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-   -   Still having issues with ignition ? (aka part 3) (https://www.rx7club.com/1st-generation-specific-1979-1985-18/still-having-issues-ignition-aka-part-3-a-969875/)

Starfox07 09-17-11 04:29 PM

Still having issues with ignition ? (aka part 3)
 
Ignition(?) Gremlins:

I've been trying to sort out a problem I've been having with my car for quite some time now.

Symptoms: Poor idle, low idle, low-rpm hesitation, poor low-rpm throttle response. I have nothing to compare the power to, as I've never driven another GSL-SE but it feels about as fast as my bone-stock B18B powered DC2 integra. The 7 has full exhaust + header. I would think it would feel a bit better than the integra. Anyways, the car feels pretty good on initial startup, but after it warms, it starts doing the above.

Things I've gone through and either replaced or proved they work correctly:

Plugs
Ignition leads
Cap
Rotor
Both coils
Fuel filter
Air filter

I haven't checked the igniters and I haven't checked the injectors. I'm getting a solid 20-25mpg highway, so I doubt the injectors have any issues. I've read that the car simply won't run at all if either of the igniters are bad. I don't know what else to check :(

I'm also fairly certain the car has a vacuum leak somewhere, but I don't think this would explain the hot/cold nature of the problem. Any ideas?

Starfox07 09-17-11 04:39 PM

Perhaps it has something to do with the intake manifold, and not the ignition? Perhaps the BAC?

PercentSevenC 09-17-11 04:45 PM

A vacuum leak could certainly cause poor idling. Checking your BAC valve would be a good idea.

Also, it's possible for the ignitors to fail partway. I had a failing leading ignitor a year or two ago. I had severe breakup at high RPM, and the car would randomly fail to start, but it otherwise ran fine.

Starfox07 09-17-11 05:39 PM

Doesn't sound like an ignitor then. My car has never failed to start, and it seems to run best at high RPM.

I remembered that I had wired the aux ports open, so I closed them. The idle is still fairly poor (perhaps marginally better) and the low end response is a little bit better. Low end torque is up, but as expected the power trails off after 6000rpm or so; when the aux ports are wired open, it makes a little bit less power on the low end but happily pushes past 7,000 even 7,500rpm.

So at this point I'm just going investigate vacuum issues. Oh joy, my favorite.

t_g_farrell 09-17-11 05:52 PM

Ignitors usually exhibit issues when they get hot. I mean after the car is completely
warmed up and the engine bay has gotten good and hot.

Ignitors are basically large transistors and when they fail it is very similiar. Cold
an ignitor may work just fine but once its hot it may fail.

It can also cause you to think other things are the problem, a fuel pump for instance.
I know this happened in my case. Replaced the pump and a few months
later the ignitors finally started completely failing when hot. In hindsight I think the
failing ignitor put a large load on the system (failing to ground??) and that would
cause the pump to go weak in the knees. This is just my personal theory and may
be BS but its what I think happened in my case.

If you have any vacuum issues, fix those first as they can cause a lot of the issues
your describing. Also get your aux ports working right, I hear it makes that engine
come alive.

bumpstart 09-17-11 09:21 PM

TPS cal going out when warm ?

Starfox07 09-17-11 10:04 PM

I'll check that tomorrow. It was fine when cold, but I suppose that doesn't tell me much. There does seem to be a deadspot in the TPS, but it doesn't show up on the meter when it's cold.

At this point, going carb looks really tempting...


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