Cdi won’t rev past 3000rpm

[GMC28 4]

I’ll do the usual digging/searching, but haven’t seen this before and thought I’d post the question:

On my short drive yesterday to/from town, In lower gears things seem fine, but I first noticed in 5th it wouldn’t rev past 3000 rpm.  Pulls/accelerates normal at lower rpm.  Happened when on the highway when I ofter let it rev into the low 3000’s before shifting to 6th.

later it rev’d normally, as I let it rev to 3500 in a lower gear just to troubleshoot.  Hmm…. Figured I must Must have been imagining things.  But then a few mins later the same thing in 4th and 5th where it just stops accelerating at around 3000-3100rpm.  
no other obvious issues or symptoms.

throttle position sensor going whonky?

 

 

[Sydney 218]

turbo waste gate stuck ?    happened to one of mine.   easy fix.   wd-40 and a pair of pliers and wiggle it back and forth till it looses up.

[Willys 747]

57 minutes ago, Sydney said:

turbo waste gate stuck ?    happened to one of mine.   easy fix.   wd-40 and a pair of pliers and wiggle it back and forth till it looses up.

As Sydney has said, This happens to mine almost on a regular basis now after allowing it to sit after a heavy rain. Somehow the waste gate quickly gets rust around rod where it travels through the exhaust manifold body and it sticks. Easy fix, I use never seize after penetrating fluid and wiggle it to the full travel of the waste gate. The hardest thing is removing the rear bumper but if you have done this a few times it's a non-issue. 5 bolts and two wires a couple of screw and it slides off.  Make sure you put never seize on all bolts for next time...

[GMC28 4]

Many thanks-

I’ll dig into that next weekend, and do some other annual maintenance.  My father loves driving it so I don’t drive it nearly as much these days.  Don’t think he even noticed any issue.  
cheers

[LooseLugNuts 557]

use a never seize that contains nickel or graphite...or both...

[GMC28 4]

Hoping to get out to shop this weekend to  get it lubed/freed up.

interestingly the little computer plugged into OBD2 shows higher avg fuel economy than usual. Makes sense I suppose with little or no turbo boost happening. But I’ve generally always driven it “gently”, and even now up until around 2700+ on the rpm it hasn’t felt much different without the boost, so I wouldn’t have guessed the fuel economy would jump like that.  

[Willys 747]

I get rediculous fuel economy with my CDI, but I also baby it for the most part. I shift up around 2500 and let it drop to 1800 RPMs cruising around. Now, I live at lake level and it's basically flat lands here, slight rolling hills.  I average 3.5 litres per hundred kilimeters driven some days if I don't try and watch the gauge it drops to 3 for some reason...maybe I'm fluctuating too much when trying to get it to drop further?  I also drive 5 over the speed limit all the time on the back roads and 10 over on the highways. It also has  had a what I would call a hardish life before me, some younger person beat it well from the way he took me for a test drive...lol.  So, maybe it's a very well loosened up engine that doesn't burn a drop of oil between changes. Who knows.
BUT, getting back to the no-boost issue....you will definately notice it when you want to move forward when the waste gate is seized.....it won't excelerate worth a damn! But if you get used to it and baby it it shouldn't bother you that much. You just need to leave even more than a 5 ton gap in traffic when you want to merge with traffic...lol.

It's definately worth fixing it....imho.

 

[GMC28 4]

Off topic from thread title, but getting into the turbo fix I see my father lost the twist lock fastener for the engine cover in the baggage area.  Anyone know of an easy place to source one of those?

[Willys 747]

18 hours ago, GMC28 said:

Off topic from thread title, but getting into the turbo fix I see my father lost the twist lock fastener for the engine cover in the baggage area.  Anyone know of an easy place to source one of those?

Possibly Ebay ...?   Or find someone who has a good scrapyard close to them up here where they could buy it for you and ship it down to you....but I think I saw them on Ebay  or something similar...good luck. My local scrapyard just crushed all their Smarts as I was basically the only regular going in after bits and pieces and space was at a premium for better paying vehicles, so they disappeared....sniff sniff....

 

[GMC28 4]

Sounds good Willys, but not even sure what to call that little piece… I’ll fumble around and figure it out.  Those aren’t that unusual, just need to work out what they’re called then the web search and eBay should yield some results.  Too bad about the smart junk yards, that’ll hurt in the long run.  Wondering if I should try and pro-actively buy a couple items that i think i may eventually need.  Bit of a crystal ball type thing, but I suppose there are a couple things on that motor that are more clearly life limited that I should consider scooping up…

I would have thought a turbo would be good to have, but reading a bit on this topic on this forum i see some have replaced them and some say they tend to hold up well.  May look at that some more.

 

Did some periodic service yesterday, as the first rains in a long while came through so it was my excuse to get into the shop.  Lubed up the turbo linkage as noted, and worked a charm.  Cleaned, serviced, inspected things and its about ready for winter.  Just need to chase down some of those plastic body “snaps” that connect the rear bumper cover/wheel well flairs to the body, which were old and broke.

[Willys 747]

1 hour ago, GMC28 said:

 Just need to chase down some of those plastic body “snaps” that connect the rear bumper cover/wheel well flairs to the body, which were old and broke.

IF you are talking about the white mounting holders or plastic mounts.....Mine broke and fell off also. I simply drilled them out so I could use a decking screw and drilled a hole to start the screw and then simply tightened it up until in the correct place. I also used 2 part epoxy that comes in a syringe and you simply squirt it out and mix the two liquids together ....I put that between the plastic and bodywork (clean paint off bodywork before adding glue) so between the glue or epoxy and the deck screw it has stayed put since very well.

 

 

[Willys 747]

Found it....here it is...enjoyu!

 

https://www.ebay.com/itm/122809438807?epid=1423328924&hash=item1c98035257:g:rZQAAOSw~Elg-PCr

 

[GMC28 4]

Many thanks Willy’s!

the snaps I’m referring maybe are different…. The new ones would just slide into place on the fender side, into the figure eight slots, then pop into the holes on the body.  Cheap, and easy, once i go get new ones.

 

For the engine cover securing hardware, that looks right, and I’ll give it a whirl, but it says its just for later model smarts.  Worth a try.  Cheers

[Willys 747]

Same mounts....as mine....push into body and slide into bodywork. The trunk lid clip comes with pin and clasp so to speak. It looks like the same pin but I have never remover the clasp part before. I thought it was just a formed hole in the bodywork but also never paid that much attention to it. So it may be the same or just the pin may be the same, your guess is as good as mine, I would risk it for that money imho.

 

[LooseLugNuts 557]

my 450 was missing the hatch pin when i bought it...i just forced a short lag bolt and it worked great for years

 

 

for those weird plastic clips that break above the wheel arches when removing the rear bumper i got some from the dealer...they were cheap

[GMC28 4]

Thanks all.  
grabbed some plastic body mounts at local auto store that I think will work.

ordered that latch pin off eBay and see how it goes…

[GMC28 4]

all good now - lubed turbo shaft, used Napa Auto side panel/fender plastic mounting connectors for rear fender flares, and the twist lock deal that Willy's recommended was the exact unit and worked great (fyi, the '06 450 uses that twist lock that shows on ebay as being for 2007-2015 models)

[GMC28 4]

well, more to the story...

 

Not sure if what i did before actually helped, but after apparently addressing the rpm issue as noted above i then let it sit again for several weeks.  But now after jumping in the Smart yesterday for the first time in weeks its back to showing the same bad behavior.  First heading out yesterday morning it rev'd up normally for a few miles, but soon after reaching operating temperature it would no longer rev past about 3100rpm.  at lunch same issue, and again last night going home.  this morning it behaved normally the whole way to work, and i drove it a bit harder than i prefer, to keep pushing the RPM's up and see if it would still rev up normally, which it did, even kept working fine when fully warmed up. 

The "warmed up" thing may be a false lead, but i mention it as maybe there's something to that.  The hot exhaust and its effect on the linkage....?

I will plan to get back there and mess (move/lube) the turbo linkage again, but does this sound like its just the turbo linkage issue still?

 

to be sure i'm clear, it hits about 3100rpm and just stops rev'ing... it doesn't slowly lose power, it just revs to that point and pretty much then its like a rev limiter comes on and pushing the throttle does nothing.    hopefully just the turbo linkage and back to normal after another clean/lube but thought i'd run it up the flag pole.

[Willys 747]

I just re-did my frig'in same issue last weekend or so...I took the wastegate actuator off the car and made sure it was hard to pull that rod and also to make sure it wasn't all gummed up..? I got it off easily surprisingly, then pulled it and it was semi hard to pull so I know it's working in that respect and not just flopping around without any spring pressure etc. Then i went after the hose that leads to it as in cleaned and checked it for any signs of rot or leaks. Nothing.  Next I reinstalled it and set the set nut way off to the left so i could tighten the adjustment nut right up to the level, I then got the adjustment nut snug lets say finger tight and then adjusted it so there was zero movement in the two mechanisms, the rod and the lever and it's swivel. Then I turned the adjuster maybe 1/2 a turn in some more and tightened the locking nut against it. My issue was i was getting too much boost and yes it didn't happen right a way either, it had to be run a few kms before it would happen. I use a ScanGageII to follow my mileages and boost etc etc   So it shows me what my boost is. It can't go much past 16.4 psi or it will go into limp mode which is what yours is doing. governs the engine to 3000 RPMs  My boost now is 15.6 psi and so far it hasn't tripped the limp mode, fingers crossed.  When the wastegate actuator was completely off I worked the wastegate lever by hand back and forth using penetrating fluid and it started working much smoother. It was sticky at each end of it's travel, maybe that helped? Now it flips from side to  side very easily. It took me 15-20 minutes of steadily switching it back and forth to it's limits. You could hear the wastegate flap or door jingle and it closed, so i knew it was working.
hope this helps. IF you do not use a devise similar to a ScanGageII find something that shows you your boost as you are driving it both hard and normally.   Remember I could go up to 16.4 normally and it never went off but when it started to climb higher it started the limp mode BS....

[GMC28 4]

thanks willy's-

i have the scangauge2 as well, and while i can't remember why i do recall that i can't measure boost... i have the MAP reading, but not boost.  installed it too long ago to remember why.  Any tricks/tips on the scangauge setup as to why I can't get a boost reading?

[Willys 747]

Nigel has his set to map and not boost so he should know how to switch between the two.  MAP isn't what my brain accepts for some reason but boost is, I don't know, but psi seems a more old school friendly measurement for my small brain to accept?  So he should be around sooner or later I'm sure.

[Nigel 287]

In the scangauge set up you can change pressure setting to psi or kpa.  I think 220 kpa is the max I’ve seen on my gauge.  210 kpa is the equivalent to about 16 psi boost.  

[Willys 747]

51 minutes ago, Nigel said:

In the scangauge set up you can change pressure setting to psi or kpa.  I think 220 kpa is the max I’ve seen on my gauge.  210 kpa is the equivalent to about 16 psi boost.  

See I told ya....lol...thanks buddy....lol

 

[GMC28 4]

Gotcha.

I’ve seen about 205 max, as I recall.  So I can watch for over that to see if it goes into limp mode for that.

I read about limp mode some years back when reading up on this forum about the car, but i never experienced it.  
i guess I’ll pull it apart and get a little deeper into the clean and lube.

 

[GMC28 4]

Wondering if i can “log” max values on the scan gauge II, to see if it does hit that overboost value now and then to kick it into limp mode.  Or is that a foregone conclusion about whats happening?  Again, I’ve just not seen limp mode on this car before, and had previously assumed I’d see some other indication if i was hit with it, like a warning light or something.