Hi,

I own a 1988 300te with a m103 and it is very hard to start. I bought the car about 4 months ago and despite everything I do the problem seems to have gotten worse. The thing is, it will always start eventually, but I might have to crank it for 20 seconds. When the engine finally does start it usually isn't running on all cylinders until I give it some gas, then it runs just fine. It has no idle issues or power problems, it actually runs very well, it is just very hard to start.

I am fairly sure it is a fuel pressure problem as it is worst after sitting for more than about 15 minutes. If you turn it off and on again after running for a bit, it starts quickly. At first I thought it could be a fuel pump problem because I could hear the fuel pumps whining and they sounded like they were on their last legs. I replaced the fuel pumps and the problem persisted. I was then sure that it must be leaky injectors, so I replaced all the injectors. The problem still persists. Note that I don't really mind throwing parts at the problem because all of these parts were beyond their service life.

The list of things I have already replaced is as follows:
both fuel pumps and check valves
fuel filter
all injectors
OVP relay
fuel pump relay

things I am about to replace:
distributor cap and rotor
spark plugs
O2 sensor

Note that while this happens on "cold starts" it's summertime in Texas and it's 100+ degrees F.

Does anyone have any idea what my problem might be?

Hi can you look for vacuum leaks on the small bore tubes,the rubber couplings split. And all earth straps, remove them all clean them up and put a little grease on them and refit. Then you can remove air control valve clean it with carb cleaner. .As you remove this valve it will have rubber hose conected , and this to should be checked for splits.

This is the part you need to clean . See below picture

This what your looking for .

Attached Thumbnails

 

He reports good idle so while the idle air control valve could probably use a good cleaning I don't think its the culprit here. Everything sounds like fuel accumulator.

found this via google.
https://**************.com/problems/fuel-delivery/102-103-104-gas-engine-difficult-or-slow-start


Does it start if you let the fuel pumps run for a bit before you turn it over?

__________________
190e 3.0 5spd Zender black on black plaid
1973 280

You're just guessing and throwing parts at it. Look at this thread, which has a number of simple tests you can run to help isolate the problem.

M103 starting problem

Duke