Engine Died On Increased Throttle, Can Only Crank-No-Start In ‘99 Suburban 5.7L

So I did a fuel pressure test on Sunday, and these were the results I got, both key on, engine off, and then engine on. I tried to upload the videos I took, but it says they are too large for the server to upload. Anyway:

With key on, engine off, the pressure went to 62 PSI, and then immediately drops to 56 PSI. Within two minutes it steadily falls down to 45 PSI.

With the engine running, the pressure is between 52-54, and like I mentioned originally, as soon as I rev the engine, it dies. The pressure goes up to 62 PSI at most right before it shuts off.

At this point, I am convinced it is the regulator, or at least one of the injectors. And me believing this is also based off other threads I read about people having problems with fuel pressure, as well as a couple of YouTube videos. The fuel pressure reaches a level that is within the 60-66 PSI range, but then just falls off pretty quickly. Also, when I listened for the fuel pump running over a week ago, I heard it running, although it may have been a little bit louder than it should be, and I've heard that it could be because the regulator has failed or is failing. What do you guys think?

carnerd3000 said:

So I did a fuel pressure test on Sunday, and these were the results I got, both key on, engine off, and then engine on. I tried to upload the videos I took, but it says they are too large for the server to upload. Anyway:

With key on, engine off, the pressure went to 62 PSI, and then immediately drops to 56 PSI. Within two minutes it steadily falls down to 45 PSI.

With the engine running, the pressure is between 52-54, and like I mentioned originally, as soon as I rev the engine, it dies. The pressure goes up to 62 PSI at most right before it shuts off.

At this point, I am convinced it is the regulator, or at least one of the injectors. And me believing this is also based off other threads I read about people having problems with fuel pressure, as well as a couple of YouTube videos. The fuel pressure reaches a level that is within the 60-66 PSI range, but then just falls off pretty quickly. Also, when I listened for the fuel pump running over a week ago, I heard it running, although it may have been a little bit louder than it should be, and I've heard that it could be because the regulator has failed or is failing. What do you guys think?

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Fuel pressure sounds normal to me. If there was a leak somewhere it would fall to zero fairly quickly. Sounds to me like an ignition component is failing with heat maybe. My guess would be a partially shorted coil overheating the module or maybe a bad crank sensor. The modules will fail to create a circuit and thus spark sometimes when they heat up. Without proper voltage to the spark plugs as you opened the throttle it developed a misfire which loaded it up on fuel. Just an educated guess from what I have seen before.

I will throw in something my 97 Express 5.7L did probably 8 years ago. Cold and wet morning. Was going to drive it to work rather than my M56S which was a handful in the rain. Well the van hit a couple of times when I cranked it over but would never start. I tried cranking it a couple times and then pinned the throttle open to purge it of fuel in case it had flooded. Well each time it would hit 2 or 3 times and that was it. I ended up taking the car to work. When I got home the van was doing the same thing. I pulled the engine cover. I could see a stray spark coming off the coil and it was wet with moisture. I grabbed a can of WD40 and shot some on the coil. Waited a couple of minutes and tried cranking it again. Instantly it roared to life. I ended up changing the coil for an extra I had laying around. The van ran smoother and had alot more get up and go. It had been acting a bit sluggish and running rough for a couple weeks prior. It had a habit of eating distributor caps so I assumed it was just another cap failing. The coils insulation had broken down and failed and the coil was arcing to the metal frame, when moisture got on it, it shorted out grounding out the spark.

My brothers 99 suburban also had a weird issue that was similar. It started running rough, then stalled out. It was night and we were 200 miles from home. I could hear the fuel pump prime so the first thing I looked at was the spark. Pulled a plug wire and layed it next to the block. He cranked it over and it had spark but was super weak and orange in color. At that time I notice I was hearing a second stronger spark somewhere in the engine bay. I turned off my flashlight and had him crank it over. Saw the blue hot spark instantly. His coil wire had a crack in the insulation and most of the spark was jumping to the transmission dipstick tube. We had some electrical tape in the truck. Wrapped the break in the wire with several layers of tape. Hooked the plug wire back up. The suburban fired right up and we made it home. Changed the plugs, wires, cap and rotor shortly after.

A timing chain jumping on a Vortec is very rare. I pulled one out of a 300K mile L30 that barely had any stretch at all. The older SBC engines with nylon tooth cam sprocket were a ticking time bomb over 50K miles but the vortecs use metal sprockets and a decent chain. I remember in the late 90s my mom picking me up from football practice when I was in middle school in my parents old 1980 C10 with a smog era 350. She hit a speed bump rather hard and the engine died. It would crank over but would not start. My dad had to come pick us up and the truck had to be towed to a shop. When she hit the speed bump the nylon cam sprocket had exploded. The shop knew racing engines and small blocks well. It ran alot better after the chain was replaced and felt alot more peppy. Years later when I tore that engine down after my little brother spun 3 rod bearings in it doing donuts in his high school parking lot, found they had put a double roller in it and had advanced the stock cam 4°. That low compression smog motor really loved the cam advance.

L31MaxExpress said:

Fuel pressure sounds normal to me. If there was a leak somewhere it would fall to zero fairly quickly. Sounds to me like an ignition component is failing with heat maybe. My guess would be a partially shorted coil overheating the module or maybe a bad crank sensor. The modules will fail to create a circuit and thus spark sometimes when they heat up. Without proper voltage to the spark plugs as you opened the throttle it developed a misfire which loaded it up on fuel. Just an educated guess from what I have seen before.

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Ok, thanks for telling me that about the fuel pressure. Wasn't entirely sure what to take from the readings, and I didn't know how quick the pressure would fall if there was a leak at all. I do have an inline spark tester, so I will check spark next. I wanted to make sure I can rule out fuel delivery completely, or as much as possible.

I would also check the crank sensor connector and wires, one of my friends truck died on him we pulled it to my house and found the crank sensor wires were bare due to an oil leak and were shorting. Reinsulated them with heat shrink and hasn't had any more trouble.

Over the week I took a look at the ignition system, and so far I went through the spark plugs, wires, and the distributor cap and rotor. I replaced the spark plugs, since they were worn anyway, and I did a resistance test on each of the wires, with all of them being within 9-11 ohms on the long ones and 6-8 on the short ones. The wire to cylinder 3 had a sticky coating at the end connected to the spark plug, but nothing seemed broken or burnt, at least on the outside.

When I checked the distributor cap and rotor, this is what I got:

They do not look good at all, and I will replace them. The outer terminals on the cap are chalky-looking, but I don't know if they are any shorter than normal, and then the middle terminal is chalky, but it also has brown spots on it too. As for the rotor, you can see a burn mark towards the middle, as if the spark was arcing through the rotor itself.

So now here's my question: is this distributor still usable at all, or is it absolutely dead and possibly even the cause of my crank-no-start condition? Also, should I be worried that there is a burn mark on my rotor?

I would start with just a new cap and rotor if that doesn't correct it then diagnose from there

United Motor Products makes a $28 cap and rotor set with brass contacts. When we had questions on the forum last year, I emailed them and they took the time to respond.

Erik the Awful said:

United Motor Products makes a $28 cap and rotor set with brass contacts. When we had questions on the forum last year, I emailed them and they took the time to respond.

More Information for UNITED MOTOR PRODUCTS DCR820X

www.rockauto.com

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I used the Blue Streak rotor on my Burb, cause I already had it, but they don't make a Blue Streak cap for the Vortec engines. So I bought one of these vented caps, installed it with the Blue Streak rotor,and am very pleased with the performance. The UMP rotor is probably pretty similar to the Blue Streak rotor (looks just like it).

My thought was to just get the regular AC Delco cap and rotor, probably from Rock Auto, but if a cap with brass terminals is actually better than the AC Delco, then I will do that. I saw other threads about having no spark, and I saw people say either go with the AC Delco or a cap with brass terminals, so I just wanted further clarification.

And just to double-check: based on my pictures, are both my cap and rotor completely dead?