• Hello Guest, welcome to the initial stages of our new platform!
    You can find some additional information about where we are in the process of migrating the board and setting up our new software here

    Thank you for being a part of our community!

B230FT Base Timing Out of Range

leecatd8209

The Fourfather
Joined
Jul 1, 2015
Location
Reading, PA
Hopefully this is the last thread about my POS 760. It's been a struggle, but it keeps getting closer.

The latest issue is that the static timing is out of range. At the end of the adjustment slots in the distributor I can only get it to ~18* BTDC.

1986 760TIC LH2.2 AW71L
- rebuilt B230FT with F pistons
- 160# compression
- ipd turbo cam
- rebuilt 15g on 90+ manifold
- kind of old 93 octane in the tank
- full stage 0 and then some
- known good injectors and 007 MAF

I'm pretty much out of things I know to check. I do have a knock sensor on the shelf, throw it on there?
 
I'd check the timing belt. Are you sure about the main pulley/harmonic balancer? May be it just slipped and the mark is not on 0 anymore. How does it run?
 
I'd check the timing belt. Are you sure about the main pulley/harmonic balancer? May be it just slipped and the mark is not on 0 anymore. How does it run?

It idles great, and runs pretty strong.

I replaced the balancer and verified that the mark coincides with the piston at TDC, and quadruple checked the cam mark as well.
 
You’re adjusting with the vacuum advance disconnected right? I’ve made that mistake. The crab dizzys don’t have a mechanical advance do they or are you running a block distributor?
 
You?re adjusting with the vacuum advance disconnected right? I?ve made that mistake. The crab dizzys don?t have a mechanical advance do they or are you running a block distributor?

There's no vacuum advance, I'm using the head mount distributor.
 
The only vacuum lines running into the cabin seem to go to the cruise switch, boost gauge, and the little overboost guy.
 
Did you take out that plastic thing in the distributor slot that can limit the travel? Do you have a 16v distributor in there by mistake? Can you move the distributor without the bolts in there further around so you can get more advance? What is it supposed to be at at idle? 18 not enough? Also wouldn't the ignition EZK determine the timing, not the fuel ecu? Options are you could program up a custom EZK chip if you wanted to...

Wait did you say you don't have a knock sensor on there and plugged in? Welp that is your problem probabbsly..

Maybe the hall sensor in the distributor is not in correct spot?
 
Did you take out that plastic thing in the distributor slot that can limit the travel? Do you have a 16v distributor in there by mistake? Can you move the distributor without the bolts in there further around so you can get more advance? What is it supposed to be at at idle? 18 not enough? Also wouldn't the ignition EZK determine the timing, not the fuel ecu? Options are you could program up a custom EZK chip if you wanted to...

Wait did you say you don't have a knock sensor on there and plugged in? Welp that is your problem probabbsly..

Maybe the hall sensor in the distributor is not in correct spot?

The spec is 12* +/- 2, and I'm just trying to get to stock. With the bolts in I can only get 18*, if I take them out I can go further, but that's not right.

I replaced the knock sensor with a known good one to no effect. This is the 8v distributor that came from the car. Perhaps it's bad?

I'm just trying to get it to run correctly at stock levels before I go messing with stuff
 
Is the TPS idle switch adjusted correctly? What RPM is it idling at?

Either one might result in more advance that expected. The knock sensor should only Retard timing, and even then, it only retards when knocking at higher rpms.

One other thought - do you have an adjustable cam gear on it? I think any non-zero adjustment would effectively result in the head-mount distributor being rotated by the same adjustment.
 
Is the TPS idle switch adjusted correctly? What RPM is it idling at?

Either one might result in more advance that expected. The knock sensor should only Retard timing, and even then, it only retards when knocking at higher rpms.

One other thought - do you have an adjustable cam gear on it? I think any non-zero adjustment would effectively result in the head-mount distributor being rotated by the same adjustment.

I haven't touched the TPS at all. Lemme lool into that.

Idle is 750 +/- 10

I have the stock gear on it. I've moved it a tooth either way and straight up is where it wants to be.
 
If it's idling at 750, the TPS is probably OK. You could at least check that it clicks going on/off idle.
 
TPS fixed my issue. I never would have looked there.

How did you fix the TPS? I am having a similar issue with my 87 760, I can only get it to retard 3 degrees with the disti twisted all the way until the bolts hit. In my case it is a generic disti, and I have a new Bosch one on order, but I am curious to know how the TPS affects the timing? I get the click as soon as I turn the TPS manually just the tiniest bit.
 
How did you fix the TPS? I am having a similar issue with my 87 760, I can only get it to retard 3 degrees with the disti twisted all the way until the bolts hit. In my case it is a generic disti, and I have a new Bosch one on order, but I am curious to know how the TPS affects the timing? I get the click as soon as I turn the TPS manually just the tiniest bit.

I replaced it with a known good used TPS. Mine also clicked, but the circuitry inside wasn't working, it was just open in all positions.

I can't tell you how or why it effects the timing, probably something about idle mapping in the EZK triggered by the closed position switch.
 
I replaced it with a known good used TPS. Mine also clicked, but the circuitry inside wasn't working, it was just open in all positions.

I can't tell you how or why it effects the timing, probably something about idle mapping in the EZK triggered by the closed position switch.
Can you please tell me how you checked that it was open in all positions? I am not sure exactly what the plug looks like inside(how many pins)or how to use my meter to check?
 
<iframe width="560" height="315" src="https://www.youtube.com/embed/0cbr--8QJio" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

Here is how you check it with ohm meter or continuity tester. One of the outside pins should have continuity when closed the other when fully open.

Hope this helps check yours.

Cutting the fully open wire only needed if your using NA harness for turbo with 5xx ecu. Disregard cutting wire otherwise.
 
And, if you like pictures ("Regina Book" version shown, LH should be the same)...

TPS-adjusting.jpg
 
Back
Top