Tuned port injection, TPI fuel rail rebuild and injector info - 88 Corvette - Part 8

Tuned port injection, TPI fuel rail rebuild and injector info Part 2

[@Michael_Lorenson]

Excellent, thanks

[@BigWillAuto]

great videos always enjoy watching you work on the C4s

[@patrickdunner39]

I took all 8 gray injectors out and put Jegs 8 piece steel injectors in. Works awesome. I also replaced the fuel regulator and EGR valve.

[@savedforever1]

What kind of regulator and is it adjustable?

[@davidstepeck2644]

My son’s 89 has the L98. Sometimes is runs well and other times it idles poorly to horribly and I feel like we’re chasing a ghost. I’m changing these injectors immediately along with the fuel regulator, even though we get 42 psi. I need to watch this video again and see if you mentioned the exact injectors to get for a 1989 Corvette with the L 98 engine engine. If you see Mike on it, perhaps you could reply to me. Thank you for this video. it was really great !

[@davidstepeck2644]

Oh great. The L98 is one of the most complicated engines to work on. 11:00 People who work on these beat their head against the wall. 16:30 Do you have a camera in my barn?

[@dante04srt]

Just received my 22# injectors from Southbay yesterday. Hopefully going to be installing them on my 92 Z28 L98 tomorrow. I've been seeing very underwhelming performance with the car and my bet is the grey Multecs are failing me.

[@catboi1188]

So nice to be able replace them for little money with Bosch units 👍 i got the yellow accels from summit racing back in the day for $200+ or so and they're junk 😂

[@mikemaifeld6280]

I am changing the injectors in my 91 it has all the symptoms you talked about

[@gm-classics]

It will be like new car

[@patrickcarnahan2751]

Can you recommend any injector sets that I should look at for my 1990 L98 Vette, I pulled the rail off and it looks like the original Rochester setup was still in there. Thanks

[@gm-classics]

Ford referb 22lb for cheap, run real good.. new delphi are avali too with improvments and are great too but more. Southbay fuel injectors will fix you up..

[@patrickcarnahan2751]

@@gm-classics Excellent, thanks so much! I'll check them out.

[@maxpineapple]

85 corvette is 24# injectors

[@catboi1188]

Yep 👍 at 35psi or so then they went to smaller units and bumped up the pressure to 46psi or so

[@jeffkildow9917]

Love the video and the garage! Just bought a 1986 IROC with the factory 305 TPI with 87K miles. I may change the injectors if mine are the "gray ones".

[@gm-classics]

86 are not the grey Multec, yours should be Rochester, but you will benefit from newer for sure.

[@jeffkildow9917]

Thanks! Probably have to take off Plenum and Runners to tackle this job I would expect

[@user-mo1yg6tf7j]

Hey Matt, first off thanks for all the videos! I have an injector question. I have a stand alone harness tpi setup on a swap I am working on. It's a 91 LB9 305 TPI-Emissions deleted, headers, Accell base manifold, ported TPI plenum&runners, Holley AFPR, and stock injectors. I had a chip made for associated mods. Started great, idled great, ran great for about 5 minutes then stalled out. So discovered it had leaky Motec injectors. So I swapped them out for south bay 24lb injectors. Starts right up now, but has an extremely high idle. Is this because the ECU needs another chip made for 24lb injectors? Or is there something else going on? Thanks for any help you can provide!

[@gm-classics]

Did you try the stock chip? Also, what is your fuel pressure set at? You may want to reduce the fuel pressure a little bit and see if that does anything for you? Also, make sure your IAC not bad, that’s the idle air control motor on the throttlebody.

[@user-mo1yg6tf7j]

@@gm-classics thanks for the response...it's idling extremely high at prolly around 2500rpm, the iac is new and TPS is an older one probably factory. I have checked the TPS, and if I'm understand results correctly, it's about 20% over from normal. But that is approx how much over it's idling, so I'm sure if it's the ECU trying to compensate for the larger injectors, or a bad TPS, also it's the non adjustable style TPS that came on the 91's. I have not tried the factory chip but it's the vats ECU, so chances are it wouldn't work anyways. I forgot to mention I installed an Accell super ram at same time as injectors, I've uninstalled and reinstalled 4x checking for vacuum leaks, and can't find any. I'm stumped, and all I can figure is that the ECU can't calibrate correctly for the 24lb.er's. But I'm not positive that's the case.

[@user-mo1yg6tf7j]

Also the FPR is set at 40psi at the moment. It was a quick check on a rail mounted gauge. I don't really want to leave the engine running for any period of time with the extreme high idle condition.

[@gm-classics]

I run 32# injectors on my 88 with the blower on basic stock hypertech chip for l98. I have base fuel pressure at about 34. It does not idle high… it really sounds like a vac leak, a crack in super ram? Try stock chip for grins.. the larger injectors will make run rich at 40 psi and even idle eratic, but cant see it just revving up that high without something else going on.

[@user-mo1yg6tf7j]

@@gm-classics gotcha, ya my first thought was also an vacuum leak. And I would think ,it revving that high at idle, a pretty obvious one. But I can't find one. I'm going to reset IAC, just to wast some time, and then keep checking for intake leak and probable cause. Thanks again for responding, I really enjoy your videos, and made me realize just how truly special the ZR1 is.