dt3257

My 928s4 starts great cold everytime, but when she's warm it's a different story. It does start everytime but it's hard starting and seems to me like it is getting too much fuel...takes a few seconds to clean her up once she does start.

Any ideas???

Is the Temp II sensor the answer or is there something else??

Mongo

I had a fuel dampner failure cause a hard starting issue. When the damper fails, it causes gas to enter the vacuum line on top of the diaphragm. The engine sucks the gas in from these lines with vacuum and can sometimes cause a premature flooding. Check both your fuel pressure regulator and the 2 dampners to ensure there is no gas in them. You can usually smell it as soon as you pull the line off.

If your temperature II sensor has not been replaced, that could be a possibility, but the operation and gas mileage from the engine will be erratic also. If you have no problems related to idle or power and just hard starting, check the items above. Good luck.

Mrmerlin

try adding a bottle of techron to the fuel you might have leaking injectors.
to verify flooding try holding the pedal to the floor when cranking, if it starts after about 4 or 5 revolutions then its either the dampers/FPR or the injectors , causing flooding.
a good upgrade is the ford 4 hole injectors,
its a plug and play operation except for swappin in the correct lower o rings to fit the S4 intake

AO

My problem turned out to be a a bad ground connection for the Temp II sensor.

Follow the LH diagnostic link in my sig and follwo the WSM for poor warm starting.

blown 87

Automatic?

mdkelly1

Had the same problem/symptoms for a couple of years. Replaced the FPR, Dampers and MAF, no change. Temp II sensor okay.

Regularly used Stabil during storage and Techron afterwards. Eventually, performance (acceleration) began to suffer as well.

Sent the injectors out to be cleaned and changed fuel filter. Problem fixed. Made a believer out of me with regard to fuel system maintenance.

See chart below.

StratfordShark

There is an excellent section in the wsm to identify whether injectors are leaking (requires pressure gauge on fuel rail test point, then eliminating whether any pressure loss is down to regulator, check valve or injectors).

But leaking injectors are likely. I had same symptoms and fixed completely with new set of the Ford Motorsport injectors from Summit.

The fuel leaks and floods the cylinder. If left long enough it evaporates which is why cold start ok. Typically if you shut down engine you can restart immediately, but if left for say 15 minutes or lonnger then enough fuel leaks to cause the start problem.

wes928s

same issue in my 86 fuel pressure drops about 20 psi when sitting for about 15 min. the start but very rough running then it clears up. What are a good replacement injectors where to get them ?

StratfordShark

For my 1988 S4 the correct injectors were the Ford Motorsport ones:

FMS-M-9593-C302

I don't know if these are the same as for your car.

They were a direct replacement on mine, aside from having to change the lower o-rings for larger ones to fit the manifold.