Bad Fuel injectors?
#1
Bad Fuel injectors?
Ok so I have a 1991 z28 with a 5.0 TPI and recently the idle has been a bit rough and car feels sluggish. I just recently changed the spark plugs and fuel filter but that didn't help at all. So I decided to ohm the fuel injectors and got a reading as follows
1 2 3 4
Front of Car INTAKE/RUNNERS Rear of Car
5 6 7 8
Injectors Ohms
1 11.9
2 11.9
3 17.0
4 16.8
5 08.0
6 17.0
7 17.0
8 17.0
Please let me know which ones are bad and which injectors are good. Thanks
1 2 3 4
Front of Car INTAKE/RUNNERS Rear of Car
5 6 7 8
Injectors Ohms
1 11.9
2 11.9
3 17.0
4 16.8
5 08.0
6 17.0
7 17.0
8 17.0
Please let me know which ones are bad and which injectors are good. Thanks
#3
Re: Bad Fuel injectors?
Ok thanks I appreciate it. If you don't mind me asking what is the normal range for the injectors for future reference? Also do you know what the stock injectors are pushing 19lb or 21lb?
#4
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Re: Bad Fuel injectors?
Stock 305 is 19#hr, use the promo code tuned for a 10% discount.
http://m.southbayfuelinjectors.com/p...7&product=1500
Below 12 is bad, typically a veritable of 1/2 a ohm between injectors. New coils will be 16-16.5 ohms.
http://m.southbayfuelinjectors.com/p...7&product=1500
Below 12 is bad, typically a veritable of 1/2 a ohm between injectors. New coils will be 16-16.5 ohms.
#6
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Car: 1988 Formula 5.7
Engine: 350
Transmission: 700R4
Re: Bad Fuel injectors?
RBob,
Why are they all bad in his case? I've been struggling with a problem similar to his, and my checked 17.0 across with 2- 16.8's.
What should they read?
Mines a 5.7
I understand replacing all if they need it.
Why are they all bad in his case? I've been struggling with a problem similar to his, and my checked 17.0 across with 2- 16.8's.
What should they read?
Mines a 5.7
I understand replacing all if they need it.
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Car: check
Engine: check
Transmission: check
Re: Bad Fuel injectors?
Your '88 didn't get Multec injectors from the factory, so it is rare that you will find a shorted coil in one.
RBob.
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Car: 89 GTA/90 Iroc Vert
Engine: 5.7/5.0L
Transmission: 700R4 x 2
Axle/Gears: 3.27/2.73
Re: Bad Fuel injectors?
If you have 3 out of 8 acting up, you should replace them all as a set because ...
#1 - age 9as mentioned) of the ones test good are limited, going to go soon, a whole set of reman'd is about $130, do you want to tear the whole thing apart again ?
#2 - a set is (should be) tested and "balanced" meaning the flow has been measured and they disperse fuel equally (close to) old ones may OHM out good, but they may not flow good.
#1 - age 9as mentioned) of the ones test good are limited, going to go soon, a whole set of reman'd is about $130, do you want to tear the whole thing apart again ?
#2 - a set is (should be) tested and "balanced" meaning the flow has been measured and they disperse fuel equally (close to) old ones may OHM out good, but they may not flow good.
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Car: 1989 GTA
Engine: SuperRam 350
Transmission: Pro Built S/S TH700R4
Axle/Gears: 3.27
Re: Bad Fuel injectors?
Here is a comparison to stock Multec vs Bosch III. The Bosch III are better in every way compared to the Multec. I've found that it's not mileage that does in injectors, but rather age. As my Multecs went about 3 years ago when I had about 35,000 miles on the car. It may be the ethanol that eats them. It may just be the age.
I will say that replacing with Bosch III made the car idle smoother than it did brand new. Definitely replace all of them while you're in there.
#11
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Car: 1988 Formula 5.7
Engine: 350
Transmission: 700R4
Re: Bad Fuel injectors?
Wow Reid, Thanks for that video!
That explains alot, and clearly the winner here.
No Jersey, just making my list and checking it twice.
After doing my Ohm tests and checking some other things, I discovered a small nest under the plenum of a very clean car. That said off comes plenum, and in goes new injectors anyway.
Will see what else in the process too.
That explains alot, and clearly the winner here.
No Jersey, just making my list and checking it twice.
After doing my Ohm tests and checking some other things, I discovered a small nest under the plenum of a very clean car. That said off comes plenum, and in goes new injectors anyway.
Will see what else in the process too.
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Car: 1989 IROC & ROLL-Z
Engine: L98 Vortec FIRST TPI
Transmission: T56, Mech Speedo
Axle/Gears: G92 J65 3.27
Re: Bad Fuel injectors?
Woah Reid, that's a hell of a video.
Thanks for posting. Purchased Bosch III's yesterday, even more excited for them to arrive now!
Thanks for posting. Purchased Bosch III's yesterday, even more excited for them to arrive now!
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Car: 89 GTA/90 Iroc Vert
Engine: 5.7/5.0L
Transmission: 700R4 x 2
Axle/Gears: 3.27/2.73
Re: Bad Fuel injectors?
Got injectors, reg, and rail on. still fighting the stupid bolt that holds the bracket on where the fuel line hook to rail. The geniuses didn't make it easy.
Going to get a 3/8 x 1/2 bolt vs 3/4, bolt hits the compression fitting. Unless I undo compression fittings and bent the line ... don't want to do that.
But finding that size at HD or AutoZone ... nope - not popular size. Going to Fazzios (Mans Hdwe Store). Its holding me up from closing it up.
Question for the Veterans:
When should I test for leaks ? Put runners on semi-loose... or before...?
Should I press schaeder valve while fuel pump is priming ? Let air out...
Going to get a 3/8 x 1/2 bolt vs 3/4, bolt hits the compression fitting. Unless I undo compression fittings and bent the line ... don't want to do that.
But finding that size at HD or AutoZone ... nope - not popular size. Going to Fazzios (Mans Hdwe Store). Its holding me up from closing it up.
Question for the Veterans:
When should I test for leaks ? Put runners on semi-loose... or before...?
Should I press schaeder valve while fuel pump is priming ? Let air out...
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Car: 1989 IROC & ROLL-Z
Engine: L98 Vortec FIRST TPI
Transmission: T56, Mech Speedo
Axle/Gears: G92 J65 3.27
Re: Bad Fuel injectors?
Test for leaks BEFORE you assemble the intake any further than necessary.
Depressing the scheader is not neasisary as the system has a return line and will auto purge the air from the system.
Depressing the scheader is not neasisary as the system has a return line and will auto purge the air from the system.
#16
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Car: 89 GTA/90 Iroc Vert
Engine: 5.7/5.0L
Transmission: 700R4 x 2
Axle/Gears: 3.27/2.73
Re: Bad Fuel injectors?
Thanks, I did the test before runners went on, good thing - had a pinched oring on one injector, fixed it and all good now, Schrader valve is acting up, weeping gas out the middle. ? Anybody else have that happen.
#17
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Car: 1989 IROC & ROLL-Z
Engine: L98 Vortec FIRST TPI
Transmission: T56, Mech Speedo
Axle/Gears: G92 J65 3.27
Re: Bad Fuel injectors?
the valve has a cone in the bottom that seats against an o ring, sounds like its worn out. Get a valve remover and take it out and check, I bet its cracked.
#18
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Car: 89 GTA/90 Iroc Vert
Engine: 5.7/5.0L
Transmission: 700R4 x 2
Axle/Gears: 3.27/2.73
Re: Bad Fuel injectors?
Yea, just got back from Auto zone and got a stem remover and AC system valve stem kit, has a variety of stems/cores w/o ring. I will pull the core tomorrow see whats up.
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