Ok, Got it apart, and it makes no sense!

[kconnair]

'84 3/4 ton Suburban with J code externals.

Has quick heats - less than a year old
Has been converted to the newer '85 up glow plug controller. Was working well last winter - and seemed to be ok now too - glow plug light was cycling.

Truck was starting very very hard cold - had to plug it in to start below 55 degrees. Was getting worse, finally didn't start even plugged in until the outside warmed up. Decided it was timing chain screwing up the IP timing. Got a timing gear set, other stuff (gaskets, etc) - Figured this was also the time to put the turbo stuff on while I have it mostly apart and the engine out.

Here's the problem - chain didn't look too bad... :confused: Heads are a later small valve with the newer style stamped shaft rockers. Other internals looked really good. Head gaskets weren't leaking, ran pretty smooth, and power was pretty good until recently. And one of the valve covers has a goodwrench sticker on it (maybe a newer 6.2 or 6.5 replacement - from sometime before 1994 when I got the truck?).

I've put about 40k on the engine, mostly commuting, light hauling, and light (3500 lbs) towing) Prior mileage was an unknown. May have had a blown head gasket at one time because it had fel-pro print-o-seal head gaskets, and some lousy silicone work. and one of the cylinders looks stained like it may have had coolant in it at one time.

Injectors?

Lift pump (I will be switching to electric anyway)

IP?

Obviously I am going to put in the new gearset.

Anyone have any ideas about the hard starting issue?


Thanks,

Kevin.

[darkroad]

Hi I had the same problem. Check out your glow plugs with a multi-meter. They should read the same. 7 out of my 8 had burnt out . From what I hear this is a common problem with them. Went back to newest AC glowplugs. And I also had added a resistor inline to increase the glow plug warm up time to 14 seconds.

Good Luck

darkroad

[kconnair]

Thanks Darkroad,

Even though I recently replaced all 8 glow plugs, I found that 5 were dead when I tested them.

Still a good excuse to fix oil leaks and do some upgrades.

Thanks again....

[john8662]

At least the quick heats don't swell right?

No-bueno!

The print seal gaskets are kinda neat looking, have pretty stiff gasket with the orange sealing on place. The newer gaskets don't look that way. They're solid blue/striped with no sealant around holes. I'm curious how well they'll do on the 6.2's.

The print seal gaskets are OEM btw.

You're right, you got a good excuse to fix leaks etc.

Just take your time.

starting on 3 plugs ain't gonna work unless it's at least 70 degrees outside and the batteries and starter are at their peak (700+ CCA batteries that is).

J

[Subzilla]

I went through this back in the fall and after checking GP's, relay, potential air leaks, batteries, timing... I decided to replace the fuel filters even though I just replaced them back in the spring. And bingo, that instantly solved the problem. She starts like a champ now and with more power and mileage. I was also experiencing a mid-rpm surge. So, check the cheap stuff first.

[arveetek]

It's amazing at how hard to start the 6.2L can be with only a few glow plugs working. With no glow plugs, they won't hardly start unless it's 90 degrees out.

I installed a new set of Kennedy's Quick Heats back at the first of November. I have had 5 burn out in less than three months. John's customer service is great, but I'm not impressed with the Quick Heats. Time will tell if they hold up. In the meantime, I installed the old 60G's back into the engine.

Casey

[Jgreemo]

I had the same situation, it became tough to start in even mild weather. Replaced the starter since it was due, batteries (one was not charging), cables, fuel line (rotten) and lift pump (probably ok but a bear to R+R with a turbo). I also upgraded to the 85+ controller with a resistor soldered in at the same time I put the quick heats in. Turned out 6 of 8 quick heats had died after a year of use. I'm using AC 60's now and no problems, especially with all the other fixes put in.

Good luck.