From the old live-operated switchboard days... I couldn't remember if it was sleeve or shield...
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Howell TBI
- Thread starter highlander
- Start date
Gezzz, I thought TRS stood for Tandy Radio Shack.. lol. TRS-80 etc.
Took awhile, well a long while to get around to get into spending time on my fuel injection problem but yesterday I fixed it. It was the fuel filter. Complicated symptoms, simple fix. Would have been much more obvious if it passed no fuel but it could flow enough to let the engine run at very low demand but the hotter and more throttle needed the more it was feeding the TBI bubbles and vapor. Drove highway speeds for 3 hours engine ran strong and smooth not even one stumble or backfire.
You may want to look at dual fuels pumps. This lets you eliminate the Fuel Selector Valve and gives you redundancy for both the fuel pump and filters.
When you run into problems with fuel, you can switch tanks and a different pump and filter is used allowing you to carry on.
In any case, I would have a different filter for each tank.
Also with EFI, unless you have a "Surge Tank", I would refill once you hit the 1/2 tank level. Otherwise with our low profile tanks, the fuel sloshes around and moves from rear (Main) to front (Aux) tanks especially in hilly areas. The pickup tube in the tanks can become uncovered and suck air causing stumbing and possible stalling.
Check out these diagrams.
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I think that is an excellent idea and will do that. I was looking at the summit racing catalog and will be ordering parts to make that up with very large capacity inline serviceable fuel filters. I already have a digital fuel pressure gauge I will be installing too, it will be nice to monitor fuel pressure since it gave me so much trouble.
There were two versions of the Holley throttle body (TB) that Howell used. An early version that had round top injectors were the best and rarely gave any issues... these were 80 pound per hour (PPH) injectors. Later versions (after about 2009) changed to smaller injectors (about 63PPH) and required the fuel pressure to be increased to about 21PSI to flow at 80PPH. The Holley TB had a built-in fuel pressure regulator, but it topped out at about 18PSI and was unstable above 17PSI. Some fuel pumps designed for these GM TB EFI systems also cannot develop the higher fuel pressure required for these smaller injectors.
Unfortunately I was one of the first to get the smaller injectors. Howell didn't seem to realize that Holley had downsized the injectors. It caused a lot of issues, even after the problem was recognized because of the unstable fuel pressure regulator. The EBL could compensate for this and I believe I was the first to use the EBL. But I finally had to change the TB to a Rochester with 80pph injectors to eliminate the issues.
Post a photo of the top of your TB showing the injectors and I can tell you what you have.
Unfortunately I was one of the first to get the smaller injectors. Howell didn't seem to realize that Holley had downsized the injectors. It caused a lot of issues, even after the problem was recognized because of the unstable fuel pressure regulator. The EBL could compensate for this and I believe I was the first to use the EBL. But I finally had to change the TB to a Rochester with 80pph injectors to eliminate the issues.
Post a photo of the top of your TB showing the injectors and I can tell you what you have.
Ok, you have the smaller 63PPH injectors so you need to get your fuel pressure up to 18 plus (21psi preferably) in order for those injectors to flow 80PPH, which is what you need so the engine does not go lean under wide open throttle. I'm not sure what or if Howell ever compensated for this change.
