Tbi not shooting fuel
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Tbi not shooting fuel
Hey guys got some problems with my car here if anybody could help me out it would be greatly appreciated. So to start off its an 89 camaro rs with a 305 tbi, the car was running mint other then the fact that it would stall out when it was hot but mostly only if you put it in reverse. Other then that only other problem is the check engine light would come on after driving for 20 mins. Other than that tho the car ran good until I went to work one day and it shut off on my way there. I was listening to music so I didn't even know it died until I went to give it gas. It didn't make any noises or jump around at all just kept cruising like it was on. Filled it with gas cuz I figured maybe it was too low, still nothing towed it home. And now here's I am a month later still trying to fix it. The car will turnover like crazy batteries completley charged and it starts with starter fluid but shuts of after burning it off so I'd come to believe it has spark.and either way that's not my problem because I'm not getting gas. I know the gas is getting to the carb because it will spray out the fuel line when disconnected from carb but once it is connected to the tbi again it doesn't shoot out the injectors. No cone not even a drip.
so down tot the details and what I've done to try and fix it so far. I got home and immediately checked the fuel pressure and it read 11 psi so I was positive it was fuel pump, even tho I could still here it good. Got a new fuel pump and filter because I figure why not do both, when I dropped the axel and got the tank out the tank looked immaculate no dust or debri in it but I figured I must replace it anyhow after getting this far replaced the pump it's self, the filter and the hose that attaches to the fuel lines, even tho old ones didn't look to bad. Anyways got it all back together and checked pressure again I was getting 16 psi or maybe a little more, but still nothing when I tried to start. That was a kick in the *** so from there all I could see it being was the tbi. I took it off and sent it to rock auto to get rebuilt I could see the fuel pressure regulator gasket was blown out a bit and the gasket under the tbi was beat as well. Got the tbi back looked brand new injectors all cleaned up and what looks to be new throttle position sensor , but after getting all plugged in and back on the intake manifold with new gaskets. Still no start. If anybody knows anything about what this could be I would be greAt full I need my car back, I think it's gotta either be a sensor, my injector wires or maybe I need a fp with a more pressure. I just feel like there's gotta be some kind of gate closed in my tbi not letting gas in because literally nothing comes out of the tbi.
so down tot the details and what I've done to try and fix it so far. I got home and immediately checked the fuel pressure and it read 11 psi so I was positive it was fuel pump, even tho I could still here it good. Got a new fuel pump and filter because I figure why not do both, when I dropped the axel and got the tank out the tank looked immaculate no dust or debri in it but I figured I must replace it anyhow after getting this far replaced the pump it's self, the filter and the hose that attaches to the fuel lines, even tho old ones didn't look to bad. Anyways got it all back together and checked pressure again I was getting 16 psi or maybe a little more, but still nothing when I tried to start. That was a kick in the *** so from there all I could see it being was the tbi. I took it off and sent it to rock auto to get rebuilt I could see the fuel pressure regulator gasket was blown out a bit and the gasket under the tbi was beat as well. Got the tbi back looked brand new injectors all cleaned up and what looks to be new throttle position sensor , but after getting all plugged in and back on the intake manifold with new gaskets. Still no start. If anybody knows anything about what this could be I would be greAt full I need my car back, I think it's gotta either be a sensor, my injector wires or maybe I need a fp with a more pressure. I just feel like there's gotta be some kind of gate closed in my tbi not letting gas in because literally nothing comes out of the tbi.
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From: Mile High Country !!!
Car: 1967 Camaro, 91 z28
Engine: Lb9
Transmission: M20
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Re: Tbi not shooting fuel
Vats ! Or possibly a bad icm .
https://www.thirdgen.org/forums/elec...pass-vats.html
https://www.thirdgen.org/forums/elec...pass-vats.html
Joined: May 2015
Posts: 674
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From: Ohio
Car: 92 RS / 90 IROC-Z
Engine: 305 / 350
Transmission: Auto
Axle/Gears: Non-Posi / Posi - Both GU2 - 2.73
Re: Tbi not shooting fuel
Other then that only other problem is the check engine light would come on after driving for 20 mins. Other than that tho the car ran good until I went to work one day and it shut off on my way there. I was listening to music so I didn't even know it died until I went to give it gas. It didn't make any noises or jump around at all just kept cruising like it was on.
Just a few random questions to try and narrow it down...
1. Have you pulled the codes related to the SES light? (VATS issue will throw a code)
2. Have you checked all SPW's?
3. Have you pulled a plug, to check for fouling, etc?
The car will turnover like crazy batteries completley charged and it starts with starter fluid but shuts of after burning it off so I'd come to believe it has spark.and either way that's not my problem because I'm not getting gas. I know the gas is getting to the carb because it will spray out the fuel line when disconnected from carb but once it is connected to the tbi again it doesn't shoot out the injectors. No cone not even a drip.
5. Have you connected an in-line spark checker to confirm strong spark? A TGO Vet mentioned your ICM (I believe) and when my ICM was going out it did this same thing...
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Re: Tbi not shooting fuel
Runs on starting fluid. Spark/distributor/wires/spark plugs are probably fine.
Had 11 psi of fuel pressure. Pump was probably fine. Still has fuel pressure. Pump/filter is not the problem.
In MY driveway, I'd be looking at the fuses for the ECM. I'd test for power at the connectors on the injectors. I'd connect a "Noid" light to see if the computer is switching the ground on and off to fire the injectors.
No power = fuse or broken wire
No ground = faulty ECM, or faulty harness. I think a faulty ignition module can cause this, but that's a rare occurrence.
Power and ground, no fuel spray = failed injectors or internally-plugged TBI body. Not likely since the original TBI had this problem, and then a rebuilt was installed that also wouldn't spray.
Yeah, I hear the VATS system is somewhat trouble-prone. Verifying that it's in good condition would be very worthwhile. I thought the VATS allowed the engine to run for a couple of seconds before killing it. I could be wrong.
Had 11 psi of fuel pressure. Pump was probably fine. Still has fuel pressure. Pump/filter is not the problem.
In MY driveway, I'd be looking at the fuses for the ECM. I'd test for power at the connectors on the injectors. I'd connect a "Noid" light to see if the computer is switching the ground on and off to fire the injectors.
No power = fuse or broken wire
No ground = faulty ECM, or faulty harness. I think a faulty ignition module can cause this, but that's a rare occurrence.
Power and ground, no fuel spray = failed injectors or internally-plugged TBI body. Not likely since the original TBI had this problem, and then a rebuilt was installed that also wouldn't spray.
Yeah, I hear the VATS system is somewhat trouble-prone. Verifying that it's in good condition would be very worthwhile. I thought the VATS allowed the engine to run for a couple of seconds before killing it. I could be wrong.
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Re: Tbi not shooting fuel
Just a few random questions to try and narrow it down...
1. Have you pulled the codes related to the SES light? (VATS issue will throw a code)
2. Have you checked all SPW's?
3. Have you pulled a plug, to check for fouling, etc?
4. Possible ECM Wire related issue? Had a weird issue where the pins weren't seated or a bad spot in the wire led to one of my injectors not spraying...
5. Have you connected an in-line spark checker to confirm strong spark? A TGO Vet mentioned your ICM (I believe) and when my ICM was going out it did this same thing...
1. Have you pulled the codes related to the SES light? (VATS issue will throw a code)
2. Have you checked all SPW's?
3. Have you pulled a plug, to check for fouling, etc?
4. Possible ECM Wire related issue? Had a weird issue where the pins weren't seated or a bad spot in the wire led to one of my injectors not spraying...
5. Have you connected an in-line spark checker to confirm strong spark? A TGO Vet mentioned your ICM (I believe) and when my ICM was going out it did this same thing...
Joined: May 2015
Posts: 674
Likes: 23
From: Ohio
Car: 92 RS / 90 IROC-Z
Engine: 305 / 350
Transmission: Auto
Axle/Gears: Non-Posi / Posi - Both GU2 - 2.73
Re: Tbi not shooting fuel
i tried checking the codes with a paper clip in the obd1 but the only code was a 12 over and over, I was told that a code 12 just tells you it's in diagnostic mode, but i think its only showing 12 because the cars not on. And I haven't checked my injector wires I really should because it looks like previous owner tampered with the harness along with other things. But I've had the car for 3 years now and it's been problem after problem not that big a deal I expected it would but didn't think it would get to the point of no start.
Questions though
1. I assumed you have but it's worth asking, have you checked the fuses?
2. Ever heard of Fuel Cutoff Mode? Just read in my GMSM that NO Fuel is released from the injectors if no reference pulse is received from the distributor...
Last edited by 92RS-HeritageEd; Sep 7, 2018 at 09:49 PM. Reason: forgot something...
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From: Crawfordville Ga
Car: 88 Sport Coupe
Engine: LT1
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Re: Tbi not shooting fuel
I have seen many times that the pick-up in the distributor will go bad and it will have spark but no Injector pulse to fire the injectors.
Have you checked to see if the injectors are getting an electric pulse when the engine is being cranked?
Have you checked to see if the injectors are getting an electric pulse when the engine is being cranked?
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From: North Carolina
Car: 1987 IROC Z28
Engine: 5.0 liter
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Axle/Gears: 273 posi trac
Re: Tbi not shooting fuel
What I would check first if one of my CrossFire TBIs stopped spraying:
Turn on ignition switch, check with a voltage meter which injector terminal reads 12V+. Unplug the negative terminal, leaving + side connected (may need to use a jumper wire). Then connect a jumper wire to a solid source of ground, rapidly tap the grounded wire to the negative injector terminal while 12V+ is being applied to the positive injector terminal.
You said you have fuel pressure at the throttle body, this should determine the functionality of your fuel injector. If the injector is functional, and you have fuel pressure, you will see fuel spray from the injector each time you tap the ground wire to the negative terminal.
That would be my first test if it were mine.
Turn on ignition switch, check with a voltage meter which injector terminal reads 12V+. Unplug the negative terminal, leaving + side connected (may need to use a jumper wire). Then connect a jumper wire to a solid source of ground, rapidly tap the grounded wire to the negative injector terminal while 12V+ is being applied to the positive injector terminal.
You said you have fuel pressure at the throttle body, this should determine the functionality of your fuel injector. If the injector is functional, and you have fuel pressure, you will see fuel spray from the injector each time you tap the ground wire to the negative terminal.
That would be my first test if it were mine.
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Joined: Feb 2011
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Re: Tbi not shooting fuel
i tried checking the codes with a paper clip in the obd1 but the only code was a 12 over and over, I was told that a code 12 just tells you it's in diagnostic mode, but i think its only showing 12 because the cars not on. And I haven't checked my injector wires I really should because it looks like previous owner tampered with the harness along with other things. But I've had the car for 3 years now and it's been problem after problem not that big a deal I expected it would but didn't think it would get to the point of no start.
Better idea: Quit using a paper-clip, and connect a real scan tool to the ALDL. Verify RPM shown on the scan tool as you crank the engine. No indicated RPM, the ECM is still not getting reference pulses, and therefore isn't turning on the injectors. Again, I think this is possible, but fuse/failed wire harness is more likely.
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