Odd and random hard starting issue

[dslhtrdr]

I've been having an odd and random hard starting problem with my truck lately. I need some advice because I'm a little stumped now, and feel like I could be missing something obvious, so here it goes...

I blew the original head gasket in my '94 12v at 337k miles. I had a new o ringed 12v head that I bought from Pure Diesel Power (thanks Garrett) and a 20 over head gasket. I bought new ARP 625's to go with it. I removed my old head and gasket, cleaned up the block deck surface and inspected everything. The cylinder walls looked great, still had all the crosshatches, and the deck was completely flat checking it with a professional grade straight edge and feeler gauges.

I reassembled everything and have been driving it for 3 weeks now, and it has begun this hard starting crap. I checked and rechecked my injection lines, no leaks. Injectors appear to have no leaks. Also replaced the fuel filter and water separator on my airdog. Replaced the fusible link for the shut off solenoid a few weeks prior to hg replacement. Fuel pressure gauge reads 45-48 psi at idle, 50 psi cruising down the road.

Current motor mods:
New o ringed head, 60lb valve springs, 20 over head gasket
New ARP 625 head studs
887 215 pump with 181 dv's (I have 024's that I want to swap in), 4k gsk, pen spring inside the ofv
DDP4's (had them pop tested during head gasket change, one needed cleaning)
Hx35/40 hybrid ht3b twins on a custom stainless header


Things I could still try:
Check my valve lash again
Install a different shut off solenoid
Try a different ofv (tork teknology?)
Ht3b needs new oil seals, figured that out when replacing the hg

And this is where I'm at. It will do it when cold in the morning or hot afternoon, been sitting for a couple days or just overnight, also when the motor is cold, or has been running recently, but it isn't nearly as bad when it's been running for awhile. I also noticed when replacing the shut off solenoid fusible link that the fuel line going into the p pump is making a weird squeeking noise when the motor is off and just the airdog is pumping fuel. Not sure if this is relevant.

If I can think of anything else I will post it up. Otherwise any help is appreciated.

 

[ChuMaDD]

You may have an air leak in your fuel system if you can hear a noise coming from the line. Are you seeing any leakage? Have you adjusted your idle screw recently? Are you batteries good? Alt charging? It seems you actually need to try some tests to rule things out. Where are you getting your FP from?

Edit: is your fuel shut off adjusted properly?

 

[dslhtrdr]

You may have an air leak in your fuel system if you can hear a noise coming from the line. Are you seeing any leakage? Have you adjusted your idle screw recently? Are you batteries good? Alt charging? It seems you actually need to try some tests to rule things out. Where are you getting your FP from?

Edit: is your fuel shut off adjusted properly?

My thoughts are an air leak as well. I noticed the squeeking sound when I had to pop my hood and manually pull the shut off solenoid up to start my truck one night, which was before the head gasket went, so I don't know how long it's been making the noise.

I can't visually see any fuel leakage anywhere. I haven't adjusted my idle scew lately. It currently idles around 850. My batteries are good and my alternator is fairly new, always charges at 14v. I get my fuel pressure reading (autometer electronic sensor) from a threaded push lock connector about 4 inches before the fuel inlet on the injection pump. I believe the shut off solenoid is adjusted correctly, but I will check that. I have never had starting issues in the 6 years of owning this truck, but I guess it could come out of adjustment.

I wasn't sure if the thicker hg was part of the problem from lowering the compression ratio a little bit, but something tells me it would be more consistent if that was the culprit.

I am going to spend some time on it after work tomorrow. Hopefully it's something simple.

 

[Diehard Ram]

Replace overflow valve. That usually fixes alot of problems.

 

[dslhtrdr]

Worked on it for a couple hours tonight.

First thing I did was replace my modded ofv with a known good one, and it didn't resolve the issue, so I reinstalled the modded ofv.

Installed a new shutoff solenoid and properly adjusted it. I replaced the 181 dv's with new 024's, and noticed that the o rings on the holders were ugly and very worn looking, so I replaced them with new ones. Took the valve covers off to check valve lash, and decided to retorque the head studs to 150. Fixed a couple leaking oil fittings, and finally removed the quick connect fuel inlet fitting to inspect it for the squeeking sound on the p pump. The sound is quieter, but not completely gone.

So since I had the injection lines off, it obviously took a couple cranks with the starter to fire up, but it did fire up relatively quickly, which it usually does after having the lines off.

If it still has the issue in the morning, I'm going to try raising my idle a little bit, which I forgot about earlier this evening. I could also pull the filters on my airdog and clean and re-coat the filter seals with oil. I guess I could also get a Tork Teknology ofv, but it may be unnecessary, since I still have 50 psi of fuel pressure.

I will update tomorrow with results.

 

[pushlar84]

to start with you lowered the compression alittle with that .020 gasket. The squeaking sound is the overflow flow, completely normal, it is just the ball coming off its seat with fuel pressure. i have also noticed having alittle higher idle helps alot

 

[dslhtrdr]

... I wasn't sure if the thicker hg was part of the problem from lowering the compression ratio a little bit, but something tells me it would be more consistent if that was the culprit...

Since its happening every time it sits for a few hours, I'm leaning towards this being the cause.

to start with you lowered the compression alittle with that .020 gasket. The squeaking sound is the overflow flow, completely normal, it is just the ball coming off its seat with fuel pressure. i have also noticed having alittle higher idle helps alot

Cranked it over this morning, still hard to start after it's been sitting for awhile. Raised the idle up during my morning break, and it helped a little. It's idling around 900 rpms. I don't want it much higher than that. So next I'm going to remove the air dog filters and make sure they aren't sucking in air, and I think I might order a Tork Tek ofv.

 

[Chevycummins]

Did the filters come with an o-ring? I have seen before with the filters that come with the o-rings cause a similar issue. I always put the new one on.

I have marine pistons in my engine and at a certain temp I have to plug the block heater in to get it to fire right off every time.

 

[dslhtrdr]

Did the filters come with an o-ring? I have seen before with the filters that come with the o-rings cause a similar issue. I always put the new one on.

I have marine pistons in my engine and at a certain temp I have to plug the block heater in to get it to fire right off every time.

The filters for my air dog 2 are like oil filters, with the smooth gasket material-like seals. This is the only air dog I have messed with and have not seen the o ring style filters.

On a side note, I think turning the idle up fixed my problem. It had a hard time firing up the first couple times after raising the idle, but this afternoon after my lunch break, it has been firing up immediately as soon as I turn the key. It has done this 4 times this afternoon, once after sitting at work for over 4 hours, which before was more than enough time for it to sit and have a hard time firing up.

I only figures that it would apparently be fixed after I ordered a Tork Tek ofv at lunch. Oh well, I will see how it does in the morning when I leave to go work on the camaro.

 

[dslhtrdr]

Thought I would give a final update on this. My truck started having the same issue again a couple days after my last update. After some more diagnosis I found a very small (and I mean very small) fuel leak coming from the end of the injector return line going into the tee/union fitting supplied in the air dog kit. I replaced the old seals with a new 8mm horse shoe shaped copper washer and it has been firing up and running great ever since.

Thanks for everybody's help. :Cheer: