DeWolf

Long shot I know but i had a similar problem on a 951 and it turned out to a minor tear in the brake booster diaphragm.

When the diaphragm ruptures, atmospheric pressure will pass through, rather than push it forward. Another symptom is an engine hunting at idle. Atmospheric pressure lowers the engine vacuum, by leaking through the diaphragm.

85euro928

DeWolf,
That's what a friend had suggested but even if I isolate the vacuum circuit that feeds the brake booster from the rest of the system I still have the same problem so I'm thinking it's not that. On second though, just for the heck of it maybe I'll isolate the brake system and see if it holds vacuum. It couldn't hurt to check again.
Thanks

Pfc. Parts

Sounds like a plan then (I mean the injectors). You know what they say. If you've eliminated air and spark that just leaves fuel. I was tearing my hair out by the time I got mine running right again, I don't even have to imagine what you're going through It's worse when you have several things wrong and you have to fix all of them before anything works. Almost drove me crazy.

85euro928

In my case it's not almost it has driven me crazy, and very disappointed too as this is the third event that a mechanical failure has caused me to miss.

Pfc. Parts

So if you're under time constraints and have a chance of recovering if you don't need to send the injectors out for service, here's what I did:

Pull all the injectors. Use the re-build kits available overnight from several vendors to replace the fuel filters, pintle caps and O-rings on each injector.

Use a 9V battery connected to the injector spade lugs with alligator clips to test each of them to make sure the solenoids open. You can either use alcohol (safer) or B-12 Chemtool (a cleaning agent) as a fluid to verify the solenoid opens, or you can just listen for the click before using any fluid at all. If they don't open (audible click) there isn't much more you can do.

If they *do* open, find a short piece of fuel line (8 inches or so) that will fit the injector intake on one end and a plastic squeeze (sport drink) bottle on the other. You may need a couple of hose clamps. . Buy a bottle of B-12 Chemtool and a plastic squeeze bottle that will tolerate brief exposures to B-12. Cut a hole in the top of a pint glass bottle large enough to accept an injector base (I used a pint Salsa bottle with a screw on lid. A Dremel makes cutting the hole in the lid pretty easy). Use alligator clips to connect the injector to a 9V battery. Don't connect *both* leads, to the battery, leave one disconnected. Connect the fuel line to the top of the injector and put positive pressure on the squeeze bottle of B-12 while at the same time momentarily connecting the other lead to the 9V battery. Be DAMNED careful the battery isn't close enough to the injector to cause a flash if there's a spark. You DON'T WANT the B-12 to ignite. This is why alcohol is safer.

This *should* force B-12 through the injector, cleaning it. If the solenoid fails to fire you have a bad injector and there's not much you can do but send it out for a professional rebuild...

BTW. I didn't suggest this. I've never done it, it's absurdly risky and you SHOULD NOT try this at home.

Even though I've never done this, I'd suggest wearing heavy gloves, a welders apron and helmet before attempting it. And a fire extinguisher. Within easy reach.

85euro928

I did this back in the fall of '11 which is why I'm not convinced it's the injectors, but hey what do I have to lose. BTW I had help doing this and I wouldn't suggest doing it along. My helper was just busy taking the picture at the time.

Pfc. Parts

Thom -

Shhhh! You aren't supposed to keep photographic evidence! Imagine what could happen if some gold digging relative showed up with those at a sanity hearing!

It might still be a failed injector solenoid. All of mine were clean when I installed them after I finished the intake and all the solenoids tested OK. The twisted part is two of them got stuck between the time I tested them and the time I got the car ready to start again, which was only a couple of months.

Hilton

I just noticed from your other thread that this car has an AFPR installed.

If you had to adjust a MAF to 900ohms to make it run rich enough, then lets step back and actually get some measurements rather than swapping parts randomly.

so.. first question.

Have you checked your fuel pressure at the rail with the pump jumpered, and at idle to make sure it is in spec per the workshop manuals?

The WSM specifies everything very carefully so you know the car will run right, so first step is to make sure its running correctly. Quick fix might be to swap a stock FPR on there, but thats just part swapping, so time for some diagnostics.

Pfc. Parts

Post #1 I think.

Hilton

Yep, I hadn't gone back to re-read the OP in days and remind myself, my mistake.

The WSM states these specs for 84-86 16V Euro:

• Idle speed pressure: 2.0 bar (29psi)
• Idle speed with left pressure regulator vacuum hose removed: 2.3-2.7 bar (33-39psi)
• Idle speed with clamp slowly applied to return hose on the level sender: > 4bar
• Relay bridged and engine off: 2.5 +/- 0.2 bar (36 +/- 3psi)

Page 24-111 has the diagnostic chart and the following pages the test plans.

Wonder if the OP replaced both fuel pressure regs, or just one? (or re-plumbed the fuel system?)

85euro928

Hilton,
Yes I've went through the test procedures for fueling and pass everything except for the amount of fuel the system will pass in 30 seconds. The manual calls for 1350cc and my system only passes +/- 1000cc. Since my external fuel filter is new I'm thinking I should replace the internal tank filter and the fuel pump.
The Euro fuel system originally had two FPR's and one damper, when one of the fuel pressure regulators died I changed the system to one AFPR and two dampers (one new and one original) and re-plumbed the system based on what others had done here on RL. The system appeared to work fine, before.
What I did find was that the new AFPR has a very slow vacuum leak, however there was no smell of fuel in the vacuum line or the device itself. I've reached out to the manufacturer for a rebuild kit.

Pfc. Parts

Thom -

Off topic, but is that an ultrasonic parts cleaner on your bench in post #66? How's that working for you? I'm getting very tired of Simple Green and toothbrushes.

85euro928

Worked great. I think it was a Harbor Freight special.

85euro928

Update (because I hate reading through all pages of an archived posts just to find out that the OP never shared the end to the saga):
(Sorry, this is not the end, just a major milestone).
So after chasing a lean fuel condition and a rough, high idle problem thinking it was a major vacuum leak I finally isolated individual componants and vacuum tested each one. I had already tested the fuel dampers and AFPR once but figured this time I would draw about 7 psi of vacuum and then leave it for a minute or two to see how well it held. When I got to my 8 month old AFPR I found that after about 30 seconds the unit would drop a pound, this continued on until the mityvac read zero. Fair enough, I ordered a new bladder, it arrived in the mail yesterday, and I changed it out last night. Viola, no more idle problems!
Thinking about this it makes a lot of sense as the AFPR was the only other thing I touched when I installed the rebuilt MAF:/ However it would have never occured to me that it was AFPR as the unit was basically new (live and learn)
BTW, I still have a lean condition above 2000 or so RPMs but I have an idea of what that is now and will let everyone know after I fix it.

Pfc. Parts

Do I get an all expense paid trip to Taft?