experts inside, if i cant fix this i am selling the z
 

first off i just installed a new motor with the hotcam with all bolt ons etc. well the car seems to run good and bad intermintently. for example right from start up the car has a very shaky and unstable idle in open loop and when it goes to closed loop it still runs the same. the car has been tuned by madwolf. when ever i come off from a stop it wants to die unless i give it more rpms while riding out the clutch. sometimes when i come to a stop the rpms will dip to about 900-850 rpm and wants to die. if i want to run the ac forget about it. the idle will drop to 900-850 rpm and will want to die.another weird observation is sometimes when i let out the clutch the rpms should drop at a steady fast rate. when this happens the car feels like it is running extremly good and i have no problems. and sometimes they drop at a real slow rate and then stay at 2000 rpms til i come to a complete stop it goes back to idle, the car feels like it is lacking power and running rougher.i have done extensive searches and good info but still the problem is still there. i have the codes p0100 for the maf and p0400 egr malfuntion.i know the maf is bad bc i flooded the motor with a little water and there was a dropplet of water on the little wire. the motor ran great after i took out the plugs and flushed the engine. but the problem came back. here are the things ive checked or replaced:

1.iat sensor - new
2.new plugs and wires
3.new ect sensor
4.new injectors
5.new opti
6.new egr soloniod
7.cleaned tb and iac passages,
8. cleaned tps

Re: experts inside, if i cant fix this i am selling the z
 

If your MAF is bad or your EGR valve is stuck open you will definately have problems. After my engine rebuild it took my car two to three days to relearn the idle. The car ran good, but when I came to a stop it would try to die and surge for a while. It even completely died a few times, but after a couple days and a couple cold starts it started running great. Maybe your ECM just needs to relearn the idle. Also check for vacuum leaks and such. The first thing you need to do is find out why those codes are being set and fix those.

Re: experts inside, if i cant fix this i am selling the z
 

If youre still running the OBD 2 computer it may be giving you some fits . I would watch it live with a scanner and watch the sensor inputs , watch for anything erratic. Also you might just for $hits and giggles desensitize your knock sensor and see if it acts any differently, check grounds to the block for the ECM (drivers side front and pass side just below the head on the block).

watch your fuel pressure to ensure that its steady. If youre not required to have emissions testing you may play with deleting the EGR and stuff.

Re: experts inside, if i cant fix this i am selling the z
 

rpms are definately up there but if its wanting to die at 850 thats just nuts, my friend had the same problem when he put a new motor in, he let his camaro sit for a while and the fuel pump went bad, maybe a possibility

Re: experts inside, if i cant fix this i am selling the z
 

update, i went for a drive and found this out, when i turn on the ac at max cold, its runs alot better a night and day difference. the rpms drop like they should and come down really fast and doesnt hang up like when the ac is on are supposed to but right when i turn off the ac the problem comes back the rpms hang and they come down really slow. the only codes i have now is p0336 crank sensor, which ive already replaced but still get that damn code. p0100 is gone and p0400 is gone. the car still idles really rough. what is causing the car to run bad with the ac off. its the weirdest thing ive heard.

Re: experts inside, if i cant fix this i am selling the z
 

If I'm thinking along the right lines the car uses a seperate Block for A/C, it could be tuning, A switch to OBD 1 would remove the Crank position sensor. I had trouble with mine at first when I did all my mods, a switch to OBD 1 cleared up alot of the finickyness.

Re: experts inside, if i cant fix this i am selling the z
 

If the EGR is leaking and not closing all the way, it will idle like S**T. Sometimes cleaning it won't help and you will just have to replace it. It's typical on higher milliage cars.

Re: experts inside, if i cant fix this i am selling the z
 

You could manually push on the EGR valve and see if it changes anything.

Re: experts inside, if i cant fix this i am selling the z
 

double check all vacuum lines

Re: experts inside, if i cant fix this i am selling the z
 

Since car runs better under A/C load there is high possibility of MAP sensor failure or vacuum leak.

Re: experts inside, if i cant fix this i am selling the z
 

well i checked the egr by pushing in the diagphram with the car running, and it wanted to die, so it checks out ok, the map sensor i have is somwhat broke. the place where the bolts go broke off on the outer edge but i still managed to bolt it on and the clip to harness is broke but the pigtail is not loose. could this be the problem. when the ac is on i still get surging at about 1000-1600 rpm, and wants to fall on its face off the line. but it isnt bad as it was with the ac off. could the map sensor be causing me all ofd these problems. could the map give you a bad idle?

Re: experts inside, if i cant fix this i am selling the z
 

Yep, If your Map sensor isn't getting good vaccume or leaking near it, part throttle and idle WILL suffer.

Re: experts inside, if i cant fix this i am selling the z
 

well heres the story, the car still wants to fall on its face off the line and the idle is extremely rough, it shakes everything, it is loping really hard and this is just a hot cam. one question i heard that on cammed cars that when u have a tb airfoil in it obstructs the idle air passage. well i took out the tb air foil and ground out the little hole on the bottom to aboout 3 times the size it was. do i need to drill out the hole with a bigger drill bit to open up the hole a little bit.

Re: experts inside, if i cant fix this i am selling the z
 

If you ported the MAF did you have some sort of programming to go with it? If you are allowing more air through it, I believe the engine needs the information to correct fuel management.

Re: experts inside, if i cant fix this i am selling the z
 

yep the ported maf was programmed in the tune, it just baffles me why it would run better with the ac on than when it is off.the idle is just horrible it shakes the shifter like 2inches side to side but the car runs great at wot. i still have the lurching feeling at about 100-1600 rpms, at this rate i dont doubt that i will set fire to the car by the end of the night!!!! well i hope not!! :mad: :mad: :eek: :death:

Re: experts inside, if i cant fix this i am selling the z
 

one other thing i have comp r lifters, ive heard people have had problems with these, just a thought?

Re: experts inside, if i cant fix this i am selling the z
 

will your tune support unplugging the MAF? If so have tried it?

Re: experts inside, if i cant fix this i am selling the z
 

The PCM will generally add a few IAC counts when the a/c is turned on. That could be a factor in the change you feel.

You say your MAP sensor is messed up. Why don't you fix it? :confused:

Instead of floundering around and guessing, you need to get it on a scanner with help from someone that knows how to read/understand the data.

Re: experts inside, if i cant fix this i am selling the z
 

Replace the MAP sensor. Reset the computer. Pull off your TB and find the small hole located in the center line of the TB, just below the the blades in the triangular area. Find yourself a drill and bit a good 1.5 the size of that hole and drill it out. This will allow MORE air to bypass the IAC which seems to be slow to react based on the complaints your car wants to die when you turn on the AC.

It also wouldnt hurt if you got a scanner and Im not talking about a code puller but a real scanner like scanmaster or datamaster b/c you might be experiencing a vacuum leak or exhaust leak of some sort.

Re: experts inside, if i cant fix this i am selling the z
 

ive been trying to buy a new map sensor but im a broke college kid working full time (trying to support my habit, (camaros)and going to school full time. ive been short on money for sometime. ive asked people about a scanner and no one around has one that i know. i live in the houston area and i know someone has to have around here with all these fbodies running around.turbo z, my car runs better with the ac on not off, very weird!! :eek: shoebox, could u shortly explain how the map functions when the ac is on. is it ignored when the ac on? does the map sensor have anything to do with idle. i have no exhaust leaks, i looked at it with a fine tooth comb but i found something interesting, when i took off the intake elbow i was looking for vaccum leaks i came across a hose in the air injection system by the coil. there was a white looking valve or something like that,. there was a little nipple looking thing that looked like it was broke off and the hole was open, is this supposed to be like that?

Re: experts inside, if i cant fix this i am selling the z
 

While the car is running place your finger over the hole and see if it changes anything. I do beleive the line has vacuume on it , although I cannot visualize which line you are talking about.

Re: experts inside, if i cant fix this i am selling the z
 

it is the part that comes off the drivers side header, its comes before the header but after the air pump. its in the secondary air injection hose, right to the right of the coil and a liitle below it looking at it from the front end. well i plugged it up with some duck tape :eek: to test it temperarly, but i think it made it idle worse.

Re: experts inside, if i cant fix this i am selling the z
 

This perhaps?

The MAP sensor monitors engine load. If it is not working correctly, your engine won't either.

Re: experts inside, if i cant fix this i am selling the z
 

yep thats it shoe box, but it is almost all the way broken off, there is just like a little nipple instead of that longer piece in the picture. would that affect anything, does it need to be pluged or does it just stay open? someone said that in the pcm there is a seperate block that the pcm runs off of when u have the ac on is that true? is there 2 different tunes for ac on and ac off? does the map sensor function when the ac is on or does it ignore it?

Re: experts inside, if i cant fix this i am selling the z
 

NAw thats a vent , it doesnt need to be plugged. I'm leaning more and more towards the MAP, is it just that it doesnt seal good or is the bolt broken to where the thing wont go down properly etc?

Re: experts inside, if i cant fix this i am selling the z
 

it looks like the map sensor is kind of at a angle on the intake, its not flat not all the way flush with it. it is very slighty not straight with the intake. i tested it for vaccum leaks , i sprayed it with a water bottle and didnt see any change.