CIS Injectors Don't Squirt

patkeefe · 10-20-2012, 05:39 AM

I have my engine on the test stand I built. It is a turbo modded SC with CIS. I am still troubleshooting this issue, but I tried to start it last night. No start. I checked, and it had fuel to the inlet of the injectors, but none squirting out. I pulled an injector and blew compressed air through it, and that was OK, the residual fuel came out. I have over 100 PSI dead head pressure at the pump outlet. I need to put my CIS gauges on the fuel distributor and see whats up.

The test stand has no accumulator. I go tank-pump-filter-fuel head. Does the lack of an accumulator play into this?

TIA,
Pat

manbridge 74 · 10-20-2012, 06:32 AM

I like your stand.

I have run a CIS engine and it did start right up w/o accumulator.

Get your fuel pressures posted.

j930 · j930's Garage

call chris carroll at Turbo Kraft in mese Az. he has someone in the phoenix area that will clean and test those injectors. i had similar issues and found that 2 were no good. i went ahead and replaced all 6. chris is a good guy, should be able to help you out.

E Sully · E Sully's Garage

I'd put the cis gages on and check the fuel distributor. Valve may not be seating right, causing low pressure to the injectors.

patkeefe · 10-20-2012, 07:52 AM

As soon as I find the missing CIS test adapter, I'll know the pressures.
Fuel distributor has been previously modded by IA, and recently redone and checked by Larry Fletcher. Injectors were just cleaned prior to install, and squirted OK.

j930 · j930's Garage

i can only give advice from personal experience. i was having a similar issue as i was not getting fuel flow from certain ports. sent back for look at and was told i had some plastic pieces in there. shop checked fuel filter, clean. we think the fuel lines after the filter were disintegrating. replaced lines and accumulator. will be starting up again next as i am waiting for everything to come in. you might look at the fuel lines.

boyt911sc · boyt911sc's Garage

Pat,

I'm not familiar with your CIS Turbo configuration but if you are using the stock air metering unit, you should be able to manually test the fuel injectors while the FP is running. It is mandatory to have a fuel pressure gauge attached for troubleshooting. It has been a while since I last saw your engine. Could you post pictures of the engine particularly the air metering unit and FD? Thanks.

Tony

aerodyn930 · 10-20-2012, 02:51 PM

Hello Pat, Remove the fuel distributor , Verify that the plunger is not stuck in the closed position, When holding the fuel distributor upright it should slowly slide out, If it is stuck let us know , Have some tricks for removal and cleaning,

hope this helps, Lou

patkeefe · 10-20-2012, 05:31 PM

Hi all:
I did get around to testing the pressures this evening. Output pressure at the pump is approximately 100 psi. Deadhead pressure at the fuel distributor is between 50 and 60 psi. IIRC, the injectors need just about 72 psi to squirt, so I'm a little short. I think this is the problem. However, I am unsure why I am apparently dropping 50 psi between the pump and the FD. Could be the pump does not have the oomph in the internals to maintain the pressure.

The pump I'm using is a cheap EBay pump, which is advertised as a replacement for the Bosch CIS pump....so guys, don't ever cheap out on this pump for the car. I think I'll just pull my stock Bosch pump out of the car, since it is on stands, and replace the one on the stand, and see where that leads.

BTW, as you can see, the fuel lines are braided SS to the injectors. The lines to and from the control pressure regulator are new high pressure fuel hose (I think Aeroquip) with a gauge in the line so I can see and set control pressures easily (I have an adjustable WUR).

Attached are some reference photos:

manbridge 74 · 10-20-2012, 05:55 PM

I can't make heads or tails of your hook up but off the top of my head injectors crack open around 45psi as I recall.

al lkosmal · 10-20-2012, 08:21 PM

Pull the injectors and leaving them hooked up to the fuel lines, place them in containers (glass jars) and observe the spray pattern. This will at least verify that you are getting, or not getting, fuel through the injectors. you can work your way back through the system...if they do not spray.

regards,
al

PS: nice test stand.

patkeefe · 10-21-2012, 07:47 AM

I raised the level of fuel in the tank by about an inch, and it makes plenty of pressure now. That was the sugar coated way to admit that I simply needed more fuel. Not sure why, since it had 1/2 tank.

patkeefe · 10-21-2012, 03:59 PM

https://www.youtube.com/watch?v=SfIcAvIcUSk&feature=player_detailpage

spuggy · 10-22-2012, 09:16 AM

Quote:

Originally Posted by patkeefe

I raised the level of fuel in the tank by about an inch, and it makes plenty of pressure now. That was the sugar coated way to admit that I simply needed more fuel. Not sure why, since it had 1/2 tank.

That's a little worrying. How could that be - perhaps something clogged the lower part of the pickup/screen in the tank so it only passes fuel when the level is high?

I know back in the day when I was running $100 cars for transport (ah, youth), a wrench/used car dealer friend of mine once advised me NEVER to run a beater low on - much less out of - fuel, unless I wanted to basically mess with everything in the fuel system. Thinking was to keep any grunge/dirt/sediment/rust in the tank just sloshing around nicely, rather than getting sucked into stuff and clogging it up...

Targalid · 10-22-2012, 09:59 AM

Hey Pat. I keep looking for a picture of or a description of your WUR, the pressure control unit, which should be in front of the fuel distributor. You got one? Is that it, up high next to the airbox, behind the coil?

willtel · 10-22-2012, 12:01 PM

Quote:

Originally Posted by patkeefe

The pump I'm using is a cheap EBay pump, which is advertised as a replacement for the Bosch CIS pump....so guys, don't ever cheap out on this pump for the car.

Be careful with cheap so-called Bosch pumps.

**** beware!! Fake bosch .044 fuel pumps pics inside! ****

spuggy · 10-22-2012, 12:27 PM

Quote:

Originally Posted by willtel

Be careful with cheap so-called Bosch pumps.

**** beware!! Fake bosch .044 fuel pumps pics inside! ****

Good info, thanks for the hedzup!

My 044 was $220 shipped from Ebay 7 years ago; it's a genuine Bosch (Czech-made) one and has worked flawlessly for over 25,000 miles.

Our host stocks them too (Wayne didn't at the time I bought mine).

patkeefe · 10-22-2012, 03:33 PM

Spuggy: How are you? Long time. My fuel tank came off my old generator. I had to modify the pickup, as I felt that dinky line made for the 6 HP engine wasn't big enough. So, I put in a 1/2 NPT bulkhead fitting. I think the nipple may stick up a little high in the pottom of the tank. I have a strainer into the fill, a filter on the inlet of the pump, and a filter on the outlet of the pump.

Willtel: That's why I never put it in the car...no confidence.

Targalid: Yes, that is the WUR up high to the left of the airbox. I relocated it so that it would be easier to adjust on the fly. It is a Brian Leask modded WUR, and it has a 4mm setscrew in the bottom, for setting warm control pressure. It was a massive PITA in the stock SC location. The WUR allows setting of cold, warm and boost threshhold pressures.