90 S5 turbo 2, completely stock.

I bought this vehicle a couple of months ago, at the time it would start but not idle. I discovered a torn turbo inlet, and other vacuum lines in rough shape. Rotor pulse was 90 on all 3 sides of both rotors. Stone cold. Cooling system holding pressure.

I decided to do a bit of maintenance. So I had the injectors flow tested and cleaned. Reinstalled with new OE insulators, and o-rings. Replaced all rubber fuel lines, a large number of vacuum hoses, and clamps. All the gaskets on the upper intake manifold where replaced with OE components, a new turbo inlet, and a fresh lof (lube oil filter).

After getting it reassembled, I went to start it. As the car had sat for a few weeks I wanted to build up some oil pressure in the turbo before I ran it. Disconnecting the crank angle sensor, and without depressing the gas pedal, I cranked the vehicle over a number of times to build up oil pressure. Then reconnected the C.A.S. and attempted to start the vehicle to no avail. I then proceeded to verify fuel pressure, checking between the new fuel filter, and fuel rail. No problem found. Verified spark, and inspected plug wires. Verified all connectors properly secured. Tested resistance across the C.A.S. everything appears solid. Retested rotor pulse, 90 stone cold.

The vehicle really seems to not be fueling. There is no external fuel leak, nor smells in the rotor housing or oil that would make me believe its flooded. I removed the efi fuse, and cranked it a number of times simply to confirm.

My question is before I remove the upper intake manifold again to check injectors pulse with a noid light. Is there anything simple I could be overlooking?

Cheers.

 

i think you should go ahead and start checking if the injectors are firing. also, verify that the harnesses are grounded.

if none of that works, then at least this gets bumped for misterstyx69, Satch or Aaron Cake to see it.

 

if you have a spare CAS, attach it to the engine harness off the engine, turn the ignition on and spin the CAS and listen for the injectors to "click".

if you get nothing audible from the engine i suspect the injector shop didn't properly store the injectors for shipping and they're seized, this is quite common with some injector shops.

if this is the case you can try to force or "shock" them open by disconnecting the first ECU connector and jumpering the 4 light green wires in the end positions to ground with the key on until you get audible clicks from the injectors. do not hold the wires to ground or it could damage the injectors. if this still doesn't work, remove them and send them back with a nice happy letter about them wasting your time and money, and it would be appreciated if they sent back some actual functioning injectors.

if they function when manually grounded, it could also indicate that you failed to ground the brass ring terminal on the engine harness to the block, securely or at all.

 

I don't have a spare C.A.S. so I just pulled the upper intake manifold. Injectors pulse is good. So let's recap. I have good fuel pressure, good spark, good injector pulse, and good compression. It must be those injectors. Luckily the shop I had them flow tested and cleaned at us local. So I'm going to pull the injectors run them back over there, and have them double checked. On Monday I'll order new upper intake manifold gasket and injectors orings. Do you think its necessary to replace the insulators as well? Keep in mind they are brand new.

 

i would also check to make sure you have the fuel lines attached to the correct hardlines.

fuel filter hose to front port, firewall return line to rear port. on Jspec engines the order is reversed.

 

have you taken the plugs out to see if they are wet?
If they are you know you have fuel.
If they got a real good soaking then they may be fouled and hindering the engine from firing up.

 

Turned out to be the injectors, the two I had in the primary rail where not flowing at all. I've got some cool pictures of them on the machine I'll post them later. I'm glad the where in the primary rail, I would've hated for it to go lean just as it was coming onto boost.

Was able to get the injectors free and flowing, however one of four is flowing about 10% less than the others. I can't seem to get it to clean up any more.

Should I replace all four?

 

are those photos of you checking them yourself? if so, i'm impressed.

i would seek professional counsel on this. send them to one of the injector outfits (Witch Hunter, Marren, etc.) and get their help. i've heard of local diesel shops providing that kind of service as well, maybe you can look into that in your area. if they can be rebuilt/refurbished, then those places should be able to do it. if they are simply a lost cause, then they should be able to tell you.

 

That is at a local shop where I had them tested and cleaned. I've had them service all my injectors on the vehicles I've purchased that have sat for an unknown amount of time. C & C Fuel Injection Specialties in Sparks NV. Great guys over there. Always helpful. They're trying to find a set of refurbished injectors for me, but haven't had any luck. I think I might cruise over to the classified section and list a WTB ad for a set of injectors.

Seriously though thanks for the advice regarding the injectors seizing up, without that tip I may have wasted a lot time trying to diag that before rechecking the injectors.

 

yeah definitely check the classifieds here. i see the come up fairly often. prices are rarely ridiculous, too.

that was all RotaryEvolution.

 

Properly utilized this forum is a force to be reckoned with. The entire New Member Section (FAQ & Technical) is fantastic even to a experienced mechanic such as myself.

Cheers

 

Update: Replaced the injectors, and the car fired right up. Sounds strong.

However I have another problem I'd like some input on. The rpm's are fluctuating or hunting about 500 rpms, and the idle is high 2500rpm. I test drove the vehicle, engine felt great, didn't quiet feel like it was boosting to its full potential. I shut it down checked fluid levels, and inspected for leaks. All is well. I went and put some petrol (fuel) in it, and on the way back it felt like it had even less boost than my initial test drives earlier. Now my first though is course vacuum leak. I've triple checked the lines, and even sprayed some carb cleaner around checking a increase in revs. I couldn't see anything visually, nor did the carb clean net any results.
My next thought was the idle air control valve, or bypass air control. I checked resistance across the terminals, 11.5. Spec is 10.7-12.0. If I unplug the bac the idle drops to about 1200rpms But when it warms up and the aws (accelerated warm-up system) turns off, or disengages, the idle starts begins to hunt again.

Thoughts?

 

Set the Green/Red wire of the TPS to 1 volt w/key to on and the engine as hot as it can possibly get (20 minute drive should do it).