I'm Back! --> Injector Swap + Re-fire Preparations

[austinsnake]

Well...I'm back at it after a 10+ year build hiatus! Ramping back up to finish my MK3.1 (#5818) in retirement. I had made lots of steady progress, just reaching a first start milestone, when work and life changes/moves forced everything into storage, and I have been hoping to finish it up some day. Well, that day has finally arrived!

It has been fun combing over the car, documents, build plan, and the boxes of remaining parts to try to remember where I left off. I drilled and bolted in the roll bars this week to get thigs off and running. That took some grinding, ratchet strapping and rubber mallet action, but alas, it all fit together and they are ready to come back off for later final installation.

Today's project is swapping out the fuel injectors in prep for re-firing the engine. Way back when, I had gotten the engine started, but it would not idle well at all. After LOTS of debugging and help from the forum, I deduced that I have the WRONG (20#/hr) injectors installed, vs. the 30#/hr type that I need to match my MAF. So, for 10 long years I've been waiting to get these swapped out and hope for a much better starting point for final EEC tuning.

OK, so if you're still with me :-)

Two questions for today:

1. The new injectors have an additional white flange at the base where they go into the intake, as compared to the ones that were in there. The dimensions and black O-rings all look the same. Does this white ring look familiar? I assume it stays on and slides into the opening. (Hope my attempt at inserting a pic works...)

2. Prep for re-firing the engine:

- Fuel: I plan to siphon out the little bit that's still in the fuel tank. What about any fuel that would still be in the lines from the tank to the fuel rails? Should I perhaps try to force that back into the tank with some air pressure? Surely whatever residual is in the lines wont burn well, but maybe a little won't hurt.

- Oil: Should I change out the oil or would it still be good after 10 years? The motor only ran for a few minutes total. Maybe smart to just change it :-)

- Water: I had filled the radiator with water, with no leaks, fan was working at temp, etc. when it was running long ago. Seems I would want to drain the radiator (hope it's not rusted after sitting for so long) and refill before running it.

- Anything else? Oh yeah, I'll have a fire extinguisher at the ready! And I'll try to capture the '2nd start' on video :-)

I will check the tranny (no leak observed), rear end (small leak observed) and brake fluid (large leak observed!) before go-carting.


Thanks for all of your past, present and future help and camaraderie in getting to a real Roadster!


Brian

[bobl]

Did the engine sit with pure water in it for all that time? If so I would be concerned about rust in the block circulating into the radiator and clogging it up. Was it freeze protected? Maybe disconnect the radiator hoses, remove the thermostat and back flush the engine in hopes of getting some of the rust out. Of course if it had coolant or was drained then it should be ok.

Bob

[austinsnake]

Thanks, Bob.

It had water in it, partially drained but likely not fully. Was freeze protected. Good idea to try and flush the radiator and block.

[austinsnake]

Thanks, Bob.

It had water in it, partially drained but likely not fully. Was freeze protected. Good idea to flush the radiator and block.

[Jacob McCrea]

I've never seen that particular white ring on the bottom of an injector, but I also assume it stays. But before you install them let me share a mistake I made with similar injectors. I bought remanufactured Bosch 30lb injectors from a reputable ebay seller, but I didn't read the fine print and didn't otherwise know enough to realize that they only flowed 30lbs at a higher fuel pressure than my 5.0 H.O. fuel pressure regulator was supplying. I did in fact buy 30lb injectors, but I needed an adjustable regulator to actually hit that flow rate. If you google search "bosch" + the numbers on the side of your injector you'll bring up a number of charts/spreadsheets showing flow rates and corresponding pressures and you can check to see what fuel pressure you need to hit that flow rate. Took me a little while to realize my mistake and lack of knowledge.

I wouldn't bother to change the oil if you've only run it a little, regardless of how long ago it was, so long as you used a "break-in" oil. But I suppose reasonable people could differ. I would flush the block for the reasons noted above. Good luck!

[austinsnake]

Good idea, Jacob, I will check the flow rate @ my fuel pressure for the new injectors. I got them installed today and the white ring fit nicely into the intake holes.

I'm gonna leave the oil for now and flush the block.

[SourceLee]

2 cents. I'd think twice about running the engine with that oil. It's been sitting in a metal oil pan for 10 years. Daily temperature swings twice a day, every day for 10 years. Those relentless temperature swings are the breeding grounds for condensation. During a decade of time you may have some condensation build up. And then you have the oil filter. What condition is the filtering media within the oil filter? Especially after sitting in oil for that long. The last thing that engine wants are filter particles floating around. To play it safe I would change the oil and the filter. Then prime the engine with one of those oil priming shafts. You're already changing the fuel and coolant. If you're changing your underwear, you might as well change your socks too.

[rich grsc]

I agree, oil and filter change, but no reason to re-prime the oil. The bearings and oil galleries will still have oil in them

[austinsnake]

Agree, no reason to take any risk, so I went ahead and changed the oil and filter.

I disconnected the fuel rails and blew some compressed air back toward the tank, then siphoned out what little was in there.

Last step is to drain the water out of the block and radiator.

[GTBradley]

I hope you had the chance to turn the engine by the front pulley bolt every so often over those ten years. It helps to keep the rings from setting in the same location for too long in the cylinders. If not, I would consider turning the crank manually a few times before having it fire up right into 1000 RPM. It will help with pre-lubricating everything and lessen the shock of start up. Tip, it will be necessary to remove the spark plugs first.

Don't forget to look at the oil pressure gauge first thing after start up and right after that look under the car for leaks.

[John Ibele]

I saw this post and meant to get back to it earlier. Just one comment:

Congratulations on returning to your build!
I love seeing persistence in action!!

Keep those updates coming :)