GSP7

My '99 4x4 diesel used to fire right up , lately sometimes it has to crank longer than usual. Not real long cranking over, but noticeably a little longer crank time. Not all the time but did it today 3 times. It always fires though.
I dont drive it every day . Drove it last two days probably 200+ miles

I just put new batteries and military spec terminals and cables on it. Battery ground to frame and body grounds good. Has 164,000 miles, new VP a few years ago , lift pump pressure is ok, Fuel filter changed 5000 miles ago, and the old one was ok anyway . I run 2 stroke oil in the fuel all the time
I plan on putting a Fass pump on it but " Idont think" that is the problem

Any Ideas why it has to crank a little longer to fire sometimes. Or possibilities?


.

patdaly

Does it do it more so when you let it sit?

Try this, if you know when it is going to take a longer time starting, try just bumping the key and waiting for the lift pump to fill everything. It should run for 25 seconds after just bumping the key. If it always fires right up after doing this, then you probably have a slight leak in the return system somewhere.

There is a t at the back of the engine that can be hard to find a leak at.

GSP7

Ok I just looked at the "T" and felt the line at back of head, No sign of leak , and no leak moisture at any injector lines either

I wait to here the LP run , then crank when I here it, I havent made a point to wait till the LP stops to crank it all the time


On Cranking,,,It varys, when I let it sit 2 1/2 hrs tonight its started pretty fast. Then I stopped on the way home and got fuel and it had to crank quit a bit only after a few minutes of sitting.
Seems like after I first drive it, then its cranks long 2nd time after a short wait period.

Could a week lift pump cause this? I was about to buy and put a Fass Titanium pump on it. My replaced stock pump still never goes below 10 psi , though I can tell its lost a few PSI as its got older recently

Ive been only driving it maybe once a week, but drove the truck several times today and Sunday and its noticeably getting worse

GSP7

Also I just turn the key to On and listen for the LP. I haven't been bumping the starter

PS Lets see,,,, I just remembered the return attached at the back of the head is a banjo (only one left on my truck) then the line comes over to the "T" and the VP return hooks in and then goes back to the tank

patdaly

Doubt it is a leak from what you describe, almost sounds like it is harder to start warm than cold.

Pay attention to when it takes a longer crank, if it is temp related, then try this, before start, while warm, pour a quart of very cold water over the VP body and see if it starts normally.

Past that, I am out of my league with VP's.

cougar

Simple things to check first. How are your batteries? How is your starter? What is your fuel pressure? If you have a charger with start boost, try starting it on the charger and see if that makes a difference. If it does, I'd suggest new batteries and a starter. If it doesn't, you maybe looking at another VP. Your symptoms are similar to what I had. Wound up being the VP.

GSP7

It has brand new batterys and terminals

VP only has 36,000 miles on it from The Diesel Store Midwest fuel injection

GSP7

I called Eric at Midwest Fuel Injection and he gave me some advice and things to check

KATOOM

Just coming in this thread..... So to be clear, does it hard start ONLY when its warm? Never when its cold? For instance, driving around and stopping for fuel or quick run in the store, only to return and have the truck hard start? That needs to be perfectly clear before going on.

cougar

I assumed my new batteries (less than a year old) were good also. I'm having to replace them. My starter is also not up to par anymore, so is also getting replaced. And, my 2 week old VP from Oregon Fuel Injection is now exhibiting some suspicious behavior. I have an appointment with the local Bosch dealer that installed it.

GSP7

"hard start ONLY when its warm" seems to be the case lately. Though it has done it first thing in the morning months ago.

Ive been having this long cranking issue for a couple years. I dont drive the truck every day, and only put 5000 miles on it in last 14 months

KATOOM

Let me tell you what I know.....

If the hard start takes place when the engine is cold or has been sitting for many hours on end, then the issue is most likely a fuel leak. To assure if a leak is the problem then you can park the truck with the nose pointing downhill which in turn lifts the fuel tank higher in relation to the level of the engine and works against the pull of gravity which is drawing the fuel in the lines back into fuel tank and thus eliminating the "prime" of the fuel system. If the truck starts better or more normal when pointed down hill, you have a fuel leak.

If the hard start takes place when the engine is cold and parking the nose down hill doesn't help then its not a fuel leak but rather something related to electrical system. Generally the issue is poor battery voltage/amperage and is not delivering the proper power upon engine cranking. Batteries should be tested out of the truck too. Batteries should be the same size, same build time (age), and same power rating. One battery with a bad cell will bring the good battery down, instead of the other way around. Corrosion can cause poor electrical signals so if road salts are normal in your area then check all major electrical connections and grounds and battery cables for cleanliness and connection.

That said, the OEM Denso starters are very stout units and need very little attention besides contacts every 100k or so. Meaning, if the OEM starter has ever been swapped out for an over the counter "lifetime warranty" parts store starter then it could most certainly be a dragging start. A mere 25 rpm in cranking speed of the starter will cause hard starts and be more of a problem with a cold engine because cylinder compression as the piston moves up is the only source of heat generated for combustion. A slower moving piston creates less compression heat.

If the hard start takes place when the engine is hot then the issue can be too much fuel pressure during engine cranking. This is because the VP requires no more than 7 psi during engine cranking and the ECM is supposed to alternate 12 volts to the lift pump in order to achieve that pressure reduction. But again, that said, the VP does best with no fuel pressure during engine cranking as long as the fuel system prime is retained at all times. Meaning, no fuel leaks. The best way to assure if excessive fuel pressure is the problem is to disconnect the fuel pump during engine cranking. If it starts normal then this is the problem. Just dont run the engine for more than a few seconds without the fuel pump connected. But.....to point out, even though there is an TSB regarding this problem with OEM lift pumps, its very very uncommon for an OEM lift pump to pose an overpressure issue during engine cranking but can be quite common for aftermarket higher pressure / higher volume fuel pumps. If you have a stock lift pump then this most likely isnt the issue.

If the hard start takes place when the engine is hot and it has nothing to do with the fuel pump then the problem could be the VP computer (PSG). The PSG sits on top of the VP and the older units have inferior solder which is more prone to deterioration due to excessive heat. Generally this happens during the 20 or so minutes after shut down whereby the 120*-150* VP absorbs the heat from the 190*-210* engine and causes the solder to crystallize. Over time these "heat cycles" will eventually lead to intermittent electrical connections in the PSG and cause hard hot starts. Usually when the engine fires you'll see a puff of white smoke and usually these poor connections can lead to "dead pedal" while driving. One way to find out if the PSG is the cause of the hard hot starts is to carry a couple gallons of water around with you and when the truck doesnt want to start normal, pour the water directly on the top of the VP and PSG in attempt to cool the PSG a little. If this helps it start then unfortunately the only fix is a new VP. Again.....that said, aftermarket remanufactured VP's dont always come with new PSG's. Some VP's are rebuilt and use the old still functioning computer. Thats no good as all VP's should come with the new updated computers. That doesnt mean all PSG related problems are eliminated either but reduces them considerable and at least gives you a clean "heat cycle" slate to start with. If you look on the side of the PSG you'll see a bar code and some numbers. If the PSG is the updated version then the first digits should be 0 281 010 890.

OK, I know thats a lot to read but let me just add one more thing..... If the hard start takes place when the engine is cold and hot and is more random then thats another problem because it means there's more than one issue and could be a combination of things. Dont discredit the electrical system on these trucks. The ISB is fully electronically controlled and is very sensitive to any conditions other than perfect. Things like a wavering alternator possibly putting out too much AC noise or grounds not making proper connections.....etc. Even the CPS can cause some random hard starting issues.

GSP7

OK ,,, I R&R'd my starter this morning. I did think it was cranking kinda slow even after I just put new batterys in a couplle weeks ago

Napa tested the old one and it was drawing too many amps...Bad...

New starter installed cranks very noticeably faster.
Hopefully this will cure my long cranking issue ive been fighting for two years .

I'll mention I got the Napa Lifetime Warranty rebuilt in mexico starter,
maybe it will be a denso core,,,,instead of getting Napa's New made in China one

Cost: $0.00

I want to thank Katoom for his excellent post !

Rick

KATOOM

You're welcome and I hope that solves your hard start condition. Plus free is nice too.