gf261

Okay...I spoke too soon I suppose. Got my new coil in, everything was fine, and then about a mile from the driveway, she starts sounding like a gocart on steroids and is making almost zero power. Ideas anyone? Is this the infamous "limp home" mode? And if so, where should I start looking?
FRUSTRATED.

Mrmerlin

check the last thing that you touched

gf261

The last thing was changing the ignition switch yesterday. The exhaust almost sounds like it's bubbling up through water, very gurgly (is that a word?) sounding. Blipping the throttle brings very slow response.

michaelathome

Be very carefull, that water might be fuel. Pull a few spark plugs and make sure that they are dry. If they are wet you probubly have a bad coil or connector.

I have mentioned it before but it is worth repeating. If you are running your engine and you are not getting sparks to a bank that fuel IS going somewhere, right out of your exhaust and risk the chance of igniting it and catching your car on fire. It has happened to other Rennlisters before.

https://rennlist.com/forums/928-forum/300961-wiring-harness-installation-vs-ebay-fire-sale.html

Michael

gf261

Will do in the AM Michael. The frustration level is WAY too high to fool with it tonight. That always leads to throwing tools, which in turn leads to replacing one (or more) windows in the house when I hit the socket that I couldn't find in the grass with the lawnmower during the first spring's mowing.

Mrmerlin

it sounds like the LH/EZK may be going bad , but you may have other easier problems to fix, try inspecting the coil wires for each coil make sure they (coils) both have the ground wires attached to the coil to head connections, inspect the coil to dizzy cap wires, check the timing marks lining up correctly

daveo90s4

Garrett,

The ignition monitoring system has two temp. sensitive probes, one for each bank. If the system measures a difference in temperature between the two banks it cuts off the fuel supply to four of the eight cylinders. The teutonic logic, as I understand it, being that if the exhaust is cooler then it must be because there is no spark. If no spark then raw fuel will be being exhausted onto the red hot cats and likely to cause a fire.

An initial first test of the problem when this occurs is to turn the engine off, wait half a minute or so and restart. This apparently resets the ignition monitoring circuit - until next time the problem occurs. If it starts and runs Ok, then probably though not definitely due to the ignition monitoring circuit cutting in - either becuase there is a real problem or because the circuit itself is malfunctioning.

The best check is to see if the green or red LED diodes on the ignition circuit monitoring relay are lit / flashing. This relay is in close proximity to the 'brains', frustratingly hidden behind the carpet and impossible to see when driving. The wires that connect to this relay are long enough, but only just long enough, for it to be temporarily relocated in front of the carpet and wihin siight while driving. (When I did this I ran an earth wire from the mounting bolt hole on the relay back to its original chassis mounting point, just to be on the safe side. Not sure if that was neceesary, but I was trying to be super cautious).

If when the engine does not run properly you then see one of the diodes lit up, then you know the ignition monitoring system is cutting in.

But from that you do not know:
A) Whether it is a legitimate warning, or if it is the monitoring system playing up, and / or
B) If it is the monitoring system playing up, which one of the two probles is giving the faulty reading.

Others I'm sure will chime in with suggestions what to do once you have identified whether the LED lights are lighting up or not, but a few other things I'm aware of with this type of symptoms:
1. There is an official service bulletin about this and how to test, what to do. It's been posted before on Rennlist. Let me know if you can't find that and I'll PM it to you.
2. This symptom is known to cause central shaft failure at as low as 1,000 rpm. so causes a quandry. Don't start the car in this situation but you have to start the car to see if you've fixed it. Mmmm.
3. You can buy an ignition circuit monitoring bypass relay pretty cheaply. This may possibly help with diagnostics. But as others have said, if you were to use this relay to bypass the system as part of the fault finding process, and with this bypass relay installed you lose spark to any cylinders, unburnt fuel will get to your hot cats. Not good. So if you were to use this relay and you were to feel any loss of spark / power you'd need to shut the engine down immediately. And carry a fire extinguisher or three. All heady stuff.

Off course if your was not built with cats, you won't have the circuit I refer to. Also if your car no longer has cats, then the fire risk will be much less.

Good luck, hope the above helps a little

gf261

DaveO...no LED's lighting up. If I'm correct, and I may not be, these are the ones in the clear boxes next to the brain computers? I'd still like to look at the bulletin you referred to if you could either PM it, or email it to me at tpr261@yahoo.com. thanks for taking the time to explain how that works.
Garrett

dr bob

Garrett--

Following on this in parallel with the TB thread--

The failure mode for the LH box sounds a lot like what you describe. A fairly common symptom of LH fail is constant clicking of the injectors with the key on but before cranking. Very rich mixture, hard to restart, hard time keeping it running. Do a little search and get more clues.


"Limp Home" is a Bosch workaround that lets you get the car off the freeway after a hot-wire airflow sensor fails. It uses a default idle fuel map, and reads the oxy sensor I think to give you just very basic simple run ability at low engine loads. John Speake is a guru of this stuff, and may chime in with more/better info. Again, a Rennlist search will net you a lot of info.

gf261

Thanks Bob. Now that you mention it, I do seem to recall that the injectors seemed to be clicking somewhat louder than I thought they should. (if they should be at all...) This was as I let her warm up before the last drive when I lost power. I will do a search though and see what I can some up with.
I think I feel nausea coming on...