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P.I. injectors


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Hi all

Just a note to pass on recent experience with having new (I think reconditioned) injectors fitted.

Out of 8 initially tried only 6 were any good. These were supplied by a company named HMI and the garage who fitted them

for me said they did not know of any other suppliers.

I thought that this information might be useful for others.

Ernest

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Did the garage sort the problem out from your previous post? Injectors are pretty simple things, unless the o rings have gone hard and are leaking, there isn't much that can go wrong. They can get stuck with debris, or need to be bled of air, but that's not the fault of the injector. 

A quick search will show a number of people and vendors that supply new or refurbished. I've bought a new one from KMI before and had no issues. 

Gareth

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Thank Gareth

The garage is a well respected engine tuning company with quite a bit of racing success behind them. The car ran really well on the 20 odd mile drive home through London traffic.  So far, so good.

I was pleased that you had a different experience with HMI injectors. I was told that they had no problems with changing the duff ones.

Ernest 

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That's good. If you get the issue again, do the pulse check on the injector lines, make sure the one you are holding isn't touching against another line and feel for a pulsing when it's idling, a steady pulsing means the injector on that line is working. 

Gareth

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A further check is to remove the injectors from the inlet manifold, and hang them in a large container while you turn over the engine.    You want to see that thet they produce a fine spray, not a dribble of a distorted fan of fuel.

A commercial coffee tin is a good size , or else construct a trough like this, with holes for the individual injectors, that you can suspend over the inlets and see each injector clearly:

 

injector test rack 1.jpg

injector test rack 2.jpg

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Steady lads, let's let Ernest build up his mechanical knowledge a little more first.

It's part of the 'fun' with a classic, learning and working on them yourself, one step at a time, but soon you'll be pulling out injectors and bleeding them in no time ;)

Gareth

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14 hours ago, kiwican said:

What is more impressive is that they have been emptied. Most people would not go through 6 jars in a life time.

 

Simon

I do, its always been my favourite for more than 40 yrs when I used to get Aussie guys on tour to bring it over in their flight cases as it wasnt available over here.

Stuart.

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1 hour ago, stuart said:

I do, its always been my favourite for more than 40 yrs when I used to get Aussie guys on tour to bring it over in their flight cases as it wasnt available over here.

Stuart.

Vegemite is a critical food. The most important food group for Australians.

On holiday in 2018 in Rome I got the craving, I must have Vegemite on toast for breakfast. I must.

Google it. A shop a couple of kms away say they have it.

My wife and I walk over and there it was, a very small jar of Vegemite. About $4 in Australia, about 2.4 euro.

The sticker said 8 euro. 

Breakfast the next day was fantastic. Worth every euro!

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Haha, Vegemite is nice but i’m a marmite man

only this afternoon I did an injector test on a member’s tr6 and found 2 recalcitrant injectors, we used a small pyrex jar which worked well

we’ll be ordering a set of refurbed injectors from Neil Ferguson, he’s served me and many others well for many years with PI parts.

steve

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I have seen the You Tube video for taking out injectors and testing / bleeding but I have never done this. It looks to be a risky activity with fine spray petrol around and then trying to get injectors back into the throttle body.

Is there someone near me who is familiar with doing this who could help show me how to do it? I’m based near / in the New Forest area. I’m happy to travel a reasonable distance if needed (hopefully the garages are starting to have fuel now ).

Also when I put the injectors in the throttle body, the fit was very tight. It was not just an easy push by hand. This was for all the injectors. I had new o rings and refurbished injectors, running with them for last year or so. But would like to feel confident to be able to check injectors and confirm all okay. I can bring marmite jar if needed :D.

Appreciate any help.

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It's not that hard, this is what I do:

  • Remove the plugs
  • Enrichment leaver on full choke
  • Tag injectors and remove
  • Insert each injector into an empty 560gm Vegemite jar ( 6 required-  might take a month to collect enough jars).Mount jars above rocker cover so injector lines slope upwards.
  • Fit a remote starter push button to the starter solenoid
  • Crank engine and observe each injector . Injectors should have a good , visible spray pattern . If you have  no spray, a dribble or a bad pattern pull the injector tips and see if that clears it.
  • When you are happy with the spray pattern reinsert injectors ( they should be a hand fit) and plugs,  Do not fit the injector retaining plates at this stage. From memory I use a touch of rubber grease on the injector O rings during re installation.
  • Start engine , you should feel a pulse on each injector line.
  • When the engine is idling and running properly , reinstall holding plates.

I used to do most of the above  with the engine live and running and without the Vegemite jars until No.5 caught alight for some inexplicable reason ( the spray patterns are not near an external ignition source but still ignited) and the fire burned the nylon line before I could extinguish it.

Anyway, if you're stuck it's not that hard.

 

 

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Mike,

Thank you for this. I like the steps / plan you outline. Taking the plugs out is very good idea in my mind and putting all 6 injectors in separate jars at same time also seems a very good idea. This is different to the YouTube clip I saw, but your experience with it catching fire was my worry but I can see this approach would be safer. I’ll still do it outside of garage and still keep a fire extinguisher close to hand but I do like approach here. I just now need 6 clear glass jars.

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Securely mounting six jars, Vegemite or not, on a running engine will require a substantial bracket.    May I suggest the common trough that I showed above?

This shows it, clamped to the plenum tube.

179835934_Injectortestrack5-2020.thumb.jpg.9025eb16446c813916cdf4bada624dc1.jpg

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Good idea, the sloping upwards of the injector lines will help clear air. I've found  sometimes a large air pocket in an injector lines will "bounce" the injector pulses and stop the flow of petrol- that's when I have to make sure the line slopes upwards and pull the injector tips open while I crank out the air.

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15 hours ago, CP26309 said:

Much safer to test them one at a time in as I said using a Jam jar with the injector through a hole in the lid. 

That’s what i do, on a running engine.

first remove all the keeper plates and jiggle the injectors to make sure they are free to pull out

start engine

extract each injector in turn and point into jar, see if there is a cone of spray

if no cone of spray then gently tap the injector and or very gently pull the spring loaded end of the injector with the injector pointing upwards to allow air to exit

at this stage the injector either starts working in which case reinsert it , or it doesnt and needs replacing

work your way along the 6 

this process has either fixed the problem when the issue was just air in the system or identified the tired / failed injectors every time i’ve done it

only take 20 minutes, and with a fire extinguisher at hand and ideally a second person to start/stop the engine is pretty safe

steve

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