99 Tahoe - Getting rid of the spider

[TahoeJoe]

Good morning gang.

Back story:
Have a 99 Tahoe, 5.7L Stock crate motor from First Mate Marne (thru Summit)
16k on the engine mechanicals trans and rear end, 270k on the vehicle
Stock with the exception of the prior owner put shorties on it and I swapped to the 0411 PCM.
New MPFI spider when I put the crate engine in
Love the ride, well maintained, clean body, gorgeous interior - worth working on (not a beater)
Most up here in MI are in the junkyard by this age

For a few months now, I had an annoying hot start issue (30 min to 1hr set after decent drive) where it would fire fast but would always stumble and miss on a few cylinders until it cleared its throat
Always stumbling on one at minimum until it threw a P0300 (#2 cyl). Sometimes it would clear out and would be fine in a few miles
Pump pressures were good (within service limits)

Long story short:
Turns out I had a #2 injector that was not pulsing when it was seeing the hot soak restart
Balance test found it! - test was fine cold, but failed #2 hot - zero pressure decay when hot
Not happy that I got less than two years and 16k miles on the new spider, I put another one in.

Now I have a similar hot start issue again.
Different though - now it just has a 2-3 second crank time before it starts with an anemic idle as it does fire up
As I sniff thru the induction system looking for a vacuum leak somewhere, getting really frustrated with this spider and manifold design.
My mind just doesn't like having the injectors buried in the manifold and using an outdated design that is nearly impossible to get good aftermarket parts for
That is a conversation for another day; man the junk DOA parts I have clawed my way thru in the last 6 months is insane.

The question:
Has anybody swapped to an external fuel rail and injectors while maintaining the factory PCM?
My mind wonders if something like a Edelbrock 3507 setup would be better suited for this ride?
Not really geeked about dumping the 0411 PCM and going standalone for the 4L60E plus using the Edelbrock control module

Thoughts

[TheMechanic]

First thing to do on a long crank is hook your fuel pressure gauge back up. KOEO for a fuel pump prime. See if pressure decays over the next few minutes (it shouldn't).
If it does you are down to 3 things. Number one the check valve in the fuel tank. Next is the fuel pressure regulator. Last is an injector(s). Not to difficult to find out which one of the three. Process of elimination.
Pick up one of the cheap bore scopes on Amazon or eBay. They are a great add to the tool box.
1. Prop open the throttle.
2. Jumper wire the fuel pump relay so it is on.
3. Stick the bore scope down and wiggle and bend it over to the fuel pressure regulator vac port that is open. Check to see if you get any fuel coming out of the port. Even one single little drop means it is bad.
4. You can either attempt to get the bore scope down individual runners to see injector tips. Obviously any leakage means bad injector since the motor isn't running. Otherwise leave the pump running for about 10 minutes with a jumper on the battery. Remove all the plugs. Have someone crank the motor over with the ignition ECM disabled. You are looking for a cylinder that spits out raw fuel. Again any fuel coming out means leaking injector. If all those are good you have a bad check valve in the fuel pump module.

[HATEHPTUNERS]

Or... dare I say it... it's time for an LS swap!

[TahoeJoe]

TheMechanic
Thanks for the refocus. I can't assume the new spider is healthy. These parts are getting worse and worse for quality these days!
I have my Autel and the scope; time to prop open the throttle and get a look inside (easy view to the FPR and its piss hole :-). I dare think I can get in the back of the manifold thru the port for the brake booster (large enough hole)
Heck for that matter I should do the balance test on each injector, which will help sniff out "a leaker"

HATEHPTUNERS
Don't tempt me :-)
It's just that this is a nice fresh 350 .030 over with a 4 bolt bottom end
It deserves a chance

[TheMechanic]

TheMechanic
Thanks for the refocus. I can't assume the new spider is healthy. These parts are getting worse and worse for quality these days!
I have my Autel and the scope; time to prop open the throttle and get a look inside (easy view to the FPR and its piss hole :-). I dare think I can get in the back of the manifold thru the port for the brake booster (large enough hole)
Heck for that matter I should do the balance test on each injector, which will help sniff out "a leaker"

HATEHPTUNERS
Don't tempt me :-)
It's just that this is a nice fresh 350 .030 over with a 4 bolt bottom end
It deserves a chance

Technically the pressure drop for injector balance works great but not for leaks. You can't reliably tell the bad injector as you are reading system (all) injector pressure and dropping each injector. Since any injector could be leaking its leak volume would be shown for each subsequent injector. You could have a leaker and not know it.
If you can't get a good look you can always just remove the throttle body. Since you already did a spider there should be no reason you can't reuse the rubber seal. That will get you tons of room to view with the Autel.

[TahoeJoe]

You are correct there!
Never thought about the leaking injector will not show when buzzed.
If I am lucky there is no decay when I hook the gage to the rail, and all test even for pressure drop

Finding vacuum leaks today.
One was an all but dead seal around the MAP sensor (sensor was sloppy loose in the hole), another was the PCV breather tube coming out of the RH rocker cover, and a third was the sad seal between the throttle body and the plastic air horn. Love how GM wont sell the seal separately. I made something work for now. I am looking at anything and everything rubber! - between the heat and the age they should look pretty rough!

[TahoeJoe]

TheMechanic,
Learned something last night :-(
Have a little pressure decay; 7psi in about 15 minutes
KOEO = 62psi
Running = 56psi
checked at 61psi after pump prime
decay after 15 minutes - 54psi

After a good drive I bleed off the residual line pressure (thru the gage)
Let it set it usual 1 hr or so.
Fires up a lot better when there is no pressure to annoy things with a drippy injector(s)

Can't get a camera in there to catch the gremlin, but suspect when I pull the top I will see it

The problem I have is, this would be the third injector in as little as three years.
Been buying the FJ504 from SMP thru whomever.
Guess I need to find something better?
Wish the Genuine GM one was still around.

Any ideas?

[TheMechanic]

TheMechanic,
Learned something last night :-(
Have a little pressure decay; 7psi in about 15 minutes
KOEO = 62psi
Running = 56psi
checked at 61psi after pump prime
decay after 15 minutes - 54psi

After a good drive I bleed off the residual line pressure (thru the gage)
Let it set it usual 1 hr or so.
Fires up a lot better when there is no pressure to annoy things with a drippy injector(s)

Can't get a camera in there to catch the gremlin, but suspect when I pull the top I will see it

The problem I have is, this would be the third injector in as little as three years.
Been buying the FJ504 from SMP thru whomever.
Guess I need to find something better?
Wish the Genuine GM one was still around.

Any ideas?

Unfortunately I have no cure for you. What I will say is over the last 5 + years the quality of parts has dropped like a stone. Brand new in the box bad parts. Even from the dealer. After a diagnosis and parts replacement I am keenly aware that the part I just put in may actually give me the same symptoms because it is bad. Last year had a 2500HD that had bad power steering. Hoses, and pump were leaking so I sold the job as a must replace these known bad components and retest to verify if concern has been fixed. It didn't. On goes my Kent Moore P/S diag tool. Tests pressure and flow. Tests says bad steering box. Ok give customer the option of aftermarket or dealer. So put on the aftermarket and same exact thing. WTF? OK on with the tester. Good flow, good pressure bad box. WOW that sucks. warranty a new box. Same thing. Same problem. I say screw it and put a hydroboost on even though the test STILL says bad box. Nope still there. Get a third new box. Had to be picked up from Los Angeles. Aargh. Still bad. Finally tell the customer it's time for the dealership box that is 4 times as expensive. Problem fixed. Have worked on/maintenance on many times since then and all is GTG.
Long story short is get good at replacing them. I can do spiders in about 35 minutes from hood open to hood closed. Done a LOT of them at the dealer including when we were changing the individual poppet injectors one at a time. Get one that has a lifetime warranty.
Parts these days suck

[HATEHPTUNERS]

Themechanic.. you are right about parts quality.. Often the "new" part in the box is WORSE than the several hundred thousand mile part you are replacing. It is a sad state of affairs. I replaced the pittman arm and an idler arm on my 94 silverado a little over a year ago. Bought MOOG as I still falsely believed that they were quality parts... a year later the idler arm is DONE... I mean like it is about to fall apart and the pieces will separate. Had to replace it. The "new" part that I got from my parts supplier out of the box was BENT... It had to be manufactured that way as I think it would break if you tried to bend it like it was bent. Ordered another one, asked for a different manufacturer... next part came and it had so much slop in it right out of the box that to install it would have been a waste of time. If anyone knows who is actually making good steering components these days please let me know as I would like to buy QUALITY parts-regardless of price, so I don't have to keep changing parts, and then paying for another alignment.

[Kzhurley]

I?ve seen where people use the marine intake which has 8 normal injectors outside of the intake. As far as I understand it?s a bolt on swap kind of deal but seems maybe they may be difficult to find anymore.

[TheMechanic]

I?ve seen where people use the marine intake which has 8 normal injectors outside of the intake. As far as I understand it?s a bolt on swap kind of deal but seems maybe they may be difficult to find anymore.

Wow you are right. Cool.
marineL31intakesidebyswide.jpg
https://www.gmfullsize.com/threads/l...e.43081/page-3

[TheMechanic]

Themechanic.. you are right about parts quality.. Often the "new" part in the box is WORSE than the several hundred thousand mile part you are replacing. It is a sad state of affairs. I replaced the pittman arm and an idler arm on my 94 silverado a little over a year ago. Bought MOOG as I still falsely believed that they were quality parts... a year later the idler arm is DONE... I mean like it is about to fall apart and the pieces will separate. Had to replace it. The "new" part that I got from my parts supplier out of the box was BENT... It had to be manufactured that way as I think it would break if you tried to bend it like it was bent. Ordered another one, asked for a different manufacturer... next part came and it had so much slop in it right out of the box that to install it would have been a waste of time. If anyone knows who is actually making good steering components these days please let me know as I would like to buy QUALITY parts-regardless of price, so I don't have to keep changing parts, and then paying for another alignment.

Found out several years ago the once made in USA Moog is now ALL China

[Fast4.7]

Or... dare I say it... it's time for an LS swap!

I do not understand why anybody would go to the effort in a heavy truck. I pulled the 6.0L I swapped into a 1987 G20 back out and put a L31 350 back in its place. A lot more fun to drive with the 350 than the 6.0L with its gutless in the lower rpm torque curve.

[Fast4.7]

This company has the OEM Delphi injectors that fit in the MFI update spider as cheap as I have seen them.

https://amfindustrialusa.com/i-30497...-7l-fj466.html

[Hondaeater]

Found out several years ago the once made in USA Moog is now ALL China

The Moog/ Federal Mogul parts are high quality and are made in many factories around the world, including some here in USA factories.

The R series of parts are for budget minded (cheap) who just need a fix and are not knowledgeable or care of the difference in quality, they focus on the cost of the part/ repair. That is what this line is for, the guy who is broke and trying to keep the jalopy going to next pay check. 3 year warranty.
The C series (CK or K) is the premium line. Lifetime warranty. These problem solver parts usually address a weakness in the OEM and improve upon it.


For more info keep reading as the parts you need and Who owns Who can make a quality difference.... Follow the money.... "Moog was bought by Federal Mogul in 1998. Due to asbestos related law suits the company went into Ch 11 by 2002.
2008 became public stock FDML." [1]

2010 opened an Asia Pacific headquarters in China. 2011 is when the Budget R series came out, coincidence? [3]

In January 2017, majority shareholder Carl Icahn [4] completed a $300 million deal for all of Federal-Mogul's stock, after which he changed the company from a public company to a private company. Icahn then sold Federal Mogul in 2018 to Tenneco.

January 2019, Tenneco acquired ?hlins Racing a Swedish company with a more than 40-year record of excellence in developing advanced suspension systems ? which now spans the automotive, motorcycle, mountain bike and motor-sport industries, and is known for its innovation and close ties to the racing industry.
The relationship between Tenneco and ?hlins actually began in 1998 when the two companies began working together to develop electronic valve technology for automotive applications. In 2003, Tenneco and ?hlins jointly launched the first CES shock absorbers as standard equipment on the Volvo S60R performance car. [2]

Apollo Global Management (is HUGE and worth watching for investment ideas) and acquired Tenneco in 2022. [5]








resources
[1] https://en.wikipedia.org/wiki/Federa...to_the_present
[2] https://www.tenneco.com/who-we-are/our-history
[3] https://www.aftermarketnews.com/fede...trol-arm-line/
[4] https://en.wikipedia.org/wiki/Carl_Icahn
[5] https://en.wikipedia.org/wiki/Apollo_Global_Management

[HATEHPTUNERS]

I do not understand why anybody would go to the effort in a heavy truck. I pulled the 6.0L I swapped into a 1987 G20 back out and put a L31 350 back in its place. A lot more fun to drive with the 350 than the 6.0L with its gutless in the lower rpm torque curve.

Say WHAT??? I've owned several FAST Gen 1 small blocks-350's, 383's 400's, and a custom 427.... I will NEVER... would NEVER go back to old school small blocks! The LS heads outflow even the best after market heads produced for Gen 1 small blocks... Head flow=power.... I'm sorry you had a POORLY set up 6.0, but I'm here to tell you that was what happened. I've built several 6.0's that will absolutely DESTROY Gen 1 small blocks if you are talking dollar to dollar builds... By that I mean give me a budget of say $3000 and let me build a 6.0LS, and a 5.7/350 Gen 1, and hands down you can build a significantly FASTER 6.0 than the old school stuff. There is no comparison... None at all.. I will not waste my time touching a Holley, or Edel-BROKE carburetor anymore as tuning an LS motor is so much more satisfying... I was born, and raised, on Gen 1 Chevy's and will NEVER touch one ever again... His "vortec" 350 is an absolute TURD in factory form... make no mistake about it, that motor could barely push the truck out of the way of an on-coming train.. I had a '99 6 door suburban that I used for hunting.. new motor, new trans, new t-case, new spider injector, EVERYTHING new... a bone stock 4.8L in a Silverado would not only beat it-it would DESTROY it by a country mile if you were running in the 8'th.... I've NEVER heard anyone say the old school Gen 1 was faster than an LS, and I'll bet you I'll never hear that again... You should have asked us to help you tune that 6.0... then you would have been impressed. You had some other issue that was holding that motor up... because... low on torque-NOT a usual LS issue... If someone stabbed a big cam in it, or it was not tuned properly, or BOTH.. then yes, I understand your complaint.. but think about what you are saying... a 350CI compared to a 364CI motor.... just on #'s alone a bigger cubic inch motor "should" produce more HP and torque.. and in the case of the LS-that is absolutely the fact!

[HATEHPTUNERS]

The Moog/ Federal Mogul parts are high quality and are made in many factories around the world, including some here in USA factories.

The R series of parts are for budget minded (cheap) who just need a fix and are not knowledgeable or care of the difference in quality, they focus on the cost of the part/ repair. That is what this line is for, the guy who is broke and trying to keep the jalopy going to next pay check. 3 year warranty.
The C series (CK or K) is the premium line. Lifetime warranty. These problem solver parts usually address a weakness in the OEM and improve upon it.


For more info keep reading as the parts you need and Who owns Who can make a quality difference.... Follow the money.... "Moog was bought by Federal Mogul in 1998. Due to asbestos related law suits the company went into Ch 11 by 2002.
2008 became public stock FDML." [1]

2010 opened an Asia Pacific headquarters in China. 2011 is when the Budget R series came out, coincidence? [3]

In January 2017, majority shareholder Carl Icahn [4] completed a $300 million deal for all of Federal-Mogul's stock, after which he changed the company from a public company to a private company. Icahn then sold Federal Mogul in 2018 to Tenneco.

January 2019, Tenneco acquired ?hlins Racing a Swedish company with a more than 40-year record of excellence in developing advanced suspension systems ? which now spans the automotive, motorcycle, mountain bike and motor-sport industries, and is known for its innovation and close ties to the racing industry.
The relationship between Tenneco and ?hlins actually began in 1998 when the two companies began working together to develop electronic valve technology for automotive applications. In 2003, Tenneco and ?hlins jointly launched the first CES shock absorbers as standard equipment on the Volvo S60R performance car. [2]

Apollo Global Management (is HUGE and worth watching for investment ideas) and acquired Tenneco in 2022. [5]








resources
[1] https://en.wikipedia.org/wiki/Federa...to_the_present
[2] https://www.tenneco.com/who-we-are/our-history
[3] https://www.aftermarketnews.com/fede...trol-arm-line/
[4] https://en.wikipedia.org/wiki/Carl_Icahn
[5] https://en.wikipedia.org/wiki/Apollo_Global_Management

Hondaeater-thanks for that.. When I call my local XL PARTS (as I am a shop with a commercial account) they do not mention any different grades of parts.. Maybe I should ask, or look to buy elsewhere to get something of higher quality. I sincerely appreciate you posting this as it makes sense. I just need to figure out how to get the higher quality parts.

[SiriusC1024]

Oreilly's carries Moog.

[Fast4.7]

Say WHAT??? I've owned several FAST Gen 1 small blocks-350's, 383's 400's, and a custom 427.... I will NEVER... would NEVER go back to old school small blocks! The LS heads outflow even the best after market heads produced for Gen 1 small blocks... Head flow=power.... I'm sorry you had a POORLY set up 6.0, but I'm here to tell you that was what happened. I've built several 6.0's that will absolutely DESTROY Gen 1 small blocks if you are talking dollar to dollar builds... By that I mean give me a budget of say $3000 and let me build a 6.0LS, and a 5.7/350 Gen 1, and hands down you can build a significantly FASTER 6.0 than the old school stuff. There is no comparison... None at all.. I will not waste my time touching a Holley, or Edel-BROKE carburetor anymore as tuning an LS motor is so much more satisfying... I was born, and raised, on Gen 1 Chevy's and will NEVER touch one ever again... His "vortec" 350 is an absolute TURD in factory form... make no mistake about it, that motor could barely push the truck out of the way of an on-coming train.. I had a '99 6 door suburban that I used for hunting.. new motor, new trans, new t-case, new spider injector, EVERYTHING new... a bone stock 4.8L in a Silverado would not only beat it-it would DESTROY it by a country mile if you were running in the 8'th.... I've NEVER heard anyone say the old school Gen 1 was faster than an LS, and I'll bet you I'll never hear that again... You should have asked us to help you tune that 6.0... then you would have been impressed. You had some other issue that was holding that motor up... because... low on torque-NOT a usual LS issue... If someone stabbed a big cam in it, or it was not tuned properly, or BOTH.. then yes, I understand your complaint.. but think about what you are saying... a 350CI compared to a 364CI motor.... just on #'s alone a bigger cubic inch motor "should" produce more HP and torque.. and in the case of the LS-that is absolutely the fact!

I do not need your help to tune an engine. Gen 3 heads barely outflow L31 heads stock for stock and LS engines are considerably weaker in torque. A 6.0L IS a GUTLESS PIG at lower rpm, I have owned them stock and modified. To me they only run good when you rev the snot out of them. Engine combination was not poor, it was a LQ4 with Lloyd Elliot ported 862s cut for 2.00" intake valves, a very mild Cam Motion 6.0 Stage 2 high lift truck cam, 210/216 @ 0.050. TBSS intake manifold and 90mm throttle body. Speed Engineering C10 long tubes. TH400 and 3.08 gears. It could not cruise 70 mph at 2,500 rpm uphill without having to downshift to 2nd gear to make it up the hill. If you compare a stock long block 6.0L even tuned to something like a tuned VK56 the 6.0L is way down on torque, just what it is. I have yet to see a heads/cam 6.0L truck make much more than 315 tq on a Mustang dyno especially with a 4L80E behind it.

I ran a tuned stock longblock L31/4L85E combination and ran it for years. I ran it on the same dyno as a LQ9/4L65E within 10 minutes. The L31 had tri-y headers, high flow cats and a straight through design muffler mated to the stock 3" dual pipes to the muffler. The LQ9 had a TBSS intake manifold, larger throttle body, headers, catless speed engineering exhaust and tune. The L31 made more torque than the LQ9 and it made its peak power numbers nearly 800 rpm lower. Down at 2,000 rpm the LQ9 was like 50 ft/lbs off the old 350. The 6.0L did not even make 240 tq and only made like 296 peak at 4,200 rpm where the 350 made 310 @ 3,400 and right at 290 tq at the hit at 2,000 rpm. So yes, a 350 is superior in every way if your driving style never sees more than 4,500-5,000 rpm. The 6.0L did go on to make another 30 hp at 5,500 rpm, but the 350 had more average torque from 2,000-5,000. I later put a GM 6395 cam in that 350 along with a set of Canadian 906s that had a bit of work done to them. Intake bowls cleaned up, exhaust ports ported, valve seat work, Comp 787 retainers and Pac1218s, pushrod holes drilled to 1/2" for the 1.6 full roller rockers. Just a little bit of head work, the tiny 196/206 @ 0.050 cam upgrade and the 1.6 rockers had the 350 making 330 rwtq @ 2,900 rpm and 290 hp @ 5,100 at the tires through a 4L85E and GM 9.5 SF 14-bolt spinning a clutch fan with a severe duty clutch sounding like a dump truck in the 100*F shop.

I never had an issue stomping a mud hole in the Gen III 5.3L trucks when they were new with a stock 5.7L vortec wrapped in a 6,000+ lbs van. They were absolutely trying as well as many of them had some form of cat-back duals on them. They bogged down hard, then reved to the moon with not much happening while I drove right by and kept on pulling away. Should have seen the look on the then NEW Vortec MAX 6.0L truck owner who could not pull on an old conversion van until he got over 70 mph. The old 97 Van ran like a 9.3 @ 70 in the 1/8 bone stock with a 4L60E, 3.73 G80 and 28" tall P275/60R15s on it. My 180 HP TBI 350 long block powered G20 ran like a 9.7 @ 68 in the 1/8. The G20 had a 3704 Edelbrock intake bored to 2", 454 TBI unit and 454 air cleaner, tri-y headers, dual 2.5" to single 3" exhaust with a high flow cat, the fuel pressure bumped up a bit and some chip tuning done by me. It made 208 hp and 315 tq at the tires through a 700r4 and 10-bolt. Not a lot of hp but loads of torque. Not hard to get down the 1/8 mile track when you run a 1.96-2.02s 60' time.

I will keep the GM HO cammed 8.1L with long tubes in my 99 Tahoe. It actually makes 550 ft/lbs of torque along with the 450 hp it makes at 5,000 rpm.

Also FWIW I have seen Gen1 23* small block heads off the shelf flowing 340-360 CFM. That is as much as a decently ported set of rectangle port LS heads. If you cannot build an absolutely potent Gen1 SBC, I do not know what to tell you! A 410 unlimited sprint car engine is close to 900 hp if not more at the crankshaft now.

[SiriusC1024]

Huh. I guess I just took it for granted that the LS platform was superior in all ways. Taking a look at dyno graphs I see what you mean. LQ4 torque comes up at about 3500rpm, but the L31 makes the same from around 2000 and holds flat.

Those came out new before I was old enough to get a driver's license. Still, I've had the pleasure of being behind the wheel of a few vehicles with one. To me, that's when trucks were trucks. Something about the 350 just seemed solid, reliable, and ready for work.

I'd have to agree. Keep the 350.

Insinuating that Fast4.7 needs tuning help is ridiculous. There are experts on here way above me in skill. He's the same gap above them. The guy could probably program for SpaceX.