I have an 89 Iroc with 5.0 and can’t get it to start. It sat for a few years so I drained and replaced all fluids the dropped the tank, replaced it along with the fuel pump assembly and fuel filter. Replaced the fuel injectors, plugs, wires, maf sensor, throttle position sensor, egr valve, fuel pressure regulator, idle control valve. Still wouldn’t start so I replaced the distributor (DUI) along with hotter coil. Re-gapped the plugs and new ECM. Still no luck. Fuel pressure is 40psi with key on and over 50 when trying to start. It turns over a couple of times and fires a little then just keeps cranking. If I keep cranking it just repeats. I’ve pretty much replaced all electrical items and am out of ideas. Bought an inline spark tester to make sure it’s getting spark for my next check. Any other ideas?

 

Fuel, spark, and compression. Need all 3 functioning properly to keep a gas engine running. Start there with your troubleshooting. The parts cannon method is expensive.

 

So you say you got fuel and spark. Wild. Did you check timing after replacing the dist? verifying TDC on piston one matches rotor spark plug one? Did you try moving dist around a bit just in case it needs more advance/retard. Did you try some starter fluid to see if that makes a diff?

 

Set cylinder 1 to tdc on compression stroke and rotor pointing to #1 like the old one. Would think it would try and run even if timing is off by a little. Bought a spark checker and will arrive tomorrow. Want to double check spark at plug to verify. Starting fluid does the same thing. Fires a couple of times then keeps cranking even when still spraying starting fluid. Tried disconnecting the timing wire to see if that made a difference but it didn’t. Wires connected correctly to each plug.

 

If it won't run or otherwise backfire / make noise on starting fluid, you have no spark.

 

I received my inline spark checker and i’ve got spark. Sprayed starter fluid into it and it started and ran as long as I sprayed it at a high rpm. Died as soon as I quit. Going to get noid light back out and hook it up to the same cylinder as the spark checker and see how that goes. Timing is at 9-10 degrees BTDC. Making some progress, wouldn’t do that until I changed the distributor.

 

If it ran with starter fluid but dies without it you don't have fuel. Shouldn't be a spark or compression issue at that point.

 

sure sounds like a fuel problem, check fuel pressure while it is running on starter fluid

 

Got it running tonight. I bought a code reader and when using it, it claimed every sensor on the car including the ecm. Found my old jumper tool and it indicated an issue with the EGR valve. That was new so I replaced the sensor since i had tried to repair it earlier. Bought the replacement off a corvette site. Still couldn’t get it to start so i taped off the intake, took the vacuum line off the brake booster, bought a $2 cigar at Casey’s and blew smoke into the hose. Smoke came rolling out from under the plenum. Ended up being a vacuum leak. Fixed it and it started up and idled. A little rough but I don’t have the timing set yet.

 

What was leaking under the plenum?

Fred

 

Runner gasket leaking. Had put new ones on and one was damaged. Put new ones on again and torqued properly. AllData says timing is 10 degrees but sticker on car says 6. Set to 6 and reconnected tan/black wire. Purrs like a kitten now. Code reader I originally bought didn’t read codes like they said. Told me 8 different codes including ecm bad. Name brand unit (Inova) and I contacted them multiple times but was told there’s nothing they can do. Donated to TunerPro and installed on Windows 7 computer and it works great. Showed only one code 34 which pointed towards issue and afr was off.

 

Good going Hojo. I had a similar problem, a few years ago, with my runner gaskets.

Fred

 

Unless you have actual run time the code scanner is almost useless.
pull the control module off and have it tested.