[Supras] cleaning fuel injectors off the car

[berniek at technicaldevelop.com]

Hi List.

    About 6 weeks ago I bought a set of low impedance Nippondenso 550cc 
injectors from a list member.  They had apparently been sitting around 
for some time, some were clogged with weird spray patterns and some 
leaked (mouth test to inlet stub test).

    I set up a circulating loop of paint thinner and an old GM TBI fuel 
pump with an internal relief valve of about 20 PSI.  Of the 6 injectors, 
4 were OK,  I did a backflush through them under pressure to remove any 
crud from the internal inlet screen, and then flowed them forward.  Of 
course the spray pattern was narrow due to the low pressure involved, 
but I was looking for differences.  In one case the pattern was 
lopsided, probably the result of gas additives which were left in the 
injectors.  Continued paint thinner flow did some good, as did repeated 
backflushing.  However, I also did a reverse flush with 100 PSI 
compressed air in both directions while energized (12 volts will hold it 
open at 100 PSI but will not open it in the first place).  Grabbing the 
pintle every so gently witth a pair of dull needle nose pliers and 
twisting it broke up the rest of the deposits.  Do not knick the pintle 
even microscopically as the spray pattern will be affected.  More 
flushes with pressurized paint thinner and compressed air got each one 
leakless and seemingly to the same spray pattern. 

    The best bet for storage of injectors is to fill them with stoddard 
solvent or paint thinner.  Open them with 12V, and use an eyedropper to 
get the stuff into the top connection.

    Hope this is of some help.

          Bernie K