My truck is driving me CRAZY: Dead in the water

[metalmonkey47]

WELP so the pump was an issue. But not the issue. It was pretty weak compared to the new one. BUT it wasn't completely the issue. I drove it around the block and pulling back in, it stalled. Now it won't idle, and runs like piss. Another look around with carb cleaner and I think I've found a vacuum leak at the intake manifold around cyl 4. I ran out of carb cleaner so I can't confirm my suspicions. However, it only took me 10 minuets to get it apart, and I have a new Nismo header gasket I've been meaning to put in anyways so I figured I'd just swap it.

 

I can't get the header off the studs without cutting the exhaust loose, so I'm going to have to clip the gasket around the earlets to let the gasket slide around it. Not a big deal since it's not around a sealing surface. 

 

 

BRB

[metalmonkey47]

Manifold gasket was no good, but not the issue. It was leaking in a few spots. The header leaked at every sealing surface, and it looked like it leaked into the intake ports in some spots. Wonderful EGR style vacuum leak. 

 

The new gasket helped with the vacuum leak I had, but didn't solve the issue. Still NO idle, and poor running. Kinda feels like a big vacuum leak at this point.

 

Ignore the spots in the picture where I cut the gasket. Had to slip it around some studs so I didn't have to pull the header off.

 

 

 

 

New NISMO Header gasket. (9996-D11280) It's so nice! 50% thicker then FelPro, flexible, and tough feeling. Header no longer leaks from what I can tell...but the engine doesn't run long enough for me to know for sure.

 

[q-tip]

Single piece Webber adapter or two piece, if two piece remove, add to round file and get a damn one piece

[banzai510(hainz)]

that header looks like th thin flange type. Maybe best ti get rifd of it.

Make sure where the washers meet that its the same thickness so the intake and exhaust washer applies both even pressure on both sides.

 

if you have to rip the gasket to get it done like that I bet thats where the leak is on that cylinder #4

[metalmonkey47]

It has a one piece, and I think that may be where the issue lies. It's either a vacuum leak, or issue inside the carb at this point. I'll have it figured out by the end of the day today I hope. Can't afford another day down. 

I have a spare 32/36 that I can toss on to see if it's going to run. I'll pull the adapter and take a look at it now.

[banzai510(hainz)]

I seen 2 adapters crack if they are the thin type litle 1/4 inch ones. Thin casting. causes no idle issue.

 

I use the bigger tall adapters now but dont like hoods w/ taller L20s

[metalmonkey47]

I had a tall adapter, but it was home made and the sealing surface wasn't flat. Didn't leak that I could tell, but it was so poorly made that I'm sure it was causing all kinds of restriction issues. 

 

I pulled this adapter off and there is one crack in it, but I was already aware of that. A corner was chipped and it cracked, but away from the sealing surface. It's been JB welded up to ensure that it wouldn't leak, and seems to be fine. 

 

 

Only issue I seem to be having now is that it refuses to idle just like the issue I had on my 210 back in the day when I didn't have 12v at the idle cut solenoid. No solenoid here though, just pure jets. I've blown about 20PSI through the passages and didn't see any difference. Cleaned and blew out the jets by hand. No gain. 

 

I think I have a big clog in the idle passage, and the air I'm blowing through is passing the clog and coming out the air jets. I'm gonna try plugging the air jet with my finger and see if I can blow anything out the idle passage. Also removing the idle mixture screws and blowing out there as well.

[q-tip]

Back in the day, when was that, 2010? I would still get a new carb adapter plate, just one less thing to worry about

[metalmonkey47]

More or less haha.

 

I don't plan on getting another. I have SU's sitting on the work bench getting cleaned up, I'm just waiting for UPS to deliver the manifold. 

 

https://www.youtube.com/watch?v=gtAvYbEqyvM

 

 

 

In the video you can see the only way it runs is if the choke is closed to the perfect place. Other then that, it refuses to idle. Revs GREAT and I even drove it down the road and back, and it ran perfect other then it's refusal to idle.

 

I cleaned out all the passages, and opened the carb up, completely disassembled it, and blew out every last passage with about 90 PSI. No change.

[datzenmike]

Says video is private.

[Farmer Joe]

do you have another known good carb to try it with? 

 

just to check, do you have points or EI dist?

 

if its points, either sand them or get a new set and get em adjusted right.. if its EI, might wanna try a new cap and rotor just to check. ive had newer parts fail after a short amount of run time, and ignition parts like that are still pretty cheap. 

[banzai510(hainz)]

I have this hapopen with a few carbs. I swapped a carb and now IM fine.

One carb is new. Never cked it out once I got mine running with a known good one. Im stupped on mine.

[datzenmike]

that header looks like th thin flange type. Maybe best ti get rifd of it.

Make sure where the washers meet that its the same thickness so the intake and exhaust washer applies both even pressure on both sides.

 

if you have to rip the gasket to get it done like that I bet thats where the leak is on that cylinder #4

This may be it or part of it. If the intake and header flanges are not close to the same thickness the washer that bridges across them will tighten mostly on the thicker of the two.

[metalmonkey47]

Welp to clear it up, the issue is SOLVED. Yayyyyyy... Well mostly...

 

To clear it up about the header, it is a thin flange header, but there are tabs welded around the sealing surface to solve the issue you guys are reffering to. I need a better header though. The flanges are not even close to flat or even. It leaks like a sonovabitch, but the Nismo gasket helped a TON. 

 

 

Anyways, I chased the issue forever and it came down to a clog in the idle jet. I cleaned the jet out multiple times, blew air through it, soaked it in carb cleaner, etc. Looking through it seems to look clear and pushing some wire through it it IS in fact clear, But I found every time I start the truck, fuel pressure in the circuit is pushing the clog around in the jet. Shut it off, and the media falls to the back of the jet where it wasn't visible. I figured this out by swapping jets around from my 32/36. Now I have a very unbalanced idle circuit so it's kinda problematic. I can't get the media out of the 38/38 jet so I'm running a 60 in one barrel, and 45 in the other where they ideally should be matching jets. Causes all kinds of weird issues.

 

I have an issue transitioning from partial throttle (light cruising or idle) to heavier throttle where the engine just seems to want to die for a split second. I can only guess at this point it has to do with the un-balanced idle circuit. I need to find a way to get the media from this damn jet. i can kind of see it, but it doesn't seem to want to come un-lodged from the tiny jet.