Injector leak down test, Hard Starting

[scott.john.mockry@bangate1.tek.com]

Scott,

You can pull out the injectors from the cylinder head and place them in some glass jars or bottles to 
watch the spray pattern and check for any drips.  The fuel pump can be energized (jump across the relay 
terminals) and then raise the CIS air flow sensor plate and watch the spray pattern and then after letting 
the air flow plate is lowered to the rest position and the fuel pump  is turned off check for any dripping 
injectors. USE EXTREME CAUTION WHEN WORKING AROUND THESE INJECTORS UNDER PRESSURE!!!!!
EXTREME FIRE HAZARD!!!!!!!

You might want to plan on replacing the  screw in injector inserts (two piece air shrouded) in the head 
along with the rubber injector seals. Those seals tend to leak (vacuum) which can cause hard starting. Of 
course you should check all the crankcase breather hoses for cracks etc.  

My 89 200TQ takes about 4-5 seconds of cranking to start after it sits for an hour. I replaced the fuel 
pump check valve but no change in the ability to start the car.  I don't think the system pressure is the 
problem at this point, because even when I energize the fuel pump for a few seconds before trying to 
start the car it still requires 4-5 seconds of cranking to fire up. I need to check the residual pressure to 
officially rule out this as the problem though.  I plan on checking the fuel distributor air flow plate rest 
position as well. I have replace all the injector seals/inserts and checked the CO % and I also checked all 
the breather hoses for cracks etc.

 Does anyone have any other suggestions for the cause of this hard/delayed starting? My 86 5000CS T 
started much quicker than this 89 200 TQ I have. The fuel distributor, pressure regulator and injectors 
are slightly different (higher pressure) than the ones used in the earlier 86-88 MC engine fuel  system.

Scott M. 


>From: ScottB2460@aol.com
>Date: Wed, 24 Jan 1996 20:07:11 -0500
>Subject: Excessive cranking/fuel injectors

>I was looking at the Product Service Publication lists and noticed there is
>one for excessive engine cranking.  I have not ordered one yet, but my 89
>200tq suffers from this and according to recent postings its something a
>number of us live with.  The independent shop said (without looking) that 80%
>of the time this is a result of the injectors leaking.  Can one do a visual
>check of the injectors and verify they are leaking, or is it all internal? 

>TIA,

>Scott
>89 200tq