Youri Ko

First test drive Update :
The thing STARTS just like it should!!! Can't wait to take Long Fuel Trim reading too see it go to normal.

"What is that hose that you pump air into? I don't recall such air hose there."

It's a hose that goes from Air Valve to Throttle Body

Youri Ko

Update :
Fuel trims are out of specs again, reading -20% on each bank and startups are long. No CEL yet though.
And idle is around 960 with AC off

Took fuel pressure test with two different gauges and imagine what - 75
psi! Disconecting vacuum line from Pressure Regulator does nothing, vacuum is good -18inch
After posting here, kind folks pointed me to spec which should be 55psi.

Next step would be to retest the FP with return line disconnected see if it's not clogged somehow - I don't feel lile replacing another part without being 100% certain that it is the problem.

Youri Ko

SOLVED

Clogged return fuel line

Ahsai

Nice work. So the fuel pressure was actually too high and the negative 20% fuel trims indicated that. It's interesting that 1128 and 1130 (too lean at idle) point to the opposite. I guess it makes sense as the DME reduces fuel under driving so it has to add fuel at idle.

Youri Ko

I'm not 100% sure that theese codes mean we are lean.
Aren't they more about "adaptation limit reached", meaning that we either went too lean or too rich?

I'll be hooking up a scanner tonight just to ascertain that the trims are back to normal. But so far, start ups are just perfect and this makes me happy after two months of hunting.

Ahsai

1128/1130 mean lean for DME 5.2. For DME 7.2 and on, they mean either lean or rich. Yours is 2001 so it should be 5.2

http://www.renntech.org/forums/topic...30/?hl=seeking

Anyway, I'm pretty sure you've found the culprit.

theclutch

so I guess the question is.... how the hell did that fuel line get clogged like that!?@? Were you not running a fuel filter?

sjg1138

Where is that fitting that you removed located? Maybe I should check mine if its easy to get to.

Imo000

Clogged return line??? How? If the return is clogged, some of that had to go through the injector strainers/filters too. I would pull the injectors, pull the strainers and have a good look at them. They should also be clogged.

Youri Ko

See Figure 4 on this page http://www.pelicanparts.com/techarti...eplacement.htm


So the fuel trims are finally normal, -5% on both banks so that's good. Cold startsup are perfect but....heat soaked restart after few minutes are as long as they used to be. When I did the fuel pressure test, I noted that the residual pressure was droping almost instantly after the pump was shot, not a good sign.

How it got clogged? I wish I knew. I got very little history on this 2001 C2 and all I know that it was barely driven in the last 6 years. I guess this is how it go clogged?!

Totally agree, as I need to diagnose that residual pressure drop.
What are the strainers btw?

Imo000

They are small mesh filters at the inlet of the injector. It drops into the injector body.

Ahsai

My guess is the fuel filter bursted at some point. Good call checking the injectors.