same time.