Curing Vapor Lock in a 5.7 Vortec FJ60 (1 Viewer)

[505 crusher]

Mine is fixed as well, but I didn't use the in tank pump. I have spare walbro frame rail pumps, so I wanted to keep the ease of changing a frame mounted pump in the field.

I bought a new tank pick up from American Toyota, then cut off the 8mm fuel supply line, leaving the return in place. Got some seamless 1/2" steel tubing from mcmaster carr and closely cloned the pickup line with a rockin' heavy duty tubing bender borrowed from a fabricator buddy. Dropped it at my local hose maker and had them silver solder the tube to the assembly and added a -8an fitting to the end.

Install was easy, dropped the tank and snaked the new pickup in. I'm running about a 4" of vacuum rated 1/2" aeroqip hose between the pickup fitting and the pump inlet.

I've been runing it in the same hot elevation changing conditions that caused me headaches last summer with no problems whatsoever. Probably 5000+ miles in the heat this summer.

Sorry, can't find the pics. Should be on another phone.

Hope that helps someone, the discussion in this thread has been helpful in diagnosing my truck. (98 5.7 vortec 4l60e)

 

[dcoy]

Mine is fixed as well, but I didn't use the in tank pump. I have spare walbro frame rail pumps, so I wanted to keep the ease of changing a frame mounted pump in the field.

I bought a new tank pick up from American Toyota, then cut off the 8mm fuel supply line, leaving the return in place. Got some seamless 1/2" steel tubing from mcmaster carr and closely cloned the pickup line with a rockin' heavy duty tubing bender borrowed from a fabricator buddy. Dropped it at my local hose maker and had them silver solder the tube to the assembly and added a -8an fitting to the end.

Install was easy, dropped the tank and snaked the new pickup in. I'm running about a 4" of vacuum rated 1/2" aeroqip hose between the pickup fitting and the pump inlet.

I've been runing it in the same hot elevation changing conditions that caused me headaches last summer with no problems whatsoever. Probably 5000+ miles in the heat this summer.

Sorry, can't find the pics. Should be on another phone.

Hope that helps someone, the discussion in this thread has been helpful in diagnosing my truck. (98 5.7 vortec 4l60e)

Interesting. Thanks for posting. I agree it would have been nice to have a more accessible frame-mounted solution. In fact that was our original bias and approach, but we had already spent too much time with our maneuvers in the frame mounted approch so I needed something more like a "sure thing" fix. I'm also curious how long the new hose runs from the tank to the pump.

 

[dcoy]

Followup

Just to jump in with the in-tank pump move - this will certainly make a difference in eliminating vapor lock because the pump no longer has to suck the fuel from the tank. The suction lowers the vapor point of the fuel in the line and this is why you get vapor lock.

Now, one other thing to bring up - I did a 5.3l vortec swap in my 80. I bought a Walbro in-tank fuel pump to replace the stock denso pump because the later vortecs and LSx motors require at least 60 psi to run. It worked for about a week. The pump progressively got louder and louder - to the point that it was unbearable to ride in the vehicle because of the pump noise. Yes - it as that loud.

I cured the problem by switching to a better quality pump. I bought a replacement denso pump for a 1994 toyota supra turbo. It's big, but it's whisper quiet and it has require pressure and volume ratings to meet the needs of the vortec series motors.

So moral of the story - do the in-tank conversion AND pick a high quality pump. I do not suggest walbro. For whatever reason the quality has really dropped and the pumps are really noisy.

here's the denso part number: 195130-1020

it runs about $200 and installs like a walbro, but it is larger in diameter. I had no problem installing it in place of my original pump.

The in tank solution still is working well in all the warm weather tests I've given it. Now the cool weather isn't providing much of a challenge though.

Reviewing the thread I noticed (or re-noticed) rockrods input here. The Walbro pump seems to be working fine so far but, as rockrod notes, it is a noisy bugger, although not intolerably so. Nevertheless, I do plan to get one of the other pumps (Denso) that he recommends when the time comes for replacement. Just had an expensive steering overhall so I'm not jumping at fixing anything that's not broken at the moment.