Somebody Help! I'm gonna shoot it!

[msummer]

Lopeing idle is a sure sign of vac leaks. What are your vac readings? Tighten manifold to ULC specs: really fxxxing tight! Also, valves way out of adj will cause funny vac and cause the same issue. I would quit chaseing ghosts and go back to the basics. Full tune up/inspection, adj valves, adv timing a bit then set carb. If all is not well and/or if vac is low search out leaks and test all parts of the emissions system.

Look above, I've done a full tuneup, timing, vac check, etc. I've sense re-tuned and got my vacuum to 16-17 @ 650 rpms. The idle is not "lopeing", rather it runs for a long time at one set point, and then runs at a lower set point for a long time (i.e. 10 mins). My "AC on" idle might be screwed up. Regardless, that is a completely seperate issue from the no-power mode.

 

[msummer]

36 ft-lbs ??? Are U serious ???

When I chew tobacco I spit @ 36 ft-lbs.

I'm no tobacco man, but I'll take your word for it Did you use a torque wrench to get to 90 ft-lbs, or just tighten it till the truck is coming off the ground? Too many cast parts in there, I don't want to snap something and create more work.

 

[Mike S]

I had a problem with my 60 running fine, then losing power. It was unpredictable but happened most often when running down hill. It would be very flat and refuse to respond properly to the accelerater.

I found that I had BOTH a leaky fuel pump and smog system vacuum problems. I replaced the fuel pump (which leaked slightly when running), and checked and reattached the vaccuum lines.

This fixed my problem, but it sounds like yours is an even more mysterious combination of problems.

 

[cahilc]

Did you use a torque wrench to get to 90 ft-lbs, or just tighten it till the truck is coming off the ground?

It was as 'dd113' had refered to ... pretty *ballsy* tight. We didn't use a torque wrench but I'll say by guesstimate ~ 90 ft-lbs. Also remember my manifold was badly sprung to the point of having to grind out the bolt holes larger, in the manifold, all the way around in order to be able to bolt it back up.

Cahil

Edit: Spring shackle nuts are factory spec'ed @ 90 ft-lbs, definitely in this ball park ...

 

[msummer]

I decided to pinpoint the exhaust leak a little better. Turns out it's not where I thought it was. I swigged some seafoam into the brake booster line and crawled under while the truck was running. It was spewing liquid seafoam out of the spring/washer flex manifold connection towards the firewall.

What are the down sides of a manifold leak? I've heard burned valves. My valves seem fine right now, based on the steady vacuum reading (less than one inch consistent variation).

 

[msummer]

I've been cruising around some since completely disconnecting the EGR. Right now, the valve vac line to the modulator is vented to the engine bay and modulator side is plugged. I also plugged the line to the upper EGR valve diaphram on the modulator side. It's been around 20-30 miles, so far so good. That's almost a record by the way (for the cruiser to run nice without a hickup). I'm feeling good, but still distrusting overall. Cahilc's ignitor should be here soon. So if something turns up, I'm going to give that a try. Thanks again for all the help/comments.

 

[TheGr8Doughboy]

I'm having a very similar problem with my 60 and am real interested in what you found out... please post an update!
thanks
chris

 

[msummer]

Here's an update:

The igniter/coil that cahilc was kind enough to loan me works great. Unfortunately, that wasn't the solution because it still has its issues. The good news is I won't be buying an igniter. The EGR has been disconnected for some time as well.

Instead, I'm going to take off the carb and dizzy and send to JimC this weekend for a rebuild/tune/recurve. Since I'm in Florida, I'm doing a JimC advised desmog and putting a header back on instead of the rebuilding the exhaust manifold. I'm going to take the month that it's down and rebuild the front axles too, they need it bad. This is my third car, so I'm not in a huge rush (other than waiting to do the engine swap on the civic).

After some extensive EVAP system study and carb study, I believe I've got a power piston sticking. Seems like the PO screwed the carb up bad. I rebuilt it and fixed some stuff, but I'm no carb expert (it was my first takedown). By having Jim rebuild and tune it on a running engine, I know I can rule out the carb if the issue is still there. Same with the dizzy.

I'm expecting to find a leak in the intake manifold. After more study and careful observation of my problem it seems like I have to have one. I'll know soon enough and post an update. Can you still develop 15-16 inches with an intake leak? Obviously size matters.

 

[jamot]

Jim does a great job on the carbs and distributors too. He did a carb rebuild and dist. recurve for me for my desmogged 85 60 about two years ago and it runs great and has great power with a specter two piece header and fluid heat riser.

On that note, while you are changing the exhaust, check the bottom of your intake and make sure it does not have a crack in it. A stuck stock heat riser can cause this( they sitck quite often) and make for 'funny' running that is hard to diagnose. Also pay close attention on how the header flanges match up with your intake flanges. The headers I've used have a thinner flange than a stock manifold and you have the option of milling the intake a little or cutting a washer in half to shim to make up for the flange thickness difference. I've also had good luck using the Fel Pro "graphflex" exhaust gasket with my header installations.

The smog stuff.... I've desmogged 6 2fs in the last year becuase of the tuning nightmare that these non functioning after thought "emission controls" cause. Truth is the engine probably is a less offensive polluter with smog gear gone and engine properly tuned.

Your suspicion of the power valve or a malfunctioning accelerator pump will prove to be right... that or a small piece of trash (very small) causing an intermitent problem.

One other poster has a very good point about basic engine tuning needs. It always has been and always is the more basic, overlooked, thing for me that is the root of the "head scratchers" I get way too often.

Good luck and the Jim C rebuild is a worth while investment.

 

[msummer]

Thanks for the encouraging post. Jim recommened the MAF header. I was going to weld around the flanges and then grind down the bead till it was the same thickness as the intake. Again, that was Jim's suggestion. I was also going to put on the heat riser and smog idle pulley replacement.

Did you follow the diagrams in the tech section exactly when you desmogged? That was my plan, looks very straight forward.

 

[jamot]

The desmog diagram Jim C has posted is the one I've used and it works fine. Really the only way to do it.

The MAF is probably a good header, I just started using the specter 2 piece and 4 of them have done well for me. I do like a 2 piece header though. I had the first one Jet Hot coated, but 2 years later it's coming off..... I spent good money on that, so I've used POR 20 on the others and it seems to work fine.

Welding the header flanges for proper thickness will work fine too, I just always had my intake milled slightly to make sure I had a good straight surface to seal against. I also used all studs to mount the intake/header instead of the combination of studs and bolts the factory used. I did that on the theory that studs (i.e. used in racing applications etc.) provide a more even distribution of torque than bolts... Really a personal choice on both milling the intake and the studs . The re-torque of the studs/bolts after several heating and cooling cycles is of course the big thing to do. People tend not to do it, because it's a pain to reach some of the bolts and nuts when everything is buttoned up, but not doing it just invites a leak and a burnt valve.

Regardless, you'll realize the benefits of the time and attention paid to the carb set up, header and desmog and proper installation of all... To me these setups are as nice as the carburated V8s I run in other rigs.

 

[msummer]

Here's a quick update. I took the manifolds off a couple weekends back and discovered many leaks, intake and exhaust. My stethoscope skill have been humbled, after noticing that very little exhaust was actually going out the pipe (most being distributed in the engine bay from a plethora of leaks). The carb and dizzy are arriving at JimC's shop as I write this and I've picked up a 2 piece SOR header to go along with my desmog.