Help ASAP, Can't Get Cruiser over 60 mph

[fliphkd778]

I rebuilt my 2f to correct a couple of problems, one of them being my wagon's inability to go faster than 60 mph. Now that my engine has been broken in, I had a chance to do some highway runs this evening.
Once passing the 55mph barrier, I give it a little more throttle to continue accelerating. At 60, it sort of bogs for a few seconds then begins wildly bucking, sort of like a large force is jerking the rear bumper.
Any suggestions?

 

[wengejor]

This bucking that you are talking about is usually due to a lean situation. I had the same thing going on over the summer and it turned out to be the fuel filter for me. Also, it could be a vacuum leak causing a lean condition at full throttle. I would get a vacuum gauge to test for leaks and replace the fuel filter if you haven't already done so.

 

[151fab]

Your title of the thread is hilarious. I immediately thought: new FJ60 owner finds top speed disappointing.

That sounds like a fuel delivery problem. But you would notice the same problem when the engine sees the same load in other gears and at other speeds too. Like when climbing a hill or trying to pass another car (note that I am again laughing after typing that phrase), etc. Do you notice these same behaviors when the gas pedal is floored at other speeds/gears?

If not then I would reluctantly say mechanical problems with 4th gear, t-case, d-shaft, or rear end. But it would have to be balance or bearing related to not show up constantly (4th gear aside).

Long shot guess: Could also be that under-hood pressures are screwing with the high-altitude thingy-mick-bob.

 

[fliphkd778]

Your title of the thread is hilarious. I immediately thought: new FJ60 owner finds top speed disappointing.

That sounds like a fuel delivery problem. But you would notice the same problem when the engine sees the same load in other gears and at other speeds too. Like when climbing a hill or trying to pass another car (note that I am again laughing after typing that phrase), etc. Do you notice these same behaviors when the gas pedal is floored at other speeds/gears?

If not then I would reluctantly say mechanical problems with 4th gear, t-case, d-shaft, or rear end. But it would have to be balance or bearing related to not show up constantly (4th gear aside).

Long shot guess: Could also be that under-hood pressures are screwing with the high-altitude thingy-mick-bob.

Hahaha what's wrong with this wagon? It isn't like other cars on the road, they keep passing me!?
On a serious note, I can downshift at 60(scary) and try to go faster, but something won't let it. Really doesn't feel mechanical. It is somewhat intermittent also, I've seem 70ish in it a few days ago. I'm going to try a new fuel filter although I emptied mine yesterday, and blow out the fuel lines....Could it be the dizzy's rev limiter sticking or something?

 

[87CRUSR]

I experienced similar problems a few years back at the high RPMs of lower gears as well. Turned out to be a vacuum related issue.

 

[Butt Ugly Chuck]

Butt suspects it's vacuum or maybe EGR related. Just for giggles, search for the EGR bypass trick and give it a whir to rule it outl.

Butt

 

[fliphkd778]

Vac gauge shows somewhat weaker reading than what I'm used to with a bit of needle flutter. I don't know much about interpreting the readings since I switched to different valve train setup; hotter cam and valve springs.

No egr or smog equipment on my setup.

 

[Butt Ugly Chuck]

No egr or smog equipment on my setup.

I should have caught that in your sig line.

Are you getting vacuum advance out of your dizzy?
Butt

 

[fliphkd778]

I believe so, I torqued down the manifolds again and the carb base nuts and went on a highway run already. WOW. I guess I had a bad leak? The vacuum flutter was reduced, the engine quieted down, starts much easier now, and pulls harder than ever. Even made it to 65 for a bit. I feel dumb for not thinking of re-torquing before posting; I didn't think I had a leak at all. Here's a little video from a hot start:

http://www.youtube.com/watch?v=HNHn6SdCN4o

I'll take it out tomorrow morning for a longer highway run and post up the results.

 

[wengejor]

sounds good. How much vacuum do you have at idle? Mine is running just under 20 with no flutter

 

[Texx]

33" tires are going to be a large part ofyour problem. That, and failure on your part to figure in the differential in actual speed and indicated. If you're going an indicated 60, 70 is where you actually are..(approx, for all the conversion calculator freeks). Throw in a hill or two, you're lucky to get out of your own way. Advance the timing until it pings, then back off a little. Instant horsepower.