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ohm tested my injectors today....some questions


Guest TurboSedan

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Guest TurboSedan

should they be tested when the engine is warm or can you test them when the engine is completely cold?

 

i pulled the plenum off the TSTE today and they all tested 11.7-11.9 ohms. obviously the engine was cold since it hasn't been started since last November.

 

i also checked injector #1 on my Cutlass just for comparisons sake (the only one i could check without taking the plenum off). the engine was warm and it was at 12.5 ohms.

 

should i be worried about the TSTE injectors? the engine seemed to run just fine last November, but last week i pulled the plugs and they were all damp and stunk of gas. seems really wierd they would be wet considering it hasn't run in months although there have been plenty of times i have had the key on which would obviously pressurize the fuel rail. i'm a little worried the injectors are leaking down.

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Guest TurboSedan

Hook up a fuel pressure tester and turn the key on. Let the fuel rail pressurize then shut the key off. Leave it for awhile and come back and check the pressure.

 

i'll try that. is there a normal amount of pressure drop over a certain period of time (like say...1hr)? i mean...does the fuel pressure gradually drop by way of the return line to the gas tank if the engine isn't started?

 

thanks

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Technically Josh if those are LG5 stock injectors I would say they are borderline and I would replace them. 12.0-12.5 is normal...above 12.6 is getting up there. 11.9 and less is too low technically.

 

Just to sooth my mind on what you were seeing....did you touch the two ohm leads together and get 0.00 ohms or was there a deflection? This is a digital volt meter right? Is it Cheng Shin made or a Fluke or at minimum a Craftsman?

 

Just trying to understand what you are seeing... :wink: :cool:

 

 

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Wel... anything under 12 Ohms is going to start to cause problems. I have one injector in my car that is at 11.89 ohms and I have a miss at idle. The rest are up and ok. I need to put in the new injectors that I got...but I need to make an appointment to take a crap lately! :willynilly:

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i also have a shight miss at idle...im not sure how i check the injectors... i got a good DMM and it god the omh setting obiously but just unsure exactly how to test them. dont wanna screw anything up

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It is pretty easy and you will not hurt the injectors doing an Ohm check.

 

Short and dirty version of exact Ohm value for EACH injector:

 

Check your DVM by touching the red and black leads together to make sure you show 0.00ohms before you start.

 

1). Do what you need to do to remove the upper intake plenum.

2). Remove the injector electrical connectors by pushing (no prying away!) the metal clip towards the body of the injector and gently pulling the connector off the top of the injector.

 

With the connector off you will see to spade connectors on the injector.

 

3). With the red and black leads of your DVM...touch the red to one spade connector and the black to the other spade connector on the injector. Do not touch the two leads together as this will show a lower Ohm value than what is there. Just make sure they do not touch each other and you have good contact to each spade connector. You will not short or arc anything doing this so don't be afraid of hurting something! :wink:

4). Order new injectors if you are 11.9 or less is the general rule of thumb.

 

An alternative to expensive stock GM injectors... http://www.tgpforums.com/index.php?topic=2954.0

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I tested all of mine last week and they all ohm'ed properly, but they were leaking under pressure, I pulled the rail, pressurized the system and watched them slowly drip. 4 out of the 6 were wet after a minute or two, and 3 out of the 4 were obviously dripping fuel. I bought replacement Bosch units and will hopefully have it up and running this weekend.

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Hook up a fuel pressure tester and turn the key on. Let the fuel rail pressurize then shut the key off. Leave it for awhile and come back and check the pressure.

 

i'll try that. is there a normal amount of pressure drop over a certain period of time (like say...1hr)? i mean...does the fuel pressure gradually drop by way of the return line to the gas tank if the engine isn't started?

 

thanks

 

There is going to be a fuel pressure drop over time Josh. I don't think you're going to find any "residual" pressure test specs for our cars though that will tell you how much drop you should see over time though. If I'm remembering correctly, they recommend what Ryan has mentioned(pressurize the fuel system, and unbolt the rail so you can pull the injectors up and visually inspect for leakage. Conduct this test on a cold engine of course!). If your injectors or FPR are leaking, you should see the fuel pressure gauge drop in a very short amount of time(a couple of minutes most likely).

 

I think just about everyone here w/ a TGP/tgp injectors has leaky injectors save for those that have replaced them. My car has been starting a little hard lately and the two of the three plugs on the front bank I pulled the other day were wet/wreaked of fuel. I pulled a vacuum on my FPR and didn't get any fuel there...so I guess it's about time for some new injectors in my TGP.

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We should see if the guy who sells those Bosch injectors on ebay would setup a group buy for us. :lol:

Seems that everyone is having injector issues lately.

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why do you guys want Bosch injectors? I got the whatever ones Jeff M recommends. that was years ago, wasnt that expensive, and all I got to do is breathe on the key and it roars to life! when you think about it, injectors are the most important thing to get right the first time. the most common common way for people to waste money is getting the wrong injector set. -

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Because they work, and I don't want to unload my bank account to buy new injectors from GM. New ones from GM are over $100 a piece..

Ours roars to life on the first key turn too, idles smooth, and finally runs good.. good enough for me.

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Well let's see. $168 plus $11 Priority Shipping compared to.....what did you pay?

 

Now are these as strong a design as the newer designed GM injectors? That is to be determined, but as it stands now with 3 cars I know of with these injectors and all running tits perfect without chip modification and with modification I would say we are on the right track.

 

Ever since I got my car back from Luke the car and I seem to have a special relationship. Now my car reads my thoughts through telepathy so I do not even have to breath on my key for it to start. :lol:

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:lol: :cool:thats good you guys found an alternative. the injectors are way over priced, I can agree that a few parts for the tgp are outrageously priced and the only way to justify paying that amount is not having a car payment to worry about. I could spend $600-$800 every 6 months or so and still pay less than a monthly car payment. I paid $109 ea, I think they came with the new style windings or whatever. Also, I am nit picky about not wanting to downgrade, but with the possibility of saving hundreds on injectors, it is still very interesting. So I am trying to not hinder your efforts.

Oh, and TGPilot, that is TMI about you and your car. what you and your car do behind closed doors is your business :wink:TOO MUCH INFORMATION! :lol:

 

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