Rick Lee

I am having my injectors professionally cleaned, but not giving the shop my car. I just want to pull them and drop them off there. I haven't done this on an engine that was still in the car. Is there a lot of fuel pressure there? Should I remove the DME relay and crank the engine over to relieve the pressure? How hard is it to get the injectors out? Are they fragile? Do they need to be put back into the same cylinder from which they came?

Mike J

There is residual fuel pressure after you run the car that lasts for a while. If you can wait overnight and the pressure should be off. Cranking with the DME off I don't think does much since the injectors are off as well. I just wrap the fuel rail connection with a rag and crack the nut to let off the pressure. It leaks a bit and then lets off.

The injectors are held in with a little clip and the electrical connector. If they are older the O ring is usually gone but the cleaners will replace the ring with a nice new one. Number 6 near the PS pump is the hardest since its tucked under the end of the pump. Its all quite doable but you will be cursing :-) . You might have to yank on them since they often are stuck in their barrels.

They are not matched to a cylinder and when they clean them they should check volume and spray pattern so they are all the same. When I cleaned mine at 75,000 miles two were spraying a partial pattern and the other four were fine.

Cheers,

Mike

NP993

Hmmm, I should do this on my car. I have 88K now.

Rick Lee

Noah, I'm taking them to IMA. $25 per injector and they can have them done the same day I bring them. I put 325 miles on her yesterday, going to Philly and back to see Van Halen (with a stop at Pat's for cheesesteaks). My CEL did not come back on, but my fuel economy is just waaaayyy too good for there to not be a lean mixture problem. I rarely drove her less than 90-95mph the whole way and was getting more than 30 mpg.

geolab

I did those on my car and it was very do-able. I would change the fuel pressure regulator while you're at it, found on the back of the left rail. Not a hard job but I second what mike says, hectic. Hardest part to me was the retaining clips that maintain the injectors on the rails. You could easily place the retaining clip in the wrong groove (there are two), so make sure the injectors are perpendicular to the rail while putting back in. At a slight angle means the clip slid from the proper groove. The retaining clips do not hold the injectors strongly, so take care.

cowtown

Rick, when I did this I left my car overnight so it would be cold, and there was still a fair amount of leakage. I was ready with those blue paper shop towels wrapped around the injectors, and it was OK. Just get plenty of ventilation in there, and do it away from your water heater and pine-scented garage candle.

They aren't particularly fragile, and I did have to tug (stright out) fairly hard to get the old o-rings to give up their grip. Those get replaced so don't worry about destroying them.

I kept them in order 1-6, but don't know if it's necessary since they should flow the same on return from cleaning.

JasonAndreas

Try removing the fuel pump fuse (#26) instead.

Rick Lee

Ok, I last drove the car on Sunday and think I will remove the injectors today or tonight. How long should this take me? If it's doable in under 30 min., I can do it at lunch and drop them off at the shop today. If this is an involved job, I'll do it tonight. What do I need to remove besided the airbox and heater bypass tube? Any tricks?

geolab

TO REMOVE ONLY: I would do it @ night. No tricks. Just be carefull for the bolts that hold the injector rails. The ones behind can be easily dropped in the engine.
As for re-installing, I would defenitely do it over the weekend, engine exposed to sun or strong light source, for all to be clear. We are dealing with fuel here. When all is done, I put the contact on and check the fuel pump for no more ticking with pressure build-up. Sight check for fuel leaks etc.
my 911th post regards

Mike J

I totally agree with Geolab...you could do it in 30 minutes but there are precautions due to fuel as well as a few tight corners to deal with. You might encounter very tight O rings for the injectors etc. I would do it in an evening, get them cleaned the next day and then install the next night. The guy I used here needed a few days to turn them around since it was pretty busy.

The worse one is #6...its under the steering pump and its tight in there.

Cheers,

Mike

Rick Lee

Ok, just pulled 4-5-6 out in about 15 min. from opening the decklid. Minimal spillage and very easy. I'm a little concerned about getting those collar clips back on when I reinstall, but I'll worry about that later. Will post photos later so you guys can read my injectors. They look awful to me.

NP993

Interested in seeing the pics and hearing about the flow test -- if yours are clogged, then I'm doing this next.

Rick Lee

No photos. I can't make my digicam take close-ups of small things. They suck. Anyway, 1-2-3 weren't too bad, though getting to the allen bolt behind #3 took a ball end allen wrench and some creativity. All injectors look equally horrible. The upper ends looked new. The lower ends looked bad. Though the tiny pins looked pretty clean. I will definitely sleep better knowing I have fresh injectors in there. Will drop them off to Ivan tomorrow and see what comes back.

NP993

I don't think you can tell by looking at them -- they might look filthy on the outside but spray perfectly. I'm curious to hear how they turn out to be.

Mike J

In my case, with about 75,000 miles, four were perfect and two had a "partially blocked spray pattern". This means the flow was partially gummed up and not all the fuel was properly atomized. I had all six cleaned and flow checked. Unfortunately I also rebuilt my motor at the same time so I can't tell the difference other than the engine runs quite strong now...who knows what part of what I did helped (new rings, advanced camshafts, everything is clean, etc..).

It should be interesting to see the report from the cleaners.

Cheers,

Mike