'78 Bus Won't Start Unless Warm Or Having Set For A Week

[dtrumbo]

Yes, the title is intriguing, eh? Here are the details so y'all will know what we're talking about. 1978 Riviera camper with a very stock 2.0L engine with factory fuel injection and hydraulic lifters.

Let me fall on my sword straightaway. The engine in my bus is very tired and in bad shape. I've bought a different engine with intentions to rebuild and I got about halfway through before the big move which has put that project on temporary hold. The point of the different engine was to keep the tired engine in the bus so it would, at least, be driveable. A leakdown test performed late last year implicated the rings being the leakage point and likely cause for the lower-than-"normal"-but-not-horrible compression. Now on to the weirdness eluded to in the title of the thread.

Earlier this spring I decided to rouse my sleeping beauty and let her stretch her legs one more time since the rebuild was dragging on and on as they sometimes do. Faithfully the bus started right up after having sat for nearly four months. I drove it, hydraulic lifters clattering from my shop to the front of my house where I parked it and shut it back down. About an hour later I loaded the kids and fired it up to go off to the little league game. With one foot on the clutch and another on the brake while waiting to see if it was clear to pull out of the driveway, the bus died and would not restart. Abandoning it for other transportation to get to the game, I returned later that afternoon and started troubleshooting. Everything seemed o.k. but it still wouldn't start. Having had a similar issue when I first bought the bus, I knew that a low battery would not have enough oomph to run the FI system. It seemed plausible that after having sat for four months I had enough battery to start the bus once, but not enough to start it again so soon after only running for the seconds-long trip from the shop to the house. I then decided to charge the battery and try again later. Sure enough, after I topped off the battery it started again. I got out to go see if I could poke or prod something to flush out any other issues and sure enough, it died and would not restart. I decided it would just have to sit in my driveway for awhile while I scratched my pate and came up with something else. Life gets busy and I didn't get a chance to monkey with it for a few days. Finally I get back in, and with apologies to the starter motor, I finally get it started by holding the accelerator to the floor and the key in the start position WAY too long while the motor "wound up" enough to start. Think pony motor on a big Caterpillar bulldozer. Once started I kept the RPM's up for awhile so the engine could warm up, close up it's way-too-loose tolerances and actually idle. Once warm the bus runs fairly well and can be driven quite successfully. I drove the bus back to the shop and parked it with humble apologies and a "check's-in-the-mail" promise of a rebuilt engine.

Fast-forward to last Saturday night. As mentioned, we've moved and I'm finally getting around to moving all of the stuff out of my old shop. In order to do so I needed to move the bus so I could get some other worldly possessions into the back of my truck. I get in the bus which hasn't been touched since spring and, of course, it starts right up and happily moves out of the shop to a parking spot out of the way. An hour later I go to put it back in the shop and it won't start. Just like before. I try the wide-open throttle with key held in the start position trick but no luck this time. The bus is just going to have to sleep outside on this glorious PNW summer night. I come back Monday and it still won't start. It hasn't sat long enough. I won't tell you what I did to get it parked back in the shop but let's just say the starter motor can really develop a lot of torque in a pinch. This coming weekend I'm going back to finally move my beloved (even though I've abused the crap out of the starter motor) bus to our new home. I'll bet money it starts right up because it will have sat for a week. This time I will drive it straight away not letting it idle/die until it's fully warmed up. Of course if I'm wrong then it's AAA time.

So... after the long-winded back story, what the heck is the deal? I'm pretty sure it's not electrical. It seems fuel related in that perhaps it's "flooding" while it's cold and then won't restart. I'm saying this because when I hold the throttle all the way open (more air) it will either restart or it will come as close to restarting as possible. More so than if I try to start it with my foot off of the accelerator. Perhaps letting it sit allows the excess fuel to evaporate or otherwise dissipate. Of course I could be totally wrong. By the way, this is all for posterity as I PROMISE that once this bus is at its new home it WILL NOT be driven again until it has a rebuilt engine installed. I simply find it curious that the longer this bus sits, the greater the chance it will start and run. Kinda counter-intuitive.

What say ye?

[Amskeptic]

Yes,
Perhaps letting it sit allows the excess fuel to evaporate or otherwise dissipate. Of course I could be totally wrong. By the way, this is all for posterity as I PROMISE that once this bus is at its new home it WILL NOT be driven again until it has a rebuilt engine installed. I simply find it curious that the longer this bus sits, the greater the chance it will start and run.
What say ye?

You running points? Get the gap opened to an easy .016". Clean the contacts and the coil spades well.
Let me know.
Colin

[dtrumbo]

You running points?

Yep.

Get the gap opened to an easy .016".

Done.

Clean the contacts and the coil spades well.

Done.

Let me know.

No change. The points were a little pitted and the gap was probably a little too small so the exercise wasn't in vain. However, it still wouldn't start until I, once again, abused the starter motor to get the real motor spinning long/fast enough for combustion to ensue.

The bus is home, resting comfortably in the garage next to his sisters. Damn my new garage filled up fast. Now to finish unpacking all my crap so I can continue where I left off.

[vdubyah73]

Try a shot of ether when it won't start, if no sputtering without ether and you get sputtering with ether look at fuel. worn rings will cause hard starting when at full operating temperature in water cooled engine. loose heads will do the same thing in an aircooled engine. had a suburban once that would run with the big dogs all day long, just don't shut it off till you're where you were going and it can sit for a few hours. symptom of fully warmed up with low compression hard start is an engine that spins over very fast compared to warm weather cold start, you know di di di di di di di di vs rrr rrr rrr rrr rrr rrr .

[dtrumbo]

loose heads will do the same thing in an aircooled engine.

This just might be what's going on. Once the new engine is built and installed in place of the old engine, the CSI team will issue a full forensic report.

[vdubyah73]

you can retorque the head bolts under the rocker assemblies. you can get at 1 or 2 without removing the rockers to check. Even if they seem tight remove the rocker shafts per bentley, leave pushrods alone, and check all of them.
the top ones, that are exposed under the cooling tin don't often work loose. they aren't bathed in hot oil.

will run better if you find loose ones and torque em.
may not solve your problem though if it's fuel related.

[Amskeptic]

it still wouldn't start until I, once again, abused the starter motor to get the real motor spinning long/fast enough for combustion to ensue.

Red/white wire from the "other" starter solenoid spade terminal going to the double relay 86? The red/black start signal from the ignition switch actually energizes the cold start valve and the fuel pump relay! during cranking. I shore would like to know if the fuel pump runs during cranking ...
Colin

[dtrumbo]

UPDATE:

As the purpose of this forum is "Find/Fix/Report Back", here I am to resurrect this thread and satisfy all three. As you may have read in another thread, I just finished rebuilding an engine I bought on Craigslist. From my original engine referenced in the above posts in this thread I only reused the exhaust, engine hanger, complete intake (air filter through intake runners) and the coil. I'll let that hang there for a minute for effect.

I did my first engine start on Friday afternoon and it fired up practically before the key was completely turned all the way to the start position (I exaggerate, but suffice to say it started immediately). I was very pleased given how nervous I was that it would start at all. After cam break-in I parked it back in the garage, drained the oil and it sat overnight. The next morning, like a little kid on Christmas I went out to the garage to finish the initial oil change and do the initial valve adjust. They're hydraulic so no surprise that they didn't have any perceptible change. It's all buttoned back up and I go to start my new creation and I get the EXACT same response as above. Cranks and sorta starts to catch but only if I hold the throttle all the way open and then it slowly roars to life belching smoke of undetermined color out the back. After I let it run for a bit I went to set the timing. I noticed that my timing light would flash erratically and the engine would slightly stumble in concert with the erratic light. LIGHT BULB!! It finally dawned on me. I removed the original black coil that had a capacitor between terminal 15 and ground (radio interference filter?) and replaced it with the blue coil that came with my Craigslist engine. Now it starts right up every time (so far).

I'm pretty sure it's not electrical. It seems fuel related in that perhaps it's "flooding" while it's cold and then won't restart.

Looking back with my 20/20 rear view mirrors, it was obviously electrical. I had all the fuel I could ever want and more but no (or little or random) spark to go with it. I'll update this thread if anything changes, but I think my problem was the coil and/or the capacitor that was attached.

[Amskeptic]

UPDATE:

Looking back with my 20/20 rear view mirrors, it was obviously electrical. I had all the fuel I could ever want and more but no (or little or random) spark to go with it. I'll update this thread if anything changes, but I think my problem was the coil and/or the capacitor that was attached.

Sounds plausible, we shall praaaaay to the fresh engine rebuild gods that your engine did not mind all that fuel wash.
Dick . . . . . about those six shims . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

[dtrumbo]

Sounds plausible, we shall praaaaay to the fresh engine rebuild gods that your engine did not mind all that fuel wash.

How many brand new engines are cranked and cranked until the fresh engine builder realizes they had the coil disconnected or the AFM disconnected or the white wire to the ECU disconnected. I think the odds are in my favor.

Dick . . . . . about those six shims . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

All I can hope for is three of them will weld themselves together and to the end of the flywheel and I'll be back in spec.

[Amskeptic]

Sounds plausible, we shall praaaaay to the fresh engine rebuild gods that your engine did not mind all that fuel wash.

How many brand new engines are cranked and cranked until the fresh engine builder realizes they had the coil disconnected or the AFM disconnected or the white wire to the ECU disconnected. I think the odds are in my favor.

Happens every day. As do engines that get 60,000 instead of 120,000 miles. I wrecked! my Lincoln's original piston rings in one weekend of thinking I had fuel starvation when it was a bad condensor.
Fricken relentless laws of physics never give you a break.

Dick . . . . . about those six shims . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

All I can hope for is three of them will weld themselves together and to the end of the flywheel and I'll be back in spec.

That would work. Did I ever tell you how the Road Warrior gave me 100,000 miles of pure gift from 1991 to 2002? Yeah, I forgot to put the dowel in to hold the #2 main bearing in the right case half. It slipped within the first couple of hundred miles and was "setting the endplay" against the crankshaft. Shards of blued steel were found in the case 100,000 miles later as that bearing kissed the crankshaft journal flange. Unbelievable! Ran great! Explained the grey swirls in the drain plate after my break-in! Me? Moron?
Colin