Hi there, my name is Stuart.

Last week I hauled a 72 Tangerine 1.7 out of a barn. PO parked it in 1988. SN 2901578

#1: Idle RPM = 2400 and climbing. As I try to track what seems to be a vacuum leak, I need help identifying some FI components.
#2 The air hoses are all in terrible shape so I'm considering buying the AA Vac hose kit for this car. Any reason to cut my own instead?
#3 Should I sort this mess out with engine in or out of the car? Engine-in lets me check one system at a time. Engine-out looks a lot easier, but I won't learn anything specific even if the hose replacement works. Maybe there are other considerations?

I've cleaned and lined the fuel tank, changed the rubber fuel lines, oil, etc. This is the third air-cooled vehicle I've brought back after a long nap but I've never worked on FI before. Right now I'm finding it difficult to ID components and keep track of their systems.

There was low PSI in the fuel line so I cleaned the fuel pump in a diesel bath by reversing the power leads (credit to "Tram" posting on the Samba FI "sticky") That worked well and now I get 30 lbs pressure at the test nipple on the FI rail. Engine fires right up but it idles at 2400 and creeps up toward 3K. After starting the engine, if I plug one of the two big hoses that enter the air filter assembly the engine dies, but after engine warm-up, plugging that hose brings idle down to around 800.

I cannot ID the origin of this hose since it comes from a T that connects the throttle body and a small can on the engine right with the air cleaner (fig. 1). Lots of suction on that hose even after I unplug it from the AC.

Click to view attachment
Figure 1

The other big hose attached to the air cleaner comes from the (I think) PCV valve (fig. 2). Plugging it has no effect on idle.

Click to view attachment
Figure 2

I tried blocking the aux. air valve? (fig 3). by pinching the hose from it to the throttle body with needle nose vice grip. I'm sure it was blocked. That worked to...until after about a minute the idle went back to 2,000 + RPM.

Click to view attachment
Figure 3

Can anybody offer some advice or encouragement? Thanks for your help and for supporting this excellent forum.

I'm gonna do a little work on your pictures and text... BRB

Ahhhhhhhh... better?

I'd say, if you have it running, have fun playing around with it in the car. This way you can asses improvemnts (or lack thereof) with a turn of the key. I'm not a T4 expert but there are many here that will chime in and lend a hand. Look around for a hose supplier and get any leaks fixed. Not as crucial as a 1.8 in that regard but, that would be a first.

I'll let the experts diagnose the rest.

Welcome!

E.

Change all the hoses before the car catches on fire! hoses from 1988 will break soon.

welcome to the madness!!

http://bowlsby.net/914/Classic/TechNotebook.htm
thats a handy lil bit of info for you. im not familiar with Djet but someone will chime in soon and DAve

http://www.pelicanparts.com/914/914parts.htm

try this one too..under fuel system diagrams etc..

There are 2 things which cause high idle on a D-Jet FI. one is a vac leak and the other is timing.

Best reference for D-Jet F.I. http://members.rennlist.com/pbanders/

Component in Fig. #1 looks like the deceleration valve. Refer to Brads' site for testing and calibrating.

New FI fuel hoses are a must after that many years ...

Go with the AA kit & swap 'em out one at a time. Your FIs might need cleaning or replacing too. Don't forget about the idle adjustment on the throttle body.

Belated thank-you to all who responded to my questions. I think that thank you's and follow up reports are important part of participating in a board. Got busy on other parts of the car.

Per your suggestions I've ordered a set of Vac hoses and replaced the fuel lines.

By spraying carb cleaner on the running engine I determined the left side fuel injectors were leaking badly. Tightening the injector bracket helped.

I then noticed that the PCV hose was incorrectly located at the air cleaner and moved it to another same sized port further "down-stream" in the AC assembly.

Idle had been 2400-30000, and after those two adjustments is down to about 900 RPM, though it still "hunts." I assume this symptom represents the rest of the many vacuum leaks that remain.

I hope that after I install new Vac. hoses, I'll be able to get a better idea about how the mechanical parts of the FI system is operating.

I agree with those who've written that working on the D-jet FI system is rewarding and achievable (doesn't require diagnostic computers). I can see where diagnosing FI it might actually be more systematic than carburetors once you memorize all the different circuits and what they do (only half-way there ).

Next step is to drop the motor, replace Vac. hoses and injector seals. Adjust valve lash and clean up the distributor.

I've also redone the clutch, clutch linkage and the brakes, but that is a different thread.

Thanks again, very much.

Stuart