More problems

Inline.................

Atta boy............

The 2 seconds of cranking before it starts is normal for a TBI motor. As for wanting to puke the first time it starts, that is for a higher mileage TBI motor as well. Mine has always wanted to stall out and runs like a junk heap for about 20 seconds after the first start of the day, after that it runs perfectly. I've replaced pretty much everything over the past few years and no change.

A bad FPR would have her running rich all the time as it would be just dumping fuel into the injectors.

They're great they work. ;-)

Doc

Thanks for the info Doc. This motor really doesn't have that many miles on it though. The previous owner said he replaced the original engine around 245,000 miles and the odometer now reads 268,000 so that would mean it's only got around 23,000 on it. Once it warms up it runs like a brand new engine. It definately doesn't have too many miles, since it doesn't puff smoke on startup like every other 4.3L with more than 30,000 miles on it. ;-) At least I know the valve seals are fairly new.

About the only thing I haven't replaced is the spark plugs because they look to be pretty clean. Oh well, at $1.78 a pop it can't hurt anything I guess (and no, I'm not going to put NGK Iridium plugs in it). LOL

-Tony

If they're clean, are they gapped correctly? (0.35")

And about the Jap Iridium plugs, they'll make your vehicle more 'reliable', he he he.

Doc

I don't know if the're gapped correctly. I have only had the #1 plug out. I'm going to replace all 6 this weekend when I get some free time. For all I know one or two could look like shit and be misfiring untill they warm up. Who knows

I would use SplitFires, Champions, or even junk-ass Autolite plugs before I even considered those gimmick NGK's ;-)

-Tony

Wow... I kept thinking about coming on here and whining that mine takes up to a second to bump over in the mornin.....

125,000Mi

GMC Gremlin

1990 GMC F/S Jimmy

higher

Replacing the fuel pump seems to have fixed the stalling out problem, but it still runs rough and misses on 1 or 2 cylinders for the first

20-30 seconds. It doesn't even have to be cold to do this. I can let it sit for an hour or two and it will do it on startup. it goes away faster than when it's completely cold from sitting overnight, though.

I hope it's the plugs, because this doesn't make any sense at all. If it were carbureted it would be understandable.

-Tony

Is this your first Chevy V-8 TBI Tony? In my experience, they run pretty crappy until they hit the first "kick-down" when the ECM switches from open loop to partially-closed loop. After they reach closed-loop they're phenominal. Also, check the ignition timing. I've always found they run better (and run smoother on cold starts) at 2-4* BTDC as opposed to spec which is TDC. Be sure to yank the EST wire before you check timing. I've run mine as high as 6* BTDC on 89 octane and it ran great.

Doc

Wouldn't a bad fuel pressure regulator (perforated diaphram) not allow enough pressure to build up causing a rough running engine?

Yes, at all times - not only on start up.

GMC Gremlin

ok that makes sense

Doc, It's a 4.3L V6... but no, it's not my first TBI motor. I've had 2 others. One was a '90 K1500 with a 350, the other was a '91 C1500 with a 4.3L. Both which ran perfectly normal on startup. My father-in-law's '93 K1500 runs excellent on startup as well, and it has 137,000 miles on it.

I have experience with half a dozen TBI trucks of the same vintage as mine, most of which have more miles on them than my engine has. Yet none of them have this rough running problem. Somthing has to be wrong to be causing this.

i haven't played with the timing or anything. I don't have a working timing light at the moment.

I suppose a new O2 sensor couldn't hurt, as well as new plugs. Other than that I'm out of ideas.

-Tony

WELL.....

Looks like I found out the reason that this truck runs like shit for the first 30-40 seconds.

I replaced the spark plugs last night, and all of them looked pretty good, EXCEPT the #5 cylinder. It was rusted and pitted beyond belief. So looks like I have a seeping headgasket. That would explain why it misses until it warms up a little and burns the coolant out of that #5 cylinder. It has also been losing a small amount of coolant from the reservoir. It's down about 2-3 inches from when I filled it a couple weeks ago.

This was always a possibility in the back of my mind, but was hoping for the best case scenario I guess. This would also explain why I thought I caught a sweet whiff of burning coolant in the exhaust every now and then on startup.

I guess my biggest question is, how long can I safely run it like this without causing severe damage? I don't have the money or time to spend on replacing head gaskets and all the little nickel and dime parts that go with it. I got a couple quotes from the shops around town and the cheapest one was still over $700... so in other words I'm going to have to do it myself, whenever I can save up enough extra money.

I'd also like to know what the hell would cause this to happen... as the engine is only about a year and a half old.

-Tony

Isn't this supposed to still be under warranty?

GMC Gremlin

Inline.................

Atta boy..................

Man, that sucks.

The kit you'll need to do the head gaskets is around $60.00 and includes EVERY gasket, bolt, etc. you'd need to do the job. Other than that it's just oil and some coolant and you're back on the road. If it were mine and I cared about it, I wouldn't drive it at all until I got it fixed, but I'm an anal futz! Hopefully it's not making it's way into the oil and eating up yer' bearings.

A few possibilities:

1. Bozo who put it together doesn't know what a torque wrench is.
2. Bozo who put it together didn't use loctite on the head gasket bolts
3. If it was just a short block and the old heads were used, they might have been warped from the prior engine grenading.
4. If it was a reman the block + head mating surfaces might not have been trued before it was slapped together.

My $0.02

Doc

You're right Doc... I wouldn't drive it at all either. Trouble is, I don't have any other means of transport to work. I work way earlier in the morning than the wife does, so can't ride with her either.

This engine is a longblock reman Target (DELCO) motor. I've heard nothing but bad news about these engines, and have had experience with at least one other that was a piece of shit as well.

If I get brave and buy the headgasket kit to do on some weekend, I take the chance of finding out that I have a cracked head, and then I'm screwed cause I don't have the money to be buying a set of heads.

I think the best I can do right now is just drive it and save money... if it eventually gerenades, I can buy a low mileage used engine from a salvage yard. I've already put almost 3000 miles on the truck since I bought it, and it hasn't gotten any worse, so we'll see what happens.

I know this is pathetic, but poor people have poor ways. I just got hired at a local trucking company a couple months ago. Good job, making real good money, but I still have not much spare cash because I'm paying off all my debts in huge chunks each payday...

-Tony

Inline.....................

I know what that's like brother! I've driven many a car WAY past the point of repair just cause I couldn't afford it at the time or simply didn't have the time to fix it.

If it's a small crack you might not even be able to see it, and on reassembley have the same problem. The heads should really be magnafluxed to be certain there isn't a hairline crack anywhere.

A couple things you can try in the meantime that won't booger it up too bad:

1. Add some pepper to the radiator, maybe 1-2 TBS. This shit won't goo up the cooling system like Stop-leak or other chemical/copper based stop leaks and just might solve the problem if it's a really small leak.
2. Run a compression test on 1, 3, and 5 to see how #5 compares to other cylinders on that side.
3. Yank the intake manifold and have a look-see. IIRC, on the 4.3, the main water passage is at the very front of the intake, running accross between cylinders 1 and 2, but there is another water passage at the back between 5 and 6 that has a partial block off via the intake manifold gasket itself. Is it unlikely, but possible, the the intake manifold gasket is shot or was installed incorrectly and is leaking coolant from the rear water passage into the intake runner for #5. It is also possible that the intake itself has a small crack and is leaking coolant from the back water passage into the #5 runner.

I once used 2" conduit for exhaust pipes cause I couldn't afford "real" exhaust piping and I got the conduit off a buddy of mine in the construction biz for free!

Doc

Well, as wierd as this sounded, I tried it. I drove it maybe 2-3 miles and parked it. About an hour later went to start it and WOW... no sputtering at all like usual. That trick really worked! I just might be able to milk a few more thousand miles out of it, maybe alot more. Any explanation HOW this works?

-Tony

Ain't that cool as hell? The pepper expands, clumps together and gets kinda tacky when it gets wet, and if the crack/leak is small enough it sticks to the walls as it's headed thru the crack, effectively sealing it. The nice thing is it doesn't crap up the cooling system like the chemical additives do, and a simple flush will clear it all out if/when you fix the problem.

I've knows guys who have run vehix 100,000 miles after dumping some good ol' pepper in there.

Doc

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