Pelican Parts Forums - Injectors are not "vibrating" (3.2 motor doesn't fire)

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- - Injectors are not "vibrating" (3.2 motor doesn't fire) (http://forums.pelicanparts.com/porsche-911-technical-forum/476338-injectors-not-vibrating-3-2-motor-doesnt-fire.html)

I've grepped a LED and some resistors and assembling my own "noid light". For the people who want to do the same:

Note the current is about 200mA@50ohm, so the resistor should be able to handle at least 2W (standard electronics resistor can only cope with 0.25W. 50ohm = 8 x 400ohm in parrallel).

Going to test tonight . . .

Noid light kit can be had at autozone on the cheap... and you'll have a set to use on all your cars. Mine came in a hard red storage case too. Saved me.

-Troy

Update: not running yet.

I was indeed surprised how cheap noid lights are, but I had the components and it toke me a few minutes to assemble.

Here is what happened last time:
Replaced fuel and hot wired fuel pump to mix residual fuel with fresh.
Checked injector signal with my hand made noid light B-) -> OK
Hot wired one injector -> only noticeable if one put finger on it. Is it really that faint?

I incorrectly installed the ignition rotor (180; wrong phase). Oopsy:) Corrected that.

It has run very briefly with start pilot several times. But it does not always start with start pilot. Why is that? Once it back fired so hard that the rubber joint after the air mass sensor came off.

Odd observations:
Fuel pump is leaking a bit.
During cranking -> oil pressure ~2 bars. Is that not a bit high?
During cranking -> rev. meter very nervously moving between 500 and 2000. We use a very big battery, so you expect fairly constant revs. But 2000, that's impossible right? I would say it will never exceed 1000. Speed sensor broken or distance too small/big? Anyone?

Additional question
Are the valves hydraulic? One guy thinks the valves do not close. But than again it ran pretty sweet several times with start pilot . . .

Starting to get a bit hopeless now . . .

You will have to remove fuel rails with injectors installed to check for actuation and spray pattern..caution disable ignition to prevent fire

ok, so cranking rev. of 2000 is not odd?

What is a "start pilot"?

Edit: If start pilot is starting fluid, it might be time for a pressure guage since you have injector pulses.

Spray into air intake and the engine can run even without gasoline. I believe some people even got that work with brake rotor cleaner. It's like a combustive gas.

Murf, it seems hard to connect the injectors to the system when they are out. It there a trick without dettaching the other things?

When I jumpered 12 volts to the fuel pump up at the fuse panel to check for leaks I could clearly hear fuel flowing through the system in back. Want to try that?

I already hot wired the pump several times. I'm sure it pumps. It even burst one of the fuel line before. So the pressure is there, it's only hard to tell whether the pressure regulator is doing its job. You got a trick to check it?

Quote:

Originally Posted by bigpino (Post 4689853)

I was indeed surprised how cheap noid lights are, but I had the components and it toke me a few minutes to assemble.

Here is what happened last time:
Answers inline in italics
Replaced fuel and hot wired fuel pump to mix residual fuel with fresh.
**are you hearing the fuel pressure regulator open and close?
Checked injector signal with my hand made noid light B-) -> OK
Hot wired one injector -> only noticeable if one put finger on it. Is it really that faint?
**I don't think it is faint a faint sound. The injectors are probably stuck. Did you try using a 9V battery to get them clicking? others have used that procedure
I incorrectly installed the ignition rotor (180; wrong phase). Oopsy:) Corrected that.
**Are you sure you have the firing order correct? I didn't think you could install the rotor backwards. Isn't there an index notch?
It has run very briefly with start pilot several times. But it does not always start with start pilot. Why is that? Once it back fired so hard that the rubber joint after the air mass sensor came off.
**what is starting pilot? Ether / starting fluid?

Odd observations:
Fuel pump is leaking a bit.
**sounds dangerous! Why not fix it before you have a fire?
During cranking -> oil pressure ~2 bars. Is that not a bit high?
**no, doesn't seem high for cold oil
During cranking -> rev. meter very nervously moving between 500 and 2000. We use a very big battery, so you expect fairly constant revs. But 2000, that's impossible right?
**seems normal. the needle bounces under cranking
I would say it will never exceed 1000. Speed sensor broken or distance too small/big?
**the fuel pump would not turn on if the computer does not see movement from the speed sensor. At this stage, I'd think the crank speed sensor either works or it doesn't. Are you sure the fuel pump is turning on during normal cranking? I think it should be since you are seeing spark. There would be no spark if the crank speed sensor were not working. The computer won't send spark without the crank speed sensor.

Additional question
Are the valves hydraulic?
**They are not hydraulic, but solid lifter.
One guy thinks the valves do not close.
**he is wrong. not until 1995 did they have hydraulic lifters

But than again it ran pretty sweet several times with start pilot . . .

Starting to get a bit hopeless now . . .

Answers above within your quoted section.

Quote:

Originally Posted by DW SD (Post 4690946)

Originally Posted by bigpino View Post
I was indeed surprised how cheap noid lights are, but I had the components and it toke me a few minutes to assemble.

Here is what happened last time:
Answers inline in italics
Replaced fuel and hot wired fuel pump to mix residual fuel with fresh.
**are you hearing the fuel pressure regulator open and close?
***Not very very sure, but while i was hot wiring the pump the other guy said he heard irregularity, suggesting is was regulating.

Checked injector signal with my hand made noid light B-) -> OK
Hot wired one injector -> only noticeable if one put finger on it. Is it really that faint?
**I don't think it is faint a faint sound. The injectors are probably stuck. Did you try using a 9V battery to get them clicking? others have used that procedure
***not 9V but 12V from the harness connector (also checked if 12V was there) and then brushed the contacts of the injector (to keep connection very short).

I incorrectly installed the ignition rotor (180; wrong phase). Oopsy Corrected that.
**Are you sure you have the firing order correct? I didn't think you could install the rotor backwards. Isn't there an index notch?
***Got the order from workshop man. : 162435 with 1 at the marker of the housing.
***I pulled out the rotor unit to replace the o-ring. Did valve adjustments in the mean while and put the unit back afterwards. There is an index notch (crankshaft "pooly" under fan), but it passes twice when the engine rotates once, hence, 180 degrees.

It has run very briefly with start pilot several times. But it does not always start with start pilot. Why is that? Once it back fired so hard that the rubber joint after the air mass sensor came off.
**what is starting pilot? Ether / starting fluid?
***yes, starting fluid. Some use brake cleaner.

Odd observations:
Fuel pump is leaking a bit.
**sounds dangerous! Why not fix it before you have a fire?
***We found out later (at the end of the night).

During cranking -> oil pressure ~2 bars. Is that not a bit high?
**no, doesn't seem high for cold oil
***Ok, that's good the hear.

During cranking -> rev. meter very nervously moving between 500 and 2000. We use a very big battery, so you expect fairly constant revs. But 2000, that's impossible right?
**seems normal. the needle bounces under cranking
***Check.

I would say it will never exceed 1000. Speed sensor broken or distance too small/big?
**the fuel pump would not turn on if the computer does not see movement from the speed sensor. At this stage, I'd think the crank speed sensor either works or it doesn't. Are you sure the fuel pump is turning on during normal cranking? I think it should be since you are seeing spark. There would be no spark if the crank speed sensor were not working. The computer won't send spark without the crank speed sensor.
***Ok, needle indication during cranking makes no sense. Check. And yes, pump runs during cranking.

Additional question
Are the valves hydraulic?
**They are not hydraulic, but solid lifter.
***Check.

One guy thinks the valves do not close.
**he is wrong. not until 1995 did they have hydraulic lifters
***As I mentioned before, I adjusted the valves according to the workshop man. It was a bit colder than the recommended room temp. (it was less than 10 degrees Celsius). Would that make much difference? Anyway, it ran quite well with the starting fluid, so I would say: the valve are ok.

But than again it ran pretty sweet several times with start pilot . . .

Starting to get a bit hopeless now . . .

My answers also in the quote. Thanks for the point by point answer.

Nutshell.

I assume injectors, but could be fuel pressure. As for the fuel pressure regulator, you can feel it opening and closing. It is on the driver's side fuel rail in the back. Turn on the pump and feel it open and close. Or test fuel pressure on rail test port. 38 to 39 psi, I think.

Someone found some Buick fuel injectors (I think) which are interchangeable. Do a search on injector, rebuild and you'll find the thread. They were much cheaper than the Porsche version, but also still made by Bosch. Forgive me if my memory is failing.

Seeking out other threads will get you to the answer on the injectors and how they either got them regoing or the injectors they used to solve the issue.

Doug

Ha, don't apologize Doug. You and the other guys are really helping me a lot. It's a bit hard without some tools like pressure gauge, but alternative quick tests sometimes do fine enough.

I will concentrate on the the pressure/regulator and injectors.

The injectors are held in with clips that will hold them into the rails!!if you don't verify good spray pattern then you should plan on sending them out to be flow tested and cleaned..then you will know for certain they are good..you need to remove all the potential problems to get it running properly

update

tested fuel pressure regulator by putting my finger on it while jump wired the fuel pump relay. There was no noticeable switching going on so I assumed that thrre was not enough pressure. So either pump is not sufficient or regulator is broken.

In the meanwhile, I checked all injectors by jump wire them to a hard 12v. They are all snappy except the one I previously tested (murphy's law). Tapping on while brushing the 12v on it got it released again.

The other guy wanted to try one more time, while we concluded that fuel pressure regulator was not working. But lady luck was smiling upon us. It started and ran smooth.

Apparently, all the injector were stuck and 12v test had unnoticeably released all the other 5.

Thank you guys for yet another solved case.

Nice! Congratulations! Probably worth exploring the FPR further. But it sure must feel nice to hear it fire!

Doug

That may explain why my car runs on 5 if I leave if for 3 weeks or so.

Yeah, it was really great feeling. I already gave up after the injector test and was calculating the costs of fuel pump/regulator, but the other guy ask me to crank it again:).

Milt, I read in an other thread that one can actually hear the difference between a worn and 'healthy' injector. By hot wiring one at the time (I did it in place, i.e. only harness detached) they should sound crisp and snappy. You can clearly hear the switching, so as for me in the initial case: if you have doubts whether you hear it then it is not working.

Can't mention enough, thanks guys.