Engine/Transmission (1994 - 1998) Modded 94....low power???

[TJarecke]

I cannot get my truck to make power. No smoke either.



Here is the list of mods;

Aeromotive a1000 fuel system with 1/2 draw straw to dual feed 3/8 lines to the pump. Custom filter setup, no factory filters. Making 40psi and lots of fuel when disconnected from the pump.

DDP4s

DVs (custom slightly bigger than 191s)

100 plate, currently full forward.

Some afc tuning but not much.

Built auto

Turbo (Silver bullet sitting on the garage floor because I can't find my fuel to spool it)



Checked the shutoff solenoid and adjusted it to 2 5/8 inch from top of pin to the bottom of the bracket per instructions.

Moved star wheel both ways no change.

Changed plate from 6 to 100 with no change.

Forgot to remove factory copper washers under dvs (only 160 pump), removed them per piers instructions. No change

Timing is still stock.

3k or 4k yet to be installed.



EGTs 1000 max on stock turbo with 14cm wastegated

Boost 20-25 psi max



Any ideas?

I am running out of things to check.

 

[PRattenbury]

Do you have any governor work done to the pump? What do you have your timing set to? Which pump are you running???

 

[PRattenbury]

Okay, I don't read too well. What is your timing set to?

 

[TJarecke]

I haven't gotten timing set yet, so it is still stock. Is that going to make a big difference between no smoke and closer to full potential?

 

[JPittinger]

You should be smokin' like crazy if you want to. Timing won't make a difference in fuel delivery, I think you have something else wrong. Have you checked that the AFC is moving? I made a plate once to cover the AFC hole with a 0 plate full forward... COAL TRAIN!!! Might be one way to tell if the AFC is hurting you.
Keep us informed.
-JJ

 

[MMcCallie]

Have you had a tune up? Valves adjusted, check compression? I wonder if your timing could have drastically slipped lower than stock, wouldn't hurt to bump it up to at least 15 degrees.

To increase smoke you'll want your star wheel and AFC all the way forward. I've read other posts on this forum about pulling the AFC out of the way and covering the hole with duct tape to test it and see if you make more smoke. Have you checked thoroughly for boost leaks?

I've recently lost tons of smoke and boost went from high 30s to mid 20s but i suspect my fuel filters to be clogged from running lots of biodiesel. Would it be too much to try going back to a stock filter and lift pump? I can't see how 40 psi, which is far more than stock, could cause your affectations. If you have that much pressure, probably nothing wrong in the tank. I've also experienced tremendous power loss from clogged air filters. Have you replaced your BHAF recently?

 

[bbodammer]

Todd, just stick with a second gen:-laf I have recently bought a 12v for a spare work truck so I might be looking to you for some insight once you figure it out#@$%!. Good luck

 

[Hammer]

Have you replaced the overflow valve at all????



All the fuel pressure you can feed a P-Pump in the world is no good if the overflow valve is weak and bypassing pressure off and not allowing the pump to get the fuel it needs.



Also...

While timing can be your friend and add some power it also adds alot of cylinder pressure. Since you do not mention if you have oringed and studded the motor I may wait to install the Bullet or raise the timing. I agree with the rest your not changing it had nothing to do with what your issue is now.

 

[Forrest Nearing]

my first thought was the OF valve...



check your fuel pressure... if your OF valve is toast, it would explain a lot

 

[TJarecke]

Fuel pressure: I am regulating the pressure after the pump so no overflow valve. THe pressure doesn't drop. I don't think the pump is moving much. I a probably bypassing most of it.
AFC: This is my next place to check. I had heard before to remove it and see what happens. That is what I plan to do.
Boost: I am also going to check for boost leaks and the line from the intake to the afc to make sure there isn't anything in there.
Timing: I am thinking 17-18 degrees. Do you still think that is too much with a larger turbo and no studs or o-rings?

Thanks for the replies. Hopefully I will get it figured out soon. I want to hit the drag strip before it closes.

 

[MMcCallie]

My timing is right about 17. 5 and i've had no problems at even 13,000' and 14 degrees F. I also run water/methanol injection. But, i had my stock head bolts retorqued and i highly recommend the same. I've been told the stock head bolts will stretch to take just about 50 psi but 45 is safer. I think with a retorque you will be OK.

 

[Extreme1]

Fuel pressure: I am regulating the pressure after the pump so no overflow valve. THe pressure doesn't drop. I don't think the pump is moving much. I am probably bypassing most of it.

So your regulator is on the return line to the tank? Where is the pump plumbed in? Where are you measuring pressure?



Based on the mods you should have mega-smoke (maybe even giga-smoke!). Timing won't do this, a boost leak will make more smoke. Check the boost at the AFC housing.

 

[TJarecke]

Measuring pressure pre pump.
Regulated about 1' from the injection pump.
My system is very similar to a 94 pulling truck in the area. The only difference is the pump used. His works great for him.

I agree I should have tons of smoke, that is why I am wondering what is going on.

 

[Extreme1]

Measuring pressure pre pump.

Regulated about 1' from the injection pump.

Let me walk through this:



Line from tank goes to Aeromotive pump.



Line from Aeromotive pump T's with the return line from the injectors (I'm guessing there is a filter in there but that doesn't matter for this)



Line from injector return T goes to P7100.



Line out from P7100 goes to regulator.



Line from regulator goes back to tank.



That's the way the stock system is set up. The regulator maintains pressure between it and the pump, downstream is not regulated. The stock system has the injector returns piped into the stock filter inlet which is between the stock lift pump and the P7100.



Is this how you plumbing is laid out?

 

[TJarecke]

Pulled my afc and found my SMOKE. Good step in the right direction. Now for finding out why it wasn't working????

Line from the head to afc seems to be in good shape.
Diaphram doesn't have an rips or holes in it.
Now what???

Thanks for all of the replies so far.

 

[JPittinger]

Pull it off and check it with shop air; should move freely but apparently it doesn't. If the diaphragm isn't the problem, check for plugs, leaks, etc. (my guess is a leak). Shouldn't be hard to figure out with it off the truck. You could take the AFC arm out temporarily and drive with your foot for a while till you have time to fix it. You could also replace the spring with one from Piers while your at it.
Good luck, JJ

 

[TJarecke]

It is off now and my brother is going to check it out tomorrow with shop air. Hopefully the problem will stick its head out.
Is the spring mod worth it?

 

[Forrest Nearing]

governor springs? yes worth it



AFC springs? not worth it IMO

 

[TJarecke]

Gov springs are definately going to be the next mod. Have a 3k but I think I am going to upgrade to the 4k before I waste my time on the 3ks.
The rpms will be helpful at the 1/8 and 1/4 mile!

 

[Forrest Nearing]

definately do the 4k