Hey bro I just want to let you know what's wrong with your truck is that your intake gasket either where it went around the riser for the fuel injector or somewhere around the outside edge is leaking air it's not your distributor cap a rotor button the reason why it's worse it's because the gasket is not seated right. It's usually the one that goes around the fuel injector riser and the intakes it several top of it once you put the intake over it you can't see it anymore and it'll usually fall or get pinched or come off if you're not careful I guarantee that's what it is. Anyways I hope you figured it out by now I just figured I'd let you know I know this from experience man as a matter of fact I got another one to do tomorrow and it's on a band with the dog house 5.0 and it sucks way worse then your truck bro telling you
The issues with the old system are tubes cracking, dirty nozzles, or bad regulator…. Since all of it is replaced with the update…. You messed something up or got them in wrong order
good video. liked watching someone else do one lol tip, pull the plug and make shure you didnt bent any pins on the connector behind the throttle body, goint to the spider inector. common thing to get a missfire or rm from the pins for the connector being bent.
I had the symptoms as you in my 99 Tahoe. I did the same exact steps as you as well and still the same issue. I replaced both the Camshaft Position sensor and the Crankshaft Position sensor and that fixed it. Make sure you use the spacers provided or the cam will rub it.
Scan data for coolant temp sensor? Should be ambient temp engine cold. Minimus 54 psi fuel pressure. Seen em run ok at 52 or so. Never under 50. Attach fuel pressure gauge, prime system koeo. Watch for pressure to drop. If it drops quickly, its either the pressure reg, (dumping fuel into the intake) fuel injector or fuel pump check valve. Check lower intake for leaks.. Did one that missed bad #5 #7 . Ended up leaking drivers side tear of intake.
i see lots of comments from the same guys on the truck sites, just throwing shit at a problem for no reason isn't the way to go. you seem to be on the right track yourself. keep in mind that if you were driving it for a long time with the fuel issue you mentioned then you have lots of build up in the entire fuel system, intake, heads etc. even in the exhaust. once you get it running it will take time to burn all the old crap out. good looking truck
I saw two guys bring up the cap + rotor and you didnt specify If you had changed them while doing your tune up. I've owned these vortecs as long as I've been driving and the cap cracking internally is an extremely common issue because it was a poor design. Itll cause misfiring on multiple cylinders, rough starts, or even no starts. Hopefully this helps. Love the videos.
Run some injector cleaner also some seafoam in the fuel tank as well as the oil see if that clears it up also check your spark plugs to see if the Gap is correct on it I have a 2000 Tahoe that one was running pretty shity I checked the spark plugs the Gap was off they were pretty white my vehicle smell a lot like fuel it was wasting a lot of fuel as well check your fuel filter also sometimes it gets pretty nasty coming through the tank for the tank and it would cause it to run crappy either way I did all that and it started running pretty well hope it helps
Looks like I'm 2 years late on this thread but I was wondering if you remember what your fuel trims were at, during the time that you had the P0300 code? Looks like I'm going to have to buy a timing light check and see if my time is off or fluctuating. Nice truck!
I have a 94 4.3, I had the same exact problem, wiggled my air temp sensor and it fixed it so I changed it out. Was telling the computer it was -30 outside so it made it run extremely extremely rich. It would dump gas and run rough and idle high
I have the exact same issue. I have a whole new upper end. To replace. It feels like the truck is running on 6 cylinders and backfires loss of power same thing as yours.
USUALLY it's caused by running the injectors to the wrong port. Theree are numbers on the central unit that show which cylinder they go to. A common mistake.... Also,some of the after -market ones had bad injectors when new. OEM type(AC/Dalco) is best,though higher priced.
Very possible that it could be causing the issue, we triple checked that they were in the right ports, but could still have messed up, or just a bad set of injectors as well. Will have to look into that.
@@BADZ71 I had one in the shop 6 months ago (get a lot of late 90's 5.7') Misfire #5. Owner installed amazon injector network (2 years ago) He said it ran good for a year, then misfire occurs. Took the top intake off, he had #5 & #7 injectors swapped! No idea how it could have ran smoothly after he installed it 2 years ago with 5 & 7 injectors swapped.....
I would suggest doing the 0411 swap on the truck and start data logging. One thing I did was I cut off the spider injector Bs and bought a multiport intake and I put individual fuel injectors on it.
had a similar issue with a recently purchased 98 k1500 5.7. It was so bad prior to replacing the spider a fuel leak from the nylon inj lines melted the under side of the upper plastic intake. The oil level was 2 qts over from the fuel washing out the rings. This condition introduced fuel to oil thinning it and premature wearing of the cylinder walls, rings, piston skirts and all bearings. Before tearing the engine down the dry comp was 160# wet was 180# previous owner ran autolite ap605 which I pulled replacing them with a colder plug ac delco 41-993 for $30 a set off ebay. Prior to tearing down the engine I swapped the spider, plugs, the coil wire(cracked insulation) , liquid moly 5w30 and wix filter. And a hard reset on the control module. Ran pretty good, at idle and highway speed seemed like the engine was wanting to seize though. Any who, hope something in there might help. BOWTIE FOR FUN!
It isn't the spark plugs..it's the new set of injectors I'm 63 years old I've been rebuilding engines since 1974. Including diesel engines and my truck is a 1999 LS 5.7 z71 I had to but the original GM mfg injectors because the ECM OR PCM in your truck will not sensor the new Injectors fuel flow plus the solenoid in the ones are in the tip end of the fuel lines instead of the original injectors having those in the body of the injectors plus the solenoids are mfg..on a different size and scale..but. I changed out all of the pugs and wires and distributor and all sensors including mass air flo sensor. Once installed the original GM injectors everything went swimmingly. However. Call SUMMITT auto part high performance company and they actually do make the correct upgrade version of these..buying these anywhere else like Amazon or ebay will cost you time and money for those new versions..good luck man..
All they did was move the injector from the top to the end of the tube and eliminate the poppet valve. Same type of injector with same flow spec. The computer can't tell the difference between the two. Your brand new spider was probably defective.
My o2 sensors got stuck reading lean and then made it run rich and caused similar problems if video wasn’t so old I’d suggest unplugging the o2 sensors and see how it ran
I have had the same problem that you having right now my injector filled up number 5 cylinder it filed my spark plugs out because they was full of gas my motor was gas in the oil had to change everything out and go back over again but your plugs are no good after gas has soaked your plugs.
I've replaced the fuel injectors on my 1999 Suburban also with same type. Mine came from China. Getting rough running and backfires now. In process of checking all the plugs and compression. Replaced fuel pump. What a pain! Have you find your problem?
Well damn! That fixed mine back in the day, but I later had to replace the whole distributor because of a bearing issue it fixed it then it shut completely off on day when driving and after checking about everything it ended up being my ignition control module I think it’s called, tiny amp looking thing upper left side of intake, anyway man it’s possible you have a valve issue? Do a compression test after running it, idk bro sorry about your troubles but I personally think the trucks worth it🤘
I have a 1998 chevy and im putting new injectors in , there is a couple of injector lines that kinda kinked and they have to be un kinked witch means i have to take the top off again and use a heat gun to make the the lines flow but mine is doing the same thing . i hope this helps oh by the way i just overhauled my engine 6 years ago new everything it frustrating
I follow you religiously man. I have a 96 z71 and I'm starting to do a bunch of work to it. I am looking at your truck kinda like a template for mine. Love the content man.
If the fuel injector put fuel in any of your cylinders and you and build up your spark plugs with gas in that cylinder your plugs are no good after that I've had the same problem that you're talking about
Not sure if you solved this yet. But I have had several of the l31 vortec that have had worn distributor gears. I know this is kind of late but maybe it will help.
Had this same issue on a 96 Z71 5.7 replaced every sensor and did the mpfi and still got shitty idle and misfire. Tore down the timing chain and found massive slop and in the process I was gonna pull the intake and reseal it and found the distributor gear was completely worn . Took a gear off a old HEI I had then did a cloyes timing set and runs great.
How did you fix this? Mine has rough idle and back fires, brakes up in higher rpm’s or under a lot of load. Also soots really bad when reving and breaking up
Never got to see how it all turned out. Don't feel bad I replaced mine with three MPI systems before I got a good on now a year later I'm having problems again. this is a new GM Engine with around 30,00 miles on it. GM really dropped the ball with this junk. I was looking here for the Ramjet swap someone did. I may do that myself sick of the China parts junk myself.
Also check the crankshaft position sensor! Mine was ever so lose on my Tahoe and I couldn’t hardly get it to crank and it ran like butt cheeks....after replacing all kinds of shit that was my problem haha
And if that doesn’t work...you could pull the timing chain cover and make sure that timing chain isn’t worn or bad because it’ll cause poor performance but usually you can hear it but sometimes you can’t... you can check it without pulling the cover by using a timing light to make sure your timing is CONSISTENT if it isn’t and the timing fluctuates that may be a problem.
Mine is doing the same thing after upgrading! New plugs wires coil o2 sensors map sensor backfires when I get one it but no engine codes and geta 8 mpg. I was getting 16 before old system quit. I am at a total loss of what to do
You figure anything out on your problem? I’m changed a ton of shit and runs fine if I stay at 20% throttle or less. I get 15mpg on the highway so it’s not bad but if I get on it it sputters and misfires
Man just yank that old SBC out and drop an LS in. You could grab a 5.3 or even a 6.0 from a junk yard, get a swap kit from summit racing and call it a day. That's what I would do anyway lol
BADZ71 there’s a number of things that could be wrong with these things man I’ve worked on them since About 10 y/o but you named a lot of the issues that it could have possibly been...have you checked your fuel pump???
I just tried the upgrade version of these spyder fuel injectors they sucked. So I had to order the original GM spyder injectors and toss the new version..
@Mary Katelen King yeah, but, I had to go through 2 sets because of the solenoid on 2 injector lines wouldn't fire off..so far they perform pretty good
It's not timing. My cam retard is within -0.9 of being dead perfect. Brand New distributor assembly. idle really isn't the issue, it's giving it gas when it hesitates.
Sounds like you need a distributor kid....New Coolant temp sensor fixed my 1995 cpi 4.3 from running rich. New throttle positioning sensor stopped the idle from hunting..
@@BADZ71 thats good.... what did you find to be the issue? The last video I saw showed it poping out the exhaust which is usally a timing issue or I have seen plug wires switched to cause it
I just got a new spider system on my 2000 5.7 gmt400 and with the key on the on postions priming up the fuel and fuel literally dumped out of my exhaust. ( I replaced new shorty headers so exhuast was not hooked up yet) . I'm hoping the spider is bad Chinese crap, injectors wide open or ecu is telling injectors to open 🤔
