I have a 97 maxima with a 01 vq30dek I did the swap about a year ago but have alwayd had cold start issues. I always have to give it gas on the initial start up of the day. And this only happens on cold days around like 20 -30 degrees. If anyone has any solutions to this problem I would really appreciate it. I use the 4thgen iacv with block off plate.

 

I had the same problem until I went to a 5/8" hose. Now I can use my remote start again.

 

Do you use the 4th gen iacv with stephen max adapter plate ? you just changed the 3/8" hose to a 5/8" hose on the same barb and it works fine in the cold now ?

 

I've done two swaps with DEK manifolds into 4th gens using that IACV adaptor plate. One had cold start issues and the other did not.

I wasn't given time by the owner of the first car to figure anything out just to get it running. Whereas the second car I had the luxury to take my time and it starts/runs just fine.

What I did different was to drill and tap larger barb connectors onto the DEK manifold. These barbed connectors are the same diameter as the ones on the IACV adaptor plate.

With the first swap I put the hoses onto the smaller plastic nipples on the DEK manifold and converted them with adaptors to fit onto the large barb of the IACV adaptor plate. The second swap I used all the same size hose and fittings for the IACV setup and the car has no issue with cold starts. All other stuff done on those two swaps were the same.

My guess would be the hoses were to small and not getting enough air into the engine on start-up and idle. The second swap doesn't have that problem, it starts so nicely some org guys don't believe that it has a DEK swap until he opens the hood.

So I would advise to go with hose and fittings that are the same diameter as the barb on the IACV adaptor plate. Also I think they are all 5/8" IIRC, it's been a while since I've done these swaps.

 

The larger hoses definitely help a lot, but in some cases they still don't get rid of the cold start issue. The problem with that issue is that there are too many variables given your exact setup and how you have things placed. I would also recommend putting the IACV as close to the manifold as possible as the farther it is away (and likewise the longer hose you have to use) seems to hurt it as well. In other words, the shorter the hose the better.

So try putting on a larger diameter hose (and of course use bigger fittings with it as prescribed above) and try relocating the IACV to as close to the manifold as possible. If you still have issues, come back to us. Also, be careful with the placement of the port for the IACV on the manifold as well. Ideally you want it near the throttlebody.

 

on the shortest IACV hoses possible, I forgot to mention that. Also put the hose right near the TB as mentioned.

 

I just thought i'd contribute to this thread as i'm REALLY not understanding this cold start issue.

I've done 6 DEK swaps. Varying between 2000-2001 motors. I ALWAYS use the 5th gen IACV, solder all my connections and sand down the mating surfaces between the engine and tranny. First turn of the key every single time. I've done the swap on my daily driver and my car started RIGHT up in 16 degree weather this season, held at about 1k-1.2k rpm, warmed up and lowered down to 750-800 as it warmed up.

Why are you guys using the IACV adapter plates?

 

to the OP, are you sure your IACV is working correctly?

 

^^^ Was gonna ask the same for all the guys that included an IACV block off plate. Did you guys even TRY the stock 5th gen IACV? The MOST you have to do is loosen the TB fast idle screw or tighten it a bit to get it perfect. Then you're done.

I have no issues with AC on and wheel turned all the way to one side...5th gen IACV is pretty good.