cozmo kraemer

I have a 94 with a street port, ported turbos @8-10psi, ungraded fuel pump w/stock injectors, downpipe, HF cat, exhaust, custom intake box....PFS purple is my management and is supposedly tuned for the setup.

Here is what happened. My idle has hunted since I got the car (month ago) sometimes bouncing a little but settling (most of the time) around 1000rpm, when the engine is hot. I installed a high flow cat into the mid-pipe and connected the air pump to make the car emissions legal. After I did this the hunting got much worse, bouncing from 600-1000 rpm constantly....car even started stalling.

I searched on here and found Damian's thread about adjusting the TPS sensor. I adjusted this to near perfect values and adjusted the idle air valve with the intake pipe off and the idle seemed to be pretty steady at around 900rpm. When I put the intake pipe back on and restarted the car. The idle began to bounce again.

I then fabbed up a set of grounding wires from extra stereo power wire I had laying around. I just made wires to replace the stock grounding wires...nothing more. This hasn't helped.

So I am asking for help on here. I read through almost every thread in the 10+ pages found when I searched for "idle" nothing really has helped me.

I was thinking of buying a Power FC or some other standalone to solve some of my issues. Would this help the idle or is it related to something else? How else could I trouble shoot the problem?

All help is greatly appreciated!

Regards,
Brian Kraemer

DaleClark

iTrader: (55)

Have you cleaned the ISC? VERY common culprit.

Dale

jd to rescue

iTrader: (3)

Me seconds that!

You can unbolt and unplug the ISC from the back of the UIM. I have found bits of gasket material and other strange things in the ISC valve mechanism that have hung it open. It is a bellows-type valve that is designed to move a plunger open and closed. Check to make sure the bellows are clear of debris and that nothing is blocking the plunger from closing.

cozmo kraemer

I dont exactly know where it is. I will go out and check to see if I can find it. If I can't I may need a little more guidance. I hope it isn't as hard to get to the mounting screws as it was for the TPS. Those were a pain!

Thanks for the idea!

jacobcartmill

iTrader: (6)

what is an ISC valve?

Bad_Karma7

Idle Speed Control

rajeevx7

iTrader: (11)

Once removed, spary it thoroughly w/ carb cleaner. This will eat most of the carbon buildup out of it. Drain it and stick a q-tip down in it and clean the spring and rod as much as possible. I have the PFS Purple and my idle is fine, so it shouldn't be your computer.

jacobcartmill

iTrader: (6)

i feel like such a noob in this FD section... someone kill me now

crosswound

its on the back of the manifold near the firewall its the only cheap white plastic piece take it off and turn your tps all the way to the right and move it back 1/4 and try to start up the car again and see if it hunts or dies down if it dies down turn it to the left some more until it fires up see if you have a hunting idle.

also set your pfc's values for the a/c e/l and whatever that other value was to 1200-1300 and turn off the idle/ignition control in the etc and turn off the 02 controller in there too.

worked for me my single turbo stopped hunting during all conditions when i did that a week later i hooked back up my isc and it still working good until the incident.

crosswound

if that doesn't work splice your a/c wire into that other wire i forgot which wires it is but its in the pfc sub forum i noticed mine hunted everytime my cooling fans kicked in when i did that it wouldn't hunt when they kicked in don't ask me why.

jd to rescue

iTrader: (3)

Not quite, but it is still a knuckle buster. I find a 1/4" rachet w/ the shortest extension possible and a 10mm socket works best.

Look for it on the back underside of the UIM. It has a long cylinder (approx. 3") w/ a trapezoidal-shaped mounting face at one end.

jd to rescue

iTrader: (3)

He has the Peter Ferrel (PFS purple)set up, not a Power FC.

jd to rescue

iTrader: (3)

I was going to say that its the by-pass control valve to you, but that is not quite correct. It is the AWS on the FD.

crosswound

my bad too be honest i thought he had a pfc.

cozmo kraemer

is it the long black cylinder with the denso emblem and a white clip. A black wire with a white stripe and another with a green stripe?

If that is it then I should be able to get to it without too much trouble. I will pull it out tonight right when I get home from work and see if that fixes my problem.

Today at lunch I was waiting at a light and it stalled out again. I hate that!

On another issue...would the Power FC clean up a lot of partial throttle hesitation I am getting. A 3000rpm pause that seems to come anywhere from 2800-3900rpm?

This car was supposed to be pretty well set up and it has given me headaches from day one!

rajeevx7

iTrader: (11)

Again, many of us are running the PFS w/ out problems. But, the PFC is a great route if you want to go wild in the future.
Add more 4guage grounds, clean factory grounds and get a good alt. That will probably help the most w/ the hesitation. Are you still seq?

cozmo kraemer

Yeah I am still sequential. I have no want for any more power than is already there. I just want the car to run as well as I know it can. I track drive every car I have owned and this was suppose to be no exception...but with the hesitation and idle issues I have to really sort some things out before it sees the track. The ground wires really helped the hesitation at gear changes. But i still have a throttle transition hesitation as well as this REALLY annoying idle issue.

Also I figured the Power FC would be a better tool for tuning a more linear powerband. I see a lot of nice charts tuned with the PFC....my car seems to have a nonlinear pull....even though the boost seems to have pretty perfect transition.

On my boost gauge...goes .5 bar to .45 back to .5 @4500rpm

zonblitz

iTrader: (9)

Cozmo, I have IDENTICAL issues and I have a PFC... I have been chasing this since before Hurrican Katrina... ok well I took a break but now at it again...

I can tell you 2 things that have helped but not yet fixed the problem, adjusting the little plunger with the white **** that should touch the throttle... can't think of name, and taking a little slack out of my very loose throttle cable..

I have read forums and tried bumping up my idle values, this did not help. After I was recently advised by Brian at Rotor Sports Racing in NC who built my engine and sold me the PFC, I lowered them to the 900 range.

some days its perfect, no hunting, no killing... other days it will kill 5 times in a row at redlights.

I checked the valve on the back of the UIM and it seemed to be working fine, no sticking or anything. But I will try resetting the TPS back to close and open up 1/4 turn. Also will try turning the idle in the etc. area (already had tried o2).

mad_7tist

hey coz .5 bar is low only like 7.x psi should be 10 psi stock. sounds like you have a control system problem or a leak. wg etc..

cozmo kraemer

It was probably about .1 higher before the cat install. And it would creep as you approached redline. Now the creep is gone but the boost is lower. What are the steps to troubleshoot that?

When I bought this car it was assured that it was in tip top running condition by Seth from Pure Sports in Ramona. I have had NOTHING but trouble with it since I rolled out of his parking lot. Leaking oil supply line to the turbo, leaking oil pan on this freshly built engine, a burnt out knock sensor (not functioning at all), burnt out and melted grounds, this hunting idle problem has cropped up, there is the hesitation....the rear suspension needs to be badly freshened. There is no Radiator ducting, the list goes on and on...not to mention the kicker....a fraudulent dyno chart they gave me showing me the car's power. I have since uncovered the donor and they aren't even closely related.

I asked him on more than one occation if the car was "track ready" and if not what needed to be done. I would expect someone from the circle to be honest....I flew out there and nothing was as described but I was in a tough spot and pressured into the sale.

I really just want to get the car running right! I have owned the car for over a month and driven it 200miles because it is constantly down. I realize a lot of you experience that, but I paid a premium for this car specifically to avoid that....

This has just been a horrible experience.

jd to rescue

iTrader: (3)

Sorry to hear that. Just stick with us, keep updating us with your progress and we'll get you running right.

YOU ARE GOING TO LOVE THIS CAR WHEN IT IS FINALLY SORTED OUT!

FLA94FD

I have a similar problem, been to the shop 3 times and only gotten worse. It's going back in Monday and I don't want to see it again until it's fixed. The problem started after installing intercooler, fuel pump and 850cc secondaries. First which may have been unrelated was stalling on cold starts once. Then about two weeks later the car stalled when dropped into neutral from 40mph. Then after going to the shop primarily for the water pump and some adjustments a rebuilt check valve (the aluminium one under the UIM) was put in. Then the car developed 500-1500 hunt after warming and still stalls when coming down from 2000+ rpm.

When it doesn't hunt the idle is rock solid at 900 rpm.

JD, I hear you but every new problem sense I rebuilt this car takes me one step closer to wishing I hadn't. I've been around performance cars all my life and never had anything with some so many problems.

cozmo kraemer

Well I took off and cleaned the ISC and it didn't fix my problem. The new clean ISC is on and the car hunts for idle just like it did before. The strange thing is that nothing changes if you unplug the ISC all together. Does that mean the ISC itself is bad? Even when it is unplugged the car bounces idle from 600-1100 rpm. This has me pretty pissed.

DaleClark

iTrader: (55)

You may need to play with the idle adjustment screws. Hit up the shop manual - there's one under the entrance to the throttle body that's the fine adjustment, and another on the throttle body linkage that's the coarse adjustment. If the throttle is sticking open slightly you could have some problems. Also make sure to double-check the TPS setting if you do adjust the coarse setting for the throttle body - adjusting that will alter the closed position on the TB.

Dale

Quickfini

iTrader: (6)

Did you check for vacuum leaks yet? I had a hunting idle and mine was caused by a dead LIM gasket.