Help with bogging, non drivability
Team Owner
Joined: Jul 2004
Posts: 28,471
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From: Hartford WI
my car is 86 vette, donor injectors were 97camaro lt1. stock vette pressure from what I read is 40-45.. stock 86 injectors 22#, stock lt1 Camaro is 24#.. my car has headers and that's about it..
I wouldn't understand why a load issue is being diagnosed by people as an injector issue, but maybe that's my lack of knowledge...
ill call FIC tomorrow.. but if I were them im sure they'll say yeah you need um, spend a bunch of money with us...
just would seem odd if its an injector issue that itll rev perfectly not in gear.
I wouldn't understand why a load issue is being diagnosed by people as an injector issue, but maybe that's my lack of knowledge...
ill call FIC tomorrow.. but if I were them im sure they'll say yeah you need um, spend a bunch of money with us...
just would seem odd if its an injector issue that itll rev perfectly not in gear.
IF the fuel delivery is wrong, the ECM might try to compensate for it. HOWEVER, it can only compensate in closed loop. If it, for whatever reason, falls out of closed loop, AFAIK, the program takes over which could be an issue.
I highly doubt it. I have sent injectors to them that they have found to be dirty and cleaned them for me. Sometimes I test them before and after to see. They just sold me an injector for another car that has 7 good and 1 bad. Bad one ohmed out good. They said it wouldn't stop leaking and I can blow into it. They could have sold me a few more too if they had lied about it.
Rev the motor and it has no load. In gear, it has load. Quite different. Besides, how do you know it will rev perfectly? You need to have sniffers and other gear to see what it is doing. It might rev fine to you but there could be all sorts of compensation in the background that you don't see.
Last edited by aklim; Aug 31, 2016 at 01:24 AM.
Race Director
Joined: Mar 2015
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my car is 86 vette, donor injectors were 97camaro lt1. stock vette pressure from what I read is 40-45.. stock 86 injectors 22#, stock lt1 Camaro is 24#.. my car has headers and that's about it..
I wouldn't understand why a load issue is being diagnosed by people as an injector issue, but maybe that's my lack of knowledge...
ill call FIC tomorrow.. but if I were them im sure they'll say yeah you need um, spend a bunch of money with us...
just would seem odd if its an injector issue that itll rev perfectly not in gear.
I wouldn't understand why a load issue is being diagnosed by people as an injector issue, but maybe that's my lack of knowledge...
ill call FIC tomorrow.. but if I were them im sure they'll say yeah you need um, spend a bunch of money with us...
just would seem odd if its an injector issue that itll rev perfectly not in gear.
Thread Starter
Advanced
Joined: Jul 2016
Posts: 79
Likes: 1
From: milwaukee wi
called FIC, they are thinking that under load it is stalling because its just getting way to much fuel... so they reccommended i either go back to stock injectors, or get a tune... i was going to get a tune anyways after i got the car running right, so now its an excuse to get it done..
im skeptical about the injectors being my issue but they work with injectors all day long so im guessing they are smarter than I.
tune is ordered.. update to follow in the next week once i get the tune.
im skeptical about the injectors being my issue but they work with injectors all day long so im guessing they are smarter than I.
tune is ordered.. update to follow in the next week once i get the tune.
Team Owner
Joined: Jul 2004
Posts: 28,471
Likes: 3,290
From: Hartford WI
called FIC, they are thinking that under load it is stalling because its just getting way to much fuel... so they reccommended i either go back to stock injectors, or get a tune... i was going to get a tune anyways after i got the car running right, so now its an excuse to get it done..
im skeptical about the injectors being my issue but they work with injectors all day long so im guessing they are smarter than I.
tune is ordered.. update to follow in the next week once i get the tune.
im skeptical about the injectors being my issue but they work with injectors all day long so im guessing they are smarter than I.
tune is ordered.. update to follow in the next week once i get the tune.
Thread Starter
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Joined: Jul 2016
Posts: 79
Likes: 1
From: milwaukee wi
guesswork.. all day long...
mail order from PCM of NC... I know multiple corvette owners with tunes from them and they are happy with results... (FIC also recommended them)
my car is pretty much stock, except long tube headers and the injectors. so i dont think a dyno tuning is really needed or worth the cost.
Last edited by tomcamaro97; Aug 31, 2016 at 11:02 AM.
Melting Slicks
Joined: Aug 2008
Posts: 2,082
Likes: 50
From: Palmdale CA
Does it still have functioning cat converters? if so possibly restricted. The 24 can cause a computer default run not so great or "reconnect VSS mode". So you may want to check it out. Do you have access to a scanner and FSM? If you unplug O2 sensor how does it run? Your condition would be called "under load"as opposed to in gear. Restricted fuel filter? Have you driven car with fuel pressure gauge taped to windshield to see if pressure falls?
Also; testing your fuel pressure under a load could also be helpful in Diagnosing the problem.
I like to Exhaust all of the trouble shooting steps before jumping on the Parts Ban Wagon.
Here is a very simple test that can be performed with a simple vacuum gauge in order for you to test for a restricted exhaust. It may also indicate other possible anomalies at the same time.
Thread Starter
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Joined: Jul 2016
Posts: 79
Likes: 1
From: milwaukee wi
thanks for the tip on that one, thats a great little trick.. I dont think that would be the case in this instance as it only does it under load. but ill give that a try cuz why not, ive got a mighty vac that i should be able to use for this.
I have a z28 that i suspect might have a plugged cat..so i will for sure be using this trick for that one.
minimal update.. so TPIS said they dont belive the injectors would be my cause. FIC said they could definately see the injector being my cause... i love getting completely different answers from trusted sources..
Guess I'll find out , cuz my Tune from PCM of NC is in the mail.. they tuned it for the larger injectors and headers i have. so at the very least ill gain some HP, and remove the injector question from the equation.. but heres hoping it fixes it.
I have a z28 that i suspect might have a plugged cat..so i will for sure be using this trick for that one.
minimal update.. so TPIS said they dont belive the injectors would be my cause. FIC said they could definately see the injector being my cause... i love getting completely different answers from trusted sources..
Guess I'll find out , cuz my Tune from PCM of NC is in the mail.. they tuned it for the larger injectors and headers i have. so at the very least ill gain some HP, and remove the injector question from the equation.. but heres hoping it fixes it.
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
well its got all new fuel pump, fulter, injectors off my lt1, so slightly higher lb/hr. fuel pressure is set at 42 at idle. if a completely mash the gas the pressure drops, but will go back up to 42 within a second or so ish... at idle/neutral.. engine runs through the rmp range exactly as it should... only does this under load...
EDIT...I might have been a little late to the game, on this post!
Last edited by Tom400CFI; Sep 1, 2016 at 11:18 AM.
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Thread Starter
Advanced
Joined: Jul 2016
Posts: 79
Likes: 1
From: milwaukee wi
unluss im wrong that would only apply on an old school with like 8psi and a mech driven fuel pump...
on a car with a fuel pressure regulator theres no way it will ever go up.. the regulator will open.
FYI: my car has a brand new fuel pump and filter.. cleaned tank etc..
Last edited by tomcamaro97; Sep 1, 2016 at 11:29 AM.
Team Owner
Joined: Jul 2004
Posts: 28,471
Likes: 3,290
From: Hartford WI
unluss im wrong that would only apply on an old school with like 8psi and a mech driven fuel pump...
on a car with a fuel pressure regulator theres no way it will ever go up.. the regulator will open.
FYI: my car has a brand new fuel pump and filter.. cleaned tank etc..
on a car with a fuel pressure regulator theres no way it will ever go up.. the regulator will open.
FYI: my car has a brand new fuel pump and filter.. cleaned tank etc..
Race Director
Joined: Mar 2015
Posts: 15,926
Likes: 579
thanks for the tip on that one, thats a great little trick.. I dont think that would be the case in this instance as it only does it under load. but ill give that a try cuz why not, ive got a mighty vac that i should be able to use for this.
I have a z28 that i suspect might have a plugged cat..so i will for sure be using this trick for that one.
minimal update.. so TPIS said they dont belive the injectors would be my cause. FIC said they could definately see the injector being my cause... i love getting completely different answers from trusted sources..
Guess I'll find out , cuz my Tune from PCM of NC is in the mail.. they tuned it for the larger injectors and headers i have. so at the very least ill gain some HP, and remove the injector question from the equation.. but heres hoping it fixes it.
I have a z28 that i suspect might have a plugged cat..so i will for sure be using this trick for that one.
minimal update.. so TPIS said they dont belive the injectors would be my cause. FIC said they could definately see the injector being my cause... i love getting completely different answers from trusted sources..
Guess I'll find out , cuz my Tune from PCM of NC is in the mail.. they tuned it for the larger injectors and headers i have. so at the very least ill gain some HP, and remove the injector question from the equation.. but heres hoping it fixes it.
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
Thread Starter
Advanced
Joined: Jul 2016
Posts: 79
Likes: 1
From: milwaukee wi
Update:
Well i pulled the ecu and it already had a tune, as i expected.. swapped it out for the tune i just ordered. made no change in performance.
desert mike... vacuum trick worked .. and was able to diagnose a partial blockage in the cat.. that has been fixed. engine seems a bit "snappier" but still did not fix the issue.
OD unit is a mess. i cant turn it off, i hit the button it goes off then right bak on... and it seems to engage whenever it wants... it even tried to engage in first gear.. i do wonder if this could be my major problem... but i yanked the OD relay and hopefully that can take the OD out of the equation for the mean time.. still no change in performance...
the symptom is slightly changed.. in that while its doing its stumble/stall thing.. the gas pedal literally will act like cutoff switch. if i give it gas it will stall till it kills out.
had a snapon solus on the car.. and nothing is sticking out as not functioning improperly.
next ill be checking my grounds just to rule them out... and then look at Ignition controll module, or just a whole new distributor...
and the brake booster is leaking, but pinched the hose so thats out of the equation.. this vette is starting to get on my nerves..
Well i pulled the ecu and it already had a tune, as i expected.. swapped it out for the tune i just ordered. made no change in performance.
desert mike... vacuum trick worked .. and was able to diagnose a partial blockage in the cat.. that has been fixed. engine seems a bit "snappier" but still did not fix the issue.
OD unit is a mess. i cant turn it off, i hit the button it goes off then right bak on... and it seems to engage whenever it wants... it even tried to engage in first gear.. i do wonder if this could be my major problem... but i yanked the OD relay and hopefully that can take the OD out of the equation for the mean time.. still no change in performance...
the symptom is slightly changed.. in that while its doing its stumble/stall thing.. the gas pedal literally will act like cutoff switch. if i give it gas it will stall till it kills out.
had a snapon solus on the car.. and nothing is sticking out as not functioning improperly.
next ill be checking my grounds just to rule them out... and then look at Ignition controll module, or just a whole new distributor...
and the brake booster is leaking, but pinched the hose so thats out of the equation.. this vette is starting to get on my nerves..
Thread Starter
Advanced
Joined: Jul 2016
Posts: 79
Likes: 1
From: milwaukee wi
sorry dude, completely disagree with your diagnosis, your just saying it with no thought process behind it, because its not stock...
its not acting like a car running rich or lean.. oh and the O2 sensor is toggling correctly.. its a complete cutout of the engine.. no knocking, no pinging.. etc etc.. just a complete cut out, absolutely no symptom of fuel injectors..
Race Director
Joined: Mar 2015
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sorry dude, completely disagree with your diagnosis, your just saying it with no thought process behind it, because its not stock...
its not acting like a car running rich or lean.. oh and the O2 sensor is toggling correctly.. its a complete cutout of the engine.. no knocking, no pinging.. etc etc.. just a complete cut out, absolutely no symptom of fuel injectors..
its not acting like a car running rich or lean.. oh and the O2 sensor is toggling correctly.. its a complete cutout of the engine.. no knocking, no pinging.. etc etc.. just a complete cut out, absolutely no symptom of fuel injectors..
Race Director
Joined: Mar 2015
Posts: 15,926
Likes: 579
called FIC, they are thinking that under load it is stalling because its just getting way to much fuel... so they reccommended i either go back to stock injectors, or get a tune... i was going to get a tune anyways after i got the car running right, so now its an excuse to get it done..
im skeptical about the injectors being my issue but they work with injectors all day long so im guessing they are smarter than I.
tune is ordered.. update to follow in the next week once i get the tune.
im skeptical about the injectors being my issue but they work with injectors all day long so im guessing they are smarter than I.
tune is ordered.. update to follow in the next week once i get the tune.
How much is the new distributor you are tossing in it?
Last edited by antfarmer2; Sep 6, 2016 at 11:32 AM.
Thread Starter
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Joined: Jul 2016
Posts: 79
Likes: 1
From: milwaukee wi
reman distributor is $80.. given it had the original and not expensive im gonna slap that in and a new set of wires on it, just to know its got new stuff...
new power booster ordered as well.
i think im going to ohm out the injectors tonight.. just to check..
does anyone have any thoughts on the OD unit? before now, the light just never came on, regardless of hitting the button or reaching temp. now with the new tune its finally coming on when the car reaches temp, in wonder if the hypertech tune maybe had this tuned out? but now i goosed it in first gear and accelleerated fairly smoothly, then the od shifted in, and the od light was blinking fast. i was like WTF (this has only happened once). then when driving in second/third..the od light just stayed on and woudlnt go off.. i hit the button and it went off for like 1/8 second then back on.. so i removed the od relay.. just to try and take it out of the bucking/stalling equation, make sense? leave it out till i get it resolved?
OH the fun of fixing a car that was sitting for who knows how many years...
new power booster ordered as well.
i think im going to ohm out the injectors tonight.. just to check..
does anyone have any thoughts on the OD unit? before now, the light just never came on, regardless of hitting the button or reaching temp. now with the new tune its finally coming on when the car reaches temp, in wonder if the hypertech tune maybe had this tuned out? but now i goosed it in first gear and accelleerated fairly smoothly, then the od shifted in, and the od light was blinking fast. i was like WTF (this has only happened once). then when driving in second/third..the od light just stayed on and woudlnt go off.. i hit the button and it went off for like 1/8 second then back on.. so i removed the od relay.. just to try and take it out of the bucking/stalling equation, make sense? leave it out till i get it resolved?
OH the fun of fixing a car that was sitting for who knows how many years...
Last edited by tomcamaro97; Sep 6, 2016 at 04:00 PM.
Team Owner
Joined: Jul 2004
Posts: 28,471
Likes: 3,290
From: Hartford WI
What will that tell you? It just tells you the coil is ok. How much flow? Who knows. How good the spray pattern? Who knows? I can sell you my other injector that has good ohm tests. Won't hold fuel but it works great if you check the DVOM.
Put stock sized injectors back and see where it goes. The only thing that matters is what size it is right now. What is the stock size vs what the actual size
Put stock sized injectors back and see where it goes. The only thing that matters is what size it is right now. What is the stock size vs what the actual size
Last edited by aklim; Sep 6, 2016 at 04:38 PM.