1.6 NA return fuel line issue

[smutts]

Helios Blue? I wan't those alloys! Good luck with the gremlins.

[burn_your_money]

I don't think it is possible for the return to suck fuel in

[8v-of-fury]

It runs well from a single bottle, but I couldn't tell if the return was pulling fuel or not then.... 

Putting the In line in a bottle of fresh fuel, and the Out line in an empty clear bottle.. it will show if any is coming out of the pump. It should come out almost instantly after starting the engine.

[jseeley]

It runs well from a single bottle, but I couldn't tell if the return was pulling fuel or not then.... 

Putting the In line in a bottle of fresh fuel, and the Out line in an empty clear bottle.. it will show if any is coming out of the pump. It should come out almost instantly after starting the engine.

I will try the 2 bottle method while searching for a replacement check valves; The return line sucking fuel in is definitely possible because I can see it happening when feeding off the main fuel tank and routing the return into a bottle, under load the return draws fuel back into the pump. The only thing besides the supply being restricted that could cause this is something internally inside the pump which is freshly rebuilt by Giles. 

[lovinthedeez]

call me a noob, but these diesels return ALOT of fuel after the pump does its thing.  If it runs off of a single bottle, there must be some other problem.  Its not like the fuel dissapears.  we call that black smoke

[jseeley]

Never had the fuel system apart before to know how much fuel flows through the return, but I agree and would expect a good amount of fuel to be returned. The car is not smoking (any more than usual) clean out the tailpipe at idle, a puff off soot under rev and clears back up at a given rpm. No one has really been able to say if sucking fuel on the return line is a symptom of anything. I've never had an issue with the car until I put the superpump in. I don't want to point a finger at the pump though because Giles's reputation is outstanding in these (and other) forums. I had always planned to get a superpump eventually, and went for the rebuild when my old IP started to become leaky, but everything was still running perfectly at that time. However if I can't solve my issue I may just buy another pump as there aren't too many things left that can be wrong. Compression test, leak-down test, good injectors, replacing fuel lines, removed water separator, quadruple checking my timing. Its all been a great learning experience, but I want my car back on the road...

Anyone know where to pickup a new check valve? The check valve on the supply side is the only thing I haven't replaced or removed yet. I can certainly remove it for testing, but I will need to replace it if it turns out to be my issue. 

[8v-of-fury]

Have you tried talking to Giles yet?

Phone: 905-940-2266
Fax: 905-940-2261
E-mail: [email protected]

I'm just saying.. not to blame the pump.. but ot phone before you go and buy a new pump after spending $800...

[jseeley]

Have you tried talking to Giles yet?

Phone: 905-940-2266
Fax: 905-940-2261
E-mail: [email protected]

I'm just saying.. not to blame the pump.. but ot phone before you go and buy a new pump after spending $800...

Yep, He believes its the supply check valve or at least some sort of suction problem from the tank. He said it shouldn't be more than 6-8Hg to pull fuel from the tank. I'll have a a mighty-vac hand pump I've been using for priming but I never noted how much suction it require while priming. I'm not at the end of all my testing, but fairly close. However if I test the IP with a separate supply and return bottle and the return is still pulling fuel IN, then I'm at a loss as to what could be wrong beside something internal at the pump. However if the symptoms of having a clogged supply is suction at the return then it all makes sense I suppose.

[rodpaslow]

I don't have a lot of experience, but I've had the opposite problem, with the return line from the injector to the pump line (banjo that has the extra line for the injector return) leaking.  Testing to get it stopped, my pump on a 90 1.6NA (stock car) there is a lot of fuel going through the return at idle.  Enough, like mentioned, that as soon as the car starts fuel will be going into the return or the bottle if you have one hooked to the return.

I would think if it's not, it is a supply issue and not the pump.  Just my 2 cents.

[jseeley]

Having a heck of a time finding a check valve... might try this->

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=170447291660

[jseeley]

Update-

I started with running the engine with separate supply and return bottles in the engine bay to make sure I was getting fuel out on the return side since I was having weird behavior before; That seemed fine, the "out" jar slowly filled. I would have expected it to go faster, but everything was running just fine. So I checked the supply from the tank as recommended by Giles; Was able to pull freely from the out of the filter in the bay with only 2 or 3 HG's of vacuum; No restriction on the supply side. Then placed a new check valve on the return fuel line because I had removed it previously after finding it was not functional (fuel flowed in either direction) That seems to cure my stalling issues when using the return to the main tank. Fuel was being supplied from the tank and returned to the tank finally. I let the car idle from about 20-30 mins, reeving it now an again. everything was going well, then it was like someone flipped a switched and it started reeving on its own, like a runaway condition. I shut her down and when back to the bottle, started up and I noticed A LOT more fuel was coming out of the return from the pump now, more like what I would expect. It also seem like much more was being drawn in as well. However the revving continued to get higher, approaching red-line. Shut her down again. Now whenever I start up it just rev's up real high and then floats around in the higher rpm's. There is throttle response but never goes back down to idle. I checked the air box for oil to see if it was actually running away, but its clean and I'm able to shut down the engine no problem. Car has never had this type of condition before. I even installed a "cam saver" plastic shield when I was putting everything back together after reading about runaway. Kinda stumped yet again... any advice?

I spoke to Giles for a bit and He recommended to bring back the idle stop screw on the pump; I had to quit before I could get to that (to start work) however. Just doesn't make sense that it would need adjusting there if it idled fine before.


Kinda depressing me that a simple leaky pump has turned into such an issue 

[theman53]

The hanging rpm sounds like a poorly adjusted Main fuel screw. Might check that too.

[jseeley]

The hanging rpm sounds like a poorly adjusted Main fuel screw. Might check that too.

Tried that; Its either backing it off so much that it won't start, or having it rev too high. There is no in-between at this time.

[burn_your_money]

Can you take a picture of the timing mark you used on the flywheel?

[jseeley]

Can you take a picture of the timing mark you used on the flywheel?

Will do as soon as I can; The car is not currently at my garage. I plan on towing it back this Saturday. Looks like a diamond though; Cam lobes are in the correct position (pointed up on Cylinder number 1) when aligned to that mark.