Can you test injectors? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

bikerbomber · 12-12-2007, 08:53 PM

Gosh, I hope someone replies to this one.

Is there a way to test injectors outside of the engine compartment?

And is there a way to test the IAC and the TPS using a tester?

I am planning on selling that TBI I bought and wanted to know what works and what doesn't so I know what I am selling. Any imput would be nice, thanks!

get me on the road · 12-12-2007, 09:18 PM

What does your IAC connector look like, square or rectangle, and how many holes does it have.

bikerbomber · 12-13-2007, 08:08 AM

It is square with four connectors. And the TPS has the three prong connector as well. Thanks!

get me on the road · 12-13-2007, 08:30 AM

Does this make sense? The 55.4 and 55.2 was what mine read when I tested it. I dont know how to test the TPS.

get me on the road · 12-13-2007, 08:33 AM

As for the injectors you could go to the parts store with your meter and see what the ohms are on a new one. That is if noone posts them.

bikerbomber · 12-13-2007, 02:14 PM

Hey thank you for that chart, it tested about 48 for both. SO I am going to hope it operates properly. The TPS measured a fair amount of differences in ohms between throttle 'points'. Between 1.4 (rounded up) and .8 (or .7?). So I think that is good too.

I tested the injectors and came up with .1 ohm resistance. I tested the ones in my truck and got same. Is it safe to assume they are in working order?
Offical specs anyone?
Thanks!

get me on the road · 12-13-2007, 02:26 PM

Quote:

Originally Posted by bikerbomber

Hey thank you for that chart, it tested about 48 for both. SO I am going to hope it operates properly. The TPS measured a fair amount of differences in ohms between throttle 'points'. Between 1.4 (rounded up) and .8 (or .7?). So I think that is good too.

I tested the injectors and came up with .1 ohm resistance. I tested the ones in my truck and got same. Is it safe to assume they are in working order?
Offical specs anyone?
Thanks!

Your selling it not me, but if the injectors in your truck read the same, I would guess everything is in working order, and your welcome, glad I could help you.

ChevyTech · 12-14-2007, 02:09 PM

Keep in mind when you are checking an electro-mechanical device, the electrical winding could be good but that does not guarantee the mechanic part will move.

It is common to see an IAC that has failed and does not move, or sticks, but the windings inside it are ok.

Same principle with the injectors. An injector could be plugged with debris or bound up without affecting the resistance of the injector.

I am fairly sure the resistance spec for model 220 TBI injectors is – should be over 1.3 ohms

There are no specs in a manual for testing a TPS the way you are testing it.

You didn’t say what year the parts are that you have, but here are specs I looked up for reply to another thread for a TBI truck.

IAC testing:

Terminals A to B should be 40 to 80 ohms

Terminals C to D should be 40 to 80 ohms

Terminals A to D should be infinite

Terminals B to C should be infinite

I suggest only using a digital (high impedance) ohm meter for doing these tests.

bikerbomber · 12-15-2007, 05:31 AM

Hmmm thanks guys for the info. I was thinking I might as well just put it on top of a 350 and see if it runs. Chevytech, I just mesured the ohm resistance from the (if your looking at the side without the throttle posi sensor) right and center slots. It measured a drop in ohm resistance the further I moved the tps arm to 'open throttle'. Didn't read that anywhere, just tried it.

Thanks fellas, I will let you know if I put it on a 350 and see if it explodes;

12-12-2007, 08:53 PM	#1
bikerbomber Registered User Join Date: Feb 2007 Location: Sierra Vista, AZ Posts: 306	Can you test injectors? Gosh, I hope someone replies to this one. Is there a way to test injectors outside of the engine compartment? And is there a way to test the IAC and the TPS using a tester? I am planning on selling that TBI I bought and wanted to know what works and what doesn't so I know what I am selling. Any imput would be nice, thanks!

12-12-2007, 09:18 PM	#2
get me on the road No Matter What. Join Date: Jan 2007 Location: Do I know you? Posts: 655	Re: Can you test injectors? What does your IAC connector look like, square or rectangle, and how many holes does it have. __________________ Currently own: 89 Chevy Silverado Previously Owned:Starting with my first vehicle 86 Mercury Cougar /89 Olds 88 /88 Chevy S-10 /84 Pontiac Firebird(I miss it) /91 Chevy S-10

12-13-2007, 08:08 AM	#3
bikerbomber Registered User Join Date: Feb 2007 Location: Sierra Vista, AZ Posts: 306	Re: Can you test injectors? It is square with four connectors. And the TPS has the three prong connector as well. Thanks!

12-13-2007, 08:30 AM	#4
get me on the road No Matter What. Join Date: Jan 2007 Location: Do I know you? Posts: 655	Re: Can you test injectors? Does this make sense? The 55.4 and 55.2 was what mine read when I tested it. I dont know how to test the TPS. Attached Images __________________ Currently own: 89 Chevy Silverado Previously Owned:Starting with my first vehicle 86 Mercury Cougar /89 Olds 88 /88 Chevy S-10 /84 Pontiac Firebird(I miss it) /91 Chevy S-10 Last edited by get me on the road; 12-13-2007 at 08:30 AM.

12-13-2007, 08:33 AM	#5
get me on the road No Matter What. Join Date: Jan 2007 Location: Do I know you? Posts: 655	Re: Can you test injectors? As for the injectors you could go to the parts store with your meter and see what the ohms are on a new one. That is if noone posts them. __________________ Currently own: 89 Chevy Silverado Previously Owned:Starting with my first vehicle 86 Mercury Cougar /89 Olds 88 /88 Chevy S-10 /84 Pontiac Firebird(I miss it) /91 Chevy S-10

12-13-2007, 02:14 PM	#6
bikerbomber Registered User Join Date: Feb 2007 Location: Sierra Vista, AZ Posts: 306	Re: Can you test injectors? Hey thank you for that chart, it tested about 48 for both. SO I am going to hope it operates properly. The TPS measured a fair amount of differences in ohms between throttle 'points'. Between 1.4 (rounded up) and .8 (or .7?). So I think that is good too. I tested the injectors and came up with .1 ohm resistance. I tested the ones in my truck and got same. Is it safe to assume they are in working order? Offical specs anyone? Thanks!

12-14-2007, 02:09 PM	#8
ChevyTech Registered User Join Date: May 2004 Location: Minnesota Posts: 4,621	Re: Can you test injectors? Keep in mind when you are checking an electro-mechanical device, the electrical winding could be good but that does not guarantee the mechanic part will move. It is common to see an IAC that has failed and does not move, or sticks, but the windings inside it are ok. Same principle with the injectors. An injector could be plugged with debris or bound up without affecting the resistance of the injector. I am fairly sure the resistance spec for model 220 TBI injectors is – should be over 1.3 ohms There are no specs in a manual for testing a TPS the way you are testing it. You didn’t say what year the parts are that you have, but here are specs I looked up for reply to another thread for a TBI truck. IAC testing: Terminals A to B should be 40 to 80 ohms Terminals C to D should be 40 to 80 ohms Terminals A to D should be infinite Terminals B to C should be infinite I suggest only using a digital (high impedance) ohm meter for doing these tests.

12-15-2007, 05:31 AM	#9
bikerbomber Registered User Join Date: Feb 2007 Location: Sierra Vista, AZ Posts: 306	Re: Can you test injectors? Hmmm thanks guys for the info. I was thinking I might as well just put it on top of a 350 and see if it runs. Chevytech, I just mesured the ohm resistance from the (if your looking at the side without the throttle posi sensor) right and center slots. It measured a drop in ohm resistance the further I moved the tps arm to 'open throttle'. Didn't read that anywhere, just tried it. Thanks fellas, I will let you know if I put it on a 350 and see if it explodes;



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