Alex S

Hey guys. I need some opinions of something to try ! Ive ran out of stuff on my end. Like the title says. Once I'm in first. And the clutch is no longer pressed down. The car revs itself to 2500 rpms. And drives itself. Like I'm pushing on the pedal. Once I press the clutch in to shift into second. The rpms DO NOT drop down to 1k. It sits at 2500 rpms which makes for a hard time shifting into second lol. Once in second though. Drives fine. And all the other gears are fine as well. This is only in first gear. I do have a zzp ECU tune. And have the 50% boost reduction. Idk if that could really be messing it up or not. Plus I am tuned for, my 42# injectors. 3.0 Pulley. And ZZP 3" Inake.

On a side note. Could be related to this problem. When I come to a stop. EVERY SINGLE TIME at about 2mph with the clutch in. The car will just rev itself up like I just tapped the throttle. Anywhere between 1500-2500 rpms. Then go back down. Which makes me look like a damn tool at stop lights. Lol.

Things ive tried
-Replaced all vacuum lines and checked for leaks
-Replaced throttle body
-Replaced MAF sensor
-Replaced belt which was slipping slightly causing it to squeak. I thought this was gunna fix the issue.

I appreciate any type of insight what so ever ! As I'm stumped. Thanks guys.

Sharkey

iTrader: (1)

did the problem start right after the tune or some mods?

Alex S

That's the thing as well. I don't know. Because I bought the car and put a motor in it. And got the zzp ECU and the mods all at the same time because it wouldn't run otherwise. Figured if Im ordering the ECU I might as well get some mods for the time being and have it tuned for them. However I don't see how the small mods I've done could really effect it. Cuz my buddy has practically the same setup. Along with a lot of people I'm sure.

jdbaugh1

iTrader: (1)

What's the 50% boost reduction you mention? I would say it is most likely your tune but could also be your MAP sensor. If your car is rolling it will stay at high rpms even if you are in neutral correct? Then when you actually bring the car to a complete stop will your rpms finally drop back down? Do you have a different throttle body than stock?

Alex S

the 50% boost reduction is something zzp offers to make the car easier to drive suposoably since I was just learning how to drive stick once it was together. Haha. And in first gear. Yes. If I push the clutch in the car will still stay at around 2500 rpms. But then once I shift to second. If I push the clutch in. The rpms will drop like they are supposed to. If I come to a stop. From first. Breaking does cause it to forcefully drop back down. But then it does that weird ass throttle blip thing.

jdbaugh1

iTrader: (1)

I bet it's in your tune and has something to do with the boost reduction. Also car shouldn't be harder to drive with boost on 3.0" pulley just gives you more power when you need it. I'd tell ZZP to take your training wheels off and see how it runs then.

Alex S

I agree completely. They claim in doesn't have anything to do with it. But who knows. Just sucks because I'll have to ship the ECU back to them and they charge $40 for any adjustments. Pain in my ass. Lol. I just need Hpt.

ECaulk

iTrader: (6)

I'm just gonna throw out a hair brained comment, since you said it's a new engine you dropped in, did you check for vacuum leaks? Sometimes the rpms can act funky when there is a vacuum/boost leak.

jdbaugh1

iTrader: (1)

I personally saw these same symptoms when we were first dialing in the tune on my car. My tuner said he was adjusting the computer to trick it into thinking the throttle body was smaller than it actually is so it would open up more and allow my car to idle with my ZZP S2 cams. While we were hunting for that sweet spot my car would act like yours and would even act like a runaway diesel when I put it into neutral. It would rev up and then come back down revving up a little less each time. Then once we got it closer the symptoms were close to yours. I could press in the clutch while the car was rolling or put it in neutral and as long as the car was rolling my rpm would stay up or rev up and hold around 3,000 rpm. That is why I asked you if you let your car come to a complete stop in neutral if the revs would come down then because that's the way mine was after we got it out of the completely wonky range.

The other time I had really weird throttle and rev hang issues that were similar was when my MAP sensor was screwed up. It wasn't bad enough to throw a code but it made my throttle do really strange things like hang and rev out when I pushed in the clutch.

Alex S

yes. Haha. That's what my first idea was. I replaced al the lines and put a hose clamp on each connection just to be sure. At first, the boost was acting up because the hoses I used were too small on the supercharger. But the boost issue went away after I replaced all of them.

Alex S

hmmm. I may have to look into getting the tune looked at then. Im hoping zzp will take a look at it for fairly cheap. As I live only an hour and 40 mins away. So far, they seem to not think it has anything to do with there ECU they can tuned for my mods.

Sharkey

iTrader: (1)

the 50% boost reduction is a setting in the ss/sc ecm that will open the bypass valve part way in 1st gear to drop the boost a to make it smoother. the factory tune uses it, some people like to remove it to make the car seem more snappy. this isnt something wierd that only zzp does, its a factory table in the ecm and wont do anything to cause a high rolling idle.

the ecm has a rolling idle mode so when you go above 2 mph it keeps the idle a little higher. iirc my car will idle around 1300 rpm when rolling. now we dont actually have access to these settings in hp tuners, so they couldnt have gotten messed up. however there are other things that can affect this, if they changed the throttle body settings for some reason, or the idle ignition tables can cause wierd things.

now im not jumping on the tune yet, but it could be an issue. go over everything else first, check for vacuum leaks from the air filter all the way to the cylinder head. did you clean your throttle body while it was apart? and if you did, did you move the blade by hand? the throttle bodies are sensitive and can be damaged, you may have a bad throttle body. if you can find another one you can use to test with it would be worthwhile.

Alex S

checked for vacuum leaks. Even sprayed brake clean over basically every area checking for change in idle. Nothing. I've also swapped to 2 different throttle bodies. One of which was my buddies that works 100%. That's what's having me so stumped. Only in first gear this happens. Or in neutral leaving first gear.

ECaulk

iTrader: (6)

Did you make sure the intake manifold is sealing?

Alex S

I mean. I don't see why it wouldn't be. It has a brand new gasket. I can double check to make sure everything seems okay though. And wouldn't that kinda effect all rpms and gears though if it was leaking there ?

ECaulk

iTrader: (6)

It can leak there, not sure how much it affects things I know leaks are more pronounced at idle or low rpm and low speed.