87 240 B230F power loss glowing red manifold

[overgreg]

After two new Knock sensors, no real change. I was hoping the first was maybe bad right out of the box, so exchanged it for another, but still have the same problem. I've been driving the car more lately and here are the symptoms:

Car runs strong and smooth when it's not having the problem. The issue usually occurs when pulling away from a stop, or within about 50 feet of pulling away. Sometimes it will move off normally, then drop power. It sounds and feels just like it's lost a cylinder or two, no power, sputtering, underhood backfire. I can shut off power and restart immediately and it will run normally, always and without fail. On a few occasions, I can shift down to low and the jolt will wake up the engine and it will recover and run normally.

There is no common circumstance such as hitting a bump or how much throttle is applied etc. The issue occurs randomly. The cars goes on the highway without trouble, it's 95% of the time when pulling away from a stop. And once it happens, it begins to happen with more frequency, but always 'resets' to normal with a shut down and restart. I've done this a couple of times on the (slow) fly by shifting to neutral, switching off ignition, restarting, into drive and off we go.

I'm stumped!

Greg

[jimmy57]

I replied earlier with 700 info because I read 240 and my brain said "740".
I worked on these whan that was a new car.
I had several with the broken solder joints in the Chrysler ignition box for the connector pins.
If you have a replacement harness the wiring connectors are the same rough ID as module pin OD.
If original harness the connectors are large OD with curved "fingers" in the socket to make connection to pins and these are subject poor connections and the fix was a split sleeve that slid down the pins for knock sensor, distributor pick up, and a one or two others.
In all cases the connector failures caused different things depending on location but knock sensor circuit would cause what you are seeing.
The knock sensor on that car is crude and is a round hollow conductor attached to body of sensor and a spring wire attached to spade terminal on sensor. Spark knock and other mechanical hammering would make the spring vibrate and touch the conductor grouding it. The wire from knock sensor in harness grounding out due to rotted insulation or chafing will cause the same thing. All the Bosch or even later Denso knock sensors are crystal microphone technology.
Lastly. I had a couple of cars that ate my lunch that ignition was ruled out as the injector duration would decrease during the low power period. Retarded ignition didn't decrease injector opening duration.
These ended up having fuel injection harness problems. One had soapy water inside the plastic harness sleeve that couldn't drain out and the water was conducting between some wires and the ground splice in that part of harness. It specifically was decreasing the ECT signal. This was 83 and 84 models with LH 2.0, but I think your LH 2.2 would do the same in response to low ECT signal. I think the symptoms on the wet harness cars was more complicated than what you have posted. I'd do a thorough check of ignition and harness.

[overgreg]

Thanks Jimmy. It seems to make sense to me that it's an electrical issue and perhaps a connection issue since shutting off power and restarting makes it go away every time, until (sometimes days and sometimes ten minutes) it happens again. Can you walk me through the connector issue again? Are you talking about the pins on the ECU or a different location? I'm being a bit lazy here I know, but is the harness easy to get off and replace, or perhaps go through and replace the suspect wiring with new ones inside the harness?

Thanks, I believe you are pointing me in the right direction.

Greg

[jimmy57]

The connector I'm talking about is on the ignition module on RH inner fender behind headlamp. Has a vacuum hose attached to a diaphragm chamber at bottom.The harness is not hard to replace but it can be fixed if the wire insulation hasn't gotten brittle and cracked on most of the wires.
The connector unplugs easily by holding the module and grasping the connector and wiggling it as you un plug it.
Look at the connector and determine if the connector look to have an inside diameter of a small trim nail (1.5 mm?)
If the harness passes the insulation and connector inspections then it is probably not the issue.
Then remove the ignition module and take it in the house to good light. Get small needle nose pliers or tweezers and check each pin that sticks up in the connector to see if it seems loose. The pins solder to the circuit board in module and can crack and have intermittent connection. A couple of the pins will cause limp home if the connection is lost and will reset with a key cycle.
If any are loose then take module apart and clean off the gel stuff on back of circuit board on the corner where connector is located. Solder every pin. Cover the cleaned area with clear silicone sealer, the window/bath stuff is fine.
Re-assemble, install and test drive.

[overgreg]

Thanks again Jimmy! I will be on this over the weekend and will report back with what I find. I really appreciate the info and help.

Greg

[Volvofix1]

The last time I saw a problem like that it was a bad ignition contol module which is located inside the right front fender. Dick K. from Fla.

[overgreg]

Finally found an ignition module a couple of weeks ago. Winter arrived just about the same time and I haven't had a chance to switch them. Planning to do that this week and will report back after putting some miles on the car.

Thanks again for the help!

G

[overgreg]

Hi All, and thanks for all your help. Very happy to say that with the replacement ignition module, after about 200 miles, the car is running great, no stalling or hesitation issues. She's back to normal! I appreciate the advice and the module was a snap to replace: one bolt, one plug and one vacuum hose.