Having ignition troubles, bAd ECM?

05-11-2018, 07:12 PM
My model is actually a 1995 s10 6 cy 4.3L vortec
Have been having ignition problems, started with a crank and no start. Sounds completely normal when cranking but it just will not start. Two mechanics managed to get it started but with no permanent fix. To do so we unplugged ECM connections and put back in. Started after that for a while but eventually failed. I thought it might be after market security system so that was removed, it started but now will not start. In the time it has been messing up the fuel filter, distributor, ICM, ignition coil, and ignition coil spark plug wire replaced. Fuel pressure is good. The most recent time it happened after driving it for a bit went to start it, started just fine, put into reverse and started backing out when it died, then would not start. Tried the unplugging of the WCM fix and it still wonít start. When itís running it is completely normal, check engine light was on but I have always checked it multiple times for a EGR FLOW INSUFFCIENT code. Could it be a bad ECM or a bad fuel injector? Please help.

05-12-2018, 07:33 AM
You could take a test light and check your ignition key switch. Check the feeds to critical items. This is on the steering column with a rod that pushes a plunger on the ignition switch. These commonly go bad as the vehicle gets older.
Some of these you need a small pair of channel locks. A small set of tamper proof torx or purchase new bolts.

Tech II
05-12-2018, 10:16 PM
These engines were known for leaking spider assemblies, leaking fuel pressure regulators, bad poppet valves, restricted fuel filters, and borderline fuel pressures......

Last time fuel filter replaced?

Will vehicle start if carb cleaner is sprayed into intake(MAF sensor and snorkel must be intact)?

Blue Bowtie
05-13-2018, 08:09 AM
You mentioned the fuel filter was replaced as part of the analysis/repair efforts, and that "Fuel pressure is good." Can you report the actual, measured fuel pressure?

As Tech II pointed out, borderline fuel pressure is common, and pressure is critical in CPI systems. The poppet injectors need a minimum of 60 PSI to operate reliably. I've had one that actually started and ran at 58 PSI, but that was an exception. Most need a solid 60, and the pump should produce at least 63 PSI in the prime cycle.

Add your comment to this topic!