I did alot of searching, but haven't gotten an exact conclusio yet on this. I recently put an S4 block into my S5. I used the S4 LIM, and the S5 UIM and vac rack.

I go tthe car started, but it runs like crap and get hot quick. It sputter and backfirs and the idle surges like when the TPS is off. I did adjust the TPS, and now set the timing. The car is runnning better. BUt it still feels like it's one one rotor or something. I checked compression, good all across.

So, is there a common vacuum leak to occur when placing an S5 UIM on the S4 LIM and block? I ground the UIM only, to get the bolt on and drilled a new hole. It seemed to line up flush. Was there more I needed to do as well as far as grinding?

I can't think of any other place for a vac leak. All the vacuum lines are hooked up utoo. Any ideas on where I may have gone wrong? I'll start checking stuff as soon as I get an idea whee to look.

thanks

 

i am having this same problem but I have a s4 with both s5 intake manis, I just got my megasquirt and just finished building it. I am gonna put it in when I go back to my house friday, I think it has something to do with the coldstart, we will see.

 

I just have the S5 UIM right now, since I found it better to leave the S4 LIM on the s4 block. Let me know if you find anything though.

 

kk I will

 

gasket leaking? is it new? did u use anything other than a gasket? maybe the gasket got pinched when you were putting it together... also did u clean up surfaces before putting it back together?

 

The gasket has like 5k on it. not new, but it looked great. All the surfaces were cleaned. I was able to tighten down the header a bit more and I think I fixed an exhaust leak, but the car still runs like crap. Perhaps the gasket did get pinched. I really do not look forward to pulling the UIM off again, but I just may have to then.

The car backfires and stutters. Is that more common for a vacuum leak or a rich condition? I know my S4 had a rich/lean adjustment near the pressure/boost sensor, just ahead of the passenger front strut. Is there something like this on the S5 too that neads adjusting after changing engines?

 

remember to fit the S5 UIM onto a S4 block, you need to trim the block slightly, otherwise the VDI solenoid hits the block, and the manifold will not seat together properly.

And you should replace the gasket or add new sealant to it.

 

you reused the Gasket?

 

main piece of info is missing:

is this a TII or n/a?

 

Sorry, Its an NA. MArk, I had no Idea I needed to ground the S4 block itself! If the VDI solenoid is hitting the block, garaunteed I have a drastic vaccum leak from it! So, I take it I should just grind under the VDI then. I'll take a good look tommorrw.

I had just thought the UIM cleared Everything fine with The EGR removed and my S5 Fuel rail. I must've have just overlooked it...I searched but I thought by using the S4 LIM I wouln't need to grind the block. I did re-use the gasket. I used Permatex Right stuff with it. I used Right Stuff for my oil pan gasket and to aid the seal on the water pump with no ill results.

 

No not the VDI, the block... too much metal is there to remove from the VDI if you are using the stock S4 rotor housings and end plates.

 

it's just a quick thing to grind the block down so it sits perfect. You also have to bend the fuel rails and vac rails a little to make everything fit.

 

I meant grind the block, not the VDI. OKay, well I'm about to get started taking the UIM off again. I'll post up how it goes afterwards. The block is all S4 and wth S4 LIM. The rest is S5. I went premix and just strapped the OMP in the engine bay to keep the ECU happy.

 

I thought you had to get the s4 LIM portmatched with the s5 UIM for it to work properly?

 

That's somthing. I noticed the 2 smaller parts on the UIM that go to the S4 LIM are just a hare smaller diameter than the matching ports on the S4 LIM. Should I dremel these a bit to even them up? I could use the S4 gasket as a template like I did for the stud to come through.Or will it not really matter if they're a bit smaller?

 

Nice. So you switched over all of the s5 electronics?
I'm going to be using the s5 UIM with s4 LIM and TB so I can keep the s4 omp. The only think i'm still trying to figure out is how to get the one bolt that doesn't match up to work.

 

Yeah, I have an S5. The only thing I had to do any kind of work on was the engine water-temp sensor since the S5 and S4 blocks have a diffrent one that is not interchangable.To get that bolt/stud to work with the UIM and LIm, I used the S4 gasket as a template and just started drilling into my S5 UIM. Got a nice fit.

NOw I just need to figure out where I grind the block at to get a flush fit onto the LIM.

 

Oh, ok, so you dropped an s4 engine into an s5 car, gotcha. I thought you had put the s5 uim in an s4.
On the bolt I just wasn't sure if it would go into the actual inside of the intake. I guess not.