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Sun Apr 27, 2008 4:11 pm

First time user so be kind.
Rebuilt the engine and installed new clutch but the manual FI beast just doesn't idle smooth (grows and barks instead of purring) and it seems to have no power. Flooring it up hills only maintains a steady decline in speed.
Advice on where should I start looking? Brakes aren't hanging up but I'd appreciate all guidance on any diagnostics that would help me zero in on a solution.
Simple stuff first as I dread that all roads will end at the FI brain.
Thank you in advance for your patience.
PAPS71fasty

Sun Apr 27, 2008 4:23 pm

manderson366 wrote: First time user so be kind.
Rebuilt the engine and installed new clutch but the manual FI beast just doesn't idle smooth (grows and barks instead of purring) and it seems to have no power. Flooring it up hills only maintains a steady decline in speed.
Advice on where should I start looking? Brakes aren't hanging up but I'd appreciate all guidance on any diagnostics that would help me zero in on a solution.
Simple stuff first as I dread that all roads will end at the FI brain.
Thank you in advance for your patience.
PAPS71fasty

well first of all, get the asumption out of your head that it is the FI that's causing your problems, and even more importantly, get it out of your head that the ECU is to blame. the fact that your car is running automatically should tell you that the ECU is fine; either it works, or it doesn't.

I would start by first (if you haven't already) replacing ALL the fuel lines, blowing out the hard lines with compressed air, replace the fuel filter below the tank, and clean out the screen that sits IN the tank.

then, I would adjust your valves, and set your timing. Verify that the points are new (keep your old condsensor) and that the gap is set right. Check the cap, rotor, and plug wires for damage and wear. Make absolutely sure that the car is timed correctly, and that the valve lash is set right. verify that the advances on the weights and the vacuum can are functioning.

After all that, check for VACUUM leaks. FI will run like crap or not at all without proper vaccum. Replace all the Vacuum hoses in the engine compartment, and clamp them for good measure. I cannot stress this enough. YOU MUST ELIMINATE all vacuum leaks BEFORE assuming your problems are FI related.

verify that you have 12V getting to the ECU, as low voltage will cause it to run rich.

Verify that your transmission to body and battery ground straps are clean and free from corrosion. verify that all the FI grounds on the central porcupine or on their respective tabs on the cylinder heads/tin area are clean and tight.

after ALL of this, if you STILL have issues, post back. remember, 9 times out 10, FI is not the problem. Don't go taking it all apart and throwing pieces at it, you'll only lose money and get frustrated.

and do us a favor as well, read the sticky's and fuel injection relief thread at the top of the page, as it answers just about everything. and then, if that doesnt help, use the search, as your general "what do I do" question comes up.... well a lot.

thanks.

Mon Apr 28, 2008 12:07 pm

What ^^^^ He said

Mon Apr 28, 2008 12:55 pm

if you lose power and it smells hot, then i would re-re-recheck the ignition timing! this is a classic symptom of too much advance.

Sat May 24, 2008 12:27 pm

Thanks for the help, here's the progress:

Fuel lines from tank to engine compartment changed, hard lines blown, new filter, tank screen cleaned...and...fuel pump cleaned in bucket of diesel (got that one from the FI sticky)
Valves , gap set. Points, cap, rotor and plug wires replaced. Original condenser was replaced years ago. Timing set.
All vacuum lines replaced and clamped.
Ground strap contact cleaned but strap still cruddy.
FI plugs secure and firm.
-------------
I'm unlucky at finding instructions on:
valve lash setting, advance weights and vacuum can functioning???
verifying 12v getting to ECU.

Car is fun to drive but still lacks pep

Thanks again for the help.

M.A.

"In the absence of intelligence, instructions are followed"

Sun May 25, 2008 12:31 pm

We have a listener here.

Good work ! ! !

Mon Jun 16, 2008 8:23 pm

Power still very lacking.
Next steps as I wander throught the FI sticky.

Vac advance doesn't hold a vacuum - new one on order from NAPA

Pulled off the intakes and found an injector with a cracked tip. Very happy that didn't take a trip down the intake. Looking for new ones.

Matt

Average cost to restore a fastback, $100...every weekend.

Mon Jun 16, 2008 8:31 pm

manderson366 wrote: Power still very lacking.
Next steps as I wander throught the FI sticky.

Vac advance doesn't hold a vacuum - new one on order from NAPA

Pulled off the intakes and found an injector with a cracked tip. Very happy that didn't take a trip down the intake. Looking for new ones.

Matt

Average cost to restore a fastback, $100...every weekend.

Did you check the M.A.P. holds vacuum? I had the same issue, and it was a bad M.A.P. diaphragm.

Mon Jun 16, 2008 8:49 pm

Check that the centrifugal advance is working properly too. If you grab the rotor and twist slightly, the rotor should snap back smartly. There is a felt pad under the rotor that needs a drop of oil on every oil change.
Your symptoms sound like low fuel pressure or not enough advance. You say you found a bad vacuum advance, so check the centrifugal one too.

Tue Jun 24, 2008 8:14 pm

Car still lacks pep and loses power going up hills...but I think I've done the easy(?) stuff per this thread and the FI sticky:

-cleaned the fuel pump in a bucket of diesel
-new fuel filter
-fuel tank sump cleaned
-new fuel lines and blew the hard lines with air, no kinks
-fuel pressure checked, 30 psi
-fuel injectors spray reasonably and aren't clogged
-vacuum advance on distributor replaced and works
-New spark plug wires, coil etc...
-every hose is clamped
-intake manifolds sealed with paper gaskets on each surface.
-timing set, valves gapped.
-sun visors installed (victories are small but rewarding)

So the fasty idles rough but doesn't die. I should replace the cracked injector but I need the car for a July 4th parade and the marshal is counting on my car to be in it...no hills thankfully.

Don't know what/where the MAP is.

I really appreciate all the help and feel stumped by this car.

Thanks in advance for additional advice.

Matt

Tue Jun 24, 2008 8:57 pm

If you can't find the MAPS it sounds like you're flying blind? Gotta have the Type 3 Bentley Manual from Amazon.com to own one of these cars!

Wed Jun 25, 2008 8:28 am

Have you done a compression check since the rebuild?

Wed Jun 25, 2008 8:37 am

MAP sensor (also called a manifold pressure sensor, or MPS) is the silver gizmo bolted to the left engine bay; it hangs down from the underside of the floor/trunk. It has an electrical connection and a hose. Loosen/remove the three screws and you can remove the MPS and bracket, and pull it out for a look. Connect a fresh hose to it, and suck, or use a mityvac pump. See if it holds vacuum. If you hear a hissing you know it's bad. You also can check the resitance of the coils, and check for shorts with a VOM. I think the FI sticky has the readings, but a search on MPS may find another citation here.

Wed Jun 25, 2008 2:04 pm

we had a similar issue the other day. so here's a hint:

let your engine idle - pull the injector plug from every injector 1 by 1 - listen to a drop in rpm (very small) - if you can't hear or feel this drop, your injector/connector/harness might be faulty

I've found a 'wiggle' wire at one of my friends FI - the injector got some power but not enough and was missing out - ergo lousy performance under load and rough idle

just an idea -

Wed Jun 25, 2008 7:25 pm

MAP holds a vacuum...that's good.

I'll do the compression check and one by one FI wire wiggle check and then check back in.

Thanks for the help.

matt
----------
71 Fastback

Tue Jul 01, 2008 3:45 pm

Fuel injector wiggle test results:

While idling - result
Pull #1 - car dies
pull #2 - nothing
pull #3 - nothing
pull #4 - car dies

thanks again for all posts.

Oh, however, 12v is going to the ECU. At least 12 v is leaving the relay on its way to the ecu.

As Hans Solo once said - I gotta bad feeling about this.

Tue Jul 01, 2008 4:55 pm

Check your trigger points. 1/4 are together, and 2/3 are together. Probably have them broken, bent, or crudded up, or just a loose/broken wire on the 2/3 points circuit.

Wed Jul 02, 2008 4:08 pm

Trigger points adjustment/clean did the trick!!!

All four are banging and I am accelerating like a foo, passed someone going up a hill!

Thanks for all the help and advice and to ALL who posted...KTPhil, flybayb,Fisher, Wolfe, architect_7,COFBack, vwfye,JSMskater

Wed Jul 02, 2008 4:52 pm

See, FI is not all that hard. And it wasnt the ECU or the harness, or needing a new set of injectors. Just a little simple common logic and testing.