Engine woes

[Ohearchai]

Was running fine, had a bit of an exhaust by passenger side manifold/down pipe joint. On the freeway this morning, 10 miles in, she starts surging and sputtering, eventually dies on the side of the road. Was able to start her again, ran rough for a few miles, eventually died and wouldn't start again. Where do I start.
Thanks.
1990 v1500 suburban 350 tbi

 

[Catbox]

On a TBI I would start with the fuel system.
Does the pump run when you key it on?
If the filter has not been changed recently, change it.
Do the injectors fire?
If not, it could be the ignition module in the distributor.

My 1995 has presented me with all of these problems at one time or another.

 

[Rickf]

You might start by testing for spark first, doesn't cost anything but time.

 

[Sad Sack]

You might start by testing for spark first, doesn't cost anything but time.

Almost sounds like the ignition module went south.

 

[1lejohn]

Every engine is the same it needs fuel , air , and a spark to run. Start with one of these and then break it down into smaller parts.

 

[Ricko1966]

Almost sounds like the ignition module went south.

TBI is weird you really need to follow the factory diagnostics,because ECM ,and ignition module both control the ignition but at different RPMS. I don't recall but I believe ICM controls spark at cranking speed,then ECM takes over. Now it gets more fun because the ECM also controls the fuel pump and injector pulse.

 

[Jawzjeep]

Check your coolant temp sensor while you're at it. When mine was bad it would work fine for a few minutes and then act stupid. Good luck.

 

[YakkoWarner]

When mine died in a similar way, it turned out to be the actual magnetic pickup inside the distributor which had failed - if that goes out neither the computer or the ignition module get any signal to fire at all.

My first test would be to give it a quick squirt of fuel (not carb or brake cleaner, real fuel) right down the throat and see if it fires off for a couple seconds. If it does, you're looking at a fuel feed problem. If it doesn't, you have a spark/ignition problem. The injector pulsing is also tied to the distributor pickup, so a no signal condition there can be mistaken for a fuel supply problem.

 

[Ohearchai]

Well I gave her a drop of fuel and she fired right up, so I guess I have a fuel feed problem. Now I have already changed the online fuel filter, when I cha get the fuel pump in the tank.

 

[YakkoWarner]

Well I gave her a drop of fuel and she fired right up, so I guess I have a fuel feed problem. Now I have already changed the online fuel filter, when I cha get the fuel pump in the tank.

Can you hear the pump running when you turn the key on? Usually they are pretty quiet - but if you open the fuel cap and listen close while someone turns the key on, you should hear the pump run for a few seconds (mine sounds more like a quiet hissing in the tank). If you don't hear it run at all, thats your next thing to trace out.

 

[Sad Sack]

Whenever I get my C15 back one of the first gifts it's going to get is a fuel pressure gauge.

 

[Ohearchai]

Can you hear the pump running when you turn the key on? Usually they are pretty quiet - but if you open the fuel cap and listen close while someone turns the key on, you should hear the pump run for a few seconds (mine sounds more like a quiet hissing in the tank). If you don't hear it run at all, thats your next thing to trace out.

Ya definitely a hissing from the fuel cap when I turned the key. So I guess the fuel pump is doing it's job.

 

[YakkoWarner]

So now the question is: Is fuel coming up to the throttle body? There is a way to test the injectors by disconnecting their wires and tapping the contacts of a 9V smoke alarm style battery to their prongs, but I will admit I have not actually done that process. Hopefully someone more familiar with that procedure will fill in the details on how to do it.

You could also (if the fittings are not badly frozen) loosen slightly the fuel feed pipe on the back of throttle body and see if anything spurts out. Obviously all the standard precautions about messing with potentially pressurized fuel (eye protection, nothing that could cause a spark, don't do this in an enclosed garage, etc) apply. Usually those fittings are frozen too tightly to do this without risking damage but with enough patience, spray lube and using the proper line wrenches you might get lucky.