Pinging, Lack Of Power, And Fuel All Over Back Of Car?

[mustang20010]

I noticed my car started pinging a few weeks ago. It lacked power occasionally, sometimes would stall when I'd first start it, and eventually got so bad the car would die at stop lights. I also noticed one day what looked like spots of gasoline all over the back of the car. Like from the bumper all the way up to the trunk. Anyway, after some vacuum testing, i determined that the vacuum control solenoid (under the pass side fender well, has red and green vac lines going to EGR valve) was bad, and I replaced it. The vacuum went from like 7-9in hg at idle back up to around 20in hg and the car idled fine and seemed normal...

Well, the car still pings occasionally under load, sometimes feels very lacking in power, and I still get spots of fuel all over the back of the car. No CEL on.

What am I missing? I already put a 255 walbro in it, and a new regulator. Ford Racing wires, MSD cap and rotor, and auto lite 25's also recent. I'm leaning towards bad cats or o2's? Dirty MAF?

Car has around 88,000 miles. Bone stock.

 

[toyman]

When you put the new pump in did you replaced the tank filler grommet? If not, that may be the source of the gasoline leak. Always clean the MAF as part of the tune-up routine. Clogged cats will affect power but isn't a common problem. Car with a base timing at 12-14* shouldn't ping using 87 octane from sea level to about 1000'. Plugs were gaped to .054" correct?

 

[mustang20010]

When you put the new pump in did you replaced the tank filler grommet? If not, that may be the source of the gasoline leak. Always clean the MAF as part of the tune-up routine. Clogged cats will affect power but isn't a common problem. Car with a base timing at 12-14* shouldn't ping using 87 octane from sea level to about 1000'. Plugs were gaped to .054" correct?

I did replace the filler grommet. I always run 93, usually from Shell, and even ran a bottle of Techron through it. I will check the timing, but it's bone stock so I don't see how it could've changed suddenly. Plugs were gapped. Maybe I'll try some of that MAF Cleaner they sell at Autozone, but would a dirty MAF really do all this? I've honestly never cleaned one.

 

[toyman]

The MAF sensor is critical. The MAF signal is used by the ECU to calculate the correct fuel load based on the air flow. I believe the EFI hierarchy order is
#1 - MAF
#2 - TPS
#3 - ECT
#4 - AIT

 

[madspeed]

pull codes?? Could be faulty ect.

 

[revhead347]

Did you check the plugs after you fixed the solenoid? Running that rich for that long might have fouled everything out.

Kurt

 

[95Vert383AOD]

Maybe check the Fuel Pressure regulator. I hear that a bad diaphragm inside may put fuel into the vacuum line that comes off it. Pressure testing for around 40psi at the rail wouldn't hurt either.

 

[mustang20010]

I'd love to pull codes...been contemplating picking up a decent OBD-1/OBD-2 scanner, but I'm having a hard time justifying $200 or so right now - especially if I did end up needing to spend decent money on whatever is wrong.

I have not checked the plugs, I guess that's not a bad idea.

I replaced the FPR before I did the vacuum solenoid. I'm guilty. I hung a part. But I felt like after installing a 255lph pump, it probably wasn't a bad idea to replace the old stocker. I did test it afterwards anyway, about 38psi at the rail.

I'm gonna stop on my way home from work today and pick up some MAF cleaner and cross my fingers, though I still am a bit concerned about the spots of fuel pretty much all over the entire back of the car.

 

[Yellow302]

I'd love to pull codes...been contemplating picking up a decent OBD-1/OBD-2 scanner, but I'm having a hard time justifying $200 or so right now - especially if I did end up needing to spend decent money on whatever is wrong.

I have not checked the plugs, I guess that's not a bad idea.

I replaced the FPR before I did the vacuum solenoid. I'm guilty. I hung a part. But I felt like after installing a 255lph pump, it probably wasn't a bad idea to replace the old stocker. I did test it afterwards anyway, about 38psi at the rail.

I'm gonna stop on my way home from work today and pick up some MAF cleaner and cross my fingers, though I still am a bit concerned about the spots of fuel pretty much all over the entire back of the car.

38-40PSI is normal with no vaccum or under load. Should be around 28-32 with vaccum on the regulator. Maybe there is your vaccume leak? There is a vaccume line from the intake manifold that goes to the fuel pressure regulator.

Vaccume leaks / blown intake gaskets / PVC tube all will idle OK and then feel like crap under part throttle and WOT.

 

[mustang20010]

Well, I picked up a can of MAF Cleaner and cleaned my MAF, but before re-installing it I decided to pull out the #1 spark plug...

That's oil on the threads. Here's a pic of the back of my car. What I thought was gas may be oil??

 

[mustang20010]

Fwiw, I know I have a rear main seal leak, I just don't have time to do it right now (I bought a Bronco to drive for winter that I'm trying to get up an running). My mustang is my DD. could that somehow cause oil to up in the exhaust?

 

[revhead347]

Time to run a compression test. That definately looks like oil on the back of the car. Oil on the plugs is the easiest way to get detonation.

Kurt

 

[mustang20010]

This is so strange. The oil spots are even on the plastic fuel tank cover. I don't have a way to do a compression test... and I don't really trust any dealership.

I don't mind getting into it, I just can't right now cause of my Bronco. Do you think it's a bad idea to continue to drive the Mustang this way for a few more weeks or so?

 

[toyman]

You only want an OBDI reader and they are about $22 here

 

[Chythar]

When driving fast enough, a low pressure zone is made behind a car. Any car, not just a Mustang. It will scoop up air from under the car and swirl it around the back of the car. Vans or trucks with a larger back end will have the problem more so than a Miata, for example.

I have a friend of mine who had a transmisison leak in the transmission of a van he once owned. The tranny fluid would vaporize when driving on the freeway and the low pressure would suck up the vapor droplets and cover the back of the van in tranny fluid. If your rear mail seal is leaking oil bad enough, it's possible the oil on the bumper is actually coming from the rear main seal leak. If the bottom of the car and tranny are covered in a film of motor oil, that's likely your problem.