View Full Version : What could cause ICM failure at engine start up?
junkhuntershond
Sep 2, 2008, 11:59 PM
My 1993 Honda Civic LX 1.5L decided to stall. The re-start attempt failed and the engine seemed to be turning too freely. My first thought is timing belt! I checked the valve timing & its on the money. When I accessed the trouble codes, the CEL blinked, but so dimly I had to shade it to make the blinks out. I had a code 8. I checked the TDC, CYP, & CYK sensors. They checked out. I checked the coil primary @ 1.4 ohms & the primary + to secondary @ 8.5K ohms. Maybe bad coil. I checked the ICM and it failed the voltage test from ground to white/blue wire. Maybe bad ICM. I had the ICM tested on a test machine, it was bad. I installed a new ICM & tried to crank the engine, no soap. I kind of thought the new ICM could be defective from the factory. So I tested it. It tested bad, in the same way as the original. I had this new ICM tested on a test machine, it was bad. I don't know if the new ICM was defective from the factory or my car ruined it. I thought of buying a rebuilt distributor with all the guts incuded. I'm try not to be a parts replacer but a diagnostician. I don't want to install & ruin any more new parts, I'm to poor. Could you please suggest my best next move to make. Thanks from an old mechanic too used to old technology.
TxGreaseMonkey
Sep 3, 2008, 06:46 AM
Too much secondary resistance--replace distributor cap, rotor, spark plug wires. Voltage is turning on components (shortest path to ground). Ensure spark plug wires are firmly seated in distributor cap. Be sure to use dielectric grease.
Perform tests, in Sections A and B, below:
https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-46563.html
junkhuntershond
Sep 4, 2008, 11:54 PM
Thanks for the direction TXGM. I'm working sporatically on the car (a lot of other irons in the fire). I'll let you know what the results are.
junkhuntershond
Sep 13, 2008, 11:33 AM
Hey GM. I've performed all the checks & tests outlined in sections A & B. All the results were good except the spark test. I also made sure fuel was getting to the fuel rail & the injectors worked. I bought & installed new cap, wires, rotor, and plugs using d-grease as necessary. I installed a new ICM Friday and tried the spark test. No spark. I cranked the engine, it rotated but would not start. I'm taking the ICM to Autozone to have it tested. I'm betting its toast. Do you know what else could be frying these ICMs? I mentioned the coil secondary ohms were about 9.5K. Is this reading too much lower than the minimum of 12K? This car is my primary transport. My secondary is my wheelchair. If you can think of any other tests or possibilities please let me know. As always thank you.
junkhuntershond
Sep 13, 2008, 11:42 AM
GM. It's mid afternoon here in Jax. Florida. Going to borrow some wheels and get this ICM tested. If ruined, going to try to get another one. I'll check back with you later.
TxGreaseMonkey
Sep 13, 2008, 11:43 AM
It's best to replace the ICM and coil at the same time, especially on cars with 120,000 miles on them or that are 10 years old. I bet the car will fire right up, when you also replace the coil. I no longer place much faith in bench testing ICMs and coils. I've seen too many test okay that then don't work in the vehicles (cars and trucks). When they are replaced, they start right up. For reliability and performance, I would just replace them and be done with it. If money is an issue, check the prices at RockAuto.com. The TEC coil is Honda OEM at a fraction of the price.
junkhuntershond
Sep 13, 2008, 11:48 AM
I'm with you man. I'll get a new coil while I'm out & about. Thanks again. 3's & 8's out.