starting fuel presure and too slow speedo meter

[gwuisman]

This weekend I used my 1970 US 280sl for the first time after the winterstop. I used the stop to do a lot of improvements myself. Many of them I learned via this site and the Yahoosite. The following two problems were done by a mechanic because they were beyond my capacity. Unfortunately the results are a little bit disappointing. So I would like to heve views of the group on them.

1. Starting.

I had to crank 3 - 4 times before the engine starts. The mechanic said that it was a fuel problem. The engine did not get enough fuel due to lack of presure on the FI-rs. These date from 2002. In his opinion the lack of presure was caused by a leaking seal of the fuelfilter holder, which indeed was wet with fuel. So he changed the filter and the seal. No leak anymore now.

He also replaced the valve seals and the pistons and adjusted the valve settings. I put in a 70ha battery for strong starting energy. Despite these efforts the starting procedure is not significantly better. Any suggestions for the next winter?

BTW. The motor runs great whem started. When warm it starts immediately in a split second. It gets worse after a pause of 2 or 3 hours. It starts for a moment and than dies. It makes no difference if I let the FP run for a minute as suggested in an earlier post or not.

2. Speedometer

The meter measures in km but shows a 10% lower speed than the real speed and it counts miles in stead of km. The cable is new. Sometimes the speedometer is instable and shows the right speed for a second or two. Sometimes it falls 10 km back when slowly accelerating and the opposite when slowly taking off the gas. Isn't that strange?

The meter has been inspected by an expert and found ok. The size of my tires is ok. What will be my next step to avoid that my wife keeps complaining about tickets because she does not want to count while driving?  

Gerard Wuisman
1970 US 280sl manual

[George Davis]

Gerard,

it sounds like the infamous Cold Start Valve (CSV) isn't working.  The engine can be very difficult to start without it.  There are several things that can cause the CSV to not work, but diagnosis is pretty straightforward.  I don't know if the tech topics on this site cover it, but it would be worth checking out.

Regarding the speedometer, the transmission could be part of the problem.  If the output flange nut is loose, the output flange can move back and forth a bit, which also allows the speedometer drive gear in the transmission to move back and forth a bit.  This causes erratic readings and may eventually destroy the driven gear.  Tightening the output flange nut may solve some or all of the problem.  It's a somewhat involved job to get to the nut, as the transmission support plate has to be removed and the driveshaft decoupled.

If you do it, or have it done, I strongly recommend replacing the flex coupling on the end of the driveshaft with a new coupling and new bolts and nuts.  If any of the bolts are loose, it will quickly damage the driveshaft flange and/or the transmission output flange.  It's also a good time to replace the rear motor mount as it has to come out anyway.

George Davis
'69 280 SL Euro manual

[Albert-230SL]

Hi Gerard,

About point 1-Starting, I know of some Pagoda owners with similar problems: Difficult cold start, but mainly: difficult start when the engine is not 100% hot (for instance: after a 30-60 minutes stop). The Cold Start Valve (located in the intake manifold) is supposed to work more or less seconds depending on the temperature of the engine, and it should work around 1 second even when the engine is hot. For some reason, many CSV don't work as long as needed (maybe it's also your case).

Some of these owners have solved this with an additional switch under the dashboard, directly connected to the CSV. They give a touch to the switch (1 second?) before cranking, and the engine starts without problems. It's not the most scientific and "original" solution, but it's easy, economical, and it seems to work (any experience in the Group?). But first af all, you could check if your CSV works -even for a short time- or not.

About point 2-Speedometer, I also agree with George:
My "Pago" had the same symptoms, and it was a loosen connection between the speedometer cable and the transmision of the car, wich I guess is the "output flange nut" mentioned by George. Once the mechanic simply tightened this connection, the speedometer readings became stable and real. Anyway it's strange, because if you have installed a new cable, that nut was supposed to be recently tightened, wasn't it?

Please, keep us informed about the origin of the problems when you find it. Best regards,

Albert de la Torre Chavalera
Barcelona (Catalunya/Spain)
Feb.'64 230 SL Euro 113042-10-002432

[hands_aus]

Hey Gerard,

Before doing any connections always disconnect the +VE battery cable.

This is an interim fix until you resolve the CSV problem.

The switch is easy to install.
I connected a wire to the LIVE terminal of the under dash light, then to a push button switch (secreted in the under dash cover), then through the grommet for the radio wire, to the CSV terminal.
The case of the CSV is the earth connection.

Start the car in the normal way but press the switch for 2-3 seconds and release it. The engine should start very easily.

During our summer I found that on the first start of the day, I used this switch almost every time.

CSV....

I bought a 12V test lamp (90 cents) from an electronics store and connected it between the terminal of the CSV and earth.
This will test the relay for the CSV. If it  is working properly you will see a BRIGHT Light when you start the engine even when you have the switch connected.

You could use a multimeter to do the same test.

If the voltage is low because of some resistance in the wiring etc, the lamp will be DULL. If it is full voltage the lamp will be bright. The difference is very noticeable.

On my car there was a semi-broken wire near the relay. I fixed it and the CSV now works reliably.

I left the switch and test lamp connected.

Albert mentioned a 1 second relay. It was an MB modification to force the CSV to operate every time the engine is started HOT or COLD.

Part # relay 001 545 1624
Part # wiring harness 108 540 10 09

Please keep us informed of your progress

Bob(Brisbane,Australia)

[gwuisman]

Georg, Albert and Bob,
Thanks for your views and great suggestions. I will do the advised search and inform you about the outcome. However, it will take some time before I can pay attention to the maintenance of the car again. The next weeks I rather like to drive with it.
Gerard Wuisman.

[gwuisman]

Georg, Albert and Bob,
In May last year promised to report on the progress in solving the problems mentioned. I had no spare time to work on the car during the 2003 season. So I decided to do it this winter, the motor work by the mechanic. The results are as follows:

1. Starting.

It appeared that the CSV relay did not function well. It was replaced and the car cranks in one stroke.

Besides that, some other parts of the US-ignition system did not operate as they should. This resulted in irritating lightly stalling around 2200 revs. To tackle this problem, I decided to convert from the US to the Euro ignition system. By doing so, some five sources of trouble-making relays etc. were excluded. Now the car drives smoothly in all rev. ranges. The CO remained 4-4,5, no differance with the situation from when the US stuff was connected.

By all these changes an old problem arose again. Too low idle at a motor temperature of about 60 degrees celsius  (140 F.). I have to work on that again but how?

2. Speedometer

Regarding the speedometer, the transmission was the problem. The output flange nut was loose. This caused the erratic readings. Tightening the output flange nut solved the problem. Now the needle is totally quiet and shows just a few kms/h lower than the real speed.

3. Jobs I did and I am going to do

The taillight frame on the passenger side and the chrome rim on the softtop lid needed to be rechromed. I was lucky that this job was done within 3 weeks.  Normally it takes 8 weeks but in these times of economic recession service is better. Rechroming of these two parts costed Euro 125. It is essential to rechrome a tailight frame in time because corrosion causes deep pits which cannot be filled. The bottom sides of the rims were rusty like the mounts. I did not know that.

The bottom side of the rims have rubber protection strings, glued in the corners. Take them out with care as they are not available as spare parts!

I am considering installing a electronic ignition. Reading the threads on the Pertronic and Crane options I hesitate to choose from them. I hope to profit from the experience of Cees Klumper whith Newtronics.

For those who want to use the MP3 player on their Becker, I suggest  checking out www.microboss.de. They sell a 'car rock' for Euro 49 which would make a MP3 payer work via the attenna input.

Gerard Wuisman.  
Spring is coming now. That means driving instead of working.