Hey all,

Last October I had a problem with the Spider/regulater assembly, and replaced it.. all was good.... Also - as a side-note.. I dunno if it's relevant or not.. but our county (Dallas County, Texas) just recently changed over to the 10% Ethanol blend of gasoline... I'm on about my 3rd-4th tank of gas on this new blend.

More recently, as in - last week... the Blazer ('95 S10 4dr/2WD) started running REAL rough and shaking almost violently when I'd stop at a stop sign. While driving, I feel a surge every couple of seconds. If I take my foot off the accelerator at - say about 40 MPH, it'll slow down for a sec... then the surge will kick in for a second, and net result is that I stay around 40MPH because of the surge... Much different feeling from when I had the REAL leaky spider/regulator last year. I'm also smelling a "rotten egg" smell - Dunno if that's simply from unburned fuel going though to the catalytic converter.. or if maybe my cat. converter is failing.. would a cat. converter failure cause these symtoms? (Hope not - that catalytic converter was changed about 4-5 years ago)

Just for grins, I opened up the manifold cover again tonight - just to see if the spider assy. was leaking again - and sure enough - there WAS some fluid in there.. but not much (maybe about 1-2 teaspoons worth on each side - passenger and drivers side of the manifold) - and it was kinda thick.. maybe like it's only recently started to leak, and is mixing with the carbon deposits under there for an oily-like sludgy liquid. I'll double check all the fuel supply connections/o-rings (nut assy.) when I have daylight tomorrow to make sure that those aren't what's leaking (I'm hoping so - as that spider assy ran about $308 for the spider/nut kit/regulator)

Anyway - I'm wondering if there's a way to test the fuel pump to see if I've got a problem with it and need to change it? Would a slight spider assy. or regulator leak cause those symtoms? Would a bad/failing fuel pump be more in line with these problems? If not - please shoot some more ideas for me to take a looksee at...

Thanks in advance,
Rex S.

 

ShadowHawk,

You maybe one of the "lucky" customers of the new ethanol blended requirement fuels. On older vehicles especially older hondas the ethanol would "eat" the rubber components of the fuel system. If you have to replace any parts of the spider and nut kit make sure that they are ethanol ready or this will happen again.

Check with the Chevy dealer's parts department in your area for parts that may need to be replaced due to this new EPA additive to reduce emissions.

 

Great... Okay...

I just sent off an email to the Chevy dealer that I got the spider kit/nut kit/gasket from. We'll see if/how long it takes for an answer. IF I don't hear from them by tomorrow afternoon, I'll give them a ring to see what they say. Geez.. the parts have only been on there 7 months...

I'll also change my fuel filter - just for grins.... Ya never know....

Thanks,
Rex

 

Just FYI for everyone, any vehicle produced after '91-'92 will have the fuel system components (viton o-rings) to handle up to a 20% ethanol blend. Beyond that, fuel and timing maps must be modified as to not decrease performance. 4-5 tank fulls wouldn't even begin to be enough time for a 10% ethanol blend to do any harm what so ever.

I for one LOVE how my vehicles run on 10% ethanol and wish that all of the gas stations around me would switch over already! The first few tank fulls will always be the clean out stage where your entire fuel system gets wiped clean of all of the varnish and deposits regular gasoline lays down. After that (in my experience), I have gotten better fuel mileage in my Bonneville and Bravada without any change in the way I drive. I have since moved and do not have a gas station that carries 10% blend anymore.

The rotten egg smell is typical of a clogging cat, but the rest of your symptoms don't sound like that is the problem. Any rich condition will severely shorten the life of the cat. Your fuel system problems prior to now, if the engine was allowed to run for long in that state, could have lead to the current demise of the cat. Additional fuel would be cause for some hesitation and run-on as you described. Try to pressurize the system and see if there are any leak points. Is it possible that an o-ring was damaged during the reinstallation of the new components?

 

Thanks for the note on the ethanol blend. Yes - I had noticed an initial boost in my MPG as well. On my first tank of 10% blend, I went from 20MPG (highway miles) to 22MPG (hiway miles) for my 120 mile round-trip daily commute to my 2nd job. While I DID notice a marked increase in my MPG, with that first tank, I also felt a lack of power from the engine in that first tank-full.. maybe a trade-off to getting better MPG.

Last year - when I had posted my initial problems with the rough idle, I had driven for appx 1-1/2 years with it in that condition - with the OE regulator dumping fuel into the upper manifold, and running rich, rough idle, etc... It's entirely possible that during that period of time that the beginnings of catalytic converter cloggings began...

Now that I've had my morning coffee, I'll get out and see what's up with the 'ole Blazer...

Rex

 

Hmm.. Never did notice any decrease in performance with my Bravada on 10% blend...

Anyway, yeah, running rich for that long could very well have ruined/clogged your cat. Typically symptoms of a clogged cat will be sluggish acceleration through the rpm band or resistance to higher rpms for obvious reasons. The faster the rpm, the more flow is required of the exhaust. If the cat is getting clogged, it'll be worse the higher the rpm.

Most exhaust shops can do a simple back pressure test by removing one upstream O2 sensor and the downstream O2 sensor and checking the difference in back pressure. Also, if there is a VERY noticable temperature difference before and after the cat (significantly higher before), that is a good sign that things are not right.

 

Ah.... Just got a reply form the Caddy dealership that sold me the replacement parts (spider kit, etc) last October.. here's verbatim what they said in their email to me:

Scratching my greying head.....
Rex

 

There are many states that no longer have anything BUT 10% ethanol blends and you are telling me that their older vehicles are just SOL. Don't think so... The o-rings are about the only part of a fuel system that ethanol will affect and viton has been used as the fuel system o-ring material since the early '90s. But this is quickly becoming a topic for a different thread.

Sounds like you should be able to get replacement parts to try it again. Good luck to you!

 

Yep - I explained to him that it was an EPA mandated fuel change - not a *choice* that I made to use the gas.. oh well.. the o-rings are fine.. I just inspected them. Maybe the connection from the nut-kit was bad or something. I'm gonna put it all back together, button it up, and keep looking for my receipt for the parts.

Thanks for the direction and assistance. I'm still a bit concerned about the fuel pump possibility (tested the relays - they're okay) - but I'll let that be another session... and I'll change the fuel filter this afternoon, anyway, to see if that helps.... Maybe the ethanol cleaned up the tank, and it's got the filter clogged, etc. etc... and causing problems...

We'll see.
Rex S.

 

That is a possibility, but the fuel in the plenum is not a good sign. Replacing the fuel filter is never a bad thing. For the price, it's good preventative maintenance.