i just bought an 89 gt. when i got it, it popped at high rpm's. the motor is stock. i changed the cam, distributor, dist. module, header gaskets, computer, intake, o2 sensors, tps, iac, fuel filter and reg., and still when you push the pedal to the floor it wont rev past 3000 rpm. then when you let off it pops and backfires. it is flooding a little but not bad. it also has a c4 with a9p comp. does anyone have any clues here. thanks
this car really sucks
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BlackGT89
Member
Another vote for fuel pump. Also check your in line fuel filter and the fuel pressure regulator . Might want to consider an adjustable model with a pressure gauge to adjust with.
get a fuel pressure gauge that you can mount inside to keep a eye on what might be happening. A adjustable fuel pressure regulator might be something to consider in the future.
Was it doing any of that before you started replacing parts? If not then you might consider that something was installed incorrectly. I would take a close look to see if the distributor was put back correctly.
Was it doing any of that before you started replacing parts? If not then you might consider that something was installed incorrectly. I would take a close look to see if the distributor was put back correctly.
BlackGT89
Member
Hi-po, you may have more than one problem. Possibly fuel / ignition or something else entirely. Pull the vacuum hose off of the FPR and see if gas runs out. If the diaphram has ruptured internally this would account for your rich condition. Could the valves be floating at higher RPM's ? How good are the valve springs and valve train components ? What about the timing chain ? Slack can make them run really lazy - until it it finally stops.
LXMiker
Founding Member
what pressure is the fuel at??
is the firing order right?? or is the distributor a tooth off??
this sounds dumb but.......
does it have cats on it??? i have seen cars with plugged cats not rev up a lot.....
but if it still is missing an backfiring that aint it
is the firing order right?? or is the distributor a tooth off??
this sounds dumb but.......
does it have cats on it??? i have seen cars with plugged cats not rev up a lot.....
but if it still is missing an backfiring that aint it
a few loose thoughts..... air filter??? - had a really plugged one on a friends car didnt get past 3500 rpm in or out of gear.
neutral safety switch might be that the comp thinks its in neutral and is limiting it, but i dont think fords do that chevys do.
use a timing light and rev the crap out of it see if the light dosnt skip a beat or 5 or 10.if its smooth you prob lies in fuel or air or computer
neutral safety switch might be that the comp thinks its in neutral and is limiting it, but i dont think fords do that chevys do.
use a timing light and rev the crap out of it see if the light dosnt skip a beat or 5 or 10.if its smooth you prob lies in fuel or air or computer
o yea i also tried pulling off the air filter, that didn't make a difference. and the valvetrain seems to be in good shape. the firing order is 13726548. i believe that is what the h.o should be. the guy that i got it from ripped the steering column out but all the wires looked to be in good shape. im not sure if the steering column wires have anything to do with the way it runs though.
JadeFalcon
Founding Member
hi_po_heads said:
theres 3 things that keep a car from revving up. ignition, fuel, or exhaust restriction (clogged cats).
BlackGT89
Member
Hi-po, if you're getting gas in the vaccum line coming from your adjustable fuel pressure regulator it means your regulator is shot and has an internal leak sucking gas pst the diaphram. I've heard of a rash of bad ones. Replace it with a new one.
IndyBlk5.0
New Member
IndyBlk5.0
New Member
secondly, what intake and heads are you running... with a combo, they call for certain fuel pressure levels.... with 24 pound injectors for a basic setup i would start at 36-38 psi... See if this helps. my car wouldnt rev and would backfire when timing was off, double check it...
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