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83' 300d
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343 Posts
Discussion Starter #1
So i have an 85' 300d turbo. I've done a valve adjustment, both fuel filters, tank strainer, egr delete, throttle linkage adjustment, and cleaned the banjo/lines running from the intake to the ALDA. That's the short list of stuff i've done - the only stuff i haven't is checked the injection pump timing and play with the injectors.

The real question is, why the heck is this car a super slow slug still???
I have an 83' that's almost identical, but it is waaaay faster off the line. Got any ideas???

While i do not have a boost gauge on the car, is it possible that the now unplugged egr and arv are causing a boost leak or obstruction? When doing the egr delete, all i did was yank the vac lines. Am i missing anything? How does this egr and arv set up work?

The car idles and runs fine, which is why i'm thinkin it's a turbo issue. Everything else is pretty much squared away...
 

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2001 Volvo V40
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2,954 Posts
First check the linkage and whether the fuel pump lever reaches the full-load position.

And how slow is slow? Do you have a 0-60 mph time? Should be around 13-14 seconds.

Check boost pressure at the ALDA, which is easy as there is a T fitting at the ALDA. Checking boost should be done at 4000 rpm at full load and should be around 0.7 to 0.8 bar.

Unplugging vacuum lines isn't enough, you need to seal/plug them so that there is no vacuum leak. Vacuum leaks should not affect performance though, but it can affect shifting.

Here you can see which vacuum lines to disconnect for a EGR delete:



The T fittings next to the red dots need to be replaced with simple (two-way) connectors.

There is a possibility that the EGR/ARF valves are in the open position, that will reduce boost.
 

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83' 300d
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343 Posts
Discussion Starter #4
How could my EGR or ARV be stuck open? And... if so, how do i close them? I want to make sure that my turbo is working properly before i go trying to hunt down problems. Any idea how i can tell if my wastegate is stuck open?



I've already done exactly what ya mentioned. I plumbed my vac system almost exactly as the map says.

As for linkage, there is a stop stud/bolt/plate on the injection pump. I didn't mess with the stop plate position, but i did make sure that the hammer on the linkage bottoms out on the plate, thus allowing full throttle. I'm basically assuming here that the stop plate is in the correct position...

As for checking boost, i don't have a boost gauge on the car. Still gotta find a dirt cheap way of checking my boost pressure.
 

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1967 250 SL, 1965 300SE lang
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3,062 Posts
My 85 wagon got a whole lot faster with the Trap Oxidizer delete kit and the EGR block kit. BUT I don't know if it is because of that, or because of a air leak at the (broken) manifold. Try to inspect the area where the manifold(s) connect to the block and make sure all of the studs are intact. I had a slow wagon too and now it isn't.
 

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1985 300CD
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2,137 Posts
My '85 300CD has the trap ox. It was very slow and had trouble shifting. I cleaned the banjo bolt and adjusted the alda. I also removed the ARV vacuum lines and plugged it along with removing the EGR and blocking the manifold.

It's much peppier now, but I still have to replace the trap ox can with the bypass pipe I have. The PO drilled out the ceramic contents from the can so it's now just a large expansion chamber. Once the bypass pipe is in place I think it will be a quick as my 300TD.
 

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2001 Volvo V40
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2,954 Posts
If you check the boost pressure at the ALDA, you can establish whether there is a leak in one of the valves.
 

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83' 300d
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343 Posts
Discussion Starter #8
Well, that retarded trap ox is supposedly replaced with a trap cat. Think the trap cat is really that much of a performance bog?

I'll look into any broken studs on the block/mani. I guess i gotta hunt down a boost gauge too.
 

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83' 300d
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343 Posts
Discussion Starter #9
Well, i just hooked up a boost gauge to the line that leads from the intake to the ALDA.

It slowly develops 6psi. It's strange how it is slow to develop and kinda slow to drop off.
I looked at the ARV. It seems that there is a spring covered in a rubber boot that seals off the cold side of the turbo. I guess without any vacuum being applied to the valve, the spring tension/rubber boot is sufficient to seal the hole in the cold side closed.

From what i can see, exhaust is generated in the cylinders, then is pushed out into the exhaust mani. From there it's first path is to the EGR pipe, then to the turbo. After it exits the turbo, it goes to the trap cat and downpipe. Right???
Is it possible that my EGR is stuck open, thus venting a HUGE amount of exhaust gas into my intake and not giving my turbo enough gas to spin up and make boost?? What's the relationship between the EGR and low boost?
 

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380SL diesel
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1,275 Posts
Well, i just hooked up a boost gauge to the line that leads from the intake to the ALDA. It slowly develops 6psi. It's strange how it is slow to develop and kinda slow to drop off.
I looked at the ARV. It seems that there is a spring covered in a rubber boot that seals off the cold side of the turbo. I guess without any vacuum being applied to the valve, the spring tension/rubber boot is sufficient to seal the hole in the cold side closed.
I'm running a Cali '85 617 in my 380SL. Initially I had all the smog stuff hooked up in order to get the vehicle retitled, but am now slowly working through things and it is amazing the difference at each stage. Took the trap cat off, and replaced it with a test pipe (testing is going rather well, by the way) as well as a block off for the EGR and the ARV. My turbo was slow to spool initially but would get to 9.5 psi eventually. After I removed the trap cat that was disintegrating and removed two large hunks of ceramic lodged in the turbine housing, it spools quickly and has a lot more power.

You should be getting close to 10psi, and it should spool quickly. Check your turbo for damage. Having that empty trap cat ahead of the turbo can't help at all. I'd block off the EGR, but you're not going to be able to do that until you eliminate the trap cat.

I built an extra test pipe when I did mine if you're interested. Also have the jig available if you want to build your own.

Hang in there, you'll get it sorted out.
 

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83' 300d
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343 Posts
Discussion Starter #11
Last i checked the turbo was in decent shape. There wasn't much shaft play.

I also applied vac manually to the EGR and after releasing the vacuum, i could hear the valve pop shut. I guess the EGR valve isn't my culprit? Thoughts?

Think adjusting the wastegate will help?
 

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380SL diesel
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From what i can see, exhaust is generated in the cylinders, then is pushed out into the exhaust mani. From there it's first path is to the EGR pipe, then to the turbo. After it exits the turbo, it goes to the trap cat and downpipe. Right???
Actually not quite.

Exhaust gas exits the cylinder through the exhaust valve and dumps into the exhaust manifold. The exhaust manifold is connected directly to the trap-cat. The trap-cat is connected to the turbo and the turbo is connected to the down pipe.

There is a connector on the end of the trap cat to which a pipe that goes to the EGR valve is connected. When the computer wants the EGR valve to open, a voltage is applied to the switchover valve which allows vacuum to go to the EGR valve which then opens allowing a relatively small amount of hot exhaust gasses to enter into the intake manifold.

The fact that the empty trap-cat sits in front of the turbo causes a lot of issues - turbo lag, temperature drop, back pressure, and who knows what all else. Ideally the exhaust manifold would connect directly to the turbo, but the closest we can get with the Cali set up is to add the 12 inches or so of test pipe.

Hope this helps.
 

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1983 300CD
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136 Posts
I had almost the exact same situation as the OP when I first bought my 1985 300CD California...super slow off the line and would max out at about 55mph.

Turns out the rubber part of the throttle linkage was almost torn completely off. I replaced this and it helped quite a bit, but the car was still very slow.

I finally discovered that nearly all of the intake/exhaust bolts had rattled loose, and the manifolds were just hanging on by a thread. Once I torqued these bolts down it ran like a champ.

I have since converted over to an entire federal turbo setup and the power difference is night and day.
 

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83' 300d
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343 Posts
Discussion Starter #16
I wish that was the case. The trap ox has already been replaced with a trap cat... From what i understand, you can verify that it's a trap cat based on a part number that starts with a 126
 

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2001 Volvo V40
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2,954 Posts
Boost pressure must be around 0.7-0.8 bar or 10-11 psi. You measure this at 4000 rpm, preferably under full load condition. Check at ALDA first, then directly (without the overboost protection valve) on the intake manifold.

You say you adjusted the linkage, but have you checked whether the pump lever reaches the full-load position when you press the accelerator pedal (use an assistent to press)?
 

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I'm running a Cali '85 617 in my 380SL. Initially I had all the smog stuff hooked up in order to get the vehicle retitled, but am now slowly working through things and it is amazing the difference at each stage. Took the trap cat off, and replaced it with a test pipe (testing is going rather well, by the way) as well as a block off for the EGR and the ARV. My turbo was slow to spool initially but would get to 9.5 psi eventually. After I removed the trap cat that was disintegrating and removed two large hunks of ceramic lodged in the turbine housing, it spools quickly and has a lot more power.

Check this link:
http://www.benzworld.org/forums/w123-e-ce-d-cd-td/1627871-what-did-you-do-your-w123-46.html#post5386130

Did the inspector specifically check for the cat?
The usual is VIN and engine number to registration.
Unless the car has been customized, for example, a 32 Duce with a 1980 302 engine. The issue then becomes 32 or 80 emission standard. The "out" is each year first day of DMV business the first 500 registrations get a pass on the later standard.
 

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380SL diesel
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1,275 Posts
Did the inspector specifically check for the cat?
The usual is VIN and engine number to registration.
Unless the car has been customized, for example, a 32 Duce with a 1980 302 engine. The issue then becomes 32 or 80 emission standard. The "out" is each year first day of DMV business the first 500 registrations get a pass on the later standard.
The summary requirements for an engine swap in CA are as follows:

[1] The donor engine must be from the same year or later as the target car
[2] The donor engine must be from the same class of vehicle as the target car (i.e. passenger car-passenger car, light truck-light truck, heavy duty truck-heavy duty truck)
[3] All the smog equipment must be present and working as on the donor car as of the date of manufacture (inspection and verification done by the BAR)
[4] If the target car is '75 or earlier there are no restrictions

When I had the BAR do the inspection everything was on the car and working as it should.

If it's a diesel swap, the title gets changed to a "diesel" as the motive power and the smog requirements essentially go away, because diesels are not subject to smog '98 and earlier.

Hope this clarifies the situation for those of us in CA
 
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