No smoke... No power... waddya think?

[WCantrell]

On the way home this evening, I was accelerating away from a light (with the valet switch off for a little more fun) and my smoke and power went away. Kind of sudden like...



I can only pull 15 lb of boost no matter how hard I stand on it. The turbo whistle is gone. I removed the intake boot an the turbo "seems" to spin ok without alot of play. No water in the oil, but was not able to check the radiator.



It runs like it has no boost signal... My valet switch is open when the power is off, so I removed the power just to make sure.



I checked the IC boots and everything looks ok...



Any ideas?

 

[HBarlow]

I don't know anything about 12 valve engines but a bad map sensor will cause that on a 24 valve. Do 12 valves have a map sensor?

 

[JLEONARD]

How old is the lift pump?

 

[NIsaacs]

Sounds like fuel related. If it were turbo issues, it would smoke. Maybe fuel filter or throttle linkage.



Nick

 

[WCantrell]

The previous owner replaced the lift pump about 5 years ago.

 

[WCantrell]

Sounds like fuel related. If it were turbo issues, it would smoke. Maybe fuel filter or throttle linkage.



Nick

That's what I was thinking, if it were the turbo I should see plenty of smoke. The throttle responds well and causes my transmission to downshift, so I'll take a look at the fuel supply.

 

[WCantrell]

I don't know anything about 12 valve engines but a bad map sensor will cause that on a 24 valve. Do 12 valves have a map sensor?

Nope, No MAP sensor for 1st gens.

 

[JLEONARD]

replaced the lift pump about 5 years ago

Well after you check some of the other basics don't neglect looking at the lift pump. They can last a long time or no time. Been there.

 

[cerberusiam]

replaced the lift pump about 5 years ago

Well after you check some of the other basics don't neglect looking at the lift pump. They can last a long time or no time. Been there.

Yep, the very first thing I would do is put a pressure gauge on the fuel system and see what it is doing under a load.

 

[WCantrell]

Yep, the very first thing I would do is put a pressure gauge on the fuel system and see what it is doing under a load.

If it is the lift pump, given my sig, should I upgrade to a piston pump?



Also, I am still running the stock turbo. I am thinking about upgrading to a pdr modified hx-35. For my rig will that be good for the $$? or should I spend more and move to a super-b? My truck is a daily-driver, and on occasion I haul a 3 horse goosneck.



Thanks for the replies!

 

[cerberusiam]

I would seriously consider the piston pump upgrade. Works quite well from my point. The other more expensive is a FASS or AirDog and better filtration.



A Super B or Super B special or other turbo on the ordr of a 60\65\12 spec turbo would be an excellent upgrade. The PDR HX35 is close to the same thing but would make sure you get a waste gated 12 housing.



The other option if you want to do the work is the HE351VE's and adapting them. It takes some fab work but that turbo is pretty good for power upgrades.

 

[WCantrell]

I would seriously consider the piston pump upgrade. Works quite well from my point. The other more expensive is a FASS or AirDog and better filtration.



A Super B or Super B special or other turbo on the ordr of a 60\65\12 spec turbo would be an excellent upgrade. The PDR HX35 is close to the same thing but would make sure you get a waste gated 12 housing.



The other option if you want to do the work is the HE351VE's and adapting them. It takes some fab work but that turbo is pretty good for power upgrades.

Is the 12 housing good for towing with an auto? I was under the impression that the 16 was better for that, providing more boost at the top end. Then again, I've heard that the 12 or 14 supply plenty of boost in the "useable" rpm band.

 

[PToombs]

Double check that you don't have a boost leak at the AFC. Best bet is to make an adapter and check the whole system. If you don't have any boost, you wont get fuel from the AFC.

Does it run like it does with the valet on? (AFC not working?) If so, I'd suspect no boost.

It just seems weird that it did it quick like, usually fuel problems creep up.

 

[WCantrell]

Found it!



The AFC diaphram is cracked. Anyone know where I can find one?



Thanks!

 

[DVolk]

Ebay has gasket kits or some parts houses that carry Bousch parts



Im confused about the " Valet switch " what valet switch on a gen 1 engine truck ?

 

[WCantrell]

Ebay has gasket kits or some parts houses that carry Bousch parts



Im confused about the " Valet switch " what valet switch on a gen 1 engine truck ?

The valet switch cuts the boost signal to the AFC. I found the recipie here in TDR. For freeway and highway driving I have gotten up to 21 mpg with my 4x4 truck. When I am towing and "having a bit of fun" its a right handy switch. Granted, it is probably more about my lead foot than anything else... I'm sure my teenage boys leave it off...



I checked Ebay out and none of their kits have the diaphragm. At least according to the pics.