Car is nosing over under acceleration

[Killercanary]

Well, I planned to attend my first race today with the car, but I have a problem. Friday night I was doing a little tuning with my eec tuner (changed the fan settings, global spark adder, and set the rev limiter to 6500 instead of the stock 7000). I took if out for a short ride yesterday and as soon as I pulled out onto my street the car nosed over. I thought that maybe it was just cold. I made it another few blocks and it did it again, then it was fine for a a mile or so. I parked the car and went into a store. I came back out and decided to hit the highway to see where my AF ratio is at since I pulled another lb of pressure out of it. I got on the highway and made a WOT pass in 3rd gear, I then left off and shifted it into 5th. I made it about a 1/4 mile and the car nosed over again on me, except this time it didn't go away. It was all I could do to keep it running. Black smoke was just pouring from the tail pipes and it was missing something awful. I got the car pulled over in a parking lot and popped the hood. I saw nothing wrong, I checked the coil and plug wires as well as the dizzy to see if it got loose or something. I got back in the car and it turned over 3-4 times before it started. I quickly got it moving and nursed it home. It seemed that if I barely loaded the car and shifted it at 2000rpms I could get around in it, but anything more than 1/4 throttle or 2500 rpms and it would sometimes nose over. The car feels just like a carb'd car does if you jump in and floor it while its still cold. I pulled all my plugs and replaced them today as the old ones were BLACK with carbon, I also re-downloaded my program into the eec tuner. I went for a ride to see if the problem had gone away but it didn't.

Does anyone have any ideas here? I'm thinking its spark related, but I'm not sure what would cause this. TFI? Stator? I'm at a loss.

 

[earleys94gt]

Do you have cats on your car? I had a similar problem with mine, where it wouldn't like to go over 2500/3000 rpm. Turns out I had a clogged cat....my $0.02.

 

[Blackened302]

what exactly do you mean by "nosing over"? sorry, i've never heard that expression.

 

[Stanger007]

Almost sounds like the MAF came unplugged or the tune got screwed up or a bad write?

Got any EEC codes?

Long story (yes I'm dumb) but I wrote an A9L tune using CBAZA strategy to my twEECer and was able to start the car and it ran like crap (same symptoms) but did run.

Wes

 

[final5-0]

I guess if it had anything to do with your latest tune changes ...
You could just load back your previous tune and do another test run

All that black stuff out the pipe makes one think it is too rich
or
As you said ... maybe not getting enough spark

Grady

 

[cbarr300]

revert back to the old tune and see what happens

 

[95strokerPSU]

My car was doing that three weeks ago..turns out the harness to the TFI module was coming out. Good Luck.

 

[Pokageek]

Definitely sounds RICH ..b ut depending on RPM and LOAD. I would go back to the old tune like Grady said..It has been a long time since I used Tweecer but I seem to remember a table where you could adjust spark based on RPM and how far down you push the PEDAL...sounds like that part of your tune is screwed up...

by "nosing" he means his front end is diving like the car is almost stalling.

 

[HISSIN50]

The first thing that came to my retarded self was also a MAF issue. Paul, can you manipulate the transfer curve or is this not likely?

Are you able to view PIDs?

 

[OrangeMustangGt]

I had a similar issue, and it turned out to be a bad o2. Did you run the codes?
did it dissapear at WOT?

 

[blksn955.o]

I really dont know too much about the eec-tuners...but with you messing with the FP could that cause the fuel tables to be squed alittle? It might be why its idle is sloppy to ok, midrange sucks and were the o2's are off at WOT things are better.

Does the eec-tuner crowd recomend the timing and FP being set at the stock levels like the tweecer?

 

[gmkillr]

So whats the diagnosis homey?
Was it what we talked about earlier?
I hope so.

 

[Killercanary]

Thanks for the replies guys. I did put a new tune in it before I took it out today, so that did not help it. This isn't the first time that I have messed with the tune since getting it back on the road, so I can not see this being the issue.

I am running an offroad X pipe, so I ave no cats.

I have checked the MAF and it is still plugged in, as well as the TFI.

I have not manipulated the MAF transfer function so that shouldn't be an issue. I've put nearly 700 miles on the new setup since getting it running and I had no issues until this started other than a idle issue at initial startup of the new combo.

JT what is a PID?

blksn955.o- I'm not sure what the eectuner guys recommend as I've been out of the loop for a long time. I don't think the FP is the issue as I used to run 40lbs with the line off, but I was running around for the first 500 miles or so on the new combo with the FP set to 50lbs. I didn't want to be lean so I ran it this way until I got my wideband hooked up and saw that I was in the low 11: 1 range at WOT so I've been backing it down a few lbs at a time until I get it into the high 12 to low 13 range, then I'll use the EEC Tuner to adjust the pulsewidth and WOT fuel multipliers.

I have not pulled any codes yet as I can not find my scanner and I couldn't buy one this weekend as no one had any.

It definitely is running rich when this problem occurs as indicated by my wideband, it seems like there is no spark to ignite the mix.

By nosing over I mean it acts like it is flooded or stalling while driving it.

I drove it Thursday and Friday with no issues. Friday night all I did was change the oil and play with the EEC settings (which are very minor, I have not changed much at all) and now I have this issue. I did pull on the serial cable a bit when I was tuning with it, maybe that is causing some sort of issue??? I tuned it from the driver's seat and the cord was stretched as far as it would extend for me to do it from there. I know the tunes are taking though as I have retrieved the modifications and they are all there like I commanded them to be, so the eectuner is getting and storing the tune. Maybe it has a bad connection with the EEC now though??? I hope to pull the codes tomorrow and pull the EEC out to have a look at it.

Rob- i didn't have a chance to work on the car tonight at all.

 

[HISSIN50]

PID = Parameter Identification Data. If you have a scanner (not reader) like an AutoXray 5000, you can toggle through and watch what your sensors are doing in real time. And since it can stream and store data, it's kinda like poor man's datalogging (with regard to finding sensory issues).

If you happened to have access to a reader like that, you could drive it and start datalogging the data when it 'noses over'.

Paul, that is an interesting idea about the connector. Wouldn't it be nice if it was something so stupid and simple. Good luck Paul.

 

[cbarr300]

I had something similar happen to me once. It turned out that the connectors that go onto my coil prongs were connected all the way and would rattle around.

sorry I can't be of more help.