Richter12x2

I've used Seafoam on many different higher mileage cars (120k+) with great success - the only exception was my RX7 which runs very rich already, the Seafoam was enough to put it over the top and I had to change the oil before I could start the car again.

But a warning, make sure your timing issues are sorted out before starting! After adjusting the TPS and getting my '85 928S project running better than it has since I've had it I went for a drive, and it still felt down on power, stumbling a bit before it took off. I had some Seafoam (new can) and decided to run it through.

Popped the hose off that feeds the torque tube in the center, and began slowly feeding it in, and put a little into the oil filler. Anyway, I've almost finished when there was a good sized explosion and a ball of flame washed over me. I jumped back and my wife disappeared (returning moments later with a fire extinguisher and a phone to call 911 just in case I was still on fire). And I watched for a second as the flames inside the side chambers burned out.

I'm guessing, I had an ignition event before the intake valve closed all the way, and with Seafoam in the intake, there was enough accelerant to combust. It blew off EVERY coupler downstream of the throttle body (luckily it was closed, so it shouldn't have affected the MAF or anything important) and I have been known to torque the daylights out of those clamps, so they were NOT loose.

The plus side is, at least this points me to why the car was losing power - if my cylinder timing is incorrect, or if I have a valve sticking, that would do it. And I still have most of my eyebrows, although I do feel like I have a slight sunburn!

danglerb

Depending on how your vacuum lines are routed ....maybe.... pulling off a vacuum hose messed up the vacuum line to brain and that altered the ignition timing.

Tell your wife to remember the camera next time.

Glad to hear it didn't get serious.

DANdeMAN

To bad you didn't have a video going..that would've been intertaning

On a serious note, good you still have your head....

UmmYeahOk

Camera Phone

Wait, what was good about that?

Richter12x2

You'll all have to excuse me while I beat my wife.

no doubt

I've seafoamed my 928 motor twice recently without incident. Seafoam added into the fuel tank. Seafoam added into the oil filler neck. Seafoam poured in small quantity over the air filter. Seafoam slowly poured into the large black vacuum and oil return lines that flank each side of the engine while the engine is running.

Add in the seafoam too fast and the motor will stall. Otherwise, no issues. Changed the oil afterward.

You say above that you added Seafoam into a "torque tube" hose in the center?? I'm not familiar with what you are saying and wonder if that hose contributed to your fireball.

Richter12x2

I'm sure it was bad ignition timing that contributed to my fireball - it's down on power and we're guessing that I may have two of the leads swapped around, so I'm going to pull the side chambers of the manifold and confirm the wire routing again tomorrow. Unfortunately it's not so easy to figure out firing order when you have two distributors, and they're not circular. :P
I'm not blaming the Seafoam - once I finally disassembled everything to screw the torque tube back on, (blew loose from the throttle body along with every other rubber and silicone coupler. :P ) it has a bit more power than it did, so the Seafoam DID help. I still stand by the stuff. Just not, RIGHT by it!

Hilton

Which is the best intake vacuum line to suck seafoam into?

The one on the manifold just in front of the throttle armature (17 in pic below) would favour one set of cylinders and give very uneven distribution.



The rear-ward one heads to the ISV (the one that dives under the intake from 12 above) , but given mine works nicely, I have qualms about putting anything liquid through it.

Possibly 5 in this pic below?



To the OP - your reference to "torque tube" doesn't make sense? The torque tube is the tube with the drive shaft between the engine and the transaxle, that runs through the tunnel under the car body.

JHowell37

There should be a label on top of your radiator that shows the firing order. I wouldn't run the engine until you are certain that the plug wires are all connected properly.

The explosion is almost always caused by having the plug leads connected to the wrong terminal.

If you don't have the sticker:

As you stand in front of the car facing the engine, on your left hand side are cylinders 1-4. Is at the front, then 2, then 3, and then 4, as you move back to the firewall. On the right hand side facing the engine, you start at the front, and moving back, 5-8.

On the distributor cap on the left hand side, going from left to right:

1-7-6-4

On the right hand side:

2-5-8-3

Richter12x2

Sorry, everything on this car has it's own special name compared to every other car in the world, and I'm new. :P Thanks for correcting me. The larger center tube that feeds the throttle body has a large inlet that (at least currently) comes out from under the intakes and makes a T with the Oil Fill vacuum port, and the other leg feeding into the valve that controls the Air Pump routing. I pulled off the leg that fed the valve for the Air Pump (passenger strut tower), connected a short length of the same diameter and very slowly added the Seafoam there, where it gets sucked into the large T that feeds both side intake chambers. (I'm sure there's a special name for those too )

What happened is the Seafoam pooled in the bottom of the chambers on both sides, and whenever the spark hit before the intake valve was closed, there was just the right mix of air and Seafoam to ignite, and the explosion blew all the rubber and silicone couplings off.

Richter12x2

Thanks for the wire routing! That'll help me when I check it tomorrow.

I have a sticker, but it shows the distributors as circles with numbers at up down left and right, so they don't really correspond to anything on my 5.0 with all 4 ports straight across (that I can tell). The cam cover is supposed to have some kind of labeling on it as well, but there isn't anything that I can see there either. The cam cover's been painted even before I got to it, and the radiator may be from a different car.

I got the car for a song, but it's an ongoing trial to fix all the things the previous owner messed up on it and put it back to good.

no doubt

17 in the first pic, 26 in the second.

danglerb

Why not run the seafoam through the ISV?

nosnow

There have been reports that US 85-86 intakes "POP". Basically the engine backfires and pops the ends off causing slight dents in the hood. Usually occurs after stop and start driving... probably the reason these intakes were only used for 2 years. Someone else may know the reason or can explain the cause I've not been willing to run any cleaner through ny 86 intake in fear of a fireball.

no doubt

It's probably better than the WD-40 that most suggest for that idle speed valve.