[Stephen4036]

First off the motor is a 98 Cobra motor not a 2v.

After the swap the car ran amazing.. my car has always seem to have a light "jerk" or "studder" at low rpm's and it seems like it's getting worse. I am NOT throwing any codes for misfires or foul plugs, etc. It now runs VERY rich, not just on the rich side, but a VERY blatant and strong fuel smell, its not coming from the rail either. I just ordered new oxygen sensors as mine are bad and on an XCal 3 data logging the one was a flat line. I would kind of like to figure this problem out before throwing brand new sensors in and have em get fouled out in a week.

Already talked to VMP tuning and we reset the pcm and unhooked my bad O2's and it still smelled like fuel. If anyone has had these symptoms and fixed the problem please chime in, or if you haven't but now ways to eliminate variables please pm me or reply in the thread. Also the car has no EGR/MAP sensors.

[97_4V_Sleepa]

check and see if your MAF is plugged in all the way, and if you have an aftermarket fuel system or fuel Reg check and make sure that the lock nut is still tight.

[Stephen4036]

maf is in all the way.

[94silverstang]

my car is doing the EXACT same thing! i'm talking about the same story and all. i could copy and paste that first post and not change anything except for year model stuff.

I have a 98 GT with a 96 cobra motor in it. has some 98 electrical parts and all.
But anyways, one of my o2's is dead acting. doesn't change or anything when hooked up on a diagnostic scanner. Snap on computer reads closed loop if i remember correctly (could be open loop?). And one other thing, i did delete the imrc plates as well.

My car seemed to run great at first too, after the swap it seemed decent,but i did notice a slight tremble at first that i thought might have been a needed tune up. now it runs like crap and runs toooo rich. it's a pain to even drive.

I changed the plugs and wires out the other day, and it runs twice as good as it did before. The thing is though, i can tell it's still running rich and it will do just like it did at first if i don't address the real problem i'm sure. car almost seems like it doesn't have power, but it does run smooth like it should be.

would really like to see someone in here help me and this guy out! lol
I'm not trying to thread hijack or anything, just desperate for some help.

thanks, glad i found someone with a similar problem.
-Blake

[04BorlaBee]

any update on the fix?

[97_4V_Sleepa]

Hey guys, I don't know if you guys both have deleted the IMRC's but when you do you need to adjust the fuel maps to compensate.



Any time your car throws a FMS (fuel management system) trouble code, the car goes into an closed loop which is programmed to make the car follow a rich MAP, instead of a MAP that measures A/F ratio and MAF. It is a great idea, seeing as the car would lean out otherwise, but does nothing for performance.

If your car is running on a closed loop, which it is if you have a O2 sensor dead, you need to check the wiring that runs next to the header on the dead side. I had the wires ground out to the chassis after the header burnt a hole in the wires. the other thing is the grommet that the wires runs through wears out over time and will cause the wires to ground out as well. To fix mine, I replaced the grommet and zip tied the wires to the side of the transmission (on a stick car, wouldn't recommend on an auto, as it gets much hotter). Also, I bought some of the fiberglass heat shield from the local parts house and slid it over the wires for extra thermal protection and clamped it in place.

In addition, check the O2 plug and make sure that the pins haven't pushed back in the retainer and aren't corroded. If they are pushed back, grab some needle nose pliers and pull the electrodes back flush with the rest of the electrodes, being careful to not exert too much force on the electrode as this will crush it. If the electrodes are corroded get some baking soda and vinegar, dust the inside with baking soda and then add just enough vinegar to get a reaction out of it. Do this 2-3 times to clear out the corrosion, then flush with water to clear out any remaining vinegar as well as neutralize the reaction, followed by WD-40 which will displace any water left in the connector. follow this up with some liberally applied Dielectric grease (which will keep you from having this problem again and make it easier to get the connectors loose next time you change the O2's).

While you are at it check, the wires on the back of the connector and make sure that they don't have any wire showing, as this is a problem with Ford O2 sensor plugs. If you see copper, or corroded copper in most cases, go to the parts house and get a new connector, some solder connectors and some heat shrink. It is easier to replace the connector than it is to take it apart and fix the wires. However, if you are on a budget (as we almost always are) and are tech savvy enough, you can fix the plug by pulling out the pins from the receptacle side, which typically rips the wires off instead of pulling the wire back through, pulling out the rubber retainer grommet from inside the plug with some needle nose, and running all of the wires through the housing (MAKE SURE THAT YOU RUN THEM THROUGH IN THE RIGHT POSITION USING THE LOCK TAB AS AN INDEX) and then the grommet. After running all of the wires through the connector, carefully uncrimp the electrodes from the old corroded wire that is still inside and de-solder the wire out of the electrodes (if they are soldered, mine were I ave had the unsoldered as well). there is a little piece of metal at the top of the electrode that looks like it has enough material to wrap around the wire with the sheathing still on it, that is what it is for. carefully bend the tabs so that you don't break them (slower is better), and strip the wire so that there is enough sheathing to crimp the little fins to. heat up some solder inside if the electrodes and stick in the wire while it is molten. remove the heat and hold for 5 seconds until the solder hardens. crimp the fins around the sheathing and apply dielectric grease to aid in reassembly. repeat this process on any of the effected wires and reassemble, making sure that the ends of the electrodes are even with the inner lip of the receptacle. congratulations you now now how to rebuild your own plugs. this process is the same for pretty much every plug that Ford makes. GM plugs are totally different and about 10x easier to rebuild. good luck

[LGHTNG02GT]

im assuming both of you guys having problems got your cars professionally tuned somewhere on a dyno?

[94silverstang]

Me and my dad did my car at his shop. We've been trying to figure out all this stuff for a while, and it's just kinda at the point where we aren't really sure what to try next. i keep telling my dad i'm gonna take it to get a imrc delete tune put on it, but he wants to try other stuff on it first which i understand as well because i don't think just the imrc delete tune that is needed is the only problem right now

i need to check out all the wires in the harness for the dead side of the o2 sensor because i think some of that wiring harness in my car has been modified before... hmmm

hopefully it's something like this so i can get this thing going!

Thanks 97_4v_sleepa

[94silverstang]

one more thing also.

Bank 1 o2 sensor reads zero basically all the time, BUT you can take the same o2 sensor still hooked up from the same bank 1 wiring that was reading 0 before on bank 1and put it on the bank 2 side and it will start reading right.

point is that it's not the wiring or the o2 sensor's, atleast that's what it's showing right now 99%.

leaky injector of some sort? any ideas would be greatly appreciated!
-Blake

[94silverstang]

bump

[97_4V_Sleepa]

Fried O2 sensor.

[94silverstang]

Originally Posted by 94silverstang one more thing also. Bank 1 o2 sensor reads zero basically all the time, BUT you can take the same o2 sensor still hooked up from the same bank 1 wiring that was reading 0 before on bank 1and put it on the bank 2 side and it will start reading right. point is that it's not the wiring or the o2 sensor's, atleast that's what it's showing right now 99%. leaky injector of some sort? any ideas would be greatly appreciated! -Blake

^

[Trick Tuners]

This might help a little.
Fuel Trims are off bank to bank - Trick Tuners Forums
Also are you guys reading the o2 sensor volts, or the STFTs? Sometimes if the maf is way out of calibration the car will go to open loop and the STFTs will be totally flat to whatever they are set to in the tune. The o2 sensor volts will then be pretty flat, probably way low of way high.

[94silverstang]

Originally Posted by Trick Tuners This might help a little. Fuel Trims are off bank to bank - Trick Tuners Forums Also are you guys reading the o2 sensor volts, or the STFTs? Sometimes if the maf is way out of calibration the car will go to open loop and the STFTs will be totally flat to whatever they are set to in the tune. The o2 sensor volts will then be pretty flat, probably way low of way high.

Well it turns out that the o2 sensors are working, but there is something strange still with them.
- Bank 1 only shows o2's operating correctly when the car is about 3250 rpm's, which i would think makes sense considering the imrc's open then... But, bank 2 o2's always show they're working, even at idle where bank 1 o2's are acting nearly dead.

I read your post on tricktuners, thanks for the info!
Do you think that an exhaust leak between the manifold and the mid-pipe would be the problem? I thought it was strange because i have an exhaust leak on the bank 1 side (where the o2 is acting crazy.

Thanks for the help.
-Blake

[Trick Tuners]

Originally Posted by 94silverstang I read your post on tricktuners, thanks for the info! Do you think that an exhaust leak between the manifold and the mid-pipe would be the problem?

Yeah dude, thats why i have it as the first thing to check!

Originally Posted by my link There are many things that can cause the trims to be off bank to bank. 1. There is an exhaust leak between the engine and the upstream o2 sensor.

The O2s are in the midpipe.

[94silverstang]

Originally Posted by Trick Tuners Yeah dude, thats why i have it as the first thing to check!

Originally Posted by Trick Tuners The O2s are in the midpipe.

Haha. yeah, just a dumb question there by me.
i'll check that out tomorrow so i can put the car on the lift.

and are they really in the midpipe? I would've never found them.. haha
I'll post up results later on of what i find out.

Thanks man, Blake.

[Trick Tuners]

[94silverstang]

haha, you know i was being sarcastic. lol

i didn't get a chance to check out the exhaust today, i was working on a trans job and didn't have time.

update tomorrow.
thanks, Blake

[The Sherman8r]

And no check engine light with these?

[94silverstang]

no i have a check engine light on, but it's mainly for other stuff (purge sensor and imrc stuck closed. but they've been deleted..)

what would the check engine light be on for?.. or what are you thinking it should be on for?

The car had an exhaust leak on bank 1. the gasket between the manifold and midpipe was hanging out since it was loose i guess. that's been fixed and it seems to run about the same.

Do i need to get an email tune now or something similar to tune for IMRC delete?

thanks!
-Blake