not running well after de-smog, help! (1 Viewer)

[Mark Mathews Creek]

My newly acquired 84 FJ60 was purchased de-smogged and has never idled well. The gas mileage is great, 14 in town but now surges intermitantly and hesitates often especially when warm. SOR tech support says that my factory us spec carb is not designed to run without smog control and that there are non-usa carbs that will work but will also need a special distributor. Is there any other options that are cheaper? I see some recommend webers but don't you still need the special distributor and it all gets so expensive. Can't I make this carb work or is there minimal smog I can re-install to get good results?

thanks

Mark

 

[FJ40Jim]

Mark,
The carb is only part of the emission control system, hence the word "system". The USA carb can be made to work with any degree of desmogging. But, I am wondering what else is wrong with the truck. i.e. How has fuel tank venting been handled? vacuum advance? decel fuel cut? distributor cap vent? AC idle up? IOW, the carb may not the (only) problem

Oh yeah, the distributor advance should be recurved to work well without EGR.

 

[mj1015]

Whoops, Just noticed who posted the last post.


I was going to say that Jim C recurved my Distributor to work with out EGR and turned out great.


Foot in mouth.

 

[Mark Mathews Creek]

wow, you have given me lots to think about. What are some questions I can ask a potential mechanic that lets me know he knows how to handle some of the things you have mentioned. I would bet that lots of the things you have mentioned are beyond the scope of my local garage mechanic. Is this the case or is it a no brainer for most?

Are some of the the items you listed above going to work at the factory setting so that I can narrow the work down to primary issues. In other words, what can I start doing myself to see a difference in how the vehicle runs?

thanks

Mark

 

[mj1015]

Got the manual?

Get a vacume gage, You cant have a 60 and not have one. Some where on here I think is a real nice explaination of of what should see on the gage and what the different readings mean.

 

[mj1015]

Here is the vacuume info.

http://www.ih8mud.com/tech/vacuum.php

 

[FJ40Jim]

wow, you have given me lots to think about. What are some questions I can ask a potential mechanic that lets me know he knows how to handle some of the things you have mentioned. I would bet that lots of the things you have mentioned are beyond the scope of my local garage mechanic. Is this the case or is it a no brainer for most?
Are some of the the items you listed above going to work at the factory setting so that I can narrow the work down to primary issues. In other words, what can I start doing myself to see a difference in how the vehicle runs?

thanks
Mark

Mark,
I don't know what the local garage mechanic is capable of. IME, this stuff is not a no-brainer for the average parts swapper technician.

I would suggest starting w/ the emissions manual and the FSM and the diagrams found on ih8mud. Try to get the vacuum & vent systems routed correctly. Do the tuneup stuff: compression test, valve adjust, new ignition and filters, adjust timing & carb per FSM. Then if it still runs poorly, you can track down the individual culprits.

 

[humper99]

My first check would be for a vaccum leak. When I got my 60 it idled like crap but ran out just fine. Turned out to be a small leak at the base of the carb that was messing up my idle mixture. Now it idles butter smooth.

 

[Mark Mathews Creek]

A bit more info: I started by checking the output of the fuel pump and I wonder to what degree this is contributing to my problem? NAPA said the output of a new pump for my 1984 2F would be between 4-5 psi. I am getting between 1.5-2 at idle and up to about 3 around 1,500 rpm. It shakes and the guage is hard to read though. Could it be that my pump is not putting out what it needs so the hesitation. The NAPA guy said he thought it sounded like a vapor lock. I wrapped the fuel line with a heavier line from the pump up to the carb so maybe that will help. I seem to only get the hesitation and surges when hot. The fuel line does run right next to the head and does seem very warm? Any thoughts?

thanks

Mark

 

[Fearnofish!]

Get a vacuum gague and go at it for an afternoon. I had three leaks whenI got mine and it was just a matter of eliminating intact lines. It's a good idea to buy about 24 ft of vacuum hose from NAPA and start replacing lines as you go through them. A bit of vacuum grease on all the fittings will give you some peace of mind as well. Why not as long as your there...

THe fuel pump sounds fine to me. But my rig has 230k on him. If you were concerned about whether or not your getting enough gas check your bowl and make sure your floating ok. Maybe a carb rebuild is in your future. It's definately in mine.

 

[hammer1]

dumb q, but where is the best spot to take the vac reading from?
also..i'de love to put an in-dash guage in my 84. any idea where to get one?
hammer

 

[Mark Mathews Creek]

I second that question, where exactly does the vaccum guage go. I see on the right (drivers side) of the carb there is a hole that seems to go to the manifold, is this where you get your reading? I have also heard that you need to get vaccum in and vaccum out from two different locations. The site referenced to in this forum doesnt really talk about the difference in reading from the two differenct kinds of vaccums. Hope this is clear.

Mark

 

[hammer1]

bump

 

[DocB]

Sounds like the idle fuel circuit; does the wire going to the carb have power? Check the timing. And the condition of the plugs. adjust the air fuel ratio by the screw pointing straight up at the base of the carb on the passenger side (hard to get to; I use a long flexy carb screw driver). Set the timing first. Set the RPMs to about 800 ish, (screw on firewall side of carb); then fuel mix to max vacuum. Plug the vac guage into the brake booster vac hose, which runs from the manifold vac. Don't forget to plug the brake booster back in. Just some quick thoughts.