i420tom

iTrader: (11)

i am pretty sure that the one side O2 sensor is bad.. it should move from 100 to 900 during normal driving and be high number at wot

ok either you are way too lean on one side of the engine or the 02 sensor is bad....
you want you O2 MV to be in the high 800 or low 900 range at WOT

camaroz28383

iTrader: (9)

your iac is maxed out and at 100% tps the voltage looks a bit low

garage_queen

iTrader: (3)

Good catch, I'll swaq them from side to side and see if the problem moves with the sensor. If it doesn't then we know it a problem on one side of the engine.

garage_queen

iTrader: (3)

I'm pretty sure the IAC passage in the Holley TB is now blocked by the Nitrous Outlet plate. The TPS problem is wierd, with key on/engine off the voltage and % are as you would expect but with the engine running it's reading very strangly. I just replaced the sensor though. Maybe my computer is bad?

garage_queen

iTrader: (3)

I don't like the TPS problem at all as the FJO nitrous controller I installed is triggered from the TPS. Won't be spraying until that gets straightened out or I'll just go mack to a micro switch.

i420tom

iTrader: (11)

please switch and post antoher datalog file when switched... i bet it will move to the other side on datamaster when you do it.. meaning bad o2.

garage_queen

iTrader: (3)

will do, likely tomorrow. Just picked up the new knock sensor. Found out the part number is the same for 93-95, then 96-97 are different.

garage_queen

iTrader: (3)

I finally got off my *** and put a new set of oxygen sensors in the car. Attached below is a new log. This log was only taken with the car sitting in the garage since I've got some of the suspension torn apart for upgrades right now too. Seems the hesitation is still there.

I did notice my IAC counts are pegged at 160. Played with the IAC a little and it didn't look to be moving at all based on a few tests I found. Just put a new one on and the pintle moves but after putting everything back together the IAC counts are still stuck at 160. Did a little reading and searching and found that being overly rich could be a possible cause, I know for a fact I'm running rich at idle. Also need to adjust my TPS which I should get done tonight.

Just for my own sanity, I tried blocking off the IAC passage on the TB and cracked the blades open a little to get it to hold a good idle. Doing this I noticed that when I bumped the throttle open the hesitation was gone or at least much less obvious.

to be continued.....


EDIT: The files from Datamaster were too large for this forum's restrictions. Download the file and change the extension from .tun to .zip and then open the zip file. Included in the .zip is an export for those who don't use Datamaster.

garage_queen

iTrader: (3)

Here's another link to the file. right-click/save as... ---> http://mafia-motorsports.com/drive2.zip

garage_queen

iTrader: (3)

fixed the low TPS voltage at idle and the code for that is now gone. IAC count is still 160 but I did see it go down to 157 for a brief period, lol.

Anyone else made any progress on getting rid of the hesitation, there were quite a few who seemed to have the same issue. Is this common for a rich condition?

06blackGTO

iTrader: (20)

I had the same problem with my iac counts pegged at 160 w/my holley 58mm t.b. I replaced my iac sensor,and it helped, but it was still high. I had to drill a small hole in each t.b. blade and that helped my car idle better and the iac counts went down in the 70-80's. I know people don't like doing that, but that is what I had to do to get it to work right. This is on my 93' h/c/i ta.

myltwon

iTrader: (1)

some aftermarket TBs have problems with the IAC passages, I think Holley was one of them like the person above is talking about. problems with casting flash or simply poor passages

garage_queen

iTrader: (3)

I'll probably pull the TB off tomorrow and have a look at the passages. Pretty sure I'd like to get the rich condition fixed in the tune before I start messing with that too much though. I've always had that TB but have not always had the hesitation so I don't think it's the root cause of the problem

garage_queen

iTrader: (3)

I pulled the throttle body off tonight and I think I can see where the problem might be. I have the plate kit from Nitro Dave's and the passage through the plate looks much smaller than what is on the throttle body and intake. I'll get some pics tomorrow and I'll run it without the plate to see if the counts drop.

garage_queen

iTrader: (3)

Diameter of passage in the Holley throttle body. (0.493in)


Diameter of passage in the nitrous plate. (0.332in)


Comparison...(yep I'll be cleaning that TB out)

LeonbergerG

iTrader: (2)

I have a 94 z And have been Having the Same Trouble. Seems like it only does it when the Car Is Hot Though. it doesnt overheat but if you take it on a long drive or are Beatin on it kinda Hard. Just Misses and Hesitates until you Really get into the throttle.

garage_queen

iTrader: (3)

well, there is definitely improvement with the plate removed. I put the TB back on without the plate and started it. I let it idle until the pcm went to closed loop. In open loop the IAC counts stayed at 160 but as soon as it switched over to closed loop they started to drop. I let it idle for a few minutes and get up to full temp and the counts made it down to 78 at it's lowest point. There is still a great deal of improvement to go but I had never seen it go below 157 prior to removing the plate. I really don't want to drill out the plate and there's not much room to do that anyway. I'm thinking I can try to adjust the throttle stop screw out a bit then adjust the TPS back to where the pcm thinks they're fully closed. Hopefully that will bring them down some more.

Still taking suggestions though.....

garage_queen

iTrader: (3)

DataMaster log from tonight's idle session is here ---> http://mafia-motorsports.com/no_plate.uni

i420tom

iTrader: (11)

I am pretty sure i have mine fixed now...
It may kinda just be a bandaid to cover the real problem but i have tried everything to get my car to stop hesistating and nothing has even helped untill now!
I noticed that when i blip the throttle from IDLE or anywhere under 1k rpms, that my o2 MV would drop way way down to 100 range or less. i would sometimes get a lean backfire thru the intake. Now the car does not run lean anywhere else when idle or driving or drag racing
So with some help from a select few people what we did was enable WOT at 5% throttle when at 1k rpms or less, I then datalogged the car and now when i blip the throttle i dont feel the low rpm hesitation anymore and the o2 sensor mv are over 900 (too rich but sucess)
I am thrilled to finally have made some progress.
i dont reccomend this unless you have literally eliminated everyother possibility

garage_queen

iTrader: (3)

I would call it a workaround. You've tricked the PCM to think that you're at WOT and the PCM ignores the O2s at WOT and runs on predefined values in the tune. I could see this being a problem for things like air conditioning as the compressor is also cut off during WOT. There could be other switches triggered in the PCM also based on whether you are at WOT or not.

Thanks for sharing the info, it could be a last resort if I can't get anything else to work. I'm making progress so we'll see what adjusting the throttle stop and the TPS will do for me then go from there.