PI head swap Issues: Rough Idle

4.6Stangrage · May 14, 2015

My PI head swap began a year ago and I have not been able to completely finish the project until now. I had several issues in the process of finishing the project which halted the project. I had issues such as a major accident as well.

Well, enough with the excuses here is what is going on.

The engine starts right up without issue. during idle it almost seems like it is misfiring. It runs pretty rough but not all the time, there are moments of smooth idle. Off idle it runs pretty smooth.

I dont have any vacuum leaks
the gas is over a year old, I have octane boost in the gas. (possible issue?)
No Stored codes, no pending codes

It seems like i may have an issue caused by low octane and the fact that i am running with old gas. I have 3/4 of a tank so I dont think adding high octane fuel will deliver drastic results.

That do you guys/ gals think?

Burninriverdiver · May 14, 2015

It helps to start simple, which I'm sure you've already gone over these. However most of my issues are from dumb little things I already checked lol... Double check the spark plug boots wires are correctly seated, make sure the firing order is right, all sensors and fuel injectors are properly connected etc... Little things can cause some big headaches. Secondly, you will need to run higher octane fuel from my understanding with the added compression from the PI heads on a NPI block (this may be the issue) and more than likely it needs a tune. Good luck and tell us what you find!

lwarrior1016 · May 14, 2015

I really don't think it will need the higher octane, I mean a PI swap doesn't yield BIG compression. Its only going to be like 10-10.5:1. That's what the 03 mach 1 came with and it runs fine on 87 octane. I would start with everything Burninriverdiver said, plugs, connections, proper firing order, all that jazz. Then, to be completely utilized you should get a dyno tune.

4.6Stangrage · May 15, 2015

Burninriverdiver said:
It helps to start simple, which I'm sure you've already gone over these. However most of my issues are from dumb little things I already checked lol... Double check the spark plug boots wires are correctly seated, make sure the firing order is right, all sensors and fuel injectors are properly connected etc... Little things can cause some big headaches. Secondly, you will need to run higher octane fuel from my understanding with the added compression from the PI heads on a NPI block (this may be the issue) and more than likely it needs a tune. Good luck and tell us what you find!

Yeah I am going to buy new wires. Ill start off with that. It seems that most of them are not fully connecting to the plug. Thanks for the suggestions!

Willis_98GT · May 18, 2015

4.6Stangrage said:
Yeah I am going to buy new wires. Ill start off with that. It seems that most of them are not fully connecting to the plug. Thanks for the suggestions!

May be time for a cop conversion. I used to beat myself up with wires back in the day. having coils that you can bolt down will make your life much easier. Trust me

Edit : You'll have to run 93. Run through that gas and fill back up with 93 and report back

4.6Stangrage · May 19, 2015

I went through the basics and I ended up finding a spark plug with cracked porcelain. I replaced all 8 plugs. I let it idle for quite some time and then drive around the block for a few minutes. The stang ran great! I noticed a significant difference in power. Sadly, I drove it on the highway and everything went to a screeching halt. Literally. I heard a squeel for a few seconds and the engine died. It would not even turn over at all. I have a feeling that the lower end is seized. It had plenty of oil and it did have pressure. I cant explain how this happened, the engine was solid (besides a blown head gasket, and no there wasnt any oil to coolant contamination) before I did the PI swap. looks like I will be getting a new block or rebuilding this one. Hmmm I am possibly thinking of a Teskid block but i need to learn more about them.

lwarrior1016 · May 19, 2015

That's a big time bummer man. Did you let it cool off some and see if the engine would turn?

PS: there is a bunch of good info on the different blocks that we can use right here in the 2v section stickies. Also, don't hesitate to ask questions. There are some very intelligent guys here that can help out, and I will do my best to help when I can.

Good luck, and keep us posted.

96blak54 · May 19, 2015

Oh this guy ^ is being modest about himself.

Remove the accessory belt. Big possibility its the a/c compressor....unless your absolutely sure its the engine. A locked up a/c compressor will will do exactly as you described.

Willis_98GT · May 19, 2015

96blak54 said:
Oh this guy ^ is being modest about himself.

Remove the accessory belt. Big possibility its the a/c compressor....unless your absolutely sure its the engine. A locked up a/c compressor will will do exactly as you described.

+1

Also if you jumping into the Teksid world be great for you. I went that route and with a tubular K you can save lots of weight on the front.

96blak54 · May 20, 2015

+1
Besure to use a known good running engine before rebuilding a taksid. Also your machinist MUST have modular teskid experience. Use a machinist known with success.

4.6Stangrage · May 20, 2015

Thanks for the replies! Yeah, I took off the belt and went to crank it over and no luck. I will have to tear it apart as soon as possible. I am very interested in using a teskid setup. I need to read up on what components I plan to use. I would like to use the heads I am currently using (the only bad thing is that they are Windsor PI heads). I do have a set of NPI heads as well. Ill have to look for a machinist around where I live. I live in northern California.