Auto repair and gremlins

Grown up thread. Why? Because mostly only adults drive cars. Searched back 2 years, didn't see a thread so figured someone here has to have car issues or need work advice.

So I used to rebuild engines even back in my local NHRA days but these days unable to do much it is much harder to work on the damn things.

My van had a odd thing occur months back where it wouldn't start up. Cranking 10 minutes until the battery was nearly dead then it fired. Once it fired it ran perfectly fine. It started normal and ran fine for 2 months after that event. I assumed wrongly at the time it was a cold start issue and due to the temperatures which wasn't cold but it was chilly.

Fast forward to last week. Same event. Once started( after jumping this time and about 20 minutes of 3 second cranks ) it ran fine. I went to 4 places each time turning it off and it fired up every time once warm. Next day it has been DOA since.

Now I have had 0 issues while it is running, in fact it runs like a damn stallion once started and for having 284,000 miles on it. It is a 4.3liter GMC Safari and the engine is so loose it hauls ass without much gripe. Engines loosen up over time which makes em spunky. Also means they are about to explode like Moby Dick one day. However that is not the cause of this terminal illness.

Battery- Check. Cranks a solid 10 minutes on 3 second bursts before clicky clicky click.

Starter- Champ. Not that old I replaced it 2 years old. It is engaging the flywheel and I can hear compression on engine.

Engine- Check. Compression. I don't have gauges anymore since bro passed away and his wife who wasn't his wife took possession of all tools in the shop and sold about 70k in cars/tools/parts out from underneath me. I mention this because not having the tools is common in all this horseshit diagnosis.

Ignition- Check. Sorta. It turns over every time. Ignitions are odd though they control a bit more than just starters, even in 1996s. Usually when it cranks reliably however it rules out chances of shorts to other functions and relays and sensors. Pretty sure it's solid though.

Sparky- Check. Thousands of volts with heart problems is not suggested. Finger slipped on the screwdriver. Regardless yup, it cooked my finger like a wasp on a testicle.

Distributor- Check. Put on a new cap/rotor anyways because it was a bit oxidized and was 2012 when I replaced it last. Some play in shaft. Doubt enough to throw timing more than 3 degrees off though which should be in limits. No more excessive play than say 5 years ago.

Fuel- Semi check. Replaced filter, getting pressure. Not sure how much. Need to find someone with a tester but it isn't starving.

This is why it is messed up. Engines need 3 things to go boom. Spark. Fuel. Air.
This means I got a serious issue where even though it is a 96 I am left with literally 20 sensors, computers and electronics failure.

No code tripping and my OBD isn't reading anything useful since 96 was entry year for most codes and it wasn't computerized like most cars.

I can tear an engine down blindfold, but all those muscle cars didn't have all these things on it and it is compounded by the fact that this van has about 3x the electronics on the engine than even our 98 Trans Am does. Why I don't know. I assume it is due to heavier hauling, multiAC and fuel reasons. Who knows why. It's a damn GM that's why. It isn't exactly easy to get to anything either. The engine is under the dash so even with center console off you can only reach 1/2 of it. The other half requires a degree in gymnastics. Made worse by the age and mileage. It is pretty damn rough in there.

I don't think I have bad gas as once fired it had 0 miss and it hasn't tripped knock/misfire/fuel codes in years. It is frustrating it thinks it is still a buck and not sick. Boy I know all about that.

Now I am in an odd situation. I haven't worked this year and my resources are extremely limited. So replacing coolant sensors, fuel pumps, coils, ecms, knock/timing sensors and so forth is pretty damn restricted and I am quickly becoming limited to ideas why this happened.

Going to clean the MAP and pull the injectors this weekend hopefully but if anyone else who actually hobbies cars seriously especially newer ones or is a mechanic, man I'm all damn ears right now.

Additionals- Again the time between the one off event months ago up until weeks ago it ran perfectly fine. A few times it took several crankings to start and it didn't want to catch when it did, once started no rough idle/misfires but that first 2 seconds sounded like a freight train of angry.
The last time I fully charged several times before starting this diagnostic process it almost caught several times but never did. I was hoping to get it going to throw the software to it and read out what I do have access to with the limited computer which is basically vacuum, rpm, temps of coolant/oil, fuel pressure and so forth. I know someone who works on them will ask and no I haven't used starting fluid. Every bucks spent is a day without food right now but I will bite the bullet and pick that up too this weekend I think. Sort of goes with cleaning/checking the MAF/MAP I planned this weekend.

LaGSaLoT said:

I would start simple and have the battery actually checked. I work for a distributor and we have a fleet of high mileage vehicles. Similar problems have occured and it's almost always the battery. Just cus it fires up one day and cranks for a while doesn't mean its good.

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Battery is not vital to any function of the engine starting other than providing power for the starter in vehicles as old as this. Appreciate the input though.

I've actually jump boxed a car and drove it around all day with no battery in it off the alternator alone before.
Being the battery would crank from max charge this duration and dash was reporting initially >12volts and it was enough to be crisp and engage solenoid everytime, the battery is easily ruled out. Those conditions also rule out faulted ground of the main cycle.
Sure much newer cars actually require one now as they fuse block right near them and demand much stricter current, but for my case all I need is volt.

As I said clearly getting fuel, I just don't know how much, I don't own a fuel gauge anymore. I already replaced filter as stated and after several bouts of cranking fuel smell is obvious. One advantage to vans is also the pita. The engine is literally inches away from your knee behind a insulated cover. I have that removed so I can sit in driver seat and even move distributor if I release the nut while cranking. Most cars you can't smell or see anything while trying to start without a 2nd person, van you can massage the engine block if you so desire while cranking haha.
Already removing injectors this weekend but I am doubtful that is it due to the fact it runs without sputter/misfire under normal throttle when it does decide to run.

Also MAF was on my list to do as well although I just did it a few years back and it has clean filter.
It is super easy to test a MAF for complete failure, IF it is running. You just simply disconnect the harness while running. It the engine dies, it's working. If it keeps running then it is faulty and you are getting bad mixture. Those things would show up on my software/OBD if I had it running even without fault code.
Starting to think no one actually read all the things I've done and planning /sadface
I know quite a bit about the buggers but I am hitting a real roadblock here. I'm starting to think I have a bad ECM, a stuck relay or a grounded wire to one of the many sensors.
I know for a fact a coolant sensor grounded will prevent start but that is USUALLY when the system is hot, not cold start.
I also know knock/crank sensor both will prevent starting as I have had that happen on vehicles before when the other requirements were met air fuel and spark. Had a little S10 when I lived down in TN and it just died one day at a job site. We stripped the damn thing down and was completely baffled why it wasn't running. Crank sensor. Once we had it and about 10 minutes to install it, boom perfect again.

The problem I am having is how do I test these things without buying the damn things reliably and most of them are $50+ a pop. I guess I need to find someone who knows more about diagnostic stuff such as can I rig a sensor hot or bridge the wires to convince it is it working and see if that results in a start for those things.

mkopec said:

How bout the throttle position sensor? Does your vehicle have one? Another thing I would check.

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It does indeed have one, the issue is like the other "vital" sensors it would be near impossible to test out without the proper tools. If I could force start the van I could actually check engine load, throttle position and everything else from my doagnostic tester and torque app

Picasso3 said:

Ok i read your post. Seems like starter fluid is the next thing? Do you want 20 bucks?

Chevrolet C/K 1500 Questions - 96 Chevy C1500 5.7L Vortec Truck won't start, Replaced Fuel Pump, Fil... - CarGurus

Fyi on my 97 k1500 the fuel pump is notorious

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I used to have this old Suburban which I loved that damn thing, anyways I went through 3 fuel pumps on that thing because every time you allowed it to get down to 1/8 tank or less it was notorious for picking up trash into the pickup and burning out. Since with the van and having the engine beside me I can hear and smell as I turn over I can hear the pump engage and disengage trying to start. Does not rule out fuel pressure or fuel relay though. Fuel relay is actually only $15 but is still only 1 of about 8 possible sensors that could be startblocking me.

It's one of those things where if it is assuming or god help us telling it it is getting a pressure it is not then ya it won't start reliably even with fuel. Rich/lean flooding or starvation. Take your pick. Normally that would result in rough running/misfire as well but whatever it happening is only happening during cold start( engine cold even at 80 degrees ). Once engine is warmed up it does a warm start just fine or so has been the case every time so far. I think that is where I really need help here. What is the difference between a cold start and a warm start on a mid 90s gm vehicle and that is intermittent . That would be the key to solving this.

mkopec said:

Thats the problem with these things once they introduced computers and 100 sensors everywhere. Youre essentially chasing ghosts. And it always turns out to be something stupid that makes the whole thing fucked.

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As I said I know my way around an engine pretty well. The problem is I only know my way around an engine. I'm sure a full time mechanic has a million little tricks where he can say if it does X then it is Y, maybe Z. I know what X Y and Z are but I don't know the "process" of elimination to tackle it.
Obviously the issue I am having is beyond probably 90% of failures. The fact it happened, then didn't happen for months then happened off and on rapidly and now dead makes me think it is a sensor or a odd short. Another thing I have not ruled out is vacuum pressure and timing chain/gear.
It shouldn't even be possible as I have compression, but like vacuum and fuel pressure, just because you have it, does not mean it is enough to start it.

I am just not physically able to tear down everything as I once was nor am I a financially able to just blindly tackle those ghosts.

I'm thinking of forcing the issue with some ether/starting fluid and seeing if I can force start it. I hate spending that $10 though and it is quite dangerous to do on a engine with such high mileage. It's very hard on them, but if I can get it to catch and start then I can possibly eliminate many things.

Lanx said:

whelp, guess i youtubed a clip, too bad i packed away most of my tools

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Ya youtube has helped some and lots of good info there but it is like shooting fish in a barrel unless you have specific issues.
Thankfully my fan is belt driven. Trans Am it is electronic and it drives me nuts because it only kicks on basically when the car is already overheating which we had happen earlier this year with a stuck thermostat.

mkopec said:

Another thing to check, maybe is the IAC (idle air control valve), if your truck has one. Those are usually a solenoid that gets gunked up over time. Easy to clean too to get it working if you can get to it depending on vehicle.

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Didn't even think about that and I do have one. Another thing that complicates all this compared to normal systems is this van has some functions tied into the master cylinder in addition to just brakes. They built these GMC's on a truck frame with high haul features. That is a bit different for me than say just a straight drag motor. It's frustrating. I would think the IAC along with EGR issues would have triggered a code down the line though, unless it is only sticking when it is cold. Makes me want to go get my Mr Heater out even though it is 85 today and "cook" the engine compartment to see if at 175+ the problem dissolves.

BTW you run risks with doing this but I've had it work well on window motors and other things. Parts that typically run 30-60 bucks at a auto store you can often find on ebay for a few bucks new. Not sure if people scamming them from warehouse, stolen or just knockoffs but for some things it is worth it.

mkopec said:

Thing is with an IAC going bad or sticking, your van would still start, just never run or get into idle.

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I've never had one fail or stick for that matter.I'll add it to the list when I check EGR/vacuum though. Should be easy enough to check.