Hey guys im switching my car over to carburated and i wanted some opinions on which route i should take. I currently have a powerdyne supercharger on my car putting out 8lbs of boost. Id like to keep a power adder on it once i switch to carb but do you guys think i should keep the supercharger or switch to a turbo set up? I would be willing to make a deal or trade my entire fuel injection/supercharger setup for carb/turbo setup if anyone is interested. Im looking to do something new with the car since i havent changed anything in years. Im open for suggestions. Thanks in advance.
Power adder with carb
- Thread starter 87_5.0
- Start date
Well i know i might have trouble with the carb set up but my car runs like crap now. The car sat for a year and when i got it back out it wouldnt run right. I tried changing all the "stupid" things it could be such as bad gas, cap and rotor, plugs but no luck. It runs choppy thru the entire rpm range and backfires. I can put it to the floor and it wont make any power, also wont make boost. Thats why ive been considering goin carb.
2vNotch
Active Member
That is not a good reason to go carb. You can have the same kind of problems regardless of which way you choose to send it fuel.
Go get yourself a code reader and start going through it. Disconnect your fuel rails and purge the old gas out of it (if you haven't already). See if there is a machine shop in your area that has an injector cleaning service. CAREFULLY clean the MAF sensor. Check the gap on your plug and ensure they're set correctly.
If it used to run right, then it will again once you figure out what went wrong with it. The fuel injection systems on these cars are not that difficult to figure out.
Don't be so hasty. Swapping to a carb in order to fix drivability issues would be a biiiig mistake. Take the time to look into finding out what the issues are with your current set up and sort it out.
Get your current combo tuned with custom chip and you'll be amazed how well it will run. You can't just slap a blower on and hit the road at WOT. They are finicky and the Air / Fuel / Timing needs to be dead on for maximum HP. I bet the car picks up a bunch of power and idles dead on with the right tuner.
I've heard good things about Quarter Horse but never used. I currently run two different methods of tuning. One is a 4 slot programmable that I got from a Dyno tuner. The other is an Anderson PMS. Folks say that it's expensive but... Add up the cost of Quarter Horse and then the Software.. you're pretty close anyhow.
None of that matters until you get the car fixed though. You can't tune away real problems with the hardware (well sometimes you can but that's not the way to go).
None of that matters until you get the car fixed though. You can't tune away real problems with the hardware (well sometimes you can but that's not the way to go).
Im located near pittsburgh. I just dont know what to do to diagnose the problem. I tried changing o2 sensors, put fuel injector cleaner in it, changing the timing and a few other things. When i give it gas its cuts in and out and boggs down and backfires, there is no power
Ever consider taking it to a local mechanic? Even if it cost you a few bucks out of pocket for a professional diagnosis, it's a helllll of a lot cheaper and less time consuming than doing a carb swap.
2vNotch
Active Member
Thankfully you checked here before embarking on this project. Converting to a carb to fix a miss is like spending a dollar to save a penny, or in this case spending $1500 to save $150.
The real mods (like h/c/i) or fuel injection have little to do with why your car runs poorly. No chip is going to fix it either. When all parts are working and installed properly the fox computer will pretty much put up with anything and run.
If it's missing that badly it probably has a code, if it doesn't the problem is likely ignition related. I'd start by bypassing the msd equipment and replacing any other ignition related modifications with stock parts. Not sure what the hell a 12 stage msd rev limiter is (yes i googled it before i made this comment), but if it's built anything like the rest of the garbage they make, that's the first place i would look.
Any decent shop that understands how an engine works should be able to diagnose the problem, it's all about the basics.
The real mods (like h/c/i) or fuel injection have little to do with why your car runs poorly. No chip is going to fix it either. When all parts are working and installed properly the fox computer will pretty much put up with anything and run.
If it's missing that badly it probably has a code, if it doesn't the problem is likely ignition related. I'd start by bypassing the msd equipment and replacing any other ignition related modifications with stock parts. Not sure what the hell a 12 stage msd rev limiter is (yes i googled it before i made this comment), but if it's built anything like the rest of the garbage they make, that's the first place i would look.
Any decent shop that understands how an engine works should be able to diagnose the problem, it's all about the basics.
Granted that there could be a couple DOZEN things that could cause this but the description above (by itself) sounds like a bad TPS.
YOU NEED TO PULL CODES!
That would be my first goal in your situation is to locate the missing portions of your harness and get the codes pulled.
Read this through from beginning to end several times to make sure you understand it all before turning any wrenches or screwdrivers. It will help you sort things out in your head and reduce the troubleshooting time. Print it off and keep it handy as you do the actual troubleshooting.
Basic troubleshooting principle: Reduce the number of variables that you have to deal with.
1. Make sure you have clean, fresh gas. Drain the tank and change the fuel filter again after you drain the old fuel from the tank.
Disconnect the fuel pump pressure line at the fuel filter or at the pressure line on the engine. If you decide to disconnect the engine fuel line, be sure to disconnect the engine line with the Schrader valve on it: that is the pressure line. Look in the A/C repair section for the fuel line tools. They look like little plastic top hats. You will need the 1/2" & 5/8" ones. The hat shaped section goes on facing the large part of the coupling. Then you press hard on the brim until it forces the sleeve into the coupling and releases the spring. You may need someone to pull on the line while you press on the coupling. Put some motor oil on them when you put the line back together.
2. See http://www.midwayautosupply.com/showproduct.aspx?productid=11741&affiliateid=10050 for more information
3.
Use some hose to direct the gas into a bucket. Beware of static electricity that can cause sparks and explosions, leave the waste fuel container sitting on the ground.
4. Use the following diagram to jumper the fuel pump to run continuously while the ignition switch is in the run position.
5. While you are watching the fuel pump into the waste bucket, watch the flow: it should be a steady stream. When it quits flowing, turn off the ignition quickly. This will keep the pump from damage due to continuously running dry.
When you add fresh gas to the tank, add 8 oz of acetone to the gas to help clean the residual fuel and make things run cleaner.
6. The next thing to do is to bypass the supercharger and allow the MAF to pull air directly from the filter and preferably the stock filter box since you have a C&L MAF. Leave it bypassed until you have gotten the engine to perform satisfactorily.
7. If you still have problems, bypass the MSD ignition box. They are a known source of all sorts of ignition problems.
8. With pressurized induction the spark plug gaps have to be less than the stock .055. Try .035 plug gaps because of the increased cylinder pressure. Check the spark plug gaps and re-gap as needed. Check plug wires by running the engine in the dark and looking for spark jumping around.
9. Still have problems, leave the supercharger and MSD bypassed. Dump the codes as instructed. Post the code numbers here and I will give you the 5.0 Mustang specific code definitions and fixes.
10. Fix all the code problems so that the engine will pass with an11 and no other codes except for any emissions equipment that may be missing or disconnected.
11. Still having problems after fixing all the relevant code issues: The bog and backfire are usually symptoms of a lean mixture: run the following checklist.
Backfiring Checklist:
Do the checklist and do EVERYTHING if you want to find the problem. Skipping around and just doing the easy stuff or the things that you already know how to do is a sure way to miss the very thing that is causing your problem.
Backfiring out the intake is either a valve stuck open or a lean mixture or spark plug wire(s) connected to the wrong cylinder(s). Check compression on all cylinders and then look for vacuum hoses loose, cracked, or misconnected. Check the line for the vapor recirculation system – it is easy to knock loose and not see it when you connect the air pump plumbing. If the vacuum line for the EGR valve and the air pump are cross connected, some very strange things can happen. Check the mass air flow electrical connection and see that it is tight, the same goes for the fuel injection wiring harness connectors up on top of the manifold near the firewall.
Sticking valves: If a intake valve is bent, has a bad spring or is misadjusted, the engine will sometimes backfire through the intake. Use a vacuum gauge connected to any convenient spot on the intake manifold. Run the engine at 1000 RPM & look for 18-21 inches of vacuum with a steady needle. A problem intake valve will make the vacuum gauge needle sweep 5-10 inches.
Lean fuel mixture breaks out into several sub categories:
A.). Vacuum leaks
B.) Air entering the intake without passing through the MAF on Mass Air cars (89-95 models).
C.) Failure of the MAF, BAP/MAP (Baro or Manifold Air Pressure, same sensor, different name), ACT (air charge temp), or ECT (engine coolant temp). These should set a code in the computer.
D.) O2 sensor problems: one or both O2 sensors with low output or bad O2 sensor heater ground. This should set codes 41/91. The O2 sensor heater ground is an Orange wire in the engine mounted fuel injector harness. Ground it to the back of the head or intake manifold.
E.) Leaking exhaust gases from EGR valve at WOT or EGR opening when it should not be open.
F.) Poor fuel delivery due to bad fuel pump, clogged filter or bad fuel pump wiring. Look for low pressure or fluctuating pressure. Standard injector pressure is 39 PSI at idle, with the vacuum line disconnected from the regulator and capped.
G.) Clogged fuel injectors.- see the cylinder balance test below
H.) Fuel injector wiring problems causing injector not to deliver rated flow (dirty or stuck shut injectors).
I.) Computer problems: (computer problems are not common like sensor problems)
J.). ROM has bad data in fuel or timing table. This should also set a code in the computer.
K.) Failure of one or more of the computer's driver transistors for the fuel injectors. No code set on this one. Use a noid test light to test the injector wiring & injector drivers,
L.) MAF calibration off or mismatched to injectors.
M.) ACT or ECT bad. Sometimes the sensors will be off calibration, but not bad enough to set a code. If they falsely read too high a temp, the engine will back off fuel delivery.
Cylinder balance test:
Warm the car's engine up to normal operating temperature. Use a jumper wire or paper clip to put the computer into test mode. Start the engine and let it go through the normal diagnostic tests, then quickly press the throttle to the floor. The engine RPM should exceed 2500 RPM's for a brief second. The engine RPM's will increase to about 1450-1600 RPM and hold steady. The engine will shut off power to each injector, one at a time. When it has sequenced through all 8 injectors, it will flash 9 for everything OK, or the number of the failing cylinder such as 2 for cylinder #2. Quickly pressing the throttle again up to 2500 RPM’s will cause the test to re-run with smaller qualifying figures. Do it a third time, and if the same cylinder shows up, the cylinder is weak and isn’t putting out power like it should. See the Chilton’s Shop manual for the complete test procedure
Dump the codes and see what the computer says is wrong…Codes may be present in the computer even if the Check Engine light isn’t on.
Here's the way to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great. You watch the flashing test lamp or Check Engine Light and count the flashes.
Be sure to turn off the A/C, and put the transmission in neutral when dumping the codes. Fail to do this and you will generate a code 67 and not be able to dump the Engine Running codes.
Dumping the Engine Running codes: The procedure is the same, you start the engine with the test jumper in place. Be sure the A/C is off and the transmission is in neutral. You'll get an 11, then a 4 and the engine will speed up to do the EGR test. After the engine speed decreases back to idle, it will dump the engine running codes.
Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great. You watch the flashing test lamp or Check Engine Light and count the flashes.
See Troublcodes.net Trouble Codes OBD & OBD2 Trouble Codes and Technical info & Tool Store. By BAT Auto Technical
If your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.
The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.
89 through 95 cars have a working Check Engine light. Watch it instead of using a test lamp.
The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.
WARNING!!! There is a single dark brown connector with a black/orange wire. It is the 12 volt power to the under the hood light. Do not jumper it to the computer test connector. If you do, you will damage the computer.
What to expect:
You should get a code 11 (two single flashes in succession). This says that the computer's internal workings are OK, and that the wiring to put the computer into diagnostic mode is good. No code 11 and you have some wiring problems.
Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.
Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.
Alternate methods:
For those who are intimidated by all the wires & connections, see Actron® for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Wal-Mart.
Or for a nicer scanner see Equus - Digital Ford Code Reader (3145) – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $30.
Or for a nicer scanner see http://www.midwayautosupply.com/p-7208-equus-digital-ford-code-reader-3145.aspx– It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $30.
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