misfires under load when cold after intake installation
01-04-2012, 08:22 PM
#1
Thread Starter
Join Date: Jan 2011
Location: NC
Posts: 21
misfires under load when cold after intake installation
hey, I have a '88 gt with what i am presuming to be a stock 5.0L. I pulled the cut and ported factory intake off and installed a trickflow street heat i got really cheep. i used the injectors over (all black with a blue band on them and part number (D1570BA) on them.) the intake has a 1" spacer between the upper and the lower as well. since the swap, when i first start the car in the mornings, it seems to be running rich and Missfires under 2000 rpm until i get it nice and warm. i thought it was an intake leak, smoked it and no leak. replaced the plugs and they all looked pretty good. messed with the timing, cant get the timing mark anywhere near the pointer but it runs good. i checked fuel pressure and that is good (30 idle 40 wot or reg unplugged) my only thoughts are the injectors being 24 lbs (not sure though im getting conflicting info) and the maf being stock. the car ran great before the intake swap with the same injectors and maf so im at a loss. any help would be great.
01-05-2012, 06:55 AM
#3
Thread Starter
Join Date: Jan 2011
Location: NC
Posts: 21
Here is a pic. It was running fine with these injectors and maf combo before I swapped the intake.
Now after messing with the timing a bit more and driving it this morning it pops all the time on steady cruising not terrible but you can tell its not right and on decel it pops and backfires alot more than normal. Someone suggested it might be an injector oring any thoughts on this
01-05-2012, 07:06 PM
#5
Thread Starter
Join Date: Jan 2011
Location: NC
Posts: 21
01-05-2012, 08:01 PM
#6
5th Gear Member
Join Date: May 2007
Location: Pittsburgh
Posts: 2,459
What kind of spark plug wires are you running? if they are the garbage aftermarket type that some places sell... not insulated properly... they will arc to the block and cause misfires. Just one of the many things that can cause problems... buying cheaper parts is rarely good. People do those kind of things.
01-06-2012, 01:55 PM
#7
Thread Starter
Join Date: Jan 2011
Location: NC
Posts: 21
I'm running accel wires. Not junk. I'm a mechanic by trade so I have already checked the obvious stuff. The car sits in a garage at night so no condensation or cold weather gets to it. Everything was running great till I swapped the intake out.
01-06-2012, 06:32 PM
#8
1st Gear Member
Join Date: Dec 2010
Location: xxxxxxxx
Posts: 78
hey, I have a '88 gt with what i am presuming to be a stock 5.0L. I pulled the cut and ported factory intake off and installed a trickflow street heat i got really cheep. i used the injectors over (all black with a blue band on them and part number (D1570BA) on them.) the intake has a 1" spacer between the upper and the lower as well. since the swap, when i first start the car in the mornings, it seems to be running rich and Missfires under 2000 rpm until i get it nice and warm. i thought it was an intake leak, smoked it and no leak. replaced the plugs and they all looked pretty good. messed with the timing, cant get the timing mark anywhere near the pointer but it runs good. i checked fuel pressure and that is good (30 idle 40 wot or reg unplugged) my only thoughts are the injectors being 24 lbs (not sure though im getting conflicting info) and the maf being stock. the car ran great before the intake swap with the same injectors and maf so im at a loss. any help would be great.
01-07-2012, 06:21 AM
#10
Thread Starter
Join Date: Jan 2011
Location: NC
Posts: 21
The dist is in right. Not off from where it was before the swap. I think the damper spun in the rubber. The mark is almost looking like its 180 out but then ot wouldnt run at all. Unless i am wrong then it has been like that since i got it. I will check it again though just sh**s and grins. It does not run badly at all. Just misfires at low rpm. I am assuming it is loading up in the morning even though I don't let it warm up for more than a minute before I leave