engine problem, replaced everything but paint
Thread Starter
Instructor
Joined: Nov 2001
Posts: 154
Likes: 14
From: NY
engine problem, replaced everything but paint
Engine misses under load. Replaced,Plugs. Cap, Wires,Rotor, Coil,O2 sensor,Fuel filter, Air filter. Idles fine, cruises ok until you give some gas then sstarts to miss and stubble but will acc. Doesn't seem to have the power it had before. Sprayed ether around intake, no speed up of idle. I'm clueless. How can I check the senors? :confused:
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 32
From: The Top of Utah
Re: engine problem, replaced everything but paint (dave85c4)
It's the paint!!!
Seriously, it sounds like a fuel delivery, or cat problem. Besides checking the fuel pressure, check the fuel VOLUME. One way is to mount a pressure guage so you car check the pressure while you're driving. If it drops off at higher rpms and/or WOT, you likely have a clogged fuel filter or a weak pump. A clogged cat won't cause missing but the power will drop off depending on how bad it is. Good luck
CFI-EFI
Seriously, it sounds like a fuel delivery, or cat problem. Besides checking the fuel pressure, check the fuel VOLUME. One way is to mount a pressure guage so you car check the pressure while you're driving. If it drops off at higher rpms and/or WOT, you likely have a clogged fuel filter or a weak pump. A clogged cat won't cause missing but the power will drop off depending on how bad it is. Good luck
CFI-EFI
Drifting
Joined: Mar 2001
Posts: 1,636
Likes: 3
From: Lafayette IN
Re: engine problem, replaced everything but paint (dave85c4)
I am going to go with CFI on this one and give a few more pointers for a TPI engine.
The schrader valve where you tap into the fuel line is on the Pass side fuel rail, near the firewall.
This is done with car in park, parking brake set, etc. Fuel pressure should first be checked with the vacuum line to the fuel pressure regulator (FPR) connected. Record that and then disconnect the vacuum line to the FPR and plug the line with a screw or a golf tee. Fuel pressure should increase anywhere from 8-12 psi.
Next, reconnect the vacuum line and turn the car off. Keep the FP gage hooked up and bleed it down to zero. Turn the key to the on position (not crank) and record FP. Also, record the time it takes for FP to bleed down to 0. A good fuel system (i.e. injectors, pump, regulator) will hold the pressure steady for quite a while. Good luck, -Matt-
The schrader valve where you tap into the fuel line is on the Pass side fuel rail, near the firewall.
This is done with car in park, parking brake set, etc. Fuel pressure should first be checked with the vacuum line to the fuel pressure regulator (FPR) connected. Record that and then disconnect the vacuum line to the FPR and plug the line with a screw or a golf tee. Fuel pressure should increase anywhere from 8-12 psi.
Next, reconnect the vacuum line and turn the car off. Keep the FP gage hooked up and bleed it down to zero. Turn the key to the on position (not crank) and record FP. Also, record the time it takes for FP to bleed down to 0. A good fuel system (i.e. injectors, pump, regulator) will hold the pressure steady for quite a while. Good luck, -Matt-
