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View Full Version : Choking after rebuild. Help me think it thru.



metalman
09-13-2009, 11:21 PM
I think I know was the problem is, but I wanted to bounce it off youz guyz.

In short. I just rebuild and highly modded my engine with 85mmTB, MPX, big head work, 60lb injectors, kooks mids and everything in between.

Problem: The bung hole :D on the driver's side Kooks midlength header is in a spot as to where I can't screw in the O2 because it hits the tranny linkage bracket. You;d think for that much money they'd put the hole in the right place! So, to be able to start the car and check for leaks, mechanical problems,etc., I made temporary, ghetto fabulous down tubes and pluged the bung with an old O2 sensor that I cut in half to be able to plug the hole while the new O2 is hanging from the harness plug above.

Symptom: Upon initial and subsequent start ups the car bucks, chokes, and stalls. I unplugged the MAFS and the car considerably smoothed out on it's "Limp Mode". So, I thought I had a MAF problem.

Solution????? (This is where I need your help) In reading up about the HEGOs, I realized that the driver's side sensors is connected and dangling in the open air (as I mention, I can't screw it in, thanks Kooks).

That sensor is reading A LOT of fresh oxygen molecules and in turn compensating by telling my injectors to dump more fuel, right? Which actually making my A/F really rich, and flooding out the spark. Am I on the right track?

Which is why my car ran so much better in limp mode at a predetermined functional A/F ratio? When I would plug the MAFS connector back in, the car stalls about 10 sec. after.

So, I guess my two questions are- Is my uninserted O2 sensor really what is making my car stall? ...and... Would it be safe to run my car in limp mode 1.5 miles to the muffler shop to install permanent downtubes or should I have it towed?

Thanks,
Metalman

TinManSC92
09-13-2009, 11:33 PM
ya! it's souds like you forgot to hook up the small rubber tube at the back of the engine on the passenger side. all i can think of. peace out!

sinhumane
09-13-2009, 11:57 PM
just unplug the oxygen sensor, it doesnt need anything in there. will run without to get you to the muffler shop.

i agree, check ALL your vac lines, and do you have a tune also?

metalman
09-14-2009, 05:48 PM
I hooked up all my small rubber tubes. The new oxygen sensor is not screwed in. I basically have a plug in there to keep 1500 exhaust air from blowing on my transmission. It is not staying running unless the MAF is unplugged.

Any other thoughts? And, would it be safe to run the car with MAF unplugged just to get it to the muffler shop?

fturner
09-14-2009, 06:17 PM
Unplug the O2 sensor for now until you get the exhaust dealt with. The car will run off the other one and you may end up with a CEL which is ok.

If you don't have a chip in that car setup for those injectors and MAF I would not be running that motor since all you'll be doing is pouring fuel into the cylinders. Get that dealt with before you head to the exhaust shop. The maf fail mode will lean you're fuel out a bit and probably enough to make the car run a bit better but don't rely on that either.

Fraser

metalman
09-14-2009, 10:03 PM
My car does have a tune. Got the Moates F3 from Dalke. He put an initial tune on it. I also got the def files for the BE from you a couple weeks ago, Turner. You recommended the Engine Management Advanced Tuning book to me for engine and chip tuning myself. That book is great. I love it so far.

I did unplug that O2 sensor today and it's still choking on start up and stalling.
How do you check voltage on TPS and MAF? Could a bad engine temp or coolant temp sensor give similar symptoms and equally be corrected by pulling the MAF plug?

Thanks for the feedback.

fturner
09-15-2009, 08:53 AM
Did you get the Quarterhorse? or do you only have the chip?

As mentioned see if there is any codes, then unplug the battery for 15 minutes to clear everything out and try starting the car again.

Fraser

metalman
09-15-2009, 10:52 PM
I have the F3 and the jaybird. I bought BE and the binary files.

metalman
09-18-2009, 11:13 PM
Did you get the Quarterhorse? or do you only have the chip?

As mentioned see if there is any codes, then unplug the battery for 15 minutes to clear everything out and try starting the car again.

Fraser

Why do you ask?

fturner
09-19-2009, 06:07 AM
If you had the QH, then you could look at the voltages for the TPS etc by datalogging it.

Fraser

XR7 Dave
09-19-2009, 09:24 AM
The real question is why you are asking the open forums for answers when you haven't asked your tuner anything yet. :confused: If you have the EEK flasher program from Fraser and the Jaybird then we can fix this problem in about 10 minutes.

metalman
09-19-2009, 02:15 PM
The real question is why you are asking the open forums for answers when you haven't asked your tuner anything yet. :confused: If you have the EEK flasher program from Fraser and the Jaybird then we can fix this problem in about 10 minutes.

No sh*$? Really? Sorry Dave. Ya know I didn't even think about it being a computer issue. I was so focused on what sensors could be bad. Like I said before. I have much to learn. I don't have his EEK flasher program, but I guess I'll get it. :)

Now, my hydraulic pump motor's not working. I thought it was the relay, but I just replaced that. I have a few old Actuators in my garage that i swap out. The brakes were working fine when I dismantled the engine in Feb. :mad: Could the actuator be stuck closed from sitting for so long? There is no noise coming from the brake unit. It's not even trying to pump right now. :(

But on the up side, it's getting downtubes and my O2 sensor put on now. So, at least I'll be able to take the O2 sensors out of the equation of why the motors not running right.

fturner
09-19-2009, 03:02 PM
I think he already has everything he needs to reflash his chip since he has the def file for BE etc.

Fraser

metalman
09-20-2009, 12:19 AM
The only thing I'm missing is the knowledge on how to do it myself.
Dave, what are your thoughts on resolving this?