Installed PI intake...now have bad miss

[cobra2798]

Installed my PI intake from my old motor onto the new one and now the car has a bad miss at idle, sounds like it has some big cams in it. changed plugs, wires, coil packs also and no difference. What are some other things I could check? the new Motor was running fine with the NPI intake but it had a crack in it. Any help would be great. thanks.

 

[02nightmaregt]

all vacume lines connected?

 

[CobraRed_96_GT]

Sure the right wires are going to the right places?

 

[cobra2798]

Do believe everything is right. Im lost

 

[bhuff30]

I'd guess it is related to a vacuum leak. At higher rpms or under load, the miss goes away? Look for a vacuum leaks around where the lower and upper intake meet. You can use starter fluid to find the leak. The engine will rev a little faster if you spray starter fluid in the area of the vacuum leak.

 

[98COBRA281]

i was having a horrible miss, and backfires, i had the to 2 back wires on the passenger side in the wrong place....

 

[lazerred02]

Did you try unpluging each injector one at a time to see if it runs differently or stays the same? Do the same with the spark plugs, just make sure that you use some well insulated spark plug wire pliers so you don't get knocked on your tail.

 

[Winters98GT]

did you take pictures? That always helps me.

Take it apart, minus the intake, and do it again.

 

[screamin gt]

Did you try unpluging each injector one at a time to see if it runs differently or stays the same? Do the same with the spark plugs, just make sure that you use some well insulated spark plug wire pliers so you don't get knocked on your tail.

but its not throwing any codes at all??

 

[lazerred02]

but its not throwing any codes at all??

I have seen stranger things happen, once it is driven it may start to throw some codes.

 

[cobra2798]

I have no CEL showing and the car has not left the driveway yet. After the install should I have disconnected the battery to reset the ECU? Plugs, wires, and ciol packs are new.

 

[cobra2798]

i was having a horrible miss, and backfires, i had the to 2 back wires on the passenger side in the wrong place....

Can you go into more detail on this? Which wires? Got a pic?

 

[98COBRA281]

Can you go into more detail on this? Which wires? Got a pic?

sorry no pic, but on my car those 2 back wires on the passenger side were the same lenght, so i could not tell exactly where they went, and i accidently reversed them, it drove me CRAZY trying to figure out such a stupid problem....

 

[cobra2798]

sorry no pic, but on my car those 2 back wires on the passenger side were the same lenght, so i could not tell exactly where they went, and i accidently reversed them, it drove me CRAZY trying to figure out such a stupid problem....

Im gonna check that out. Now the wires you speak of are coming of the passenger side back of the intake? Plenum?, TB?

 

[bhuff30]

You don't have a CEL yet because you haven't given the car a full heat cycle. After driving the car for a while, the computer will do some tests and diagnostics and most likely throw the CEL on after that. The same reason why clearning the codes and going to the emissions check station doesn't work.

 

[Greenscobie86]

I just did this swap this weekend...

One question for you: Did you make ABSOLUTELY CERTAIN that there are no remnants of water/coolant/carb cleaner in the plug holes. It took me a good 10 minutes to blow all eight of them clean with an air hose after which I got in there with a rag and my finger.

I'm sure it is something very simple... One thing I'll tell you though, you will have a nice grin on your face when you take it out and romp on it for the first time with the PI intake....

 

[cobra2798]

I just did this swap this weekend...

One question for you: Did you make ABSOLUTELY CERTAIN that there are no remnants of water/coolant/carb cleaner in the plug holes. It took me a good 10 minutes to blow all eight of them clean with an air hose after which I got in there with a rag and my finger.

I'm sure it is something very simple... One thing I'll tell you though, you will have a nice grin on your face when you take it out and romp on it for the first time with the PI intake....

You hit the nail on the head. We did the swap on friday and there was water/coolant in some plug wells that we used the air hose on to clean out, however that did not seem to work. Today I went out and started it and she is purring perfect! I think it just needed some extra time to dry out. I know the fealing of the PI intake, this intake is off my old motor that I blew up, used motor I bought had a cracked NPI intake but I got the motor for next to nothing so I had to do it. Anyway she is up and running.

One more thing, I notice the car has a little deeper, smoother exhaust note. Car has the same exhaust setup but the motor is a 98, do they sound any different? I heard the 98 motors had different exhaust manifolds?

 

[badstang02]

Hey,dude..i just wanted to ask if you put the pi heads on your car,i didnt see it on you rmod list,and if you didnt i would suggest you get those cause,the car wont run right without them.and I know its head swap and can be a pain in the ass,but you'll probably pick up a few extra horsepower to,because it will bump up the comression on your older short block,i did the same thing on a customer of mine's car and that was the problem...its worth a shot,man..latter

 

[mustangman9812]

Hey,dude..i just wanted to ask if you put the pi heads on your car,i didnt see it on you rmod list,and if you didnt i would suggest you get those cause,the car wont run right without them.and I know its head swap and can be a pain in the ass,but you'll probably pick up a few extra horsepower to,because it will bump up the comression on your older short block,i did the same thing on a customer of mine's car and that was the problem...its worth a shot,man..latter

his car will run fine without them, I dont understand your logic here.

 

[cobra2798]

his car will run fine without them, I dont understand your logic here.

I dont understand either, car runs strong. All that work for an extra 10-15whp is really not worth it to me, maybe someday but im happy with it now. Its a DD so im not looking to make it much quicker.