Hard starting, hot or cold

[gophergunner]

So as the title says, i have trouble starting my blazer, especially when its cold, but even after its been running and the engine is hot it has a fairly lengthy bit of cranking before it will start.

Its apparently a rebuilt 6.2, its in an 89 blazer, i was told it has approx 40 000 km's on the rebuild. After i got it i advanced the IP by 1 tooth on the drive gear. I don't know if this is an appropriate way of doing it, but i bought this thing froma mechanic in the area who specializes in 6.2's and 6.5's so i was trusting his advice. its also got a new set of marine injectors as well as a GM-3 turbo from a 6.5. I also changed the water pump to a reverse rotation so i can run the serpentine belt setup. Glow plugs aren't new, but they have all tested as having continuity, so i'm assuming they are good yet. But i have completely removed the original glow plug controller/relay and replaced it with a starter solenoid and i use a pushbutton to activate it. My starter has never caused me trouble yet, it has never hesitated to stuck but i only run 1 battery from a big rig. its 1150 cranking amps, seems like enough because it never has trouble spinning the engine.

On a side not, i have not yet adjusted my IP to compensate for the turbo......

So i'm a little lost as to what my problem could be. My wild assumptions make me think its related to removal of the glow plug controller or else it has something to do with the IP timing or fuel metering.

I'm welcoming any help, even if you feel like your lecturing me about my setup, let me hear it because i do want this thing to start and run nicely.....even though you may laugh when you see the picture of it. Keep in mind its a trailered off-road beater:D

http://i50.photobucket.com/albums/f350/gophergunner/00090016.jpg

[DmaxMaverick]

A mechanic that suggests, and practices, advancing pump timing by indexing the timing gear should have his own warranty department. It is possible, and likely, this has moved your timing adjustment ability out of the envelope. This can certainly effect your starting ability, among other things. The timing needs to be set correct, and adjusted by rotating the pump (loosen 3 nuts, rotate the pump, tighten). It is designed to be adjusted this way.

[gophergunner]

A mechanic that suggests, and practices, advancing pump timing by indexing the timing gear should have his own warranty department. It is possible, and likely, this has moved your timing adjustment ability out of the envelope. This can certainly effect your starting ability, among other things. The timing needs to be set correct, and adjusted by rotating the pump (loosen 3 nuts, rotate the pump, tighten). It is designed to be adjusted this way.

he was telling me it should improve the starting and give it a little more "pep" off the line.

but from what your saying is i should set the IP gear back again and adjust the timing by moving the IP itself?

[DmaxMaverick]

he was telling me it should improve the starting and give it a little more "pep" off the line.

but from what your saying is i should set the IP gear back again and adjust the timing by moving the IP itself?

Yes. If your timing needs more adjustment than the pump rotation offers, you have bigger fish to fry.

[gophergunner]

well i don't know if it needs more adjusting than what the pump offers, since it did start and run before i touched the IP gear.

but are you also suggesting that the IP timing is the main issue with the starting here?

[DmaxMaverick]

well i don't know if it needs more adjusting than what the pump offers, since it did start and run before i touched the IP gear.

but are you also suggesting that the IP timing is the main issue with the starting here?

We won't know until you straighten it out. If it worked before, and it doesn't now, that's a pretty good indicator. Any "unexplained" failure can usually be traced back to a point where something changed. Pump timing is very important to starting characteristics. Also, make sure your HPCA is operating properly, or your start and warm running characteristics will never meet on common ground. You will end up with one or the other, not both.

[gophergunner]

Well this thing struggled a bit to start before i messed with the IP gear. Originally thats why i even touched that gear in the first place. For a while it was starting just fine, usually on first try if it was plugged in when it was cold out.

I think i shall start tearing into it next time i'm home and have a chance in the shop.....set the IP gear back to where it was and then go from there.

Thanks for the info.....if anything else comes to your mind, i'm willing to listen

[DmaxMaverick]

If it struggled to start when cold, but improved when plugged in, that usually indicates a glow plug system problem. The HPCA could be part of it, as a more retarded timing will not combust fuel as well on a colder engine. What's the state of your glow system? Which plugs and how are they fired? How long? How cold are we talking about?

Another thing to consider when adjusting timing, is the rotation direction. Keep in mind the pump rotates opposite the cam/crank.

[tomtaylor]

The other thread that i wanted to post to is closed so here I am with a comment about the fuel cap problem;

I'm reading here to find every idea I can to check out on my truck for cold hard starting and of course among the dozen things to check is fuel cap. I didn't really think that would be the problem but I am in the middle of changing my fuel tanks(one is off and the other still on and full) but I had removed the fuel cap on the full tank because I was going to suck all the fuel out didn't get around to it yesterday so the truck sat for 24 hours with no cap.

I have had hard cold starting problems since I put this engine in and with the previous engine and planned on solving this starting problem now with the tank change out. It only happens on first start and will easily start when totally cold right after shutting it off or if I come back and test it again in an hour or 2 or 3 or more but left overnight, same problem occurs.

After reading all the ideas to check I thought the fuel cap would be the easiest and quickest for the first check. I thought it would still be hard to start because the cap had been on for 1-2 full days without running before I took it off so I thought it would take at least 2 tests to be sure about the results.

I was wrong... it started right away and it hasn't done that on 1st cold start for the last 10,000 km's
It ran a rougher than normal for about 20+ seconds (usually doesn't do that) so I think it just purged a little remaining air. Normally once it does get going after excessive cranking it runs fairly smooth and then 100% smooth after 5-10 seconds.

So i am glad I didn't start tearing apart the injection system etc. as I may have found my solution now. DEFINITELY CHECK THE FUEL CAP FIRST, it's cheap and quick to do.

Anyone know where to get a good replacement for the factory cap...LMC?

I really love the info in these forums!

[DmaxMaverick]

The other thread that i wanted to post to is closed so here I am with a comment about the fuel cap problem;

I'm reading here to find every idea I can to check out on my truck for cold hard starting and of course among the dozen things to check is fuel cap. I didn't really think that would be the problem but I am in the middle of changing my fuel tanks(one is off and the other still on and full) but I had removed the fuel cap on the full tank because I was going to suck all the fuel out didn't get around to it yesterday so the truck sat for 24 hours with no cap.

I have had hard cold starting problems since I put this engine in and with the previous engine and planned on solving this starting problem now with the tank change out. It only happens on first start and will easily start when totally cold right after shutting it off or if I come back and test it again in an hour or 2 or 3 or more but left overnight, same problem occurs.

After reading all the ideas to check I thought the fuel cap would be the easiest and quickest for the first check. I thought it would still be hard to start because the cap had been on for 1-2 full days without running before I took it off so I thought it would take at least 2 tests to be sure about the results.

I was wrong... it started right away and it hasn't done that on 1st cold start for the last 10,000 km's
It ran a rougher than normal for about 20+ seconds (usually doesn't do that) so I think it just purged a little remaining air. Normally once it does get going after excessive cranking it runs fairly smooth and then 100% smooth after 5-10 seconds.

So i am glad I didn't start tearing apart the injection system etc. as I may have found my solution now. DEFINITELY CHECK THE FUEL CAP FIRST, it's cheap and quick to do.

Anyone know where to get a good replacement for the factory cap...LMC?

I really love the info in these forums!

The fuel cap is usually the first thing I recommend, and as you've found out, it's never a waste of time. I see it frequently here and most other forums, the suggestion goes ignored, and they immediately go after the expensive stuff. Often in the end, they've changed and touched so many things, they never really know what the original problem was. A correct diagnostic procedure is almost always many times easier, less expensive, and more timely, than any "shotgun" method.

Anyway....
Get whatever cap offered at your local parts house (cheap is good). I've never seen a correlation between price, brand, and longevity. Just make sure it's SPECIFIED for Diesel. If it doesn't say ON THE LABEL, it isn't a Diesel cap. If you're looking for a brand label, Stant is as good as any (and is often the OEM mfg).

[tomtaylor]

With my new tanks I bought new sending units from Rock Auto and I see they sent me the earlier model with 3 tubes coming out the top. My 86 has 2 tube (fuel feed and return) I assume that the #3 tube was a vent line for the earlier models that went back to the engine bay, can you confirm this? And if I use them to vent the tanks does it matter if I have vented Diesel fuel cap?
Thanks.