I have a 93 RR. On an ever increasing occurance, the EFI light comes on and the engine quits for a second or two. It then continues, but will not idle (slows to nothing and quits). If I restart it, it runs fine until the next occurance. It only happens when I'm moving. Doesn't matter if the engine is warm or not. It happens on a smooth road and in the rough, although the rough seems to make it worse (more often).

I have replaced all the sensors except the O2's, cleaned the MAF, cleaned and lubed all connections, checked the fuel pump relay and the fuel pressure. All appears fine.

I thought it might be an intermittent short or broken wire somewhere, but haven't been able to find it, if that's the problem.

So, anyone know what the symptoms are, of bad O2 sensors? Or, could something in the ECU be failing? Any other suggestions on what to check/replace are appreciated.

Thanks.

M

Alternator?

Look at the code reader (under passenger seat next to ECU) and see what codes you may have triggered. You may have to reset and start again (if you've been frigging around with it) to get the most recent event.

If you get code 03 you have a "interuption of memory", or something similar...(yes I get those myself, I have a code reader sitting on the othe rend of the couch that reminds me of this) which is either a fault in the ECU or a fault with input generally from the coil signal wire, or distributor feed to coil.

.....or the alternator....or bad battery ground......:flipoff2:

Grounds are all clean. Alternator connections clean. Lots of electric power being produced.

The code display works, but is not throwing any error codes when the efi blip happens.

I've checked all ignition connections, new dist cap, rotor and wires, cleaned the distributor p/u, changed the coil and tried two different p/u amps, all with no improvement.

Next, I guess I try changing the ecu.

This is driving me crazy. :mad3:

Could the ignition switch be the culprit? Put a meter on the switched power and monitor it when you are driving it and the symtoms appear.

JP

Checked the ignition. That wasn't it. Going to borrow and change the ecu this weekend and see if that has an impact........

Haven't been able to source a used ecm, but am now getting an error code.

It shows an 03 code. I am having trouble find out what that means, though. I found a reference to "ecm memory recently cleared", but have no idea what that means or implies.

The issue is now getting worse, with the engine suddenly cutting out while at speed. On restart, it starts and stalls. This occurs for about a minute. Then it will start and run ok for a while until the cycle does it all over again.

I'm about to take a bloody sledge hammer to the vehicle.... Grrr.

Any thoughts?

M.

I'm about to take a bloody sledge hammer to the vehicle.... Grrr.

Any thoughts?

M.

Make sure it's a big hammer. Wear gloves and eye protection. Oh and take pics.

I had a bizarre fault with mine where it would stumble and stutter and then be fine, changing the fuel pump relay cured it for a bit but then it came back. Turned out the fuel pump was on its way out and was creating back-emf which was arcing across the relay contacts and causing them to get covered in crap.

New fuel pump cured it but the easy test (and rather longer lasting solution that it should've been) was to jumper across the relay, as long as you remember to remove the jumper when you turn the car off you're OK.

I had a similar problem last year that kept getting worse over a couple of months. In the end I figured out that it was not the EFI but the coil... new coil and no more problems since last summer. Just to be clear this issure was causing random stalling, random rough running, and the EFI light to come on. Also this was on a 87 RR.

I quote from your own post, listen to Matt, and X2 on the "interuption of memory", typically self induced though.

If you get code 03 you have a "interuption of memory", or something similar...(yes I get those myself, I have a code reader sitting on the othe rend of the couch that reminds me of this) which is either a fault in the ECU or a fault with input generally from the coil signal wire, or distributor feed to coil.

sudden cut-out´s on the move let me first think of the ignition system, too.

Could it be that you get "heavy misfires" due to intermittent igniton failure which confuses the ECU (thinking the O2 sonds or sth. failed) ? Just a thought.

Then there is that ignition module on the side of the distributor. It is known to suffer from heat and cause sporadic ignition cutouts when hot. You cannot reproduce the fault when things are cold. But, maybe, a really bad module might even do symptoms then. ??

I do not think the ECU itself is causing that. It´s much too often accused while it only tries to make the best of what the sensors tell it. Still, with error codes concerning the memory - no idea what to make out of that.

Sounds to me like power is being interrupted to the ECU. Grounds, ignition switch, battery cables.

like I said back in reply #3....it's a poor signal or interuption of power. 90% of the time it is a loss of signal from the coil.