DutchManDann

I'll state my question here so people can avoid reading the novel below if they are short for time: when you swap a non-PI engine (1998) with a PI engine (2001 Windsor) in a 1998 GT, will the computer require a tune to accommodate the new engine?



I swapped out my tired 98 GT's engine with a 2001 Windsor block with around 40,000 miles on it. At first the engine had a misfire in it, but it ran nicely other than that. I drove it around for a bit, and then it sputtered a little and started running nicely. Now The new engine runs pretty much perfectly, except there is a small issue.

At idle, there is an occasional "misfire" (I quote because it is barely a misfire), it results in a small "poof" in the exhaust and the engine shakes a little bit. The misfire occurs every 2-4 seconds.

I was just wondering if the computer needs a re-tune to accommodate the new engine? I tried cleaning the MAF and the fuel injectors, but it could be possible that one of the fuel injectors is just broken.

*Also the check engine light sometimes comes on and reads "P0171" (System too lean, Bank 1) but then it shuts itself off rather quickly. Sorry about the paragraph of information.

Thanks

JC316

If it's detecting a lean system, that is likely the source of your misfire. Either the O2 sensor needs to be replaced, or you have a vacuum leak somewhere. It doesn't need a tune to run, tune just gets some more power.

DutchManDann

Okay thanks for the reply, I checked all the vacuum lines and I made sure everything was plugged in, and then the P0171 code went away so it may have been one of those two

sn95_331_GT_ yellow

FWIW an 01 motor should be a Romeo, not a Windsor...

how many bolts are on the valve covers?

DutchManDann

It's definitely a windsor, I put it in myself and I had to research a lot of compatibility stuff because my old engine was a romeo. The 2001 engine has an 8 bolt crank and 13 valve cover bolts. I know it's an '01 because the engine was rebuilt in '03 by ford and I contacted the Ford dealer about the rebuild and they confirmed that it's an engine out of an '01 Mustang GT

96GT226410

+1. If you had Ford double check, get the VIN, see if the engine code is an X (Windsor) or a W (Romeo).

Any luck with your "misfire" yet?

ESABATM

This is wrong...they are all X. Means V8.

DutchManDann

And the engine is without a doubt a Windsor, I might even have a picture of the W cast marks...

The misfire has gone away, but only when the car is warm. when the engine is completely cold, it still has the minor "poofing".

The way it runs when it is cold reminds me of when my old engine had bad spark plug wires. When revving at low rpms it would sort of "lose power" but then gain it again once past 2000ish.

When the car is warm, it doesn't do any of this. Very weird. The check engine light has stayed off for over 200 miles too, probably worth mentioning.

96GT226410

You are correct, I was told lies! I did some research and learned two things: The Windsor engines made it in some 2001 Mustangs and the engine code won't differ a Romeo/Windsor.

To the OP, sorry for causing any issues with your thread. Which ignition setup did you use (the coil packs or COP)? You say you used the Windsor "block", which heads are you running?

DutchManDann

No worries at all, as far as I know it's Windsor heads as well. This is not for certain however. The engine is completely stock, but it was rebuilt be Ford in 2003. I'm not sure what exactly was rebuilt but as far as I know the Mustang 4.6 wasn't being produced in the Windsor plant in 2003.

As for the ignition, I converted from coil packs to COP. I had to make a new wiring harness that connected to the the plug that plugs into the coil packs and runs to each of the COPs.