pgtr

...On a carbureted V6 like an '84 2.8L for example?

And what are some of the typical warning signs of a failing pump?

Thanks!

//<86TA>\\

iTrader: (15)

poor idle, ramdon stalling, hard starting, ect.

they can last for many many years. Im sure there are still 60's cars running with the original mechanical pump

Gumby

If you question it, change it.

pgtr

OK.

It has 190,000 miles on the original 2.8L V6.

For years now on a long sustained acceleration say from 0-75 entering an expressway - starting at around 50 it sometimes has a few slight 'hesitations'. That's gone on forever. It's done it for so long and never really bothered me. Nor has it ever gotten worse.

The 'real' issue is a bit more significant and essentially has disabled the car all of a sudden starting a few years ago:
NOW the engine fires right up and within a second or two dies. Over and over.

If I hold my foot on the gas once it fires up I can kind of coax it along and keep it running at 2500 to 35000 rpm. It will NOT idle.

If I drop it into drive I can get it down the road but it lurches and surges, runs poorly and lacks power if I try to accellerate much at all.

Some of the symptoms suggest fuel delivery. Fuel filter is fine. ENgine is kept in a good state of tune - (plugs, filters, oil, timing, wires...).

It also acts a bit like a stuck EGR valve. But it moves freely by finger. It's only a year or so old too. (there is also an EGR vacuum solenoid I haven't considered...)

Vac hoses are all present and accounted for - besides I can't imagine a bad or open one causing it to run 'this' bad.

I would like to check the pump volume and pressure but w/ an erratic idle... that might be problematic. I could dribble gas into the (VaraJet) carb vent and see if I can get it idling long enough to warm up a little, open up the choke and finally run the tests.

I was curious if pumps (or cam lobes which drive them?) were known to be problematic or had a predictable lifespan but it sounds like these are as long lived as most mech pumps tend to be.

Currently I don't suspect the following:
Ignition - most parts are changed at regular intervals and there is no misfiring, missing or backfiring.
Carb - it happens both at idle AND at RPM under load - 3 different fuel circuits within the carb - with a clean filter it's unlikely a carb would have that many failures.
Fuel filter - inspected it already and looks like new but I'll drop a new one in anyway.

Yes I could start replacing any old part I suspected until problem is solved. However, I prefer to troubleshoot subsystems up to a point.

Thanks

ked5911

Does not sound like its the fuel pump but if you want to replace it I have a new one I'm selling. Switching to electric. PM if interested.

pgtr

Hmmm, any ideas what it does sound like?

ked5911

Have you checked the fuel pressure just before the carb? That will tell you if its your pump. It could be working but not at full pressure.

pgtr

Yes. Actually it turns out it is putting out great volume and pressure.

I'm starting to lean towards a float problem as in too high and/or loss of buoyancy.

After further analysis of the problem - the erratic running/idling seems to be when it's cold and the choke is fully set (a rich condition) which could be further enriched (overly?) by a float adjusted too high and or sitting too low in the bowl due to buoyancy.

Once I struggle through the initial erratic startup period - it's running 'OK'. But it will still stall occasionally particularly if I turn a sharp left (sloshing fuel in a potentially over full bowl).

Just a thought at this point. I'm going to check further into that and go over all the choke operations carefully this weekend.

Interestingly enough - replacement floats are available through auto parts stores.

Anybody know if time/age can lead to loss of buoyancy in an '84 E2SE carb float?

CamaroManBlack

How in the world has that engine managed to survive to 190k?? That's almost unheard of for the carbureted 2.8's!!

Time and age definitely kill carb floats in these cars. My 84's first engine was killed by a surprise sunken float, and so was my friend's '84. Both stock V6 engines. Make sure you change that oil if it sank, too. Once they sink, they dump fuel into the crankcase and wreck the already-soft bottom ends that these motors have. Gasoline in the oil today can often mean a spun rod bearing tomorrow, when it comes to these carbureted 2.8's. Especially if they get driven the way most of us like to drive them.

I had a similar issue with my old '83 Camaro, but that car was able to idle. My problem was the fuel filter (the paper one in the carb). However, if your car will not idle and has the suring issue, I doubt it's something like that. Sounds more like carburetor issues...maybe time for a rebuild. At minimum, I would change the float, needle, and seat. Also check your primary and secondary choke pull-offs. Those can mess up your carb operation, too. Also, you could be leaking air at one of the gaskets. Good luck!

Gumby

Ever rebuild one of them carbs?

Just wonder if the float comes in the carb kit or not?

Looking online I don't see the float show in the kit.
Its an extra $12.

CamaroManBlack

Yeah, I've rebuilt them half a dozen times or more. This varajet is a very easy one to rebuild, very simple without complex adjustments. All you need is a Torx bit set, carb cleaner, a ratchet, and the rebuild instructions from the kit. Seriously speaking, including the time it takes to pull the carb off the car and then reinstall it after it's done, I can rebuild one of these carburetors in 45 minutes or less. For a first-timer, you can probably plan on and hour to an hour and a half. 13mm flex socket is a huge help with the rear carb mounting nuts.

And take it from me, when you're done with the rebuild, do NOT pump the throttle any more than necessary for installation while the carb is dry (no gas in it). If you pump the accelerator pump diaphram while it's dry, you can actually cause damage to the rubber that will result in decreased pumping ability and therefore hurt acceleration on the road. Pumping it once or twice won't hurt it, but pumping it half a dozen times or more will.

No, the float doesn't come in the kit. Everything else but the float does. Sounds like the price has gone up, too...I think I spent $6 and change the last time I bought one at Advance Auto. Price it at Napa, too....I've been finding them cheaper on a lot of different items lately.

Gumby

Glad ya posted that to jog my memory as I do know that the neophreme [spel?] or what ever ya call it floates they switched to [they all use to be brass] get fubared by the alcohol they put in gas. Making them pouris after time.

wonder if there is a brass float upgrade like for the 4bb qjets???

any insite on how much of this crap can be lost if you have no smog checks?
Just to clean things up and lose the rats nest?

http://thirdgenchat.org/85173auto.jpg

yep diagram is for an 85 s15 2.8 auto carb engine.
But Im taking the intake n carb, dizzy off it for my 86 stick Bird.
bye bye to the mpfi money pit.

[and your past makes me wonder about the 77,000mile s15 I just bought for them parts, as the kid only drove it 10 miles after getting it and spun a rod bearing. He thought it was from a bad thermostat, which sounds dumb. Wonder if he got gas in the oil. It was an around town only truck that sat most of the time. Though the engine was checked out by a reliable shop, by time they got it the gas smell could of been gone enough from the oil to tip them off as to why it did that after only a 10 mile trip on the eway. But all it needs is a new crank and its ready to go. All else checked out well. Cept one rod bearing.]

CamaroManBlack

I've never been able to find a brass float for these 2SE/E2SE Varajet carbs. All the Neoprene/whatever material. If you find a brass one, definitely let me know where you found it so I can go out and get one too!

As far as the low miles on the spun rod bearing...the oil probably broke down. Letting a vehicle sit for long periods of time (such as months) with conventional oil is not a good thing to do. Conventional oil will develop acids in the crankcase over time, which damage the engine oil viscosity enough to cause accelerated wear to moving parts. That's why it's said that you should change your oil every 3,000 miles or 3 months (for conventional oil). If the carb float sank in addition to having older oil in the crankcase, that would speed up the process in destroying the rod bearing.

As far as deleting emissions vacuum hoses and whatnot...yeah. At the very least, plug all ports on the carburetor where you delete hoses. But I'm not sure what you could delete without hurting the way the engines run. Older S-10's/S-15's had no-emissions 2SE carbs. Very few hoses or other connections. Check 1982-83 applications for that one.

pgtr

I'll go you one better than that. It doesn't burn any appreciable oil either and gets a solid 25+mpg in mixed driving.

It's down maybe 1 qt at 7500 miles or so. I follow GM's recommended 7500 mile change interval using appropriate API rated oil. Once every couple years I use a little Sea-foam to remove carbon if I start hearing a little pingiing from buildup. The real trick I think however is to catch the intake manifold gasket BEFORE it leaks water onto the crank. If the manifold gets to a point where it leaks, the engine is quickly a goner.


I'll check out the float and I'd also been meaning to go over the choke-pull off as well. I'm fairly certain nitrophyl floats are the only option avail. I rebuilt the carb 3 or 4 years ago. I did NOT replace the float at the time - didn't think to and it didn't have any symptoms or problems. It's been running fine ever since.

I need to also ensure the secondary is not kicking in too early/easily.

Finally I sometimes wonder about the computer controlled advance on the distributor. Since there is no vac advance I'll have to check the FSM and see what checks can be made.

Thanks for the comments/suggestions

I'll post w/ any success I may have if anyone is interested

Gumby

I think he is just suprized as its carb'ed, these 2.8 runs forever.
Mine has over 220,000 and runs strong, no oil burn, 25-28 driving like I stole it.
Being in the 2k club isn't a big deal anymore on these.

But now all the MPFI stuff is a money pit crap hole and going carb. Why I had to jump in there n pick his brain on the subject.

pgtr

According to other forums I've heard mixed opinions. They can last reasonably well IF you catch the manifold gasket BEFORE it leaks. Otherwise you can lose your main bearing(s) quickly.

I've heard 2nd hand that the carbs and distributors out of 2.8L trucks don't have all the emissions stuff. So maybe a same/similar year Blazer etc w/ same engine would offer a simpler 2SE carb and vac adv distributor vs the E2SE carb and computer controlled distributor. I have no idea what effect these truck components would have on mileage.

Gumby

e2se is computer assist carb right?

I should have the 2se then as it s has no computer hook ups.

only that gay heat plate under the base gasket.

CamaroManBlack

I seriously have never heard of a carbureted 2.8 V6 lasting anywhere near 200k. MPFI motors, yeah, but not the carb'd engines!

And you're still getting 25 mpg's with it? That must be one well-maintained little engine! And it's never been rebuilt??

I also never knew the motors had a problem with intake gaskets. I thought that problem didn't start until GM went to the plastic intake gaskets. At any rate, fuel in the crankcase from a suddenly-sunken float is what killed my engine, and the one in my buddy's car, too. He and I have been told by a lot of people that the float issue was a big problem with these engines. Evidently, we never made mileage enough to find out about intake gaskets issues, haha.

Yeah, E2SE has the TPS and Mixture Control Solenoid. 2SE does not. Gumby, I think you're going to be disappointed with the carburetor in terms of power. Factory 2.8 Camaro's & Firebirds were only rated at 107 HP with the carburetor. MPFI was more than that (132HP?? something like that???).

pgtr -- good luck with the issue. Definitely let us know how it turns out.

Gumby

Well after some looking the 2SE is a nice carb, I can see how he gets 25 still.

The small 35mm main bores is ideal for fuel metering control at idle n part throttle, great for MPG/EPA but not performance. So the added 46MM bore with an air valve with a single metering rod. Metering control is governed by the air valve opening, So a sutiable mixture prevales reguardless of how far or "fast" the secondary is opened.

Now why is that a big deal, all them hooptie qjet mods to be able to snap all 4 wide open with out a bog, as the air valve can flop open to quick. Hence the needed of the vacum brake.

The 2SE doesn't need a vacum brake [has one though], with that gone and the tang that stops ya from going WOT at will, it gonna get a perferct does of fuel and respond like a deamon. Once the unneeded EPA added parts are removed.

pgtr

I have the standard 2.8L aka the LC1. The 'optional' or special high performance 2.8L for '84 was the LL1 I think. It has about 125hp vs 107hp. It too had the E2SE AFAIK. I get the feeling the LL1 was not very common.

No rebuild. When the water pump started leaking and I also went in to do the intake gasket preventative maintenance at the same time - I decided to go ahead and put in a new timing chain set. I'd guess I did this at around 170k. The original timing chain set looked fine. I noticed no improvement with the new one. I do basic maintenance but nothing extraordinary.

According to some online resources (60 degree V6 forum?) the 2.8s are prone to leaking around the water jackets - particularly the rear ones over time. Anywhere in the 100k to 150k it can get to a point where a little water gets through and leaks right over the rear bearing... I'm told you get little if any warning. Luckily I caught mine and I could indeed see where it was working itself towards a leak in exactly the manner described. That 'achilles heal' caught I should be set to go in a while. I watch the MPG and get a steady 25mpg weekly. I check the oil and generally when it get's down to about 1 qt low it's about time to change (7000-7500mi).

I eyeballed the float this weekend after removing the vent. It was virtually submerged. Perhaps it lost some bouyancy... The fuel was right up at the gasket level. But it was not overflowing into the evap hoses etc from what I could see. My oil 'looks' fine. Anyway I bought a new E2SE float for $7. Unfortunately I encountered 2 problems so didn't finish:

1) The replacement float did not fit - it appears my '84 E2SE actually came from the factory w/ what is referred to as a 2SE float. The E2SE replacement float is slightly bigger and it interferes with the lower of the two plastic fillers. Original 2SE carbs only used a single piece filler and the larger float. Seems there was some hybrid crossover issues between the 2 carb variants in my case. Rather than exchange for matching 2SE float for my particular carb I decided to adjust it and fit it w/o the lower filler element. The upper element still fits fine and now I have a slightly larger bowl capacity, a float w/ more volume and perhaps more buoyancy. Essentially the bowl is now closer to a 2SE - it should work fine either way... we'll see...

2) My TPS went out - tested it just after putting the air horn back on (swapped the floats while leaving carb on the car) and got odd voltage readings. I suspect I may have damaged it when I was servicing the float. So needless to say I didn't finish the job as I need to pick up a TPS now.

While I was at it I tested a number of related emissions items per the FSM including the thermac and TVS and the various vac diaphragms - everything checked out OK. About the only thing I didn't check was the dwell reading on the MC solenoid.

CamaroManBlack

You know, I had forgotten about that float issue. I had the same thing happen to me when I bought mine, and ended up having to bring in the old one to be sure I had a correct match. At the time, the parts store had the difference listed according to emissions options, not carburetor type.

But yeah, if the old one was submerged, it was time to replace it.

I've never heard of a high performance 2.8. I'd be interested to find out what made the extra horsepower that you mentioned.

pgtr

The new TPS came in today so I put it in this evening. I'll tentatively say 'success' w/ the new float. Note this is not the 'correct' float for this particular carb configuration but by leaving out the lower float bowl spacer this slightly larger float fits fine. The upper spacer is still installed and should minimize slosh.

Caveat: I had the key on while I was adjusting the TPS so when I fired it up and took a quick test run the choke was not engaged (it had warmed up w/ the key on and it was getting dark so I didn't mess w/ waiting for it to cool down). It ran fine other than struggling slightly at idle the first minute or so due to a cold engine running unchoked. I'll test it for sure tomorrow but tentatively it seems fine.

I remember the submerged float thing from years ago when I tinkered w/ QJets a lot. Another tip I'll pass on - if you pull air horns frequently - a quick shot on the gasket w/ something like 'Pam' (the cooking stuff) makes it easier to remove the airhorn w/o messing up or having a gasket stick.

The HO 2.8L V6 for '84 has 18 more HP. I looked a while back myself out of curiosity - never came up w/ much of anything online. It runs a slightly different spark plug is all I can tell you off hand - probably different heat range I bet.

thanks

pgtr

Final follow-up: drove beautifully to/from work. Smoother running. No hesitation anywhere. More readily accelerated WITHOUT downshifting. It's been a subtle degradation over the years which I didn't realize how bad it was until know. Am optimistic the MPG may improve slightly.