Hello Friends,

I need to milk your mech-brains…

Patient: 1994 Chevy Suburban with a 350 and TBI.
Symptoms: Turns over, tries to start but will not fire up.
Current Health Status: Nice blue spark on all 8 and the coil, plenty of fuel, battery well charged and engines turns over fine.

I have two of these vehicles. I have tried the computer from one even though it had good fire, installed a new control/ignition module, cap, rotor, wires and plugs. The piston comes up, timing mark is at 0 and rotor is aiming#1. We bought the car not running. The lady said it just died and won’t crank back up. I have ruled out fuel and fire, so what could it be?

I had this happen once on a engine I built and the valves were adjusted too tight but it does not appear the valve covers have ever been off the motor so I don’t think that could be it?

I am lost and would appreciate any prognosis you may offer.

Thanks,
Scott

 

Doesn't sound too encouraging..... sparks should be brilliant purple-white.

No- start is about the easiest thing to troubleshoot. Compression, fuel/air, spark. All you gotta do, is eliminate em, one at a time.

Compression doesn't just generally go away, all of its own accord, from one minute to the next; unless the timing set has failed (plastic teeth stripped off the chinesium gums of the cam sprocket). Easy to check. Line up the timing mark, look at where the rotor is, spin the engine some even number of times, say, 4 (you stop just as the timing mark is coming back up the 4th time); is the rotor pointed the same? Yes; the timing set is good. No; change the timing set, without touching anything else, and MOST ESPECIALLY without twiddling on the distributor hosuing.

What happened when you poured a little gas into it? Start/no-start

Start: it's a fuel problem
No-start: it's a spark problem

I'm thinking you'll find it to be spark related.

Compare the 2 vehicles' sparks.

 

Wow - great advice. I will dig in to this one this weekend. I tried pouring gas in and starting fluid with the injectors unplugged but all it does is turn over about 2 times and do a small pop off like it wants to crank. I am going to check the compression this weekend.

Thanks!

 

Don't bother with the compression test, unless something has been worked on IMMEDIATELY prior to this. Too much like work. Scary. Don't go there.

Take off the dist cap, unplug the coil, and have somebody spin the motor with the starter while you watch the rotor.

 

I must be sofa king we todd did! It was the spark like you said sofaking!

I changed the coil and it fired right up! I guess the spark it had was not enough?
Thanks for your much appreciated advice!!!
I really do appreciate it when others are willing to lend a hand (or brain cell in this case).