byrdman454

I have a '85 that just started running very poorly. It takes throttle to get it started then idles by itself, but the whole car shakes. It also seems to be missing out or poorly running at throttle as well. There is a strong rich fuel smell from the exhaust. The car has the stocks cats, but does have the Porken s300 chipset installed. The o2 sensor is only about 1 year old.

Here is what I have done so far, need some ideas:
-Pulled all spark plugs and checked for fire. All good. Only one plug looked sooty.
-Swapped MAF with a known good one, no change.
-Cleaned grounds and main connector near jump post.
-Checked o2 sensor wiring for burn through. It was routed correctly and intact.
-Checked fuel injectors for clicking with stethescope. All seemed to be clicking.
-Checked all vacuum lines. Nothing was unplugged.
-Pulled vac lines off the fuel dampers and regulators. No fuel found.
-Checked the idle control switch to make sure it clicked at idle. It does.

Not sure what else to try besides reverting back to stock chips, damper, and plugs. It has been running fine on the s300 chips for several months.

leperboy

Did you check the Temp II sensor?

Matt

byrdman454

Cleaned it, but did not check it with a meter yet. I will go do that right now.

byrdman454

Checked the Temp II. It is within spec.

byrdman454

Are the '85 LH modules known to fail like the S4? When my S4 LH failed, it was running way rich until I had it rebuilt.

PorKen

Sounds more like ignition. You've checked most everything for the fuel.

Coil wires?

Ignition amp?

leperboy

The LH 2.2s don't fail like the S4 LH 2.3. I don't think I have ever heard on here of a 2.2 failure and the advice I was always given was to check elsewhere first.

You said you had spark. Do you know how strong it is? Check the connections at the ignition coils and check the ignition modules.

I had a loose ignition coil plug recently and the car would run (like crap) but I had to give it throttle at start-up to get it running.

Matt

vdubr

Sounds like its running on half the motor. The ignition are two separate systems. For the ignition, the two modules are under the hood in front of the headlight bar bolted to a metal plate. One of these fails and you are running on 4 cyl. I would start there. Unhook them one at a time and see if it changes anything.

I think the fuel systems are split in the same way. Hence the two computers on the s3.5. I suspect this was an attempt at a limp mode type of system.

is your a 32v?

byrdman454

This '85 is a 32v US version. I pulled the coil wires off and reinstalled, no change. I also unplugged the ignition amps, cleaned the connectors, and reinstalled. No change. Is there anyway to check these parts besides replacing with a known good one?

byrdman454

I did notice that the ground wire that is attached the driver side coil bracket is severed. Not sure if this has always been like this or just recently. Would this have any effect? I cannot find the other end of the ground wire anywhere which is why I figured it has been broken a long time ago by the PO, but I could be wrong.

WICruiser

It sounds like either too much fuel or not enough spark. You have run through the easy fuel system checks so do the easy ignition system checks (coils, coil wires, including coil grounds, caps, rotors) remeber there are two of everything and so if one is not up to par the engine will run on 4.

Be very careful if you are misfiring or dumping in excess fuel the cats can get very hot. We don't need to hear of another one lost to a cat fire.

byrdman454

Where are the coil grounds located?

vdubr

Unplug the amps one at a time.

WallyP

Fix the coil ground.

If you have or can borrow an inductive-pickup timing light, you can check the plug wires and see if you have lost one ignition system. Also check the coil wires to make sure that you have voltage there.

Mako 928

The coil grounds are located in the area of the coil bracket and then connect to the engine behind the cam gear housing.