Iamwilliam

Still no luck. Replaced pretty much everything except injectors.. I know I’m getting power to cold start for 5-8 seconds when cold and signal to each injector connector via noid light, and injectors all click when supplied with 9v battery. Something is allowing fuel to lose pressure, I’ve already replaced fprs and fpd and check valve.. either I have a defective new part or it’s gotta be an injector not closing completely so fuel leaking into cylinder… any other ideas before I just drop the cash on injectors?

GerritD

Hi, I know your pain...I feel just the same with my 928s...I believe your problem is not injector related.
In your case - fuel pressure drop - there are 4 things that can drop the rest/holding pressure:
- check valve fuel pump
- pressure relieve valve in the FD
- injectors
- fuel accumulator
- leaking FPR

My problem is a bit different : all my pressures are within specs, even my holding pressures
The only issue fuel delivery...
But I have the same symptoms : hard start warm + cold.
And what I always noticed is that the idling rpms during cold start are too low : 800 rpm instead of 1100 rpm....

Iamwilliam

I have even worse numbers at cold start. Idle is under 500 and I sometimes have to feather throttle to keep it alive, but once it’s warmed up the idle gets up to 900. I am currently installing a wide band o2 with gauge so I can monitor the air fuel ratios. That should give me ideas of whether it’s too rich or too lean at start up

soontobered84

Iamwilliam,

Is there ANY chance that the original Bosch injectors were replaced with Chinese injectors? I bought a set of "Chinese" injectors from a company that were marketed as "rebuilt Bosch" for my GTS. My GTS had run fine prior to the installation of those injectors, but the injectors I had installed prior did not have the retainer slot in the top of the injector. I had cut a slot in those injectors and they had worked just fine, but I wanted to replace them with injectors that already had that retainer slot.
From the time I installed those "Chinese" injectors until I reinstalled the previous injectors, my car would barely run. I finally narrowed it down to the "Chinese" injectors. Once I reinstalled the previously installed injectors, it ran great.

Iamwilliam

i never considered the spark plugs. I bought them from pelican so I assume they are real. Maybe I’ll put originals back in and see what happens. When I’m driving it hard after warm up. The car flies so I didn’t think it was a spark issue.

Darklands

He told about injectors, not plugs….

Iamwilliam

haha how the hell did I get plugs from that? My injectors and cold start have been cleaned and tested twice. Print out with flow rate and patterns all in good shape.