Bought a used truck....which fuel system cleaner?

[Trav]

Thanks but lots of folks here at BITOG are knowledgeable about a lot of things,like most mechanics (I'm to old to be called a tech and i like the term mechanic ) i knew hardly anything about grease,oil and even less about antifreeze other than you bought a jug of Prestone,peak or whatever (it was all the same at one time)and some distilled water,i learn something new every day here.

New replacement units are almost always MFI,on this engine its very easy to do.You need the unit like the one i posted from AA,a bracket and a gasket.Time is about an hour and a half.
No ECM flashing or other parts are needed,its a straight forward swap.
If you can change spark plugs and an alternator this job is within your capabilities.
As i said before this is really a beneficial upgrade and will safe you a ton of aggravation in the future.

The A/C
Any guesstimate on price would be wild speculation as it could be anything from a leaking schrader valve or line o ring to a compressor seal or evap core that may need the dash to come out to get at.
It may just be low on refrigerant over the years and the low pressure switch is keeping the compressor from turning on.
Take it to a good automotive A/C shop and get it diagnosed with an estimate.Expect to pay $75-100 for a decent estimate depending on your area.
Believe it or not the dealer maybe your best bet as every corner gas station with a service bay seems to have become A/C specialist with summer coming.

 

[demarpaint]

Originally Posted By: Trav
Believe it or not the dealer maybe your best bet as every corner gas station with a service bay seems to have become A/C specialist with summer coming.


+1 I made the mistake of bring an AC issue to a local hack. I paid for an estimate and he told me I needed "O" rings on a Ford, a common problem with the older vehicles. After a few days, no AC. Back to the shop, I was then told I needed a condenser which he did at that time. At that point I had a feeling this guy was clueless, and I told him to charge the system up and add dye, which he should have done from the beginning. It turns out I had a pin hole in a hose, in a hard to find spot, which I diagnosed myself and changed out, or I would have been back to this clown a third time. Shame on me since I have all the tools, but didn't have the time!!!! Bottom line bring it to someone who really knows AC work, not a hack parts changer! Older vehicles can leak refrigerant from more than one place, and finding one leak doesn't mean the job is done!

 

[JDD]

Originally Posted By: Chris B.
Huh. I always thought the 96-98 Vortec fuel system was bullet proof and very reliable. I bought some Gumout with Regaine "Hight Mileage" fuel system cleaner tonight. I'm going to add it in the next tank. I'm going to do two tanks full and run them both dry to clean her up. Think this will help? The truck is running pretty good as far as I can tell.


Remember---the reply you received is from someone in the fuel system cleaning business---so take it for what it is.

I know a ton of people/businesses with Vortec 350s in their fleets with your same injection system that have been esentially trouble free. The 350 did not go Vortec until 96. A large part of the Vortec change was going to the central point injection system (The 'spider') and revised intake system---resulting in a lot more power and torque. The CPI system is just not that much of a problem area for the large majority of owners. There were issues on the earlier ones, especially the '93-95 5.7 derived 4.3 V6 (the 4.3 went Vortec in 93), which also has a spider. By '97 the reliability was improved on--especially in the V8. The problem was not the injectors, but the materials the fuel lines and connectors were made of that lead to cracking and leaking. The likeliest fuel system issue with your truck will be your fuel pump.

 

[JDD]

Originally Posted By: Trav
No these spiders with poppet nozzles were far far from bullet proof even when new.
Gumout and MMO may help a little but it cant cure the inherent poor design of this spider.

Check the injectors out,it may have been converted already,if there are wires to each individual nozzle then its converted.
The problem with the original is there is only one main injector called the "maxi injector" that feeds the individual fuel lines,at the end of these lines is a poppet nozzle not an actual electronic fuel injector.

GM bean counters "borrowed" this main injector theme (in basic theory anyway)from old diesel injection.The major difference is the diesel that used a similar main system has a very high pressure mechanical pump.
This GM unit depends on an electric in tank unit.
If the pump is not delivering optimum performance (min 45 psi) 100% of the time then the poppet's will fail to pop.

The spider conversions eliminates these issues.
Be very careful using cleaners in these,DO NOT use chemtool!
One of the materials used in these units is polyamide 66 its normally very chemical resistant it but can be damaged by some harsh solvents.
The damage may not appear immediately but result in future line breakage or leaking.
Gumout and MMO will be fine.


Why would you suggest the OP replace his fully operational FI system? There are a ton of these trucks on the road with a boat load more miles on them on the original components. Why not suggest that he drive it until it konks out and THEN fix it and save a bunch of $$ until it does? Why fix what's not broken??

 

[Trav]

Quote:
Remember---the reply you received is from someone in the fuel system cleaning business---so take it for what it is.



Lets get one thing perfectly clear right now!
I neither offered to clean or replace or to sell anything,PERIOD!And if i did its not your business anyway.
I gave a fair explanation and left him to decide what he wants to do about it.There is more than enough information about this on the web.
He asked about cleaning them and i gave my opinion based on the fact this unit he has 14 years old and not worth the trouble to clean.

You made your comment so leave it at that.

 

[JDD]

Ooooohhhh, OK
A little sensitive aren't we, Trav?

 

[Trav]

Not even a little bit.
When someone starts insinuating there may be some ulterior motive for me posting something its best to nip it right in the bud.
I talk straight and i deal straight,if i have something to say i say it.

 

[JDD]

Originally Posted By: Chris B.
Thanks Trav!

How do you know all this stuff? Your knowledge is amazing!
I'm no mechanic so I have all my work done for me by a local garage. How much should I expect to pay for the fuel injection conversion? Also do you know AC systems on the truck? My AC is not blowing cold air at all. Worst case senerio how much should I expect to pay to fully repair the AC system? Many thanks!


Dear Chris B: Do not be persuaded, cajoled, or otherwise influenced to think you need to replace your fully functional, low mileage FI system to the tune of several hundred dollars. Yes, there are a lot of knowledgeable people here on Bitog. Unfortunately, some like to instill fear in those that maybe have less knowledge of a particular subject that their vehicle is defective in some manner without having direct knowledge of that vehicle. The person to trust is the person that actually has inspected your vehicle and given it a clean bill of health---your mechanic. Do not fear your truck's FI system. If it works, it works. If/when it becomes defective, replace it with the improved system that was recommended. Until then--enjoy your nice, low mileage truck.

 

[Chris B.]

Sounds like a plan. So what symptoms will I see if the fuel injection does start to go bad on my truck? Thanks again everyone.

 

[ltslimjim]

I had a ticking injector once on one of my first vehicles; clogged I'd imagine, that happened after I ran an overly concentrated amount of 3M in my gas tank while at a 1/4-1/2 full. FWIW...

 

[JDD]

Originally Posted By: Chris B.
Sounds like a plan. So what symptoms will I see if the fuel injection does start to go bad on my truck? Thanks again everyone.


If it's the injector spider, GENERALLY, your mileage will drop quite a bit and you will smell gas after shutting it down. That's if there is a leak in the fuel lines going to the spider and then to the actual injector poppets. Again, the poppets often are not bad, but as was indicated before, GM truck fuel systems are sensitive to enough current getting to the fuel pump. So sometimes, it can be mistaken that injectors are bad, when in fact it is the fuel pump. If by chance you ever have to replace your fuel pump, do it with a 'factory' AC Delco unit.

All that being said, overall, the fuel system on your truck was/is a sound design. I have a 96 GMC 5.7 with 148,xxx miles with original injectors, trans, engine, electrical system, AC, front end. The only major surgery it has had is the lower intake manifold gasket and a fuel pump. I just replaced the water pump too, but I don't consider that a major item. Good luck. I'm jealous of your truck. I wish I had one just like it.

 

[Trav]

IMO on this subject you are just plain wrong!
These poppet valves were terrible and there is enough proof to back my statement.
Your mentality of not preventing a well know and documented issue before it happens doesn't make sense to me.

Your argument as i see it is if its working then its fine.
True using that argument someone with a older GM3800 with 75K on it should not worry about changing the lower intake manifold gasket because its not leaking right now.
Changing the gasket before it leaks into the oil is sound advice.

Quote:
Dear Chris B: Do not be persuaded, cajoled, or otherwise influenced to think you need to replace your fully functional, low mileage FI system to the tune of several hundred dollars. Yes, there are a lot of knowledgeable people here on Bitog. Unfortunately, some like to instill fear in those that maybe have less knowledge of a particular subject that their vehicle is defective in some manner without having direct knowledge of that vehicle.


What are you trying to prove here?
The advice was fair and accurate,you think you know better and that's fine but that does not mean someone else is in some way trying to persuade, cajole,or otherwise influence.

I say to Chris B do your own research.
This is turning into a personality conflict and unfortunately because of someone needs to prove "they know better" and the fact that own one that has worked okay for years is blinding them from even researching the subject further.
Here are just a few links on this subject.
Sure run the truck,all i was saying is while its still running good you can plan ahead and save if need be to take care of it before it happens.

BTW GM themselves recommend this upgrade!


http://www.carterfueldelivery.com/fuelpumps/_pdfs/support/TEC1623_CPI.pdf

http://www.lindertech.com/dirty_dzn.htm

http://www.arb.ca.gov/newsrel/nr021103.htm

http://chevroletforum.com/forum/tahoe-suburban-25/99-tahoe-wont-start-new-battery-need-help-11688/

http://www.tomorrowstechnician.com/Artic..._injection.aspx

http://www.napaechlin.com/upload/NAPAEchlin2/Documents/English PDFs/DYK_VortecFI.pdf

 

[demarpaint]

Great info Trav, thanks for sharing! I had a friend that had issues with a Tahoe with this system and ended tossing a lot of $$ into repairs.

Would a better fuel filtering system help?