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-   -   Timing question and stalling question (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/timing-question-stalling-question-537611/)

twilight slide 05-07-06 03:26 AM

Timing question and stalling question
 
3 questions. . . is it possible to get an accurate timing reading from just cranking the car? i ask this because my car will only run for about 2 seconds. second i compression checked the trailing holes instead of the leading, does this matter? haynes says use trailing, but i read somewhere else to use the leading. i forgot to hold the throttle open and add some oil into the spark plug hole, but the car read 80-80-80 75-75-75. also the car taks a good 5-10 seconds to catch, but if i cover up the AFM, as soon as it starts pulling my hand in (2-3 secs) it catches, and i can keep the car runining for a little bit by varying the air it is getting. any ideas on these?

hIGGI 05-07-06 06:50 AM

stock ECU u wont be able to get accurate timing from cranking (timing has to be measured at steady idle (~750-800 RPM)

HAILERS 05-07-06 08:43 AM

The ECU retards the timing during the Start cycle, so you can't do that.

Maybe with a bit of trickery you could. You'd have to disable the pin 3B so the ECU won't know it's in the Start cycle. Then remove the lead plugs so the engine will spin faster. Give that a try and I THINK you could actually succeed in setting the timing with a light. Never done that myself though.

Actually you should not have to do that. Put the front pulley on the Lead mark. Pull the CAS. Align the bottom marks on the CAS. Now look into the top of the CAS with it's cover off. Take note of the position of the *gears*. Stab the CAS and adjust it so the CAS *gears* are EXACTLY where they were prior to stabbing the CAS. That should get you very, very, very close to the correct timing.

HAILERS 05-07-06 09:42 AM

1 Attachment(s)
Here's a jpg of a Palm connected to a RTEK2.0 showing the Lead and Trail timing during a cold start:

HAILERS 05-07-06 11:22 AM

1 Attachment(s)
Here's another car that has just started and only run for a half minute or so.

twilight slide 05-07-06 12:13 PM

would incorrect timing result in what i described or am i just looking at a bad engine?

twilight slide 05-07-06 01:22 PM

yeah so i restabbed the cas, nothing really changed. got the car running for maybe 5 secs, largely by manipulating the throttle cable and blocking almost all airflow at the AFM. gonna try comp check with premix in the leadings see what i get.

HAILERS 05-07-06 01:46 PM

It sounds more like a very, very large air leak. We have no idea if this is a turbo or not. Look at the inlet duct from the afm to where ever it goes. Brake booster feed off????

twilight slide 05-07-06 02:20 PM

sorry yeah it's a jspec turbo. afm to turbo is good. turbo to IC to elbow is good. brake booster feeds from the rear of intake manifold and is good. airpump removed, ACV and split air are blocked off. solenoids are pulled off the rack, and hardlines vacuum capped. i don't think i'm missing anything big enough to cause this problem. any ideas?

twilight slide 05-07-06 03:34 PM

so where would be a big enough vac leak to keep the car running? cause if i completely cover the afm it will start immediately and keep running for a few seconds.


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