Black Smoke after Intercooler Install - Help!

[NJ KZJ78]

Hey gang -
Yesterday installed a front mount air to air Garrett intercooler on the 1996 KZJ78. Routed the pipes through the old horn spaces and through the back. Bought a throttle adapter for the connection to the air manifold on the passenger side and it came out really clean. Pic attached.

Everything is hooked up and clamps are tight. I start her up and she has a really rough idle and black smoke coming out of the tailpipe. This never happened since i’ve owned her. I went back and tightnes clamps, and ran soapy water over pipes to detect if any leaks. Couldnt find any.

NOTE: i have an EGR delete. Removed it last year. I do not have a manual boost controller or boost gauge installed.

I am hoping it is something simple. The only thing i can think of is the intercooler is a bit more than i need, but an oversized airflow wouldnt do it, would it?

Has anyone run into this problem? Or know enough to advise what this might be or what I should do next?

Thanks guys

 

[AVL KZJ78]

Hey gang -
Yesterday installed a front mount air to air Garrett intercooler on the 1996 KZJ78. Routed the pipes through the old horn spaces and through the back. Bought a throttle adapter for the connection to the air manifold on the passenger side and it came out really clean. Pic attached.

Everything is hooked up and clamps are tight. I start her up and she has a really rough idle and black smoke coming out of the tailpipe. This never happened since i’ve owned her. I went back and tightnes clamps, and ran soapy water over pipes to detect if any leaks. Couldnt find any.

I am hoping it is something simple. The only thing i can think of is the intercooler is a bit more than i need, but an oversized airflow wouldnt do it, would it?

Has anyone run into this problem? Or know enough to advise what this might be or what I should do next?

Thanks guys



View attachment 3963024

View attachment 3963025

The presence of the intercooler circuit would not cause those symptoms, even if your IC is oversized. Any leaks at joints will only be evident under boost, not at idle or low load, and a boost leak would not cause your idle problems either. I might look into your throttle body adapter- Trundles lists it for non-egr throttle body applications, and your KZJ will Have EGR. Hard to tell from their website pics what their adapter does over the EGR butterfly in the throttle body. If it is a flat plate might it be interfering with the butterfly shaft(s) and somehow preventing the TPS from registering correctly? Also, how did you attatch the throttle linkage that used to be mounted to the crossover tube? Does your mount let the TPS shaft move correctly?

 

[NJ KZJ78]

The presence of the intercooler circuit would not cause those symptoms, even if your IC is oversized. Any leaks at joints will only be evident under boost, not at idle or low load, and a boost leak would not cause your idle problems either. I might look into your throttle body adapter- Trundles lists it for non-egr throttle body applications, and your KZJ will Have EGR. Hard to tell from their website pics what their adapter does over the EGR butterfly in the throttle body. If it is a flat plate might it be interfering with the butterfly shaft(s) and somehow preventing the TPS from registering correctly? Also, how did you attatch the throttle linkage that used to be mounted to the crossover tube? Does your mount let the TPS shaft move correctly?

Hey @AVL KZJ78 , thanks man. so here is where we are at: we bypassed the intercooler to see if the intercooler was the issue. We also did an air test and the flow was great. So we eliminate the intercooler being the problem.

Next: there is a small butterfly that remains from when we deleted the EGR system. It has two small solenoids on it. We found it was rubbing on the new trundles adapter we installed. We adjusted it slightly and even used zip ties to mimic that being removed. When we ran the engine it still emitted black smoke.

We tested for air leaks amongst all pipes. Everything is sealed tight.

We removed the new trundles adapter, and reinstalled the air intake pipe and disconnected the intercooler pipes… as if it was back to stock form. The engine ran great! No black smoke.

To your point, The only thing we are now thinking is the trundles adapter covers a small little hole at the throttle body/intake point. Perhaps the adapter we are using is the issue.

Suggest on next steps?

 

[AVL KZJ78]

Hey @AVL KZJ78 , thanks man. so here is where we are at: we bypassed the intercooler to see if the intercooler was the issue. We also did an air test and the flow was great. So we eliminate the intercooler being the problem.

Next: there is a small butterfly that remains from when we deleted the EGR system. It has two small solenoids on it. We found it was rubbing on the new trundles adapter we installed. We adjusted it slightly and even used zip ties to mimic that being removed. When we ran the engine it still emitted black smoke.

We tested for air leaks amongst all pipes. Everything is sealed tight.

We removed the new trundles adapter, and reinstalled the air intake pipe and disconnected the intercooler pipes… as if it was back to stock form. The engine ran great! No black smoke.

To your point, The only thing we are now thinking is the trundles adapter covers a small little hole at the throttle body/intake point. Perhaps the adapter we are using is the issue.

Suggest on next steps?

As suggested in your other thread, I would remove the EGR (or both) butterflies from their shafts, and if this does not work you will have to use an adapter (or cut the stock crossover) that has a provision for the EGR airflow circuit.

 

[kgrove]

The next couple generations of 1kz powered Prados had a top mounted intercooler. Could you source one of those and adapt that for your front mounted IC? I assume those would accommodate the EGR butterfly. You could possibly source a used one from Ebay Australia, though many of the vendors there don't ship to the US.

 

[bj70bc]

thought this was solved.....

 

[NJ KZJ78]

As suggested in your other thread, I would remove the EGR (or both) butterflies from their shafts, and if this does not work you will have to use an adapter (or cut the stock crossover) that has a provision for the EGR airflow circuit.

@AVL KZJ78 Ok so you are saying if we remove the small butterfly and use the trundles adapter with the blank plate that covers the butterfly air hole, then it will alleviate the black smoke?.Thank you. We are going to try to remove the butterfly today and see if that works per your suggestion. Fingers crossed
If not then cut the stock
Crossover

 

[Tanner H]

@NJ KZJ78 Yep that shouuuuuld solve your problem.

removing the little plate can be frustrating as you dont have a ton of room to work with in there while the throttle body is still on the truck. the valve rotates up (as shown in the photo below)

people have stuffed a clean rag in the intake underneath the plate to keep debris from falling into the intake. from there, you can get creative with removing the heads of the screws. dremel, file, chisel, tiny hacksaw, etc... once the heads are gone, the plate will come off easily. you can now rotate the crossbar by hand and use tiny vice grips to back out the rest of the screws.

Once the plate and screws are gone, you can leave everything else intact.


Keep us posted. I feel like we are in the home stretch here.

 

[GTSSportCoupe]

Removing throttle plates (and EGR) is the best thing you can do for a 1KZTE and 2LTE.

If not removing throttle plates, the small throttle must be forced open permanently (and not blocked by intercooler kit parts).

 

[NJ KZJ78]

@NJ KZJ78 Yep that shouuuuuld solve your problem.

removing the little plate can be frustrating as you dont have a ton of room to work with in there while the throttle body is still on the truck. the valve rotates up (as shown in the photo below)

people have stuffed a clean rag in the intake underneath the plate to keep debris from falling into the intake. from there, you can get creative with removing the heads of the screws. dremel, file, chisel, tiny hacksaw, etc... once the heads are gone, the plate will come off easily. you can now rotate the crossbar by hand and use tiny vice grips to back out the rest of the screws.

Once the plate and screws are gone, you can leave everything else intact.


Keep us posted. I feel like we are in the home stretch here.

View attachment 3965317

Thanks man. I think we are almost there. We removed the small butterfly and put back on the trundles plate. Still black smoke/soot! Even removed the intercooler and put a straight pipe in and still black smoke. Really didnt want to cut the crossover intake pipe in case we need for future. So, to be creative we drilled a half size hole in the blank plate section of the trundles adapter to mimic the stock crossover pipe and allow air to flow. Kept the small butterfly off. We fired her up and she hummed beautifully. Now we are going to enlarge the hole on the trundles adapter, keep the butterfly off entirely, and let her fly.

Thanks to you @Tanner H @AVL KZJ78 @bj70bc and everyone on this forum. I hope this post will serve many of you in the future who plan to do this much needed intercooler job. The adapter route is definitely the route to go to keep it clean so long as you can navigate the throttle/butterfly step.

 

[NJ KZJ78]

Thanks man. I think we are almost there. We removed the small butterfly and put back on the trundles plate. Still black smoke/soot! Even removed the intercooler and put a straight pipe in and still black smoke. Really didnt want to cut the crossover intake pipe in case we need for future. So, to be creative we drilled a half size hole in the blank plate section of the trundles adapter to mimic the stock crossover pipe and allow air to flow. Kept the small butterfly off. We fired her up and she hummed beautifully. Now we are going to enlarge the hole on the trundles adapter, keep the butterfly off entirely, and let her fly.

Thanks to you @Tanner H @AVL KZJ78 @bj70bc and everyone on this forum. I hope this post will serve many of you in the future who plan to do this much needed intercooler job. The adapter route is definitely the route to go to keep it clean so long as you can navigate the throttle/butterfly step.

 

[Tanner H]

Welp I cant say i understand why it was still blowing smoke after removing the valve...but glad you figured it out haha.

 

[AVL KZJ78]

Glad you have found a solution. I am trying to understand this. I think it makes sense if you have NOT removed the large butterfly- with the large butterfly closed, and the flat portion of the Trundles adapter blocking air flow through the passage withe the small butterfly, the engine can't get enough air to run smoothly and goes rich, causing black smoke. If all this is correct, everything should work correctly with just the main butterfly removed, as there would be no restriction to airflow at any throttle position.