Need help diagnosing surge/stumble after Project Reset: Abandoned here by local expert

[redshiftquasars]

NOPE, for as much as Mark posts on here, doesnt take comments on his posts, & always asks for you to hit the like button he should see this and make it right or explain why the truck doesnt run. The $ thing is well, 40's cost ALOT in many ways. As a matter of pride & backing up alot of talk I would think Mark will make it right or post some explanation of why it isnt running properly, he certainly has the knowledge, parts, & pride and experience. Your 40 was in good hands and if it isnt running correctly there will be a solid reason or something new since Mark had hands on, just my opinion.

I’m starting to think it’s the fuel…. It’s been sitting for some time.

 

[charliemeyer007]

A couple of bottles of yellow fuel dryer should clear up water in fuel issue. Paper elements in fuel filter will not easily pass fuel if they are wet with water. Put on a new one, set old one in the sun for a few days - it will dry out and be good as new. Weak mechanical fuel pump - put a $10 diode electric pump in line and see if it runs better.
You could make a fuel transfer system and hook it in bypassing your tank and fuel pump for testing.

You can also use the transfer unit to drain your tank.

 

[Skreddy]

Vintage cars and carburetors in particularly are simply not going to be as linear or black and white about operation and performance as one’s 2023 Camry. It is not unusual for a vehicle worked on by an expert, (or those of us with 30-40 years experience that play expert on the internet) to suddenly be “un-fixed” soon after “fixed”. Don’t hate the player; hate the game! (Or get out and buy a new 250 series or a Bronco!

I love my wife’s Bronco!

 

[peesalot]

Bad/old gas can cause line/filter clogs, pump issues, carb issues ( bowl & jet & idle circuit ) , I dont recall if there is a drain on the under seat tanks, there might be an access hole underneath ?

 

[middlecalf]

A bit lost with the status of the workflow between the different threads, but was the distributor replaced? I see in the other reset build thread Mark referencing the coil’s orientation being corrected, and the non-OEM Mallory dizzy being on the replacement list with a cityracer one you ordered, IIRC? With all that there is the electrical side of the puzzle to look at to include points, resistor, plugs and coil health, as well as timing.

 

[Gotta40]

lots of variables going on, but it might be something like mine where it had to be jetted larger for the header. nobody puts headers on in the performance world without tuning for it. around here people think you're crazy thinking it might need to be richened, but it solved my drive ability issues immediately.

 

[dazerb]

I wanted to share where I’m at after my **Project Reset** experience, because I think there’s value in documenting both the good faith going in and the current reality coming out.



I brought my **1971 FJ40** to **Mark’s Off Road** for a major reset because Mark has a strong reputation in the FJ40 world, and I trusted that experience. My truck came in with an **FJ135 engine**, **FJ145 original head/manifold**, and a **Weber carb**. It was actually running pretty well before the project.



The goal was to improve the setup by installing:

- a rebuilt **original carb** rebuilt bu Marks Off Road

- headers supplied by Mark’s Off Road

- a new intake manifold supplied by Mark’s Off Road



To be fair to Mark, I did hear back from him, and he said he did not remember the truck was still not really usable in its current state. He told me he would think about next steps, and I appreciate the callback. At the same time, that response also reinforced how alone I’ve felt in this process, because from my side this has been an unresolved and expensive problem for a while now. So while I’m glad the conversation has reopened, I’d be overstating it if I said I haven’t felt largely left to sit with the outcome on my own.

Is trashing the guy here going to get you where you want to go?!

This seems to be our social media world now. Ugh.

 

[WartHog73]

As @Gotta40 said - there are lots of variables here. Not sure when your tank was last drained and cleaned, but good to ensure that. Ensure new fuel filter. Not sure what is going on with your dizzy and timing, but check to ensure this is not an issue and timing is correct. If no issues with fuel tank, fuel delivery, distributor, timing, and you have no vacuum leaks, you may then need to recheck your carb.

You may not want to hear this, but I got three different carbs rebuilt in quick succession and when I got them back, none had working secondaries and after taking them apart, they had incorrect parts, etc. Had to redo all of them. If you have the time, it just goes to show that it is always good to try to learn and try to do yourself. Pinhead has some good tutorial videos on it (search the site). In my case, once carb got properly 'rebuilt' it was like night and day (and I'm not thinking about an engine transplant at all anymore).

 

[JohnnyC]

Are you starting and running the truck correctly with the new to you original carb choke?

You get very use to driving a weber with auto choke... but the cruisers are finicky and have their own technique for starting and driving... most carbureted trucks that era ... my weber I would tap the gas ... it sets the choke and gives fuel to start even in summer... winter gets a bigger tap

Original carb setups some you tap the gas then choke and start... and some that tap is too much gas ... some need a tad of choke to start off then are good to go

my brothers Malibu I would flood starting because it didn't start the way my triumph did and if his choke wasn't in the right spot it would totally bog down and backfire even ... if you drove too long with it ... it would foul the plugs... hated that demon car

I don't know if you tried and are even versed at using the choke.... just thought I'd throw that out there... if you tried choking or not

 

[osamenor]

I will just throw in my $0.02 and repeat what others have said, check the fuel/fuel filter, check to see if it still sputters when it's warm (mine misses when it's not totally warm), Mark did a lot of work and installed a lot of money worth of stuff on your truck, and your value is there.

He is really helpful on the phone, too. He has helped me with a lot of stuff and talked me off the ledge a few times.

 

[msapers]

Before I go into advice mode, a word about Mark: In my dealings with him over the years, I've found him to be unimpeachably honest. One thing to know about him is that although he is active here on Mud, he doesn't do his actual business online or via email. If you need to talk to him CALL HIM.

Ok, now I have a question for you: Was the vehicle ever brought back to Mark for the distributor replacement and final carb tuning? In the the thread that you linked to, it leaves off with that being the plan but it had not been done as of the last post. I would encourage you to not judge the state of tune that Mark left your truck in if, in fact, he was never given the opportunity to complete the tuning process. It is impossible to properly tune a carburetor without the exhaust and ignition that will be used present and accounted for. It makes sense to me that he would hold off on final tuning until the exhaust was done and the distributor swapped.

If you can clarify that, we can all help you a little easier.