Puzzling low power/performance issue *unless* timing is over-advanced

Try cleaning the MAF sensor to see if that helps.


The proper term is REDNECK engineering. :laughing: :upside_down_face:

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It might be worth your time to check the cam timing. One cog off on the belt will cause your problem.

For cam timing look at the rockers/lifters for the point where the exhaust finishes closing and intake starts to open.
That should be right at TDC (180 cam degrees from ignition TDC).
If there’s overlap, intake and exhaust should be equally depressed at TDC.

If the spark plugs wires aren’t connected to the plugs correctly, that could cause this symptom. In fact there was a puzzler about this. Ray had a customer w/a poorly running engine, and no luck diagnosing the problem. Later Ray noticed his shop-employee (a mechanic) was moving all the spark plug wires to different plugs on a customer’s car. Puzzled, but not mentioning anything to the mechanic, Ray came back later and found the car was now running well. As I recall the mechanic (for a reason I forget) wanted to either retard or advance the timing beyond what was possible by turning the distributor, and the only way to do that was to move plug wires so the no. 1 wire was connected to plug 2, the no 2 wire connected to plug 3, etc.

well, i’m pretty sure if i do this i’ll end up with something like the pretty drastically advanced timing that it had from the PO. my concern is that – while driveable – this would cause long-term damage, like clogging the cat, busting the exhaust manifold, etc. – basically a redo of what happened already.

curious if you have (hillbilly?) thoughts about how to tell whether “wrong”-but-sounds-good timing is causing damage?

[hi folks, i got prevented from posting for 24 hours as a new user posting too much! hopefully won’t be knocked off again.]

yes, that makes sense and in fact, the cam was originally one tooth off (on the mighty max/ram 50 it’s common to accidentally set the timing belt to the seam between head and block, rather than the obscure line 1/2 inch below it). that’s why i took everything apart and reseated the timing belt. i’m pretty sure the cam and crank are now on matched marks! i’ll upload pics in a bit if that will help.

yes, thought about that. i’ve swapped out the MAF from the known-working truck, to no effect. will try again though, just in case!

to be clear: you’re suggesting i pull the valve cover, and then watch the movement of the exhaust/intake lifters on the #1 cylinder to confirm that the exact middle of transition from exhaust closing to intake opening is (cam) TDC?

and i understand that this cam TDC will be 180deg away from the TDC i find by feeling for the compression (air pushing out borehole)?

and this will provide independent confirmation of the punched dot matching the timing line on the block?


well, the plug wires are definitely set, from #1 at TDC, to #3, #4, #2, which is the correct firing order per manual.

this has been true throughout.

in trying to understand the story you relate, i’m wondering why one would move the plugs over, and whether that relates to the “redneck engineering” approach mentioned before. ie… something about that approach kind of implies – “well, if it has good acceleration, forget what the timing light says!” – even if you have to move the plugs, change the tooth of the dizzy, etc! i “know” this is dangerous, but why exactly – and how can i tell?

the cam timing being off by a tooth is the biggest concern for me. clearly this would lead to intake and exhaust being all whack with the piston location. as i say, per my understanding of the manual etc. etc., it is set correctly – but could i be wrong somehow? stretched timing belt? improperly set tensioner? something else???

deeply puzzled…
(and grateful for all the suggestions!)

The one thing you mentioned about advancing the timing and that leading to sooted spark plugs is a bit odd to me. I read this as the plugs are not sooted up with the timing retarded?

Retarding the timing has a rough effect of causing the air/fuel mix to richen. Advancing the timing has the effect of leaning it out. It would seem to me that some bucking might occur with the latter unless it is running rich due to another problem.

Running rich can also be caused by a leaking fuel pressure regulator or worst case; low compression in the engine.

I reiterate about too much timing advance. In some cases it is noticeable due to spark knock and in some cases the developing damage may creep up on the unsuspecting person behind the wheel. When things go bad pistons can disintegrate and also take out the cylinder walls along with causing valve/valve seat damage.

Sorry I can’t be of more help but if the vehicle were mine I would connect a vacuum gauge and see if anything pops up. They are cheap, easy to use, and can reveal a lot in seconds.

thanks, @ok4450! these are useful thoughts, and it definitely may be worthwhile to explore this angle more. responses inline below:

well, i don’t really know. they were originally fine when i put in new ones, then pretty badly carbonized when i first checked them after test driving with the timing set “correctly” at 7 deg. checking them again now, when testing for compression stroke, they were carbonized again. however, i think when i did a test drive with the timing at extra advance, the tip started to clean up. not entirely sure, but that would match your suggestion. will check this more tomorrow.

this i’d not learned before! very useful…

before i started focusing on the timing being off, i knew it was running rich (because of plugs). i assumed that was related to the whatever is causing the timing to be off – but what i’m hearing from you is that maybe it’s the other way round! ie. maybe the rich mix is the underlying issue currently, and the timing has to be super-advanced to lean it out enough to sorta-work. yes?

yes and yes!

i’ve tested compression and it seems fine. one of the reasons i’m still working on this truck so much – seems like good innards, if i can get this darn puzzle figured out.

when i thought the issue was just rich mix, i was “sure” it was the fuel pressure regulator. they’re a huge pain to swap on these, requiring taking the whole intake manifold off, but i did swap it with the parts truck’s. but no improvement. sigh

(just testing the fuel pressure is kind of challenging because there’s no port and requires completely specific tool to attach one. and it’s a metal line, so cutting it and splicing one in is hard too… but maybe i just don’t know how? or should try to find the tool?)

are there other problems that could cause running rich, i may not have thought of/heard about yet?

yeah, this is why i’ve taken the truck out of commission even though it “could run”-- for the last six months now! really hope to get this figured out!

no, you have been and are being a huge help! it’s got to be something, right? and coming up with ideas is great.

i’ll get myself a vacuum gauge and do some testing.


Leaking fuel injectors, wrong fuel injectors.

People have been known to put higher flow rate injectors into engines thinking more fuel = more power, then end up with similar problems.

like going from 18 lbs./hr to 23 lbs./hr

Yes to all of your questions.
I am assuming this engine does not have variable valve timing.

So are you getting pinging when the timing is advanced that much?

Something wonky is going on, because advancing the timing shouldn’t reduce the fuel burn - that’s usually what happens when you retard it too much. You should also notice a power loss if you advance it too much, which goes to my question above. Overly advanced timing causes the explosion to happen while the piston is still on its way up, and the explosion fighting the piston shaft not only reduces your power output for obvious reasons, but also causes that pinging sound, and if it goes on long enough will cause damage.

If you’re not getting pinging, I suspect you’re “advancing” it to factory spec because something is way off, but that’s not a situation you want to just live with because whatever made it go off that far is likely to get worse, and then you won’t be able to adjust it to spec anymore.

I’m not sure if your truck has electronic timing or not. Mine didn’t, but it was an '88 and technologically was barely more advanced than Fred Flintstone’s car. If yours doesn’t, then the distributor will have weights and springs in it to adjust timing as engine speed goes up and down, and those can get out of kilter and cause issues. That may be what’s going on with the wiggling timing marks.

What I would do is find a hot rod shop, or a shop that’s been around a long time with an owner who never throws anything out. You’re looking for someone with a distributor tester. Have them give your distributor a workup to see if something’s wrong in there.

Was the distributor removed and possibly reinstalled out of time?

Found this, Interesting note grounding the mode wire
First the cam belt timing should look like this.

closer look at the bottom end

you have to make sure the balance shaft on the drivers side is in the correct position.

dowwn load this manual for instructions http://www.mmeierle.com/images/Max/1…2%20ENGINE.pdf

page C 34 has the instructions. You will want to save that manual for future reference.

The actual Timing procedure is a bit of a trick, since the computer controls the timing, you set the “BASE” timing by grounding the timing mode wire and setting the distributor to 3 to 7 degrees BTDC

The timing mode wire is here…Timing Plug.JPG remove the cover and ground with a test lead or similar.

more information and procedures are available in the 216 manuals post here


Good luck


Since you mention that the compression “seems fine” I will ask what those numbers are. Low compression can also create a rich condition due to incomplete combustion.

The general rule of thumb is that good compression will be 20 X the compression ratio.

I doubt the timing belt being one notch off would cause this symptom. That’s a red herring imo. If you ever hear loud sounds coming from the engine, like coins rattling in a shaken metal can, stop the engine immediately; that’s serious pinging and will damage the engine. I had that problem one time when I inadvertently switched a vacuum line on my truck. The vacuum advance input to the distributor got connected directly to intake manifold vacuum, so it was running way too advanced at idle. And , yeah, I could definitely hear the “coins rattling around in a tin can” result. I wouldn’t advise just timing the engine by ear. You have to figure out why this is happening, otherwise you’re never get the smooth running engine you want. Your symptom is a clue, so get your Sherlock Holmes deerstalker hat firming on you noggin, propose a theory, and do the experiments that prove or disprove.

all between 160 and 170. which is pretty spot on with a compression ratio of 8.5. the “seems” part is because it’s a cheap gauge, so i’m not sure the absolute numbers are perfectly accurate – but that they’re relatively close is good.