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-   -   air in fuel when making right turn. (https://www.dieselplace.com/forum/63-gm-diesel-engines/20-6-2l-diesel-engine/444896-air-fuel-when-making-right-turn.html)

GMdiesels 01-22-2012 03:53 PM

Maybe the IP is starting to go?

smackzed 01-22-2012 07:20 PM

maybe? I installed a used IP that came out off my blown engine last year. No idea of age. It has plenty of power and starts fairly easy even in cold weather but the truck has been smoking some. I think the smoking is injectors tho since it's substantially more out of the DS than PS.

I don't know what to think. i tried to make it do it by making particularly sharp rights but I couldn't make it happen.

kbrew2001 02-01-2012 11:55 AM

Hi there a newbie to this site here. My experience with my 91 6.2 K2500 man 4 spd ext Cab w/ long bed and currently with 265,000 miles!!!, I found a few years back the same- making a turn and the engine would surge while at a lower speed. I found everything as it should be (hoses, lines, cable etc.) except the electric lift pump was out and the engine still started and ran fine. Although when starting cold it would smoke a blue/ gray for a few(5-15) seconds before clearing up. After replacing the electric lift pump problem went away. also verify the fuel relay. Good luck.

379detroit 02-01-2012 12:21 PM

just don't turn to the right ):h

smackzed 02-01-2012 06:58 PM

hmm tghat's interesting. I've done the lift pump test that I know of (mechanical pump) and it passes but I think I have a pump for an sbc rather than the 6.2

smackzed 02-13-2012 05:53 PM

So I'm finally going to have some time tomorrow to look at things. Here's an update so far.

Have had many difficult starts including 2 no starts. Once I got it towed and we thought it was bad fuel but I don't think so any more. The next time my mechanic came down the next day and after almost an hour of bleeding air we got it to start, with one start then die in the attempt.

I have a clear line on the return and there are very fine bubbles coming through. Not always but they are present. there is absolutely NO signs of a fuel leak anywhere. So this means what? It's after the fuel pump or before?? Maybe the fuel filter? There is no fuel in the valley and no sign of fuel at the throttle seals. I've tightened and re-tightened all the hose clamps and the fitting at the fuel pump. Also there is no fuel in the oil. The situation happens regardless of the amount of fuel in the tank. Although the 2 no starts were when the tank was quite a bit less than full although I added 40 litres/10 gallons , bringing the tank up to almost full and still had the no start situation.

Oh and i do have a very small fuel leak in the return system. In the steel line just above where the pass side injectors return into the main line. I don't think that could cause these problems though could it? I've had that leak for 2 years or so. It's always drained the IP return in the bottom 1/2 of the return but the top 1/2 stays full at least that was the case a couple years ago when i had the clear line on. I removed it quite a while ago because it was getting brittle. I just put it on again an hour ago or so so I'll have to see if the top 1/2 is draining now. If so could the siphon effect be doing that? I know lots of questions, lots of variables.

Tomorrow I'm going to pressurize the system. I'll also use some clear line most likely if that doesn't work. Any other suggestions?

Thanks in advance


smackzed 02-14-2012 12:14 AM

Anyone feel free to comment. Anything before morning would help.

Margot 02-14-2012 08:51 AM

I had a similar thing. I ended up pressurizing the fuel system and finding 2 very small leaks, that didn't leak fuel, but let air in when sitting (enough to make starting after a day almost impossible).

turbonator 02-14-2012 03:48 PM


Originally Posted by smackzed (Post 4512349)
Anyone feel free to comment. Anything before morning would help.

maybe your advance plunger shaft seal is pulling in air.. we have 2 pumps that do it, and we just did a high idle mod switch and it stopped doing it, and we are in the process of re-sealing a pump now... exactly the same problem, but we run an electric fuel pump, so there was less time to bleed it... although it did it just under load.....

smackzed 02-14-2012 04:48 PM

Well she started and stayed going yet today. After finding one leak and replacing that line I still had problems. Noticed fuel in the frame channel so bypassed all the steel line from lift pump to as close to the tank as I could get. Very little fuel came out of the steel line when I cut it. Put some clear line on and cranked it 4 or 5 times. Barely any fuel in the line. I'm going to try to get it started with a 5 gallon jerry can.

The really weird thing is that when I try to start it there is more air than fuel going through the return, but when it was running yesterday there was very little air in the return line.

this is really annoying.

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