okay LT1 WTF
01-26-2013, 12:28 PM
#1
okay LT1 WTF So i bought a project car 96 z28. prev. owner had diag. done at a shop and said it needed a fuel pump, cylinders were compression checked and passed. So I changed out the fuel pump and still nothing. car has 130k on it and sat for 3 years prior to buying. yes, i changed out fuel filter. I'm dreading its the opti... but knowledge limited to LT1s... so don't know if they have other common problems. Need to get this thing running asap.
Thanks in advance!
PS forgot to add, car has power and spins over no problem, just doesn't have the extra kick to fire i guess. is there an external coil hiding under the water pump i can't see??? Starts with starting fluid directly into TB.
Thx
UPDATE Feb. 16th
power to the relay, has continuity from relay to the box where the pump pigtail plugs to, new relay, pump, filter... pump DOES NOT CLICK ON.... VATS??? ECM????
Also what is the loud humming noise under the hood when you turn ignition off???
AND I hear a clicking noise under dashboard every so often...
PS I do not have a keb fob.. so is the VATS kicking in? Car does not start for the few seconds and cuts out like VATS is suppose to.
UPDATE Mar 10th
car runs. coil, icm test out good. car runs really rough. pump is brand new and is acdelco. i had to swap over rubber gromet from old pump plug bc new replacement pump had one too thick and wouldnt fit in connector box properly. not sure if the plug and connector box isn't making a good enough connection??? and having lack of fuel pressure. got entire fuel rail, pressure reg and injectors off perfectly good running LT1 and made no difference. so thinking it has something to do with where the fuel pump plugs into....? anyone else have a problem with this before?
Thanks in advance!
PS forgot to add, car has power and spins over no problem, just doesn't have the extra kick to fire i guess. is there an external coil hiding under the water pump i can't see??? Starts with starting fluid directly into TB.
Thx
UPDATE Feb. 16th
power to the relay, has continuity from relay to the box where the pump pigtail plugs to, new relay, pump, filter... pump DOES NOT CLICK ON.... VATS??? ECM????
Also what is the loud humming noise under the hood when you turn ignition off???
AND I hear a clicking noise under dashboard every so often...
PS I do not have a keb fob.. so is the VATS kicking in? Car does not start for the few seconds and cuts out like VATS is suppose to.
UPDATE Mar 10th
car runs. coil, icm test out good. car runs really rough. pump is brand new and is acdelco. i had to swap over rubber gromet from old pump plug bc new replacement pump had one too thick and wouldnt fit in connector box properly. not sure if the plug and connector box isn't making a good enough connection??? and having lack of fuel pressure. got entire fuel rail, pressure reg and injectors off perfectly good running LT1 and made no difference. so thinking it has something to do with where the fuel pump plugs into....? anyone else have a problem with this before?
Last edited by FU_I_AM_UltraZ; 03-12-2013 at 08:26 PM.
Trending Topics
01-28-2013, 02:42 PM
#9
Staging Lane
Join Date: Nov 2010
Location: Texas
Posts: 98
Likes: 0
Received 0 Likes
on
0 Posts
02-08-2013, 09:44 PM
#13
Just rented the test guage.. ZERO PRESSUE!!! NEW fuel pump and filter! Coil and ICM are good, maybe the relay. I just saw there is a relay for this car it's by the pedals... i'm gonna replace that tomorrow and see how it goes from there.... any other suggestions guys?? EARS OPEN!
Thanks for all help so far!
02-08-2013, 10:10 PM
#15
What ramair said, It should prime for 2-3 seconds and then stop when you put the key from off to on (without cranking).
Could also use the test wire under the hood to send power to the fuel pump.
You can also just jump the relay befor you make a trip to the parts store.
Could also use the test wire under the hood to send power to the fuel pump.
You can also just jump the relay befor you make a trip to the parts store.
02-08-2013, 10:15 PM
#16
Staging Lane
Join Date: Apr 2008
Location: west valley utah
Posts: 81
Likes: 0
Received 0 Likes
on
0 Posts
why do I feel like VATS is stopping it from starting???
my car would turn over but not start and it was VATS stopping it from running,
it doesn't let the injectors fire, and kills the fuel when cranking.
my car would turn over but not start and it was VATS stopping it from running,
it doesn't let the injectors fire, and kills the fuel when cranking.
02-08-2013, 10:27 PM
#17
Launching!
Join Date: Oct 2011
Location: Dixon, IL
Posts: 284
Likes: 0
Received 0 Likes
on
0 Posts
VATS wont cause zero fuel pressure. Like said above use a jumper wire if its not priming
02-09-2013, 12:09 AM
#19
On The Tree
Join Date: Jan 2013
Location: honey brook,pa
Posts: 111
Likes: 0
Received 0 Likes
on
0 Posts
So does the pump prime like ramair was saying if it does then u either have leaking fpr or leaky injectors. If the pump don't then recheck ur wiring on ur pump.
02-09-2013, 12:25 AM
#20
Welcome to the LT1 world. Everyone immediately blames the optispark, and after they go through the trouble of replacing it (not a huge deal really), they hate the design even more because that wasn't the problem. And after they get the issue resolved, the optispark usually fails because they replaced it with an Oreilly's brand china unit, and have to replace it again.
Then, they sell the car and tell people how bad opti sparks/LT1 cars are, even though nothing was *usually* wrong with it in the first place. /rant
How did you replace the pump? Did you drop the entire tank or do the trap door mod?
Then, they sell the car and tell people how bad opti sparks/LT1 cars are, even though nothing was *usually* wrong with it in the first place. /rant
How did you replace the pump? Did you drop the entire tank or do the trap door mod?