89 LX - Extremely rich & pinging under light throttle

[mavmavv]

Thanks for all the help so far guys, its been great.

I just got my new computer in for my LX, plugged it in and reset the computer. I warmed her up and read the codes. KOEO I get code 11, which is good.

Key On Engine On im getting a few codes.
21 - Not at operating temperature
94 - Air Injection not working
44 - Air Injection Not working

The air injection stuff im not worried about, I had to plug some vaccum lines to get stuff like EGR hooked up. From what Ive read this should not be a drivability issue.

I took her out for a test drive and shes driving the best shes been, but still pretty bad. She seems to be loading up on fuel. Anything over 1/3 throttle gives me pinging, without my foot in it, its drivable, but still wrong.

When im idling her I can tell shes loading up on fuel. You can smell it extremely strongly. All it takes is a quick jab of the throttle to 2500-3000 RPM to send out all that unburnt fuel, thick black clouds out the pipes.

Ive replaced the TFI + PIP in the distributor, there are new plugs, the Coolant Temp Sensor is new, new O2 sensors, and now a new computer. I made sure the EGR is functioning by hooking up engine vaccum to it and it indeed collapses and bogs the motor. Im getting about 25inches of vaccum at idle also.

Could it be the fuel pressure regulator? I checked to see if it was leaking fuel from the vaccum port, but no go. Could it somehow be stuck open, im not sure if thats how they even work. Either way, something is amiss with the fueling. Any ideas?

 

[Fox8950]

Fuel pressure regulator getting any vacuum at all? No vacuum = open all the way. Also pinging is usually a sign of over advanced timing, crap gas, or a combination of the 2 if I'm not mistaken. Sorry can't help more couple things to check anyhow.

 

[mustangmike6996]

do a few things here... hook up a vacuum pump to the regulator and see if more or less vacuum has anything to do with how it is running...

also

make sure the timing is set properly

and

check for leaking fuel injectors by hooking up a fuel pressure gauge to the rail and looking for pressure bleed off.

leaking fuel injectors can cause poor running and excessive fuel use

 

[mavmavv]

Yeah, I havent checked fuel pressure yet, ill go pick up a gauge tomorrow. Ill try that method with the vacuum pump also.

The Regulator is getting a ton of vaccum, maybe the diaphram got stuck in one position?

As for the timing, I havent gotten it to run without pinging. Its not old gas either. I have it set very mildly, not over advanced at all. Oh well, I knew it was a beater when I bought it...

 

[Fox8950]

+1 on the leaky injector, don't know why I didn't think of that just replaced one 2 weeks ago. Pulled the plugs and all looked good except one was fouled black and stunk like gas. Changed that injector out and am finally getting alot better gas mileage (mine wasn't leaking enough to effect performance but killed my gas mileage)

 

[mavmavv]

So if thats the case, those things must be leaking pretty damn bad. Because its a serious smokeshow when I blip the throttle after its been idling.

Also, whenever I have gone to check the fuel pressure its been rather lacking. (This has been after the engine has been shut off) Its supposed to be somewhere around 40PSI, correct? Which should come shooting out of the rail with a good amount of force. Whenever Ive checked, it just kinda barely squirted out.

 

[HISSIN50]

Ensure your vac lines are correct. It sounds like you could have a MAP sensor issue.

Be sure the EGR is connected to the EGR solenoid (that a line isn't misrouted).

Be sure the caris up to temp when pulling codes.

Good luck.

 

[mavmavv]

The vacuum lines are indeed correct (except the AIR lines that are throwing codes). The EGR is connected to the solenoid. It was stuck at first, but I massaged it back to life.

Should I drive the car around a little before pulling codes?

How would I go about checking a map sensor?

Edit: Did some reading here http://forums.stangnet.com/showpost.php?p=6172363&postcount=7

I Got a code 22 when I first put in the new computer, then reset the computer after a few code reads and it went away. But it sounds like this could also be a problem. Ill check this out also. Stupid EFI, makes me appreciate carbs.

 

[PUNISHER RACING]

A block in the EGR system will cause a car to increase cylinder temp and detonate

 

[jrichker]

Code 22 MAP (vacuum) or BARO signal out of range. The MAP or BARO sensor is pretty much the same sensor for both Mass Air & Speed Density cars. The main difference is where it is connected. Mass Air cars vent it to the atmosphere, while Speed Density cars connect it to the intake manifold vacuum. Its purpose is to help set a baseline for the air/fuel mixture by sensing changes in barometric pressure. The MAP or BAP sensor puts out a 5 volt square wave that changes frequency with variations in atmospheric pressure. The base is 154 HZ at 29.92" of mercury - dry sunny day at sea level, about 68-72 degrees. You need an oscilloscope or frequency meter to measure it. There is no way you can use a common cheap voltmeter or DVM to accurately measure the output signal.

The MAP/BARO sensor is mounted on the firewall behind the upper manifold.

Baro or MAP test using frequency meter - run the test key on engine off. The noise from the ignition system will likely upset the frequency meter. I used a 10 x oscilloscope probe connected from the frequency meter to the MAP/BAP to reduce the jitter in the meter's readout.

If it is defective, your air/fuel ratio will be off and the car’s performance & emissions will suffer

Some basic checks you can make to be sure that the sensor is getting power & ground:
Note that all resistance tests must be done with power off. Measuring resistance with a circuit powered on will give false readings and possibly damage the meter.
Check the resistance between the black/white wire on the MAP/BARO sensor and then the black/white wire on the EGR and the same wire on the TPS. It should be less than 1 ohm. Next check the resistance between the black/white wire and the negative battery cable. It should be less than 1.5 ohm.

The following power on check requires you to turn the ignition switch to the Run position.
Use a DVM to check for 5 volts on the orange/white wire. If it is missing, look for +5 volts at the orange/white wire on the TPS or EGR sensors. Use the black/white wire for the ground for the DVM.

 

[mavmavv]

Ok, just got my hands on a fuel pressure gauge. Everything looks about right. 30PSI at idle and shoots up with a blip of the throttle. So it may just be the BAP sensor. Ive got one on order for the store tomorrow. Hopefully it will finally mend things up.

I am going to watch it overnight though and make sure there is no leakage overnight, but for the amount of raw fuel spilling out, id expect to see a major amount of leakage right away.

Update: Its bled off about 15PSI of pressure after 2 hours or so, is this normal?

Update 2: Went out there a little later now to run some more tests. Im now getting a Code 21 KOEO which is bad Coolant temp sensor reading. The funny thing is, that when I turn the ignition OFF the sensor shows the appropriate temperature, but with key on, it reads as 0. Another thing to look into!