Nothing left to check? VP 5.7GSI wont start - good fuel pressure, good ecm, wiring
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Actually your on the right path its just a bit elusive. As of right now its finding a tbi injector that runs at 30 psi. It may well turn out that once the engine runs you will have to recalibrate your tune to get things right. If I were you is cancel the diacom and prepare yourself for mefi burn. It's to bad you didn't order the std 17 based on what I now know the std 17 should be able to replicate the original injectors. With the burn program one could have recalibrated the file on the water and improved overall performance quite a bit. The drauma continues.
Posting from A cell phone sucks but the bourbon and wings are great.
Posting from A cell phone sucks but the bourbon and wings are great.
Last edited by Pliant; 05-21-2015 at 10:34 AM.
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Actually your on the right path its just a bit elusive. As of right now its finding a tbi injector that runs at 30 psi. It may well turn out that once the engine runs you will have to recalibrate your tune to get things right. If I were you is cancel the diacom and prepare yourself for mefi burn. It's to bad you didn't order the std 17 based on what I now know the std 17 should be able to replicate the original injectors. With the burn program ons could have recalibrated the file on the water and improved overall performance quite a bit. The drauma continues.
Posting from A cell phone sucks but the bourbon and wings are great.
Posting from A cell phone sucks but the bourbon and wings are great.
Edit: just thinking about that, the TJ 11's seemed to hold up fine to 30 psi but i am very confident they were not spraying enough fuel. What else would explain my poor cold start, which can be fixed with extra fuel ?
Once it's running I'm pretty sure it's lean still, since it doesn't stumble or run rough and miss like it would if it was rich. It bogs really bad and has a hanging idle after revving.
Last edited by nunnink23; 05-21-2015 at 06:54 AM.
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So you better understand what's going on
1 Tj11 injector delivers 85lbs @......13 psi
2. tj17 injector deliver's 55 lbs @.... 13psi
Your mefi system is delivering.... 30lbs of pressure.... not 13lbs..... below is a decent read and a flow calc.The injector tj11 was flooding the engine badly
The tj17 can be used as a 4.3 injector @ 13 lbs or a 454 injector at 30lbs thats been the whole confusion Gm did this in 94/95 note the ebay retailer stating in large letter's HIGH PRESSURE AT 29 LBS. With one disclaimer did Standard build that replacement injector to the same standards so to speak as the original GM injector..
http://www.rceng.com/technical.aspx
http://www.summitracing.com/parts/sm.../applications/
Check the application charts out notice the narrow years GM used that injector and noteably the 7.4..... the years of the high pressure fuel pumps
http://www.dynamicefi.com/TBI_Fueling.php
•2.8l and 3.1l engines: 33 #/hr
•4.3l engine: 45 #/hr (note: some units have different flow rate injectors. This is done to help with fuel distribution.)
•5.0l engine: 55 #/hr
•5.7l engine: 61, 65, & 68 #/hr.........................................
•7.4l engine: 46*, 75 & 81 #/hr.
Again here's the speed bump you have been running into note the yr model again...
*Just watch for the '94 - '95 BBC truck units as the injectors only flow 46 #/hr at 13 psi. Which is 74 #/hr at the 30 psi these TBI units use. On the up side they come with a 30 psi FPR. The down side is that the injectors are small.
And some more for future reference they are speaking to this issue
http://www.gearhead-efi.com/Fuel-Inj...und-injectors&
1 Tj11 injector delivers 85lbs @......13 psi
2. tj17 injector deliver's 55 lbs @.... 13psi
Your mefi system is delivering.... 30lbs of pressure.... not 13lbs..... below is a decent read and a flow calc.The injector tj11 was flooding the engine badly
The tj17 can be used as a 4.3 injector @ 13 lbs or a 454 injector at 30lbs thats been the whole confusion Gm did this in 94/95 note the ebay retailer stating in large letter's HIGH PRESSURE AT 29 LBS. With one disclaimer did Standard build that replacement injector to the same standards so to speak as the original GM injector..
http://www.rceng.com/technical.aspx
http://www.summitracing.com/parts/sm.../applications/
Check the application charts out notice the narrow years GM used that injector and noteably the 7.4..... the years of the high pressure fuel pumps
http://www.dynamicefi.com/TBI_Fueling.php
•2.8l and 3.1l engines: 33 #/hr
•4.3l engine: 45 #/hr (note: some units have different flow rate injectors. This is done to help with fuel distribution.)
•5.0l engine: 55 #/hr
•5.7l engine: 61, 65, & 68 #/hr.........................................
•7.4l engine: 46*, 75 & 81 #/hr.
Again here's the speed bump you have been running into note the yr model again...
*Just watch for the '94 - '95 BBC truck units as the injectors only flow 46 #/hr at 13 psi. Which is 74 #/hr at the 30 psi these TBI units use. On the up side they come with a 30 psi FPR. The down side is that the injectors are small.
And some more for future reference they are speaking to this issue
http://www.gearhead-efi.com/Fuel-Inj...und-injectors&
Last edited by Pliant; 05-21-2015 at 11:29 AM.
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So you better understand what's going on
1 Tj11 injector delivers 85lbs @......13 psi
2. tj17 injector deliver's 55 lbs @.... 13psi
Your mefi system is delivering 30lbs of pressure.... not 13lbs..... below is a decent read and a flow calc.The injector tj11 was flooding the engine badly
http://www.rceng.com/technical.aspx
1 Tj11 injector delivers 85lbs @......13 psi
2. tj17 injector deliver's 55 lbs @.... 13psi
Your mefi system is delivering 30lbs of pressure.... not 13lbs..... below is a decent read and a flow calc.The injector tj11 was flooding the engine badly
http://www.rceng.com/technical.aspx
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Ok below is a example of how much injector you had going on there...note the displacement
http://www.azspeed-marine.com/asm496mahest.html
63 lb/hr or 80 lb/hr injectors. Optional programming to run on 89 octane pump gas.
Basic tbi function
http://chevythunder.com/gm_throttle_...ction_pg_1.htm
One thing about tbi, is that if you suspect a faulty injector, you can hook up a timing light and point the beam at the injector and see the spray pattern, and see whether or not it is correct or not.
Last edited by Pliant; 05-21-2015 at 12:05 PM.
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It has a hanging idle after revving? Have you checked for vacuum leaks? Iv lost track on its forum. Carb clean around the intake and throttle body. Or a smoke test.
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Edit: I should also mention that yes, it does have a hanging idle, but not when revving in neutral. I noticed it the most on the water test, after trying to increase above idle speed. When I returned to idle, I needed to blip the throttle a few times to get the idle to settle down.
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Here's some ACDelco Injectors I found under the radar. It lists 94-95 7.4L truck.
Do some searching and see if this # is interchangeable.
ACDELCO Part # 2172282
http://www.rockauto.com/catalog/rafr...ktemplate=true
Do some searching and see if this # is interchangeable.
ACDELCO Part # 2172282
http://www.rockauto.com/catalog/rafr...ktemplate=true
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Expensive little bugger's but they should be very close and hopefully they will fire, i wish he had taken a neon or timing light to observe the pulsing it would have made thing's much clearer there may be some issue as to timing since the injector's seem to que off the dist firing wouldnt that be something...
https://drive.google.com/file/d/0B3w...Z2s/edit?pli=1
Check page 30 it lays it all out
And the tj17 crosses over
https://drive.google.com/file/d/0B3w...Z2s/edit?pli=1
Check page 30 it lays it all out
And the tj17 crosses over
Last edited by Tail_Gunner; 05-21-2015 at 04:32 PM.