Cranks but no start, then starts immediately

[Vaughn MacKenzie]

I have a '98 24-valve with 243,000 miles, 90,000 on the brand ? VP44 replacement by the previous owner. Lately quite often when I crank the engine it turns over but will not start. If I turn the key off and retry it, it fires instantly. It was doing it about 1-2 a week, now about half the time. Hoping it's not the injection pump. Fuel pressure is good, 15-18psi. When it starts it's smooth and no smoke other than the normal puff when it fires.

 

[petersonj]

You could have a small undetectable leak in a fuel line. Fuel lines may not leak fuel out, but a crack in a hose can let air in, allowing the fuel to drain back to the fuel tank when the truck is parked. Try parking the truck with the nose facing downhill. If the starting problem disappears, then start looking for a fuel leak.

Have the truck checked for trouble codes. Codes could help lead you to correctly diagnosing the problem.

- John

 

[Chief USA]

Try taking a look here:

https://www.bluechipdiesel.com/troubleshooting-1

 

[Vaughn MacKenzie]

Thanks for your input John & Chief. It doesn't act like a fuel problem, when it fires it runs perfectly smooth with no blue or white smoke. None of the troubleshooting items listed at Blue Chip match my issue.

Yesterday I had a ton of running around to do. I started the engine 14 different times, it only acted up once. That particular time it had been sitting for an hour, level. The first start of the day at 30 degrees and no grid heater it light right off, nice and smooth.

I started it 8 times today and it started normally each time. Maybe the problem will mysteriously vanish, like the torque converter lockup problem that suddenly went away.

 

[KATOOM]

Hard starts are caused by very few things, which means hard starts are generally not ever random. There has to be a pattern to how and when it hard starts. List what that pattern is and it will usually lead you directly to the cause. Meaning, does it do it only when the engine is cold, hot, after sitting X period of time, parked uphill, parked downhill, etc...?

 

[Joe Mc]

Vaughn, Some years back (before I did the Vulcan Draw Straw) my truck would do the same thing = long crank, no start, then after a few times it would start right up and be fine. Didn't matter if it was cool or warm and was always on first start of the day or after sitting for an hour or longer. I started inspecting the fuel system - short story is - on top of the fuel tank module (inspecting with a flashlight and inspection mirror) I noticed a gradual bend section of hard pipe going into the top of the module that had a spot on the bend with allot of dust and the rest of the downward bend was not as dusty but more like it was darker in color than the rest. As it turns out, after cleaning the dust and scuff pad the pipe there was a pin hole, this line/pipe was the feed to engine. What was happening was; after sitting air would get in the pin hole and the line would drain back into the tank creating a loss of prime. After I did the draw straw, big line kit and etc. all has been well.

 

[Vaughn MacKenzie]

That was an interesting issue Joe. Good find on that!

Katoom here is a summary of what I have noticed:
· Doesn't seem to be temperature related, happens whether it's 25 or 55 degrees. It has started instantly at 25, and cranked a long time at 55

· If it doesn't fire immediately, it will not fire at all if I keep cranking. I kept on the starter 15-20 seconds straight once to see what would happen and it didn't fire

· No white smoke out the pipe when cranking long

· It seems to do it more often on the first start of the day, but lately it has been the opposite, it always starts immediately in the morning

· The last time it happened the truck had been shut off for 1-2 minutes

· The time before that it had been sitting an hour

· Truck is always sitting level. I'll try parking uphill or downhill and see if that changes anything.

· Lately it has only done it 2 times in the last 5 days, and I have driven it a bunch (tons of startups every day).

 

[KATOOM]

This is the general guideline rules for hard starts:

1) A fuel leak in the fuel system will cause the prime to be lost. Leaks dont have to drip either as air can be entering more than fuel is escaping. The severity of the leak will determine how much cranking will be involved to start since the prime has to be pumped back. And also how long between run times for the hard start. Lastly, a leak will generally only cause a "first startup" hard start of the day problem.

2) A grid heater system not functioning as it should can cause hard cold starts but if the engine temperature is registering on the dash then there should be plenty of heat to not rely on the grid heater.

3) A slow cranking engine will cause hard starts. Slow cranking can be from poor battery condition or dragging starter. A mere 50 rpm reduction in cranking rpm will cause a hard start...especially on a cold engine.

4) Over-pressurizing the VP injection pump will cause the fuel solenoid and timing ring to hydrolock fully advanced. As you crank the pressure releases and the engine will start. This is only a hard start problem when the engine is a full operating temperature. Also, typically only a problem for those people who've replaced their fuel pumps with aftermarket fuel pumps like FASS or Airdog...and have a reman VP.

5) A faulting CPS can cause the engine to hard start or no start depending on severity of the faulty sensor. You can test them with an ohm meter or replace it.

6) If there are ANY aftermarket electronic engine performance devices then they should be completely disconnected to rule them out as a problem.

 

[BoeingDiesel]

If it were me, I would replace the fuel return check valve on the VP. It's an inexpensive item and may help in the elimination process. Also, I would do a detailed inspection of the banjo fitting on the back of the head and the tee fitting for the return line. I think it was Moparman 1973 that suggested to eliminate return fuel line problems was to park nose down on a downhill slope. Obviously that's easier said than done. Katoom commented on some very important points. Best of luck...these old 2nd Gens' are a labor of love.

 

[KATOOM]

If it were me, I would replace the fuel return check valve on the VP. It's an inexpensive item and may help in the elimination process. Also, I would do a detailed inspection of the banjo fitting on the back of the head and the tee fitting for the return line. I think it was Moparman 1973 that suggested to eliminate return fuel line problems was to park nose down on a downhill slope. Obviously that's easier said than done. Katoom commented on some very important points. Best of luck...these old 2nd Gens' are a labor of love.

Just an FYI - I highly suggest NOT touching the VP return overflow banjo only because it can cause more problems like leaks which will definitely cause hard starting. The overflow simply consists of a check ball and spring and rarely if ever go bad or cause problems.

Parking downhill helps diagnose a leak in the fuel system because parking with the rear of the truck upwards raises the fuel tank more level with the engine which prevents gravity from pulling fuel back into the fuel tank. The fuel system prime works just like the same as putting your finger over the end of a drinking straw in a glass of water and pulling the straw out of the glass. The water remains in the straw until you remove your finger. The fuel remains in the lines until there's a leak which allows the fuel to escape and the prime has to be regained.

 

[Jason Laughlin]

My truck is doing the exact same thing. Its so intermittent its hard to diagnose. I have a FASS with fuel pressure set at 15psi and the truck is not throwing any codes. Started 6 times today and did it twice, runs absolutely perfect, has power and no surging. Blue Chip gives tips on hot starting problems and cold starting problems but not for intermittent. If it was losing prime it would be hard to start all the time? My 89 12v has a leak at the fuel filter and if it sits more than 4 hours it has lost prime, consistently, I don't believe our problem is prime related. Could it be electrical related? I have electrical problems sometimes.... Im in south Louisiana so no hills to park on.

 

[Tractorat]

Very similar to symptoms I had a couple of years ago. Turned out that the cap on top of the fuel tank was cracked. Problem went away when I had a sump and bottom feed installed on the tank.

 

[KATOOM]

Turned out that the cap on top of the fuel tank was cracked

Thank you for bringing that up because there is an issue where the fuel tank vent is plugged and causes the fuel system to pressurize the fuel tank which can cause hard starts and running conditions. Generally this is because there's also an injector problem because the injector overflow runs back into the return fuel system. But nonetheless, if the tank becomes pressurized or vacuum because of a clogged tank vent then you can listen closely to the fuel tank cap when removing it. You may hear the whooshing sound of air escaping or rushing in.

 

[Vaughn MacKenzie]

Good thoughts everyone, thank you. I haven't had a chance to park on an incline yet, just isn't any angled places to park where I live and work unfortunately.

I just have a strong gut feeling it's an electrical or electronic issue. Like the injection pump isn't getting a reliable signal to open up the fuel relay at cranking time. Maybe my Fuelab pump is causing too much pressure, the 100gph one I installed a few months ago. It is around 18psi at start. However I tend to be a "gasser starter." I never wait for the grid heater unless it's in the low 20s or colder. I usually go straight to cranking so there's no chance for it to build any pressure ahead of time.

By the way I have a Beans bottom feed fuel pickup. Fuel pump is by the tank. As for the fuel return line I'm not sure if I want to dive into that just yet. Hope to do some troubleshooting over Christmas.

 

[Joe Mc]

Maybe my Fuelab pump is causing too much pressure, the 100gph one I installed a few months ago. It is around 18psi at start. However I tend to be a "gasser starter." I never wait for the grid heater unless it's in the low 20s or colder. I usually go straight to cranking so there's no chance for it to build any pressure ahead of time.

My GDP system (Walbro pump) delivers high gph also, I have the relief set @ 21# and it "always" stays at 21# (regardless of Go pedal position or Edge setting), one exception is when the grid kicks on then it'll drop to 20#, so I don't think the VP is getting too much pressure = assuming the gauge/sending unit is close to VP and giving correct reading. As I understand the VP doesn't like more than 22# of head pressure. Double check your gage with a mechanical.
As for being a "gasser starter" tisk, tisk, tisk, (LOL) you should be a little bit more patient and wait for the "wait to start" light to go off. Just MHO.

 

[Vaughn MacKenzie]

Well soon after my last post the problem got worse. Much worse. It would fail to start on the first try every time, and usually it would take 3 tries. This happened just as my battery was failing for good. It had been marginal for a while, it would crank over fast for several seconds which was usually plenty long enough to fire it. But then it was getting to where I couldn't crank it much, and a couple times I had to jump start to get going.

I put in a better battery and since then it has started perfectly ever single time, immediately on the first try. It's been 8-9 days and started perfectly since then. That is rather strange since I've had a battery fail on a 24V before and never had a starting symptom like this. The old battery still spun the motor over nearly as fast, so I'm not sure how it was contributing to the problem. Maybe my alternator has a bad diode and a battery with weak capacity doesn't absorb the AC spikes as well.

Who knows.

Crossing my fingers it's gone for good!

 

[mini14]

my truck acted like yours, I pulled the starter to find the insulation of the wire that goes from the solenoid to the starter was cracked and the wire would touch the starter body. while it was out I soldered the wire where it connects to the solenoid. It was a replacement starter high quality from a rebuilder. my factory denso no longer had cranking speed and would cost way more in parts then a good reman. You could also have a sticking plunger or bad contacts. Ive replaced them several times on my trucks and others.

 

[Jason Laughlin]

I figured mine out. Blue chip diesel talks about a wire that has a short that will delay the fuel pump. Thats it! I turn the key to the on position and wait to hear the fuel pump. Once I hear it, the truck starts 2nd turn, every time.

 

[Mike B.]

Well soon after my last post the problem got worse. Much worse. It would fail to start on the first try every time, and usually it would take 3 tries. This happened just as my battery was failing for good. It had been marginal for a while, it would crank over fast for several seconds which was usually plenty long enough to fire it. But then it was getting to where I couldn't crank it much, and a couple times I had to jump start to get going.

I put in a better battery and since then it has started perfectly ever single time, immediately on the first try. It's been 8-9 days and started perfectly since then. That is rather strange since I've had a battery fail on a 24V before and never had a starting symptom like this. The old battery still spun the motor over nearly as fast, so I'm not sure how it was contributing to the problem. Maybe my alternator has a bad diode and a battery with weak capacity doesn't absorb the AC spikes as well.

Who knows.

Crossing my fingers it's gone for good!

Vaughn I'm sticking with you ultimately needing an ECM. One of my failed ECMs acted in a similar manner getting progressively more problematic. I agree that it would be unlikely that the battery or alternator are at fault here. That said who knows is right considering the way these things are electronically interconnected.. I can only image the electrical issues that will pop up 20 years from now on the 3rd & 4th gen trucks. we're probably getting off easy

 

[MAYoung]

In case the problem returns, you may wish to re-visit KATOOM's comment. I just recently replaced my starter with a factory re-manufactured part. It has been several weeks but the hard start problem seems to have been solved. In my case, the first start of the day was fine but after warming up, it would take maybe 5 seconds before firing. I thought it was the VP44 going bad.

But KATOOM's comment about the speed of the starter may have been spot on. I could not notice a decline in starter rotation but the starter was not a factory reman and had been on the truck for over ten years. That starter rotation speed made a big difference. (To tell you the truth, however, I do not even notice the starter speed because the engine now starts with one touch of the key.) For you, the slow rotation may have been buried in your batteries, which I can wholly believe. Been-there-done-that.

Good luck. Let us know how it works out.