Jess's TGP has developed an odd problem.
Upon starting the motor cold, the idle will slowly creep up to 1500-2000 RPM (sometime it spikes directly up to 2K). It's not a steady idle, it fluctuates on NO pattern up and down a couple 100 RPM while it's idling high. BUT, once the car is put in to gear, it idles fine. Whether it be while driving, or coming to a stop and putting it back in to Park, it idles fine.
It's had this problem off and on for a couple of weeks. The first time we noticed it, the problem wasn't just a high idle in Park, it also wanted to idle higher in any drive gear. I unplugged the battery for about 20 minutes, and then reconnected it, and it started up perfectly fine and the problem didn't come back for another week.
She had to drive an hour and a half on interstate this morning to Salina. When she started it in the morning, it idled high for a while, and then eventually settled back down to a normal idle (around 1K). When she got to Salina she stopped someplace, and then started the car shortly after that to leave, and it idled fine.
It's a real come and go problem, and it's got us baffled as to what the problem is. The IAC valve is only about 6 months old, and the TB passages are clean. The upper intake gaskets are new, as is the TB gasket. The way it fluctuates at idle, it seems like the ECM is having problems. She has a TG160, and we haven't tried putting the stock chip back in to see if that stops the problem.
Anyone got any advice? It's much appreciated.
I'd take the IAC out and clean the pintle and the seating surface. Then I would unhook the battery, reconnect, and start her up. Scan it and check the IAC counts. If everything is working okay, you'll have a good baseline. Then when it starts to act back up, pull out the laptop and check it out again. See what's going on. If it doesn't come back. It was probably just some carbon on the pintle. Good luck.
Did you reset the IAC valve? I just put one on about two months ago. you have to turn the key to the on position for 5 seconds (but don't start the car) then turn it off for 10 seconds (that resets the IAC). After you have reset the IAC you have to take the car above 40 mph to get it to seat correctly (if not the computer will not know when to close off the vacuum port) .
Not to steal the thread or anything but I've had the similar with my TGP ever since we put the new engine in the car, even with about 3 different IAC motors it still idles high in park while its cold, and does it EVERYTIME.... It will idle high until I put the car in drive, and then will finally idle normal when I put it back in park. I have tried the idle relearn with the TopGun Chip to no help? Any ideas?
I have had the same problem with mine since I put the engine in in late August. I haven't driven it in over a month, but that will be priority number 1 when it comes out of the garage. That's hard on the tranny. I think it's a vac leak.
Luke, what numbers/words are written on the TopGun 160 EPROM :?: :?:
God910 had this same problem and I told him the chip (stock or mine) has a table to compensate for a Low Battery Voltage condition, that bumps up the IAC Motor/Idle Speed when voltage drops too low. I suggest to everyone with this problem to also check their Charging Volts :!:
Jeff M
Mine has done this since I did my topend swap. All the sensors were either new or cleaned. It doesn't make any difference if I unplug the sensors either. But I have a brand new battery and brand new alternator and it charges just fine and it won't idle down until I drive it. I disconnected the battery and let the chip learn, and this worked for about a week and a half and then it started up again. I can't find the problem.
Shawn
Quote from: dbtk2Mine has done this since I did my topend swap. All the sensors were either new or cleaned. It doesn't make any difference if I unplug the sensors either. But I have a brand new battery and brand new alternator and it charges just fine and it won't idle down until I drive it. I disconnected the battery and let the chip learn, and this worked for about a week and a half and then it started up again. I can't find the problem.
Shawn
3 things come to mind right off, a grounding problem, the IAC is closed with the throttle plates too far open, or the IAC tables do not like your new setup-intake/cams....or since you have a different intake AND cam, you breath different too.....so, more air (with more fuel) needs more timing to burn all this......, or since on the compression stroke you compress this "more air" higher and you take the timing down instead, guess you will have to decide 8)
Jeff M
OK, I work as a lot tech for the chevrolet dealership by my house and I get to drive and move the cars around in the lot. Even the 2004 idle high when you first start then. My guess is it kind of acts like a choke when you start the car (just my thought). So it doesn't seem to be a problem. Also if your tach is off then its going to look like its idling higher than it really is. But for the most part its normal (IMO).
Quote from: SpeedDemonOK, I work as a lot tech for the chevrolet dealership by my house and I get to drive and move the cars around in the lot. Even the 2004 idle high when you first start then. My guess is it kind of acts like a choke when you start the car (just my thought). So it doesn't seem to be a problem. Also if your tach is off then its going to look like its idling higher than it really is. But for the most part its normal (IMO).
Mine will actually idle high ~2500 or so UNTIL i put the car in drive.....
My GTU and Nitrodaves old TGP idle fine at start up. Well the TGP idles like at 1500 and comes back down and stays there after a few seconds. The TGP did have a lightly dischaged batt..but it stayed fine in idle without putting into gear to fix the high idle. Mind you with bad coils, bad turbo :? A ALDL scan would be nice.
Whoa! This took off! :shock:
Jeff, it's funny you mention the charging volts. I've noticed the lights have been a bit dim lately.
Her car has been sluggish lately too, and there's a whining coming from what sounds like under the hood. I can't tell if it's alternator whine because it only does it while driving AND accelerating. If your not driving (aka sitting idle), revving the motor will not reproduce the whine.
I'll check her charging volts, and post the EPROM markings on here. I need to check my charging volts anyway since my headlights are getting dim on the 5 speed.
Lets hope its charging volts, cables etc, easier then the other guys with their problems 8) You can also check the ground and power cables by measuring the voltage drop DC from one end and the other of each main cable. Fire up the engine, throw on a load such as headlights, have the woman idle the engine at 1,500 rpms then measure for DC Volts from each end of the ground cable (battery and engine) should be .1 volts DC or less, preferable less than .1 :!: Same running condition for power, grab from the alternator feed/at alternator and at battery positive, you can have up to .5 VDC, preferable less. If you failed the ground test, time to yank all of them and test the strength of the connection of the cable to connector/spade, clean all contact areas if cable to connector are good and tighten back down/re-check voltage drop (I like to grease them to stop moisture and corrosion from happening later as it does!!). Power cable, same checking and cleaning though I need to check a known good setup I have to see if our cable is a little undersized which it looks like to me and with the length of the run!! To check your alternator other than its charging volts, which should be 12.8 to 14.5 (idle with no load, load with rpms up) set your volt meter to AC and check the voltage, all alternators put out some AC current/volts but if you get .5 VAC or more, diodes are failing, time for a rebuild! IceBurg makes a 140 amp upgrade kit (not a complete alternator, just to upgrade and rebuild yours), Delta Y double wire wound armature, and cast into the rear case, heat fins for the rectifiers mounted there on the flip side, and a larger 10mm high-temp grease rear bearing. Powermaster also but cost big bucks but seen theirs has a 4 wire armature and the same 140 amp rating but at idle it puts out 90 amps which is more than most upgrades do and this rating goes up faster towards the 140 amp max rating. All right, I need to shut up and get some other work done.
Jeff M
Quote from: Jeff M3 things come to mind right off, a grounding problem, the IAC is closed with the throttle plates too far open, or the IAC tables do not like your new setup-intake/cams....or since you have a different intake AND cam, you breath different too.....so, more air (with more fuel) needs more timing to burn all this......, or since on the compression stroke you compress this "more air" higher and you take the timing down instead, guess you will have to decide 8)
Jeff M
I thought maybe it was because of the topend too, but if I relearn the idle then its fine for a week or two. And it ONLY does it until you put the car in gear, once you put it in gear its fine. When you put it back in park or neutral the revs are down where they are supposed to be. It will start out around 2k-2500rpm, when you put it in drive the revs drop to like 1000 or less and its fine after that. I know I need to get the chip tuned for the stuff, but I don't think thats the whole problem. I don't remember for sure, but I think the car might have been acting up before the topend swap as well, but I know its been doing it AT LEAST since the swap.
Shawn
Quote from: dbtk2Quote from: Jeff M3 things come to mind right off, a grounding problem, the IAC is closed with the throttle plates too far open, or the IAC tables do not like your new setup-intake/cams....or since you have a different intake AND cam, you breath different too.....so, more air (with more fuel) needs more timing to burn all this......, or since on the compression stroke you compress this "more air" higher and you take the timing down instead, guess you will have to decide 8)
Jeff M
I thought maybe it was because of the topend too, but if I relearn the idle then its fine for a week or two. And it ONLY does it until you put the car in gear, once you put it in gear its fine. When you put it back in park or neutral the revs are down where they are supposed to be. It will start out around 2k-2500rpm, when you put it in drive the revs drop to like 1000 or less and its fine after that. I know I need to get the chip tuned for the stuff, but I don't think thats the whole problem. I don't remember for sure, but I think the car might have been acting up before the topend swap as well, but I know its been doing it AT LEAST since the swap.
Shawn
This sounds a lot more like my problem, i never noticed it as much before the engine swap, but ever since the new engine has been it, it as definitely had the problem?
Check for vacuum leak? Pull off the Crank Case Breather Hose and place your finger over the hole while revving the engine, if you finger is held at all there is a vacuum leak in the lower intake. If not then idle engine and use propane torch (not lighted!!) to bath any areas that might be a vacuum leak such as around the gaskets, TB etc, engine speed will change when raw propane finds a vacuum leak. I don?t care if people got new alternators and batteries :) , it?s a simple test, leave nothing to chance or continue to be bothered by this problem and maybe be embarrassed when you do find an odd problem in the charging/starting system later :oops: .
Last would be to play with an chip emulator with the engine running, there are a few timing tables but maybe a lot would be answered if a scan shows odd values with the IAC Counts!? (talking and thinking here). Maybe the INT is resetting since it cannot get a good hold on the fuel trim, there are a lot of things to check in a scan. Back to the chip, there are a large number of idling tables with such things as IAC control and setup, others too that effect how the engine?s idling is considered when in P/N etc, far too many to list here, and spend a week describing each or a combination of some that could play a part :? . It may be that the issue was not enough before the swap to be a bother and now with the swap, the problem is more noticeable.
(oops, edited/corrected)
Jeff M
For the problem from my point of view...
PCV on my car has been moved from the stock location *under the plenum* which was plugged, and moved to the side of the plenum, and the propane trick has been tried to no avail, we are going to intercooler pressure tester and see if we can find any that way, the engine is much to loud to be able to find any small leaks.
maybe doing the chip thing will be the only way of fixing the problem, we'll try a few things you have suggested first of course, then get into the more drastic stuff if need be..
Well being up for too many hours and see what that gets me :roll: I corrected my description in that last post :oops: .
Jeff M
I know it doesn't have a vacuum leak. The very first time I started up the engine after figuring out my oil leak problem, it definatley had a vacuum leak, but I fixed that. The plenum gaskets and the EGR block-off plate that I made were both leaking. Put new plenum gaskets in (again), and resealed my block off plate with RTV and the vacuum leak went away. With 20in.hg. at idle I'm douibting there can be a vacuum leak somewhere. Not only that, but the engine idles smooth and doesn't hesitate or miss at all. It could possibly be in the chip, and thats why I wasn't worried about the problem, because I figured that I would correct it when I edited the chip, but since others are having what sounds to be the same problem, I'm thinking maybe it isn't in the chip.
But anyways, definately no vacuum leak.
Shawn
Ok, so you don't have a vacuum leak 8) Still be good for others to ensure this with theirs, leave nothing to chance or be pissed later :lol:
Jeff M
One thing Luke left out... at times the little beast does a fun trick where, from rest, it will accelerate to around 20-25mph without me giving it any gas. Sometimes it will continue the entire time the car is running, and other times it starts behaving when I come to a complete stop. There seems to be no pattern - I'll start it once and it's fine... start it again a couple hours later, and it's acting up.
Quote from: kittieOne thing Luke left out... at times the little beast does a fun trick where, from rest, it will accelerate to around 20-25mph without me giving it any gas.
Did you buy a TGP or an old AUDI?? :shock: Some of the "old farts" on the board may remember those! The days of the "accelerated by itself" Audi cars back in the 80's? :lol:
Sounds to me like you may want to check the throttle body return spring and also hook it to a diag tool to also see what the IAC counts are. That issue would drive me crazy for sure! 8)
The TB spring is good..
I finally got a chance to hook the car up to the laptop, and I ran a scan on a cold engine, and recorded until it fully warmed up. Of course, this time it idled just fine. All the IAC counts, and read outs looked alright, nothing was unusual. I'll post the file up here when I get a chance to copy it off of the laptop.
Well like Jeff said look for vacuum leaks. It is possible that when it is really cold that a leak is opening up from metal or a plastic piece shrinking so much from the cold letting air in.
It is a tricky one...but hell Luke you found the wire shorts on your TGP when no-one else had a clue what to look for. Be one with the car...talk to her...feel the car!! :wink:
My car has recently developed this problem, sometimes revving up to 3k or more! Once I drive it it still happens every time I depress the clutch. I did replace my Alternator, and it is a 105 amp, but I don't think the engine would rev that high...?!
cant u use carb cleaner instead of propane to find vaccume leakes, my car idles just the same, its wierd
brake cleaner works too.
I'll also run a aldl scan on my TGP..it just did it today...could be that it hadn't been on for weeks. 2500 rpm from the get go.