Hey guys Ive tried to research this but its too unusual to narrow down on a search at this time, with that said here is what Ive got...
1995 Chevy C1500 350 5 speed 170K+ miles. This morning I was heading to work no problems, I get about 10 miles or so down the road about a 15 minute drive and the engine starts sputtering it would idle ok hitting about 2000-2500 RPM is when it would start to cut out jerk around real bad, you could see the tach bouncing the shift light would flicker then it died. I coasted off the side of the road opened the hood nothing immediately jumped out. I tried to start it again it took about 3-4 attempts till it started, then died. Started again, I head back home got about a mile up the road and it died on me no start at all not even a hint of a fire off.

The only things Ive had to fix ignition wise was about a year ago I replaced the coil, ignition module and did plugs wires etc. This isnt my daily driver so its prob only seen about 2-3000 miles if that since then. It was hard to tell if there was any fuel coming out so Im leaning towards fuel pump, filter? I havent had a chance to do any work on it today but will tomorrow and was hoping SOMEONE had run across a similar situation or could point me in the right direction. This thing has to be easier to work on than my TPI system.

Thanks in advance!

 

Monte SS
I would check for any stored error codes first.
Secondly - check fuel delivery. Fuel pump can be forced to operate by placing a jumper into FP relay socket. A better way is to verify fuel pressure with a FP tester or a gauge. With this many miles fuel pump and in tank rubber hoses are known to fail. Reformulated gas is also known to destroy rubber.
Thirdly - See if injectors (TBI) are firing fuel during cranking - provided that fuel pressure is OK. Take off air cleaner during cranking observe if injectors are spurting fuel. Check ignition with spark plug tester.

I hope this helps

//RF

 

Ive got a fuel pressure tester for my TPI system but Ive never hooked it up to the TBI system, is there a port like in the TPI rail or how do I tap into the fuel line to check for pressure? Ill hit all the basics in the morning, I didnt get home till late tonight to be able to do anything with it.

 

Monte

There is no test port for measuring fuel pressure in early TBI systems that I'm familiar with. Later TBI's may have it - I just do not know.
In early TBI systems - fuel pressure test kits use insertable T section right at the TBI supply inlet. TBI T section should be available at better auto-parts stores - OTC7665, Tool Aid 37650 and check for use with your FP kit.

You can also measure TBI pump current draw with Amp-meter, which may be around 3 to 5 amps, with PFI pumps pulling 4 to 6 amps on average.

//RF

 

Code 32. Guess Ill go get a Vac and a new EGR valve just in case. The truck started right up this morning, idled fine reved up no probs. I didnt let it warm up just yet till I can get a Vac Gauge and test to see what happens. Damn EGR Valve $80 though!

 

This sounds like an ignition problem. The tach will bounce all over when the spark cuts in and out. A bad module or something similar will cause this as well as possibly dropping the DRPs. Could be anything from poor connections, inadiqate heat sinking compound, bad grounds dirty distributer base, failing module (they die FAST if you have spark leakage somewhere), low voltage to the ignition, etc.

 

Well, not an EGR problem, I bought one of those Mighty Vac pumps and a new EGR. I thought I read on here somewhere that the EGR valve should hold a vac, when I checked mine it wouldnt so I checked the new one, same thing it doesnt hold a vac. Ran the engine about 10 minutes and about 2500 RPM with no problems had the auto xray running at the same time to watch any unusual parameters, none were found. Shut the engine off unhooked the bat to clear the code waited 5-10 minutes hooked it back up and as soon as I started it and reved it up, started stumbling again let it idle a minute and reved up fine. shut it off let it sit 10-15 more minutes started same thing, checked for codes and none were stored.

Pulled a plug wire, started it up good strong spark but it cuts out at the higher RPM's and watching the tach it bounces around so much it leads me to believe the ignition module is fubared again, but the only problems Ive ever ran into with an ignition module are it just shuts down first one ever died on me the engine just shut off, second one it killed the signal for the injectors (that was a PIA to troubleshoot) Ive never seen it die off at a certain RPM only for a while though.
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Didnt see this posted till after I posted mine. Ill have to check that out tomorrow time to go to "work" its a rough life having to fly helicopters for the military and get paid to do so! Ill post any more findings I come up with.

Thanks for the info so far guys.

 

The best way to verify DRP problem is to put O-Scope on a distributor reference input line from distributor, Circuit 430. DRP Pulse is a low voltage referenced pulse (300 mV) - if ignition module is poorly grounded or if there is ground connection issue all may cause DRP pulse not going low enough (in voltage). EMI may be another cause - due to leaky spark plug wires may cause DRP problems.

 

...and if you dont have an O-scope? is there any other way to check it?

 

You can use a DVM with frequency measurement capability - for example Fluke 83 Series 5 and the like.


//RF