Clogged cat, or fuel problem?

[Scallywag]

I think I may also have the same issue on my BA Mark.

Sometimes the car jerks if I gently step on the gas while it's in motion which is usually the precursor to the laggy feel. I mostly hear the pop usually when it begins to lag on acceleration. This may not be smart of me to do, but sometimes when it lags I floor the pedal to see if I can get past that feel. Sometimes it continues to pick up real slow and forced while other times it kicks in as hard as I'm flooring it and then ride like normal.

It'll idle rough for a little bit and then go back to feeling it's turned off from being so smooth, successful WOTs sometimes results in the egg smell as well. If you're outside while idling you hear what sounds like a weird chugging/air suction noise from underneath the car.

My guess would be by the exhaust manifold and maybe that contribute to the stumbling feel.

 

[96_Lincoln_LSC]

gonna jump on the band wagon here..

Car runs fine most of the time... but there are occasions when under slight acceleration it seems to misfire.. but i NEVER repeat NEAVER get a check engine light for anything... it is sever enough at times for me to think of a blown head gasket but that would surely throw a CEL right???? if it were a clocgged Cat and since my O2's are turned off in the tune, i assume no CEL for the miss?

Anyone got a place on East Coast near Philly or New Jersey that will remove my 3rd cat? replace with Xpipe... or hell even hollow it out?

 

[sprocket]

No, a CEL is not a sure thing with a blown head gasket. Trust me, I know. I think these computers are a little too liberal with misfires. I don't know where the threshold is for a misfire to cause a CEL, but it sure doesn't seem low enough to me.

Head gasket failures aren't too common with these engines. Mine was absolutely confirmed by testing the cooling system for hydrocarbons. You use a bulb to draw air above the coolant in the reservoir through some blue dye. If the dye turns green there is exhaust gasses in the coolant. There is also oil in my coolant and coolant in my exhaust.

 

[warrioralumni08]

Nope, not the cats. Got them hollowed out and they looked good. So its either an ignition problem, or with fuel, or perhaps a weak torque converter actually. The car does make a screeching sound when shifting, at wot, and when it revs to 6k to shift it seems like when it gets to 5 it pulls too quick on the rpm, but I'm not going anywhere? :/ Never have dealt with a weak torque converter so I don't know the symptoms at all. Guess I should hook a fuel pressure gauge to the fuel line, and see what the pressure is at when it gets to 5k. What else should I check?

 

[Staffamerica74]

spark plugs changed ever?

 

[warrioralumni08]

New spark plugs, new cops, no oil on spark plugs, new fuel filter, walbro fuel pump. I suppose ill go after a new fuel pressure regulator, and do a trans flush this weekend, and possibly dig into the top end of the engine to see if anything is gummed up or clogged.

 

[warrioralumni08]

Alright, so after testing fuel pressure, here are the results. With the fpr vacuum still connected, key on, barely moved, had to prime it maybe 5-6 times to get it up to 40. Key on engine running, 28-30. Fpr vacuum.disconnected, key on, 10 psi, had to prime a couple times again to get up to 40 psi. Key on engine running, 35 psi. Now, I'm not sure if your supposed to disconnect the fpr vacuum while driving, so I left it connected. Seemed to keep steady at 30-32, increased more as you gave it more pedal. Now 3/4 of throttle, 40-42 psi. WOT, resulted in rapid loss and was steady at 15-20 the whole time I was in it. As Jay stated, I do believe its the Walbro now, as it isn't sending the right variable signal, for more fuel, when its needed at WOT.

Thoughts?

 

[warrioralumni08]

Double post

 

[97MarkJA]

Walbro is on its way out. Get a focus SVT pump and be done with it.
http://www.lincolnvscadillac.com/showthread.php?t=71667
http://www.lincolnvscadillac.com/showthread.php?t=72168

 

[chris2523]

yep. definitely not enough fuel.

 

[warrioralumni08]

317 ****ing dollars for the focus svt pump, and that's without tax. My spare Walbro in the garage, doesn't sound too bad from my Gen 1, neither does a 255 Walbro. Any other places I should check, besides the stealership?

 

[97MarkJA]

Gen1 and the 255 are not variable voltage pumps.
Check amazon for the focus pump.

 

[chris2523]

rockauto is around 200.
amazon is around 180.

check PFS204 part number.

 

[racecougar]

As everyone else has said, the gerotor-type pumps are not going to last long in a PWM arrangement. A stock replacement turbine-type pump would be fine for a NA Gen 2. Take a look on RockAuto.

The noise you're hearing during WOT shifts is the serpentine belt slipping.

 

[98lincmk7lsc]

Check the mustang/cobra forums. Sometimes you can find them on there cheaper.

I got mine from a friend (mustang owner) for $40.

 

[warrioralumni08]

Hmm, I got a Bosch, off of fleabay, same part number as on Rock Auto, 69603 for about 50 less. It came with no pigtail, nor a new screen, but in the correct Bosch box. Now examining the pump, it looks to be the right one, but I noticed some of the other pumps on Rock Auto have the connectors protruding from the pump, instead of getting plugged into. Also, the wiring that came with the car, that I cut off and have laying around, plugs into the pump, with reverse polarity? Should I just cut and splice, and switch them around?

[/IMG]

 

[chris2523]

nope. that's correct. the mark viii wiring is counter intuitive.

 

[warrioralumni08]

Ahh, what joy! Today, I dropped the tank and installed the new fuel pump, fresh oil change, and dry fired her, then she started right up. Took her around the outer city limits, and she screams past 5k with ease now! Makes me pretty happy, but it's possibly time for some giggle gas now.