half-dead injection pump?

[waqas]

Hello group,

I finally re-started my '65 230sl after many months of work (rebuilding the fuel-feed pump in waqas-time takes months... what can I say). The car initially took much effort to start, but eventually did. I Imagine the injection pump needed to re-pressurize the fuel-lines. Prior to this, I'd installed a new battery, new fuel filter in front and hoses in the rear, cleaned out trunk filter as well as fuel-pump inlet filter, and blown compressed air through all solid fuel lines (main feed and return lines, as well as the two lines attached to the tank).

Unfortunately, only three cylinders were firing. I replaced all the plugs with new NGK BP5ES and re-started. I removed them and noted that plugs from cylinders 1,2,4  showed no combustion at all (the rest showed dark soot as if the engine was running extremely rich). With the engine running, I removed each plug wire and noted changes in the idle pattern, and confirmed that cylinders 1,2,4 are not running. I did a compression check and all cylinders showed uniform compression (all roughly about 7-8 atmospheres on my guage). I attached each plug wire to a spare plug and placed on the valve cover so I could see the spark, and the distributor seems to be firing all plugs. Next, I swapped out the injectors from cylinders 4 and 6, and repeated the experiments: cylinder 6 was still firing, and cylinder 4 was still not.

It appears that fuel is not reaching injectors 1,2,4 (and it seems that the injectors are probably fine). Having searched through the archives, I plan to replace the injection pump oil, and to check that the injection pump rack moves, using a 4x0.8x40mm bolt through the front access hole on the pump (as prescribed by JA).  Is there anything else I should try before allowing the panic to really set in?

Thanks in advance!

WAQAS in Austin, Texas

[rwmastel]

From my somewhat accurate memory, I believe you can disconnect the fuel lines from the top of the injector pump and attempt to see the plungers moving as you turn the pump crank shaft.  Search the forum for "stuck plunger" or "pump plunger" or similar to get accurate information.

What's the history of the injection pump?

Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both  tops
1994 E420

[waqas]

Thanks Rodd, I'll modify my search and continue through the archives. (so much great material-- I've been searching/reading every night since the weekend!)

History as far as I know: car was in Germany until about 1979, when the American air-force chap relocated back to Texas. He owned it until I bought it from him last year. He didn't have much to say about the pump (and I never asked). The car was running with him until some thieves stole his gasoline (and likely stirred up decades of crud in the tank). The car was continuously stalling. He then decided to put it up for sale. I bought it thinking it I could perhaps try to revive it (other people take in stray pets, I take in stray cars...) but couldn't get around to it until now. I cleaned up the fuel lines and replaced the pump with another (as well as other assorted items as outlined in the main post above). You now know as much as I do.

Now off to wade through the archive again...

WAQAS in Austin, Texas

[Shvegel]

are you refering to the pump at the tank or the injection pump that you changed?

If you remove the side cover of the injection pump you should see the pistons(plungers) moving up and down. You might need a mirror.

[waqas]

I am referring to the fuel injection pump bolted to the engine. I had previously replaced the fuel-feed pump in the back.

Thanks for the tip-- I shall try removing the side cover.


WAQAS in Austin, Texas

[waqas]

Today, I removed the little threaded cover in front of the pump and screwed a 4mm bolt into the rack to try to move it: no luck! It was stuck in there ... also, moving the throttle linkage did not affect the rack (I had my finger on the bolt-head while moving the linkage). Is there some other way it moves?

Next, I disconnected the fuel lines on the injection pump, removed an outlet fitting from the pump housing (feeding cyl. #1), and then attempted to remove the check-valve: it would not budge at all! I tried all sorts of jury-rigged ways, including Joe Alexander's recommended method of screwing-in a metric fitting around the check-valve, but I had no luck whatsoever! Meanwhile, I've soaked the first 4 injection pump outlets (fittings removed) in PB-blaster. Tomorrow, I shall again try to budge the check-valves.

Any and all suggestions are most kindly appreciated!

WAQAS in Austin, Texas

[glennard]

Hi, Pump will not pump correctly as long as the rack will does not move.  The rack rotates the pistons as it moves, thus increasing/decreasing the metered amount of gasoline.  Apparently your pump is rotating.  The pistons maybe going up and down or stuck up.  The rack is stuck at some position-between 0 and 100 percent.  Review the comments/thread on how to free up the pump. I expect to bring a frozen pump to PUB(Pagoda University Blacklick) for hospital work.

[glennard]

Hi, Pump will not pump correctly as long as the rack will does not move.  The rack rotates the pistons as it moves, thus increasing/decreasing the metered amount of gasoline.  Apparently your pump is rotating.  The pistons maybe going up and down or stuck up.  The rack is stuck at some position-between 0 and 100 percent.  Review the comments/thread on how to free up the pump. I expect to bring a frozen pump to PUB(Pagoda University Blacklick) for hospital work.

[Shvegel]

I made a tool to pull the check valves. If you want to borrow it I will be home this weekend and would be happy to mail it out to you.

patrickprice(at)hotmail.com

[waqas]

Patrick, Thanks very much for the kind offer. I shall contact you off-line.

I guess the more important questions are:
o How much force is typically required for removal of the check valve?
o Will I damage something by applying too much force while removing these?
o Is the check-valve to cylinder-wall tolerance similar to that of the plunger to cylinder-wall?  (the latter is very close-- apparently "millionths of an inch" according to JA). If so, then I can understand that the check valves might be corroded stuck...

In Joe Alexander's excellent injection pump tour, he shows that these can be removed by simply pulling them out via a metric fitting. Mine seem to be really stuck in there (even the supposedly functional injection outlets).

When I get home this evening, I'll see if the penetrant-soaking had any effect. Thanks again for all replies!

WAQAS in Austin, Texas

[waqas]

Glennard,  Thanks for the reply-- I'm looking forward to meeting you and everyone else at the PUB!

I plan to open the side-hatch and douse all the plunger return-springs etc. in penetrant.  I'll keep everyone posted.

WAQAS in Austin, Texas

[glennard]

Wagas, Side hatch cover removal and 'Deep Creep' or 'Jig-a-Lou' etc. and push/pull on the rack(M4/5 bolt) should do it.  Avoid major disassembly!  That pump is a fine piece of machining, eh?

[Shvegel]

wagas,
Unless the pump is rusty penetrant will do you no good. What you need is a solvent for the dried fuel(varnish) that has accumulated in your pump.

Here is what I did to my stored for 26 years pump:

Remove the pump from the engine

Lay it on it's side with the side cover removed

Remove the inlet and outlet fittings for the fuel rail(fore and aft on the side with the side cover)

Fill the fuel rail with Laquer thinner thru one of these openings

Block up the bottom of the pump a little so you can pour a little laquer thinner on the bottom of the plungers(pistons) through the side cover. I seem to recall just filling the entire side but without having a pump in front of me I can't remember if there are any rubber seals in the area that should not be submerged in thinner. Don't worry about the plungers as they do not have seals. They are so finely fit into their bores that they do not leak without seals(gaps smaller that fuel molecules)

Let it sit for a half hour or so

Dump or sop up the excess fuel in the side of the pump so you can lay it flat again. Leave the thinner in the fuel rail.

while turning the gear determine which plungers are stuck and ever so gently waggle them from the bottom with some sort of pick or hook tool. I used a dentist's pick but if you are not really confident with your hands you might want to dull it a little before you go jabbing around in there. I recall working the plungers back down by hooking the spring on the bottom of the plunger and helping it back down.

Under no circumstance should you touch the sides of the plungers where they fit into the cylinders. If you scratch it even a little you are done.

[graphic66]

Another great solvent for insantly removing gasoline varnish and carbon is decarbonizing fluid. You get it at marine stores. It is commonly used in 2 stroke engines to decarbonize the cylinders and pistons. OMC calls it engine tuner, Mercury has a version and at West Marine they have some generic stuff also. I use it at every oil change. I think this would really eat up the varnish in the pump fast. It makes carb cleaner look like water. I have sprayed gumout on fuel varnish and scrubbed with no results. I spray on decarbonizing fluid and it just melts it away. It really cleans an engine great also. Somewhere around 1980 they stopped putting dispersants in gasoline and two stroke engines had to switch to TCW3 oil which has dispersants. Thats when they came out with the decarbonizing aerosol and also a fuel additive. I also use the OMC fuel additive every now and then.

[waqas]

Folks, thanks for all the advice! I think Glennard is correct-- that sure is a fine piece of machinery, so I won't try to remove the check valves until I've had a decent go at jiggling the plungers/pistons loose from below (side access hatch). I've already removed the access hatch and doused things in lighter fluid instead of penetrant (I've had reasonable results with regular barbecue lighter fluid in the past for cleaning injectors). If there's no movement by tomorrow, I'll try the decarbonization agent. Thanks again, I truly appreciate all the help!

WAQAS in Austin, Texas

[waqas]

Patrick,
Thanks for the step-by-step description. I think I'll postpone removing the pump until absolutely necessary. I've been using my sizable collection of ice-lolly sticks (my snack of choice during car-work here warm Texas!) as the 'wiggle' tool. I'd like to avoid sticking anything sharp into the innards of the pump...

WAQAS in Austin, Texas

ps. ice-lollies are known as popsicles here in the states... and I can't even begin to recount how many times I've used the sticks as harmless levers or wedges, etc, etc while working on aluminum parts!

[waqas]

After much wiggling, I got the rack to move by about 1mm (using the 4mm screw). My question is: how much is it supposed to move from lean to rich?

Also, on the R-11 pump (as opposed to the R-18 pump which clearly shows the springs and part of the plungers) the springs are not quite visible (you can barely see the top of the spring). What's a good way to wiggle the springs on these pumps?

WAQAS in Austin, Texas

[Markus]

You should be able to move the rack about 1/2 inch in either direction against a spring load, and should return (spring back) to the  nominal/neutral position, and it should do this with minimal effort. It should "glide" back and forth with no catching, or hanging up requiring any force to move it again.

[waqas]

That would explain it. I still have much to free up!  Thanks for the info. I've doused it in a decarb agent, so I'll check again tomorrow. The rack seems stuck in the full-rich position (the rack is closest to the access hole in the front of the IP).

I still think the stuck plungers are the primary cause of the stuck rack, but could the starting solenoid behind the pump be a possible culprit? (I believe it moves the rack to full-rich during startup). Can I remove the solenoid in order to access the other end of the rack? (I don't want to disassemble anything critical... yet)

Thanks again for any and all help!

WAQAS in Austin, Texas

[Markus]

I think your on the correct path.  Three things I would try:
1.  Remove start solenoid, check function of solenoid, and pin length, and travel when activated. Check if that has improved rack movement. If not.
2.  Remove warm run device, check rack movement, gently push down on plate that leans the mixture, it should move against a spring load, simultaneously, wiggle your rack bolt.  Check rack movement. If not.
3.  Remove altitude compensator, (if installed) check rack movement.
4.  With those components removed, if none of this achieves the desired rack movement results, the rack may not be moving because of rust/condensation/bad fuel followed by inactivity or, something has gone a miss with the mechanical linkages that normally move the rack from rich to lean. If in the case of the later, the IP would need to be serviced by a qualified IP technician. How did this vechicle run before all the work previously mentioned?  Is the basic linkage set up correct?

[waqas]

IThis evening I removed the starting/enrichment solenoid behind the pump, and it seems like it's working. I had trouble with the WRD screws, so I've applied penetrant for tomorrow.

In addition, I had a friend manually turn the engine while I observed the top edges of each plunger spring: plungers 1,2,4 are stuck (their springs don't move at all). Looks like they need to be coaxed back down.

Given the poor access to the bottoms of the plungers (this is the R-11 pump), I think I need to follow JA's advice from another thread: remove the check valves, and then gently tap down on the tops of the stuck plungers with some kind of wooden golf tee.

So a sprayed enough 'deep creep' on the check valves to completely drown them; came back an hour later, and the deep-creep was still pooled there. Are there _any_ gaps around the check valves? (for a thin fluid like a decarbonizing agent to flow through)

I understand that the early pumps did not have the ball-check valves. Does this mean these NON-ball-check valves are incapable of holding fuel in the injector lines?  If so, this would imply that they should at least allow fuel (or other liquid) to drain back into the pump from the check valve top (which my pump is clearly not doing).  of course, this would beg the question: why are they called check valves if they don't hold fuel from returning back to the pump when the car is switched off.  Bottom line: how much [benign] force is appropriate to pull out the check valves? (is there a seal, and how tight is this seal?)

Thanks for any clues at all!

WAQAS in Austin, Texas

[ja17]

Hello Waqas,

These check valves on the early pumps consist of a spring and a "cone style check valve". This arrangement is quite different from the check valves on the later pumps.
Your check valves are similar to a valve in your cylinder head but it is upside down and the spring keeps the valve closed normally so you will not have much luck around it with penetrant. You will have to remove the fittings above them on the pump and then remove the spring and each "cone style valve" at this point you will be able to see the top of the plungers and add penetrant.

Joe Alexander
Blacklick, Ohio

[waqas]

Hey Joe, thanks for the reply!  Based on preliminary pulling/tugging, I've concluded that I'm going to need to press out the check-valves. Does this sound right?  Of course, I'm going to place a few large washers around the top edge of the pump/check-valve opening to ensure the soft aluminum housing doesn't get damaged.

Any other thoughts?

WAQAS in Austin, Texas

[waqas]

After having watched first-hand how Joe freed-up Glennard's IP during the Blacklick Tech Sessions (in a matter of minutes!), I finally decided to tackle my own IP. I had previously tried some other tools and tricks, but to no avail.

I used the little air-fitting Joe recommended, and used it to press out the check-valves for pistons 1 through 4. I could now clearly see the pistons stuck in the highest position (1,2, and 4 were stuck high). I then repeated the following sequence of steps until the rack was free:
(1) doused everything in deep-creep (including the little access hole for the rack in the front of the pump)
(2) alternately tapped down on the stuck pistons with a wooden golf tee as recommended by Joe, until each piston had hit the camshaft
(3) turned the crankshaft in front of the engine by hand (with socket wrench)
(4) tried to wiggle the rack using a 40mm long bolt screwed-in to the rack from the front access hole
(5) repeat from step (1)

Once I was able to slide the rack back-and-forth with the bolt, I kept moving it until it was loose enough to spring back to it's normal position. I then tested the rack using the linkage, and noted the rack only move a small amount (a few mm), and then sprang back to it's rest position.

Once I'd connected everything back (torqued all fittings to 18 ft-lbs), I started the car and cranked until the fuel lines were charged-up, and she started up! I drove her around the block a few times, just to clean out the system a bit. I think I'll try to adjust the linkages next. I won't worry about about rebuilding the IP until other things have been sorted out first.

Guys, thanks for all your help in this adventure. And thanks especially to Joe for patiently showing us all at Blacklick how its done!

Waqas ('Wa-kaas') in Austin, Texas

[ja17]

Congratulations and hello Waqas,

It looks like your trip to Blacklick is already paying off!

Joe Alexander
Blacklick, Ohio