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Hi,I have a 1990 camaro with 305 tbi. The car started running like crap and having no power when I went to start it the other day. I discovered one of the TBI injectors quit working and wasn’t spraying. I watched this video on how to replace them and there is a part where he lubes the new rubber o rings with “super lube”. Is this recommended ? I don’t have super lube so if so what would you folks recommend? Also would you guys recommend using “gasgacinch” on the paper gaskets? (The guy in the video used a razor blade to scrape the old gaskets off,which probably wasn’t the best idea as you can score the metal) The rest of the process looks pretty straightforward.
Last edited by JimRockford; Nov 15, 2021 at 09:17 AM.
No need for fancy goops on the gaskets, super lube is just another type of lubricant. Any oil will suffice. Just clean off the old gasket stuff, razor blade is fine but as you mentioned you do have to be careful. Double check your fuel pressure first. The TBI injectors are pretty robust, which cannot be said for the fuel pump.
Thanks for the tips “shifty”,would Vaseline be ok to use then for the o rings? I also have some CRC silicone spray. If not I can buy some silicone grease before the injector arrives.
Before you replace the injector you might want to touch a 9 volt battery across the terminals to see if it clicks or not. I've also had injectors that didn't click but after a few good whacks with a screwdriver handle started working again. If it does click fine though, you may have a wiring issue. You can confirm if it's a wiring issue by switching the injector connectors and see if the failure stays with the injector or the connector. Happy hunting!
Thanks for the advice guys. I’ll try that 9volt trick tonight when I get home. So I’m curious. If you tap the injector with a screwdriver and it starts working did you guys have them stick on you again? I’m thinking I should still replace it even if it starts working after tapping it.
About four days before the injector quit I was driving and it started running rough for about 10 seconds then smoothed out again. I didn’t know what the cause was until yesterday when I went to start the car and it ran like crap again and this time it didn’t smooth out. I discovered the injector on the drivers side wasn’t squirting anymore.
Just tried the 9volt battery test. No click at all and I tried several times. Whacked it with a screwdriver handle too and it didn’t start working. Still only one injector working. Switched connectors,same thing. No spray.
Generally speaking are these injectors fairly reliable or is this a common occurrence?
Last edited by JimRockford; Nov 15, 2021 at 05:32 PM.
Just tried the 9volt battery test. No click at all and I tried several times. Whacked it with a screwdriver handle too and it didn’t start working. Still only one injector working. Switched connectors,same thing. No spray.
Generally speaking are these injectors fairly reliable or is this a common occurrence?
I'd say they are fairly reliable...the TBI injector in my truck lasted a good 200k plus miles. Itd work on and off though once it gave up.... I just got an old junkyard TBI unit i had sitting with original injectors from 1990 and used that for at least 3? years now.
They're pretty reliable, but everything breaks eventually unless you have magic parts. I had one go out one night and limped it home before finding the same result you have. Replaced and all was good again.
Thanks guys. Appreciate your sharing your advice and stories. You’re right,mine lasted 30 years so I can’t complain,and like you I was able to limp the car home,running terribly rough with no power at all,but it made it home. I was shocked when I discovered none of the local parts stores had one in stock and they are $108 for remanufactured ones. Thankfully I picked one up brand new for less than half that price online. Now I just have to wait for it to come.
Last edited by JimRockford; Nov 16, 2021 at 09:11 AM.
Yikes, prices have apparently gone WAY up. At least I think I still have a few spares from when there used to be tons of our cars at the JY around here. I should find them and check them all for function. Thanks for the inspiration!
1. I had an injector stick. Installed a Treasure Yard TBI unit on my truck, engine ran terrible. One injector didn't spray. As I was figuring-out my next course of action...it began spraying. Engine has run fine for years and years since then. It might be worthwhile for you to put an ohmmeter across the two electrical posts on the injector, to see if the injector failed because the coil of wire opened, or if maybe the injector "stuck" due to deposits. IF (big IF) you get an appropriate resistance measurement, and IF the wire harness has been verified to have power and pulsing on/off/on/off ground using your multimeter or a 'noid light with the engine cranking, you could drop the injector into a tub of FRESH gasoline fortified with Techron, and see if soaking overnight, or for a week frees it up. COVER the tub of gasoline so that it doesn't vaporize and explode in your garage.
2. Buy your gasoline from a "Top Tier" gas station. "Top Tier" fuel has added detergents to keep the injectors and intake valve clean. I also drop a 20-ounce bottle of Techron Complete Fuel System Cleaner in the gas tank at every oil change--6000--8000 mile intervals or so. https://en.wikipedia.org/wiki/Top_Ti...rgent_Gasoline
3. The top piece that you remove to access the injector is often warped. Get a piece of glass, (for flatness) and some fine sandpaper. I used 220-grit. A couple of strokes against the sandpaper, and I saw that the middle of the piece was the "high spot"; from that point on, I made sure to hold the regulator body in the middle not at the outside edges. Even with me holding it/pushing it at the high point, it still took an entire sheet of sand paper to get to what I considered acceptable flatness.
I quit at this point. Didn't figure I needed to scrub even more metal off the part. It's worked--no leaks.with a fresh gasket. I did apply some schlubba on the gasket. Vaseline would be fine. I used Gasgacinch on the upper side, not the bottom side.
While you're in there...consider adding a shim pack under the lil' plate the regulator spring sits on, between the bottom screw and the plate--to jack the plate up a little bit, and therefore increase the fuel pressure slightly. I used a few #6 or #8 flatwashers. Note that not all of these TBI regulator assemblies are built the same way--what works on one style may not work on another.
Last edited by Schurkey; Nov 16, 2021 at 05:20 AM.
Yikes, prices have apparently gone WAY up. At least I think I still have a few spares from when there used to be tons of our cars at the JY around here. I should find them and check them all for function. Thanks for the inspiration!
Youre welcome. I was surprised too. I had to search online for a while to find one reasonably priced. There aren’t any of these cars in the junkyard anymore. At least not out here.
“Schurkey”, is there a reason you only put the gasgacinch on the top of the gasket? Does gas dissolve it? Supposedly (according to gasgacinch) it’s liquified neoprene and they claim it’s resistant to most automotive fluids. I used it on my thermostat gasket and housing and it’s not leaked a drop.
The price of gas out here (SoCal) has skyrocketed. Some stations are charging $4.75 now. So I tend to look for whoever is offering the best price. Thanks for the tips. In the video I watched the person had a real bear of a time getting the old gasket residue off.
No silicone greases or such should be used. It poisons O2 sensors. The petroleum jelly works.
Be sure to use blue locktite on all screws that are within the top of the TB. These are the three that hold the pod in place along those that hold the injector cover on. Don't want any to come loose and...
No silicone greases or such should be used. It poisons O2 sensors. The petroleum jelly works.
Be sure to use blue locktite on all screws that are within the top of the TB. These are the three that hold the pod in place along those that hold the injector cover on. Don't want any to come loose and...
RBob.
Can the seals be installed as they are without any lube? I only mentioned it because the person in the video used “super lube”.
I ordered the injector online so it will be a few days before it’s here.
Also,is there a specific direction the injector must face or either side as long as the connectors are in line with the harness?
Just tried the 9volt battery test. No click at all and I tried several times. Whacked it with a screwdriver handle too and it didn’t start working. Still only one injector working. Switched connectors,same thing. No spray.
Generally speaking are these injectors fairly reliable or is this a common occurrence?
Sounds like that injector is done for.
I'd say reliable 389,500 miles and both TBI injectors still were working well.
FWIW - I had one injector stop spraying one time. It was a blown fuse at ~325,000 miles IIRC. After fuse was replaced it ran fine for another 65,000 miles.
A lubricant is required otherwise you will never get the lower o-ring into place.
There is a stud on the injector that lines up with a slot in the lower pod.
RBob.
Ok,good to know. I’ll put Vaseline on the o rings then. In the video is shows the injector making a “click” when it’s seated correctly all the way. I was still wondering why one person suggested only using the gasgacinch in the top of the gasket only
I'd say reliable 389,500 miles and both TBI injectors still were working well.
FWIW - I had one injector stop spraying one time. It was a blown fuse at ~325,000 miles IIRC. After fuse was replaced it ran fine for another 65,000 miles.
Are there separate fuses for each injector? I doubt that’s the problem since there’s still current when the ignition is cranked at the leads,but I’m still curious.
Are there separate fuses for each injector? I doubt that’s the problem since there’s still current when the ignition is cranked at the leads,but I’m still curious.
Yes, the fuses are separate. Each TBI injector has a fuse. I doubt it's the issue in your car case as well.
Note two injector fuses. Diagram for 1992 Camaro
Last edited by Arctic White 91 RS; Nov 17, 2021 at 11:35 AM.
Thanks Arctic White,nice Camaro by the way! One last question. Are the heads on the fuel lines to remove the injector assembly SAE or METRIC? This is my only “modern” American car and I know they were using both inch and metic on some of these vehicles in the 80’s. I only have inch line wrenches.
Are the heads on the fuel lines to remove the injector assembly SAE or METRIC? This is my only “modern” American car and I know they were using both inch and metic on some of these vehicles in the 80’s. I only have inch line wrenches.
The top of the injector assembly, with the regulator, comes off without removing the fuel supply hoses/tubes.
Gasgacinch works really well. It cleans off easier than some of the other goops used.
So if my cars been sitting a four days or so and hasn’t been started do I need to worry about there still being fuel pressure built up? My part should be here tomorrow or Saturday.
Got my injector today. It has the gasket for the housing and the rubber o-rings. There’s one o ring that appears to be made of porous foam. Can someone tell me where that’s supposed to go? It’s not shown in the videos I’ve watched online or in the paper inside the box with the injector.
Last edited by JimRockford; Nov 22, 2021 at 06:59 PM.
I'd expect the answers to your questions will be in the service manual for a TBI-equipped vehicle. Some service manuals are available for free download, with links on the GMT400 web site. https://www.gmt400.com/threads/88-95...manuals.43575/
This one has an exploded view of the throttle-body assembly on page 4--14.
Yup. Is it sized appropriately to fit as the dust-seal?
I dont know. It’s only 4am out here so it’s still dark and I haven’t taken the assembly apart. I was hoping someone would have come in and solve the mystery by now so I’d know for sure once I pulled it apart. Other than that it looks pretty straightforward.
I saw another thirdgen video dealing with just the injector replacement and they just took the top off the assembly on the car and replaced it in a matter of minutes. They didn’t show the installation of that piece though. It doesn’t appear it’s to be installed on the injector itself though. Looks like the metal ring and then the large O ring go on top of the assembly and the small o ring gets pushed on the bottom of the injector,then the injector gets pushed into the pod,the housing gasket,and small 8 shaped gasket get installed and then it’s all bolted back together
Last edited by JimRockford; Nov 22, 2021 at 09:09 AM.
Hi,Just wanted to say thank you to Schurkey,Shifty,Arctic and everyone elso who offered advice. I installed the new injector today and the car fired right up and runs great. the hardest part was getting the old gasket material off. that part was a real bear! I did the best I could but it wasnt perfect Its too bad someone doesnt invent a spray that just dissolves old gaskets so they wipe off! anyway after I got it all back together and started the car it appeared to be leaking from the top of the injector pod I replaced so I tightened the housing down at all bolts again and it seemed to stop. I wasnt sure how tight the bolts are supposed to be but once the engine warmed up they seemed looser so I tightened them down more. I tired to be careful because its aluminum and I didnt want to strip anything.Hopefully the leak doesnt come back.I dont want to mess with the stupid gaskets again. I put everything together correctly.metal ring,then rubber on the top.lubed both O rings with vaseline. I did manage to break the thin plastic vacuum hose going to the thermac piece on the air cleaner. Ill try to get one from the parts store tomorrow.
By the way,in case anyone else was curious,the little foam O ring is indeed the "dust seal" than installed under the fuel pressure regulator.
Last edited by JimRockford; Nov 22, 2021 at 07:02 PM.
