First drive

C

corsachili

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I have finally driven my newly reassembled CSL. For those that might have lost the thread, this project began with me trying to determine what was causing a very annoying stumbling/hesitation problem that I could not fix. I ended up with the head off, learned that the head had been butchered, contemplated many different options and ended up installing a used stock D-Jet head. During this period I had the engine compartment painted and a few problems with the original paint fixed.

After many trials and tribulations I finally got the engine back in and have now taken the car on two short test drives.

It's too early to know for sure if the problem has been fixed. The car does run, but there are a couple disconcerting problems. The first is that from 1K to about 3K the engine feels rough, almost like it's not hitting on all cylinders. At 3K is cleans up and smooths out rather nicely, but then the pinging starts, as if the timing is way too far advanced. I don't know how sensitive the D-Jet engine is to not having an air filter, but I am currently do not have one installed as I have had a bear of a time finding one. I'm supposed to have one today, so hopefully that will be the fix (although I can't believe it will). I had the timing set at 7 degrees BTDC with the vacuum hose connected (as called for, and the setting I had with the previous head) and it pinged badly. I retarded it 2 degrees and it's still pinging. Is it possible that the stock head has too high compression and that it doesn't like the 91 octane fuel us Californicators get? Do you other CA based CSi owners have to use Octane boost to keep your cars from pinging?

We'll see if the airfilter makes any difference in the rough running or the pinging, but as I said, I can't believe it will. I'll check in later when I've got an airfilter.
 
TJ, the first thing I would do is buy some 104 octane at the union 76 at Foxworthy and Almaden expressway to see if it is the fuel.

And yes, my Csi does not run good on CA gas. I had to retard the timing a little.
 
D-jet is a speed/density system that uses manifold pressure to adjust mixture, the air filter has nothing to do with that. If anything the car may make a little more power without it ;) just change the oil often...

the engine is higher compression than the 'US' engines and without the ability to retard timing for knock and the like, crappy gasoline could be a problem. I'm also concerned about the (increase in?) ethonol additives here lately. maybe try some octane boost stuff or that other fuel.
 
i have a euro (german delivery) 73csi. at the suggestion of peter s, i've been adding "octane supreme 130" to what passes for gasoline here in CA. i've been happy with the results -- bye bye pinging.

http://www.batterystuff.com/fuel-treatments/


usual disclaimers apply.



-Adam

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Mechanical Advance

You could put it on a scope and check the total advance, should be all in at 4000 rpm. I also have a fairly tight Euro '73 and have no problem with 91 octane. It has 32/36 Webers and runs a bit rich, but I set it to 34-35 degrees total advance and it runs great, no stumble. Maybe be the bits inside are worn or have been modified......or it's a mixture problem.
 
For my Euro Spec M90 motor, I add 25% toluene to my 91 octane gas. Smoothes things right up. I run stock timing with Bosch W9RLS Silbur plugs.

I am not super familiar with the D-Jet, but my M90 is an L-Jet.

When I redid the head on that it also ran like crap. It turned out to be a combinatoin of Throttle Position Sensor setting, and MOST IMPORTANTLY, vacuum leaks. Even the slightest amount of leaked air will cause the car to lean out. Lean runnig aggravates pinging and causes all manner of rough running issues.

To see if this is an issue on the D-Jet try removing the oil cap while the engine is running. It should get a bad case of the shakes...

The primary culprit is the valve cover. Make sure it is sealed on both sides of the gasket. I use Permatex Hylomar (gooey non hardening). The other areas are the various breather and vacuum hoses, and the dip stick o-ring.

Fix those before you try any other heroics.

HTH

S
 
Thanks everyone for their advice. I've done a few things si nce I first posted. I poured in a bottle of octane boost (104) and retarded the spark a bit (4 degrees BTDC at idle, vacuum hose connected). That helped a lot and the pinging seems to be gone. The roughness has also gone away, perhaps just the head getting cleaned up as it hasn't been run in some time (remember, this was a donor head, and its history are completely unknown). I have to take it for a longer drive to see how she acts, but the octane boost defnitely helped. By the way, Toluene is the major ingredient in all octane boosters and carb cleaners.
 
interestingly enough, D-jet should not suffer from vaccuum leaks as much as L-jet due to its design. Since D-jet measures manifold pressure, it will automatically adjust the mixture to the new pressure (caused by the leak). You will probably not notice a small to medium leak for that reason. Meanwhile L-jet will either stop running or run very poorly because it has no way to meter and adjust for that leak (being an air flow system).
 
I figured the D-Jet would be somewhat different from the L-Jet.

If it is still missing, then try splicing a 5 K ohm potenmtiometer into the air temp sensor (I assume it has one of these to measure air density). Higher resistance typically means lower temp, and so you can remedy a lean condition this way.

S
 
TJ,

Two thoughts.

First, 91 octain is not enough to stop the pinging. Either one small bottle of booster per tank or 4 gallons of 100 octain "happy gas" works for me. 91 octain is fine if you dont put your foot into it. Orrigionaly designed for 93 leaded which I have been told is about 94 octain.

Second:

Have you rebuilt your distributor. The D-Jet uses both the standard advance and the lower mechanical contacts for data to the ECU. The springs can get junked up or corroded and have an effect on the power band. The lower contacts can also wear out and generaly require replacement every 60K. Last the lower seal can allow oil to pass through and reduce the function of the lower contacts. If a few hard left turns start you sputtering, thats oil on the lower contacts.


Good luck,

Tom R
 
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