380SL STOPS

02/26/2004

Hi Jon, You have a great website; and you sound like you love MBZ. You are doing MBZ owners and enthusiasts a great service (no pun intended).

I love my 380SL (85), bought used as a gift for my "going over the hill" with a little style about a year and half ago. Car has 130k orig miles, and aside from drip of oil from engine pan, and at rear axle, seems to be in great shape (not mint, just well cared for).

I've had no problems with it (the air doesn't work, but the tops mostly down) except for sometimes the engine would die when I was idling/waiting, or rolling slowly to stop. I would just shift to neutral, and start again. I've had no complaints with fuel efficientcy, as it gets me 20 plus miles on the freeway (most driving), and about 18 or so in a mix of town and freeway. Also, I noticed that it generally takes a little longer cranking to start than most of my experience with older cars, not a lot more, just not instant start.

Recently, after about a year of owning the car, and having the car stop now and then, nothing causing alarm; and not getting more frequent, etc... The car stopped while I was going about 30mph, and I thought that a little strange, but started up and continued. Then the same afternoon, stopped again going about 35mph, and was harder to get started. The same day, after stopping about three times, stopped, and couldn't start. I wants to start, but won't stay running. Finally, it gave up all together, and would try to start after waiting for ten minutes, but wouldnt' stay running.

I towed it home, and thought that the fuel filter (which in the year I've owned it, never changed, tho' did change oil filter and oil). I changed the filter (didnt' look really dirty, the gas that drained from it, just a little bit brownish, but flowed right out of the canister in both directions). That made no difference, still wouldn't start. So, I changed the fuel pump, after removing it, and hooking it up to battery on the + and - leads. The pump just sat there, so I thought, "AHA, that's it!", and replaced it.

Initiallly, after re-installing, I turned the ignition on to listen for the whirr/or click of the pump... nothihng.... I thought (and correctly, after consulting the book) that there might be some relay, or sensor that wouldn't let the pump work, unless certain conditions were met). I tried to crank the engine a bunch of times, left the ignition on for a few moments, etc... Finally it did start; and ran just fine. I turned motor off to replace the filter/pump cover, etc... and it started again just fine... After about three or four times starting it, I decided to drive it down the road for a test drive... The same thing happened, motor just died (going about 20mph, and the gas pedal had no response, and kind of puttered to a stop)... Cranking after it died only resulted in the motor sounding like it wanted to start, but wouldnt' "catch". Subsequent attempts only had the starter cranking, no startup... If I wait a few minutes, it would again seem to want to start, but not 'catch'. I had to walk home and tow the thing again.

I am not totally ignorant of cars, as I grew up repairing them.. but, must admit that the new cars have gotten me to not do anything but oil changes, tuneups and small repairs. I consulted a repair manual, which mentions the K-Jetronic system, and related fuel pump items. It speaks of a fuel pump relay, as well as some kind of safety switch/sensor platel; for what kind of safety, I have no idea.

The book is very BAD, as it tries to cover too many models, systems in one book. There are few pictures of parts, etc... only diagrams, which dosesn't really help a novice mechanic like myself.

The test is verbatim:

The pump will only run if the starter motor is actuated, or the motor is running

1.) remove air filter

2.) turn on ignition and briefly depress the sensor plate

3.) remove coil wire from distributor

4.) connect voltmeter to positive terminal and ground

5.) actuate starter. Voltmeter should indicate 11v

6.) if pump only runs when sensor plate is depressed or only when engine is cranked, replace fuel pump relay.

7.) if pump is already running when ignition is on, replace the safety switch.

I am willing to try this test, however, following is not clear (no pictures, et, just diagrams, which don't show location of units in question. Where is the safety switch/sensor plate (diagram seems to indicate they are both one unit). Where is the pump relay?, and what does it look like (looks like a box from the diagram).

I know from earlier checking of whether the NEW pump was working (after installing), and ignition was turned on, there was no voltage coming thu the fuel pump; so does this mean the safety switch is okay?

Do you know of other things I might check for the problem mention here? Could there be a problem with the computer?

If' I can't get this thing going with simple tests/procedures, I will have to take to mechanic, but there aren't a lot of dependable mechanics in CORNVILLE, AZ. And I'd have to tow it a fairly long distance (live in the country).

Thanks in advance for any help you might afford me from your experience.

richard

Your problem sounds like the fuel pump relay. When you first turn on your key you should hear the fuel pump hum or buzz for about one or two seconds. If you do not hear this then it is relay time. Remove your glove box liner. AS you look straight in (after removal) the fuel pump relay sits about 10 o'clock. There are two black relays sitting side buy side. One is for your climate control and should say "klima" on it. The other relay will say 8zyl or kickdown on it. Pick one up from www.germanstar.net and you are all set. JON

JON,

You are just one amazing DUDE !! I found the relay (and yes, the pump does nothing when ignition is turned on). I found the relay with a flashlight after removing the glove box liner.

For your information, the relay is located more (in my way of thinking) towards 2oclock (if clock is parallel to bottom surface of glove box).

I looked over towards 10oclock (leftish facing into glove-box), and there weren't any black boxes, except for one with a fuzzy pad-like thing on surface and a couple of wires coming out of it. With a flashlight looking all around, I was able to see the "8zl12v- kickdown" words on a little black box. I guess the other black box to the left (much bigger, and has screwed down flange to left) is the kilmate control, although I couldn't see any words to that effect (Bosch-Gebleseregler12v is what's on it).

I called Germanstar and ordered the part from them. Also mentioned your name and website.

Thank you ever so much... I will let you know how it turns out (I'm pretty sure that's what it is, considering the details).

Would NEVER have thought to look there for the relay !!!

richard