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Fuel injector test

I've got a 1974 2.7 cis which has been sitting for at least 10 years.

I cleaning out gas tank and everything right up to the fuel filter.

I put some fresh gas in the old girl and she started,but only ran on a few cylinders.

So I put new fuel injectors on her and did the jar test.

2&4 have no fuel at all , 3&5 are getting alot more,this was about 30 seconds

Here is a pic of results 1,2,3,4,5,6,cyl.

Thanks for any ideas




Old 11-25-2011, 09:45 PM
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Did you *have* to put them on the back of your corvette? Or are you just trying to tell us something :P
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Old 11-25-2011, 10:27 PM
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Did you replace the fuel filter?
That gas looks very dirty.
Clogged injectors from what was in the fuel lines?
Take them off and soak them in some injector cleaner to get the Crud out of them.
Then try it again.
Hopefully your fuel distributor is functioning correctly.
Maybe clogged lines, take them off and make sure they flow well?
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Last edited by timmy2; 11-25-2011 at 10:53 PM..
Old 11-25-2011, 10:50 PM
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Ive got new injectors,Idle setting is backed off alot,I'm not sure how to set it,not sure what I should try next.

Last edited by mixer911; 11-26-2011 at 12:14 AM.. Reason: tech
Old 11-25-2011, 11:45 PM
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New injectors with bad gas will clog right up.
You've got a lot of varnish in that fuel. Maybe enough to plug them up.
Change the filter and then let the lines flush out without the injectors attached.
You want to see fuel that is the same color as fresh fuel coming out of each one at the same rate.
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Old 11-26-2011, 12:17 AM
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You can try swapping the injectors around to see if the injectors are clogging or if the fuel distributor is not putting out evenly.
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Old 11-26-2011, 04:07 AM
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In this picture of an old fuel distributor I bought to refurbish, you can see how corrosion can make a mess of things. Behind each o ring is a very narrow slit that can become clogged. Also in the second picture is a small filter that is in my 73.5 cis fuel distributor for each injector line.

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Old 11-26-2011, 04:28 AM
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Do this advise.......

Quote:
Originally Posted by E Sully View Post
You can try swapping the injectors around to see if the injectors are clogging or if the fuel distributor is not putting out evenly.
Ed,

This procedure should be done to determine the root cause of the problem. And a very sage advise to offer. As long as you could get the correct system fuel pressure or delivery pressure to the FD, the fuel filter is good. No need to replace a good working fuel filter unless it is 5 years old or older.

Tony
Old 11-26-2011, 05:58 AM
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The filter was changed,and the gas was fresh.
Today I'll drain fuel again and put fresh in ,charge the battery,and swap around the injectors.
I'll post results
Thank you for your input.
Old 11-26-2011, 09:01 AM
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He already said twice that the tank was cleaned and fresh gas is in there.

mixer911,
When you refill the tank, use a can of Techron for 1/2 a tank.
I'd remove the injectors and let the lines run into the jars briefly to see if the FD puts out an equal amount.
Old 11-26-2011, 09:45 AM
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Quote:
Originally Posted by Gunter View Post
He already said twice that the tank was cleaned and fresh gas is in there.

mixer911,
When you refill the tank, use a can of Techron for 1/2 a tank.
I'd remove the injectors and let the lines run into the jars briefly to see if the FD puts out an equal amount.
+1, he said what I said, what she said....

The varnish is from the fuel that remained in the system downstream from the filter to the injectors when it sat for 10+ years. It is going to take a while to clean that all out just running the car's fuel system with additive cleaners. I would suggest you take it off and flow some carb cleaner through it.
I had mine off and cleaned it all up and it runs nicely. Sat for 4 years and was gummed up. And yes, I installed new injectors.
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Old 11-26-2011, 10:01 AM
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Long ago, I built an injector cleaner...a simple air chamber with a port to screw the injector into...supplied by air from the compressor...and a battery to trigger the injector.
The idea being to back flush the injector with air ( and cleaner added to the chamber under the injector being tested) and triggered several times to exercise the unit.
Seemed to work nicely and saved the cost of new injectors many times.
Bob
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Old 11-26-2011, 10:40 AM
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Too bad we can't hook up electrical to our old CIS injectors. They are only mechanical in the early CIS.
No plug to hook up to!
They can be sent for rebuild or just cleaned in an ultrasonic cleaner. I will be doing the latter with the set I removed.




No Plug...
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Euro 1978 SC Targa, SSI's, Dansk 2/1, Bitz kit EFI.
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Old 11-26-2011, 10:47 AM
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Quote:
Originally Posted by timmy2 View Post
+1, he said what I said, what she said....

The varnish is from the fuel that remained in the system downstream from the filter to the injectors when it sat for 10+ years. It is going to take a while to clean that all out just running the car's fuel system with additive cleaners. I would suggest you take it off and flow some carb cleaner through it.
I had mine off and cleaned it all up and it runs nicely. Sat for 4 years and was gumed up. And yes, I installed new injectors.
Timmy 2 ,How do I do that ?Are you saying I should remove the FD and run carb cleaner through it?
Old 11-26-2011, 12:29 PM
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I removed the injectors and put the lines into jars.
CYL. 2 and 6 no fuel
The rest of the lines had fuel ,but different amounts.
Old 11-26-2011, 02:19 PM
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I bet the distributor is caked with crud. E Sully has a thread that discusses taking it apart. I would read a lot of threads before taking it apart. You need to go into this with confidence.
Old 11-26-2011, 07:52 PM
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Thanks Bob

I wasn't going to do anything without a go no go from you.
I agree FD needs to be taken apart.
It seem like open heart surgery
I've read most all posts about it ,God willing and with some support I might just pull it off.
It takes a whole village to restore a Porsche
Old 11-26-2011, 10:43 PM
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Quote:
Originally Posted by mixer911 View Post
I wasn't going to do anything without a go no go from you.
I agree FD needs to be taken apart.
It seem like open heart surgery
I've read most all posts about it ,God willing and with some support I might just pull it off.
It takes a whole village to restore a Porsche
LOL, Open Heart Surgery..... Almost had to get that done yesterday....
Blew up my airbox last night. PO had glued it and I didn't see that when it was out. wouldn't start, then kapow! blew the pop off right out too! Almost a cardiac event...:

Pulled my CIS off the car with engine in place this evening, didn't even partially lower it. Anything is possible if you take it slow and careful.

New airbox ordered from our host should be here this week. Up and running again by Saturday?
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Old 11-26-2011, 11:04 PM
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If you take the fuel distributor apart, make sure you keep track of exactly where each part came from. Under each little hat and spring are shimming washers. They can vary in thickness and mixing them up can alter the amount of fuel delivered to the injectors. Some reassemble without sealant, others use various sealants. If you use a sealant, use it sparingly. The thin steel plate between the distributor halves has a small pin hole in it. Don't let the sealant block this small orifice.
One of the problems with cleaning cis injectors is the small filter screen inside the injector. Spraying cleaner through them will not remove debris in the screen. I have back flushed mine by carefully pulling the pintle out and back flushing them. It is possible to damage them if not done carefully. In the picture, borrowed from another forum, you can see what I mean.
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Old 11-27-2011, 04:24 AM
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Quote:
Originally Posted by mixer911 View Post
I wasn't going to do anything without a go no go from you.
I agree FD needs to be taken apart.
It seem like open heart surgery
I've read most all posts about it ,God willing and with some support I might just pull it off.
It takes a whole village to restore a Porsche
Before taking the FD apart, I'd consider removing it from the Mixture Control Unit and leaving the FD submerged in injector cleaner for couple days.

A suitable container like a coffee can with enough cleaner in it might do it. Just turn/move the FD to get the air out of the openings.

After couple days, carefully blow out with air, then refill all the openings with IC and reconnect all lines. Make sure that your fuel pump actually has the necessary pressure of ~70 PSI to "convince" the FD to work or else.

I think it's worth a try before dismantling.
Old 11-27-2011, 07:15 AM
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Old 11-27-2011, 07:15 AM
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