My car (a '93 945T with ~ 140,000 miles) has died a few times while driving down the highway, maybe once or twice a month. I'll be driving along, and the engine just dies. I'll pull to the side of the road and it won't restart immediately, but if I let it sit for a few minutes, it'll start up and run with no problems.

It's not the crank (RPM) sensor, I just installed a new one a month or so ago (thinking that was the problem). The dying problem happened before that, and after.

The codes from the engine diagnostics are:

#2 sensor: 312
#6 sensor: 144

These are the same codes I pulled from it before I changed the crank sensor (and then cleared the memory).

Code 312:
Fault Condition: Signal missing for knock-related fuel enrichment
Causes of Fault: Wiring break between EZK terminal 4 and FI #28

Code 144:
Fault Condition: No load signal from fuel injection system
Causes of Fault: Bad fuel injection relay; faulty wiring from LH to EZK; bad LH module

Based on this, I'd say the thing to do would be to replace my fuel injector, but I wanted to run these symptoms by this board to see if there is anything else I should look at.

Also, what does "Wiring break between EZK terminal 4 and FI #28" mean? I don't know what the EZK terminal is, I assume FI #28 is my fuel injection system.

Thanks!

Code 144 is almost always, I'd even say 99.9 % of the time, the fuel pump relay. It's white, and lives behind your ashtray, second row, first relay from left to right. Hope this helps,

Chris

Two other things to replace- because I immediately thought "crank sensor", but the other replies are on the right track too-
1) Ignition power stage
2) Radio Suppression Relay- often overlooked, but essential.

Both jobs you can tackle yourself without any special tools.
--
Rob Bareiss, New London CT ::: '87 244DL/M47- 230K, 88 744GLE- 220K, 82 245T-181K Also responsible for the care and feeding of: 88 745GLE, 231K, 87 244DL, 239K, 94 855GLT 189K

What do you mean by ignition power stage? Is this the same as the fuel pump relay?

I need to order a new turn signal lens in the next few days (fell off last weekend somewhere), I'm just trying to figure out what to tell whichever company I go through what exactly I need.

So far, I've got the fuel pump relay, turn signal lens, and probably the radio suppression relay.

Thanks to everybody who has replied, it looks like an easy enough job, once I figure out which parts I need. I assume the radio suppression relay is near the fuel pump relay, thus when I pull that board out I can do both at once.

- Mike

Dear Mike,

May this find you well. The radio suppression relay is NOT near the fuel pump relay. The former is in the engine bay (near the strut towers) and the latter is on the relay block (behind the fronter, center console ashtray).

More specifically, the radio suppression relay is mounted on the fender wall, behind the power steering reservoir on turbo models, and on normally-aspirated models is mounted on the fender wall, forward of the ABS unit.

The radio interference suppression relay governs power flow to the injectors.

The ignition power stage (which I think is the power amplifier) is located to the right of the airbox (on a normally-aspirated model) behind the headlights, on the driver's side of the car [US/Canada].

Hope this helps.

Yours faithfully,

spook

I've not yet bought the parts, is there anything else I should pick up?

So far I have:

radio suppression relay (US$40)
radio interference suppression relay (US$20)
and a turn signal lens that fell off, ~ $55, not the cause of this problem of course.

I know that I don't need a new crank sensor, I just replaced that a few weeks ago.

Also, I took a look in my Haynes manual last night but didn't see anything about the radio interference suppression relay, is this called something else in the U.K.? (the Haynes manual is the UK version)

Did replace the 'white' fuel pump relay? I think you have one.

These symptoms sound like they could be caused by a bad ignition control module. Have you ruled that out?