Garage Storage Organization and Garage Cabinets

tonyz2897 · **Sorting out Idle issues. Need suggestions.**

Here's the situation. Whenever it's running in open loop (first few seconds after a cold start or cts unplugged to set timing) it idles smooth as glass. Just as soon as it warms up enough for the a/f guage to bounce or the cts is plugged back in, it starts idling a bit rough with a random miss and and a little pop out the exhaust that goes along with the miss. Off idle, the car runs great. I'm half convinced that it's the O2 sensor even though it's only a few weeks old. Much as I hated to, I had to use a Bosch sensor when I did the turbo swap.

The old one was hopelessly stuck in the swingvalve and the bosch unit was all I could get on short notice. I'm just curious to see if anybody has any suggestions as to what else it might be or any tests I could try to make sure it's the O2 sensor?
Thanks in advance,
Tony

_9_ · 04-01-2005, 07:47 PM

Well, if you unplug the temp sensor (which eliminates computer control of timing), it sounds like it could be the computer not acurately contolling timing. If you have access to a scanner that would be good. even better would be if you had access to a lab scope. The scanner will tell you if the computer is advancing timing correctly and the lab scope would show you exactly what the 02 sensor is doing. if it's 900 mV it's rich, 100mV is lean. Usually o2 sensors die lean. If you can get a wave form of your o2 and it is straight lean, try to make it rich by giving it propane, if your o2's voltage signal doesn't rise any then that would be a safe bet that your o2 is dead.

-Courtney

Putter · 04-01-2005, 09:22 PM

Sounds kind of like the normal TD idle.......vroooooooooooom va va vroooooom...........va va vroooooooommmmmm..... with a little note to the exhaust as well.

Anyone else want to back me?

tonyz2897 · 04-02-2005, 02:01 AM

Thanks for the information guys. This seems to be a little more than the normal TD idle though. When it misses, it shakes the car pretty good. I'm pretty sure it's not a mechanical issue since it's not constant. I'd really like to get it on a scanner. Any suggestions on one that would be good? Looking for something that will maybe log data too. It'd be nice if I could find a decent deal on ebay, but I want to make sure that what I get will work with td's.
Thanks,
Tony

_9_ · 04-03-2005, 11:25 AM

Well all I've ever used is the snap-on "brick," so I can't really tell you what else will work good with our cars. I would make sure whatever you buy has a movie funtion, that way you can hook it up to your car, arm it, and then record when you get that misfire. Review your movie and see what your sensors and ECU are doing.
In my opinoin though the snap-on scanner is probably way too much to spend just for this, if you had your own shop and did plenty of diagnosing then sure.

tonyz2897 · 04-03-2005, 12:57 PM

Right, definately too expensive just to diagnose 1 problem but I have a use for it even after I get this straightened out. I'd like to find a rig that I can log data with and then upload it to a pc to view that way I can compare runs. Say for instance I add more fuel or more timing. I can then compare that run to a baseline run to see the difference in o2 volts and knock count to tell if I'm going in the right or wrong direction.
Thanks,
Tony

Putter · 04-03-2005, 02:07 PM

I think D-cal can datalog and record multiple sessions can it not?

tonyz2897 · 04-03-2005, 04:59 PM

Pretty sure you're right about that, but can you use Dcal through the diagnostic connector or do you have to wire in a cable to the LM?
Thanks,
Tony

tonyz2897 · **I think I may have accidently found the problem!**

After setting the timing back to 12 deg. I decided to do my twice daily detonation/lean plug reading. What I didn't consider is that having just run the car with the CTS unplugged to set the timing, it had been running extremely rich. Extremely rich that is on every cylinder BUT #4.

Plugs #1-3 had a good dark color like you'd expect from running rich, but #4 was white! The only conclusion I can draw is that I've been running 22 psi of boost with a lazy injector in #4.

I'm going to test the theory by swapping the #4 injector and plug to the #3 cylinder and idle the engine with the CTS unplugged for awhile. If #3 then has a white plug and #4 a dark one, I'll know for sure the injector is the problem.
The only reason I can see that I haven't had a detonation problem or a piston meltdown is the alky. Since it's an independant system and spraying into the intake, I guess it's been rich enough to keep #4 adequately fueled. Thank God I noticed this before I started bringing the boost up more.

Tony

tonyz2897 · **update**

This is just freakin' wierd! I swapped the injectors between #3 and #4, ran it a bit with the CTS plugged back in to burn the carbon off the plugs, checked the plugs to confirm that they were clean, then unplugged the CTS and ran it again.
I was expecting to find that #3 was now the lean cylinder since that's where the injector in question went. Instead I find that all 4 cylinders now appear to be fueling evenly.

I'm at a loss here. Just switching the injectors between cylinders seems to have fixed the problem, but there's gotta be something I'm missing.
Any ideas?
Tony
Oh, BTW, the idle issue is still there.

Putter · 04-03-2005, 09:00 PM

I've heard alot of un-equal air distribution problems on the intakes, plus the exhaust manifold makes things worse yet. Just an idea, I can't remember, I think the user D-Cal on here was having problems with fuel distribution here a while ago too.....

tonyz2897 · 04-03-2005, 09:33 PM

I just wonder why the problem seems to have fixed itself?
As for the idle issue, I found out that raising the fuel pressure (pinching the return line) causes the idle to smooth right out. So I'm still convinced it's a fueling issue.
Thanks for the help,
Tony

daytonajesse · 06-27-2005, 05:10 PM

Any luck with the issue yet? I seem to be having the exact same problem you describe, while idling I get random misses and the car shakes. off idle its fine no noticable issue untill im stopped. The car always had a lil miss to it like Putter said, but didnt get worse like it is now untill I fixed my timing (was set at 8degrees advanced!! fixed back to stock 12degrees) Any ideas?

Reaper1 · 06-27-2005, 06:23 PM

The little "miss" you guys are describing sounds like a normal TD...true, it shouldn't shake the car, butthe reason the car smooths out when you raise fuel pressure, ect. is because if you pay attention to your A/F gage...the same time it misses is the same time the O2 swing is full lean. At least this is the way it is on my car. You will also notice that the miss goes away when you turn on the A/C(if you still have it). Same kind of deal except the computer adds more air/fuel/timing to keep the engine from bogging at idle.

The reason the problem "fixed" itself was probably due to a loose connection at the injector plug. I've seen and experienced this myself. Even with a BRAND NEW injector harness. Check the wires going in to each injector plug(and specifically the suspect one) and make sure they are seated all the way in the plug and make good contact with the prongs in the injector.

tonyz2897 · 06-29-2005, 12:02 PM

I haven't fooled with mine in awhile since the tranny has been out of it, but I agree about the miss coresponding to the lean swing of the a/f. The thing that gets me is that I just can't believe it's normal for one main reason. Who would have payed for a brand new car that idles that bad? Anyhow, I think the solution I'm going to try is to have a cal done with O2 fedback ignored at idle. Since the Daytona is going to come back as more of a weekend driver/strip car, I don't think I'll mind the drop in fuel economy.
Tony