Introduction and a question on poor starting.

[gorkyb]

This is very cool, please explain the logic here...

Engine sucks in smoke from jar and if plenum leaks somewhere, we should see that smoke coming out of the leak? is that it?

[fixkick]

great question!
Google "engine smoke machine to find vacuum leaks."

the commercial machines are $$$, easy to make, DIY , has a Diesel glow plug in a box and some diesel oil and a 12vdc power supply,

no engine is off. or it gets lung cancer... LOL
keys in pocket.

you pump in smoke (to plenum) using shop air, regulated. to low flow.
and find the leaks,?
the hard part (very hard) is knowing what must not leak and what will. (there will be some that look bad, and are not, like TV shaft, tiny leaks.)

normal leaks is the shorter list.
1: the main air intake will leak, so you block that at air cleaner.
2: the tail pipe will leak because 1 head valve is always open.

one poor guy with nasty 8v throttle body had internal leaks, cracks from icing we guess. a monster to find,

can see injector cushion leaks here.
on other gaskets.

[zukitrek]

Im going to be doing this in the near future. Im still doubtful of a vacuum leak that I might have. Thanks for sharing and good to know you solved your problem.

Cheers!

Hey Fix, big regards!!

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So I makeshifted a smoke machine using a peanut butter jar and a pack of cancer sticks and found nothing.

I then jumped terminal 2&4 on the diagnostic terminal intending to check duty cycle of the ISC, and it immediately killed the engine. I found that strange, so I backed the bleed screw out two turns, and the engine was able to run with the jumper in place.

When I checked the voltage across 6&4, it showed a duty cycle of ~80% even with two turns of the screw (!!!!). Turns out that some PO turned the bleed screw all the way closed! Another turn or two out and I was getting 50% duty cycle and very nicely regulated 800 rpm idle.

With the jumper removed, it regulates very well and runs MUCH better. When started hot the rpm jumps to 1200 momentary and then settles at 800 without any hunting! We'll see how it starts cold, but I think this one may be solved.

Hey Fix can I try all this on mine to get it to 800rpm idle or mine changes being a 16v? If its a go I can wait to try it.

REgards.

[fixkick]

http://www.fixkick.com/fresh-air/smoke.html

[zukitrek]

Im going to be doing this in the near future. Im still doubtful of a vacuum leak that I might have. Thanks for sharing and good to know you solved your problem.

Cheers!

Hey Fix, big regards!!

---

[quote='renaissanceman' pid='3505' dateline='1422746731']
So I makeshifted a smoke machine using a peanut butter jar and a pack of cancer sticks and found nothing.

I then jumped terminal 2&4 on the diagnostic terminal intending to check duty cycle of the ISC, and it immediately killed the engine. I found that strange, so I backed the bleed screw out two turns, and the engine was able to run with the jumper in place.

When I checked the voltage across 6&4, it showed a duty cycle of ~80% even with two turns of the screw (!!!!). Turns out that some PO turned the bleed screw [b]all the way closed! Another turn or two out and I was getting 50% duty cycle and very nicely regulated 800 rpm idle.

With the jumper removed, it regulates very well and runs MUCH better. When started hot the rpm jumps to 1200 momentary and then settles at 800 without any hunting! We'll see how it starts cold, but I think this one may be solved.[/b]

OK, but how does he test duty cycle? Special tool, DMM? He writes about jumping pin 2&4, are those the same you jump when retrieving codes?

[renaissanceman]

On the 16v, the connector has 6 pins. In my case, you connect 2 and 4, and then measure the voltage across 4 & 6. voltage/2=duty cycle.

On the 8v it is similar, but only 4 pins.
http://www.rhinopower.org/diag/cel.html

I'm going to guess that you connect pin B anc C and then measure voltage across A and C. My 1993 FSM is currently 800 miles away in CA with my 1993 tracker, so I can't check for sure. Sorry!

---

Sorry, I looked closer -- looks like you ground pin D (connect D&C) and then measure voltage across A and C. I would guess the voltage/2=duty cycle holds.

Cheers!

[zukitrek]

As always thanks for clearing that out Mr. Fix. Thanks also for sharing Renaissanceman.

Cheers!!!

[fixkick]

zukitrek

see this page yet, ?

the 1996 Full FSM page on this is there, and will not work on OBD1, and that page does show all possible ways to do this, if unsure , ask.

http://www.fixkick.com/IDLE-AIR/dutycycl...e-air.html

[zukitrek]

Sir you are like Tina turner sings