Is there a "Ru" around??

[Joe Sharp]

/L's '72 1.7 has an intermittent problem. It will be running great and then drop 2 cylinders (3 & 4). Checked plugs, they're wet at low speed lots of blue smoke. I'm under the assumption that the triger points fire 2 injectors at the same time. I pulled the trigers and changed them with my 2L points. It ran great for about 3 miles, and then I limped back home in frustration. This can last for seconds or miles. HELP!

[bowlsby]

Sorta right.

The trigger points in a 1.7/2.0 D-Jet, fire 2 cylinders at a time all right...1/2 loads x 2 for each firing cycle. Cylinders are paired for this function as 1+3 and 2+4.

When 1+2 or 3+4 go out...check the injector grounds at the rear center of the engine. The grounds are paired together for each side of the engine. Souunds like you have an injector goround issue, which is an easy fix.

[Dave at Pelican Parts]

Actually, I think the grounds are paired up front pair and rear pair. When one side goes out, I suspect fuel contamination. But the grounds are a lot easier to check and clean than the injectors and the fuel filter, so it is very much worth checking them first.

--DD

[norustscott]

adding to Bowlsby, When the FI injector trigger points fail to send the correct trigger signal, does the injector fail open or closed? I think the answer is both depending on wether they failed open or closed. Joe indicateded that the plugs are wet ... indicating that if the trigger points are to blame then they would be failing closed keep the injectors open. I had this problem once, however, then car still ran and not bad, although very rich...step on the gas and it would go...not like "Limping home"... I would submit that the problem is not the trigger
points but an electrical problem... BTW, Blue smoke, Joe, usually is burning oil. over rich operation creates a dark gray to black smoke condition plus very toxic smelling fumes...

[Dave at Pelican Parts]

Hrr, just read my own post, it didn't say quite what I wanted it to.

When the right-side injectors go out, I suspect that there is crud in the fuel that is clogging things up. The fuel goes through the right-side fuel rail first, which is why those show the effects first.

But again, it's so easy to check the grounds that you should do that first.

--DD

[bowlsby]

Actually, I think the grounds are paired up front pair and rear pair.

I am sure on this one Dave. FIs on cylinders 1+2 and 3+4 share common ground circuits. A simply continuity test of any D-Jet FI harness will confirm the conditions on the harness if it is in question.

Daves point is well made though, it could be a fuel delivery issue through the fuel lines...if they are plugged up. I guess you could open the fuel lines and see if you get good fuel flow through the fuel lines when the fuel pump is running, and certainly then recheck fuel pressure when it reconected. A plugged line should show up as higher than normal fuel pressure.

A fuel injector can fail in several ways. If it fails to 'open' it could be plugged or have an inoperable valve causing it to not provide any or little fuel. If it fails 'closed' it aslo wont provide any fuel, but you'd probably have too high of a fuel pressure and the unjectors wont squirt. It casn also suimply leak, which is commopn...and then it would provide too much fuel casuing a rich rinnung or even no runningn condition. have the injectors tested by a reputable injector service if you have any suspicions.

JB

[larrym]

i spent one whole summer fighting a problem like this on a 73 2.0; it turned out to be fine rust from the fuel tank getting thru to the injectors... it got to the point i carried an injector testor & hoses with me so i could backflush the injectors whenever they decided to quit; it made for a lot of roadside stoppages; first solution was to install triple filtration out of the tank & before the fuel pump, one of which was one of those old tractor gizmos with the glass bowl, which confirmed the problem; second stage was to junk the fuel tank; get an injector inspector from JC Whitney so you can pulse the injectors correctly.

BTW, i doubt that injectors fail "open " unless they are plugged open by crud or "closed" unless electrically dead

[norustscott]

Trigger points can fail in a close position causing the injector to stay open....

[Joe Sharp]

Hey. I'm sorry I took today off and I'll work on it tuesday. You guys are the best, Thanks.
Joe