ERG Delete plate / running rich questions

[Flex BT]

My AMC 258 i6 / 4.2l has been having problems running rich and even putting fuel into the oil. I'm hoping the fuel in the oil issue was caused by installing a new fuel pump. The diaphragm in the old one wasn't broken, but looked cracked as if it might have been the culprit. Anyhow...

I used to have a Weber 34 carb. Piece of , ran rich, tried everything (new jets, the whole 9). Now I have a weber 38. It runs nice but it still reeks like gas every time I turn it on. The fuel pressure is regulated at 3.5. I just replaced basically the whole fuel system from the tank fill lines to the carb and charcoal canister and it's still stinky. The Weber carbs bypass the ERG valve, which is currently plugged on the outside. A mechanic I know suggested I put a plate over it just to make sure it's not affecting the system in any way. Does anyone make such a plate or will I have to dremel one out of some sheet steel or something? Is it possible this is the problem? I have vacuum leaks that I can find, I can spray the whole engine area down with starting fluid and no difference in RPM. The compression tests good. I'm going to install new exhaust / intake gaskets to ensure that is not an issue. The ignition system is all enhanced to make sure the spark is good... MSD 6A, high vibration coil, teamrush dizzy upgrade, new plugs and wires. I'm about to arrive at my wits end with this thing. Any other ideas?

 

[JR74CJ5]

wow... well you've mentioned everything I was going to say / suggest as reading... Thought would pop up and then your next sentence would be it already lol

when you "smell" the fuel, is it from the carb, exhaust, etc?

Do you have a good air filter installed during these times you're smelling fuel?

Just other random probably way off base thoughts... Perhaps timing a little off maybe? Letting some fuel out before ignites or after? (then smell through exhaust)

Really sounds like you're beyond my help from here though...

 

[Flex BT]

The smell is coming from the exhaust I *think* but it seems to just saturate the air. I have verified the line on the balancer as TDC and set the timing to 8-9* BTDC. With the ignition upgrades I understand I could possibly move that number up but I also read timing to advanced could possibly worsen my issue.

As far as an air filter, the only one I know of on my jeep is on top of the carburetor :/ I have also replaced the PVC.

 

[JR74CJ5]

As far as an air filter, the only one I know of on my jeep is on top of the carburetor :/ I have also replaced the PVC.

that's the one i was referring to...

Just wanted to make sure it was "on" when you were smelling the gas, "if" it was coming from the carb area...

Have you tried adjusting the carb mixture screws down, or cleaning the air filter (if k&n) / replacing it? Maybe you're not getting enough air, or too much fuel.

You can (and should) bump timing a little more with the upgrades you've done. I'm not sure about making it worse or better though. Also the spark-plug gaps can be opened up further as well (I know you said new plugs, what gap did you go?)... maybe that would help to completely burn up all fuel in the cylinders before exhaust stroke.

 

[Flex BT]

Upping the timing is something I could try for sure... The plugs were one of the recommended brands (can't recall which right now) gapped to .45 I believe. I have tuned, retuned, and tuned again the carb. The Air filter was new, I applied the K&N filter oil to it per the instructions. It does however have the same problem with the filter on and off.

 

[grozam]

If you found a bad diaphram on the old fuel pump, you should change the oil and filter before you run the engine as gas might be in the crankcase. Also if you had a vac. leak it would run lean not rich.

 

[Old Dog]

Have you ever thought of getting rid of the weber for a good MC 2100.
Just a thought as way to many people have trouble with webers.

 

[sheddiggs]

I upgraded my '73 AMC 258 i6 / 4.2l with HEI, MC2100, and an '81 intake/exhaust. I found a nice EGR delete plate surfing online. I don't recall the manufacturer, but you should be able to Google it.

 

[Flex BT]

Cool. I just bought the Weber 38 a few months ago, I can't justify getting a 2100 right now. I'm really hoping to get this resolved without too much more expense.

I will say this... when I was changing my timing it seemed like I could advance it as much as I wanted and the engine RPMs would just climb and climb and never drop down (I probably didn't go past about 20 or so BTDC but they kept going up). I've heard people say you can go to around 12 safely with the mods and I've heard others say that's dumb and will ruin your engine. I kept it stock to avoid any pinging / possible damage. What's the best way to ensure I'm upping the advance but staying in the safe range? Is it true you have to be actually driving, not just hitting the throttle to get the pinging to happen?

edit: I did also change the oil after the fuel pump. I thought for SURE that was going to be the culprit.

 

[Old Dog]

Is it true you have to be actually driving, not just hitting the throttle to get the pinging to happen?.

Yes the engine has to be under a load. Going up a hill and giving it throttle is the best test. The more load the better.

 

[mtnwhlr]

I would give it as much timming as it will take if it's not pinning you are fine. If you are getting some pinning back it off just enough to get it to stop. I think timming is your problem by what you have said.

 

[Flex BT]

How do I know when a good place is to stop? Like I said the rpms just seemed to keep going up and up. Is 12 a good place to start? 14? I'm also a little worried about not recognizing the pinging.

 

[JR74CJ5]

When the RPM's go up, you can lower your idle adjustment setting / screw to compensate.

12 is a good place to start and test for pinging. That's where most of the ignition modules suggest timing be set to. Does your particular set up come with a suggested adjustment to timing?

When I bought my streeetfire ignition box, and DUI HEI distributor, it mentioned in the install instructions the new recommended timing of 12 degrees.

 

[Flex BT]

No recommended settings. The one thing that is stock (but new) is the dizzy module itself. I'll look for some recommendations for mods after the team rush upgrade.

I do have a vacuum gauge, is that helpful in any way with setting timing?

 

[johnnyreb]

you need a timing light. vacuum gauge works best for adjusting carb. Make sure your dizzy advance is disconnected and plugged when you time it.

 

[Flex BT]

I set my timing to 12*BTDC. No knocking during a test drive but it did seem like there might have been a little bit of lifter noise. It's a pretty definite loud pinging or knocking, right?

 

[Torxhead]

For an excessive richness problem, I would consider a possible problem with the needle & seat assembly or the float adjustment. Rather than a few degrees of initial timing.

 

[Supertrunk]

With the Webers, one of the first things to do before even starting with jetting or adjustments, is to verify your float settings. They have two different specs; one for the black plastic floats and one for the brass floats.



Hope this helps.