New truck to me, z24i electro-injection woes

[Notapilot69]

I'm already not registering it in CA, I'm not a resident! Carb is sounding better and better but have to fix the spark issue still 

 

Loss of spark on the neg side makes sense. The module is inside the distributor and can't be replaced per the FSM. I have one coming from a friend. Fingers crossed it works! 

[Charlie69]

If the one from your friend does not work let me know I have the distributor from a Z24I.  I do not know what year it is.

Edited August 12, 2020 by Charlie69

[Notapilot69]

Thanks charlie! I'll let you know. I appreciate y'all keeping up with this rollercoaster with me 

[Charlie69]

If you end up going to a Weber let me know I believe I have a spare carb Z24 intake manifold.

Edited August 13, 2020 by Charlie69

[datzenmike]

You'll need an older fuel pump.

[Charlie69]

I might have a good used factory fuel pump for carb.

[Notapilot69]

Going to try this new dizzy and go from there. Should be here next week. Thanks fellas

[Notapilot69]

Hello all. Finally got a "new" used dizzy installed. No change. Still falls on its face under full throttle. Only code is 21 - ignition signal. Any thoughts? I have no idea what it could be at this point. 

[datzenmike]

Over on the right (passenger) side inner fender are two small round black vacuum switches. You'll know them by a small black rubber hose and two wires on plugs to each. Pull the hoese off and plug them and try driving it now. Don't worry one shuts fuel off on deceleration and the other turns off the exhaust side plugs under heavy load. We should eliminate these as a cause.

 

 

[Notapilot69]

Sounds good Mike I'll try it. 

[Notapilot69]

On 9/8/2020 at 11:27 AM, datzenmike said:

Over on the right (passenger) side inner fender are two small round black vacuum switches. You'll know them by a small black rubber hose and two wires on plugs to each. Pull the hoese off and plug them and try driving it now. Don't worry one shuts fuel off on deceleration and the other turns off the exhaust side plugs under heavy load. We should eliminate these as a cause.

 

 

I don't have those i guess, looked everywhere on the passenger side fender. Two blue relays but they don't have any vacuum lines running to them. The hunt for the problem continues I guess. 

[datzenmike]

 

 

The two round black plastic things under the rubber hoses.

[Notapilot69]

On 9/10/2020 at 10:45 AM, datzenmike said:

 

 

The two round black plastic things under the rubber hoses.

nothin, I don't have those. Positive the TBI trucks had them?

On 9/8/2020 at 11:27 AM, datzenmike said:

On 9/10/2020 at 10:45 AM, datzenmike said:

 

 

[datzenmike]

No I'm not. Hoping to learn through yours.

[Notapilot69]

On 9/14/2020 at 5:10 PM, datzenmike said:

No I'm not. Hoping to learn through yours.

Looks like no switches. I'm trying to figure out what else could be cutting out the spark despite there being power to the coils. Maybe the two ignition modules? They're $50 a piece on rock auto I might bite the bullet and try them 

[Charlie69]

Mike what are these?

 

[datzenmike]

Altitude compensator on right and boost control valve on left.

[Icehouse]

You need a parts truck. haha Then you can just swap stuff until it's fixed.  My Z24i truck has a similar issue at 20% throttle when it's warm, luckily it's a 4x4 and you always need more then 20% to keep it going down the road at speed.  This tread sure makes me not want to try and fix it!  

[Notapilot69]

I definitely need a parts truck. A buddy is about to provide me with a new harness and coil modules. Maybe that'll do the trick. 

[Notapilot69]

Hello all, long time no post.. 

 

I got an ECU and a used Manifold/tbi from a guy in Reno. Going to swap the ECU in and see if there's any change. His truck wasn't running perfect before he parted it out but sounds like he was having fueling issues. I'm weary about the TBI.

 

I wanted to grab his harness since mine has been spliced a bunch, but didn't realize the body harness and engine harness is connected without any plugs or anything. What a horrible design! I'm not tearing apart the whole interior for that. 

[datzenmike]

The injectors are NLA and the D21 Hardbody Z24i injectors are not the same.

[Notapilot69]

I should specify, these parts came off basically my trucks twin. 86 720 z24i 4wd

[Notapilot69]

Tried the replacement ECU, no luck. Put my timing light on both intake and exhaust #1 coils while revving it, both are shutting off under load. I think it's just a matter of power to the intake coil shutting off the same time as the exhaust for some reason. Is there a way I can "hot wire" the coils to test this theory? 

[datzenmike]

Get a test lamp and see if power is being shut off on the + side of the coils first.  Don't forget this is a CAS crank angle sensor not a regular distributor. The ECU may shut off power to the coils OR it may just stop the ignition module from grounding the - side to produce a spark. There may be a good reason it doesn't want the engine to rev up.

 

I have a FSM for the '86 Hardbody and it doesn't have a diagram to show how the coils are powered or wired.

 

 

[Notapilot69]

9 hours ago, datzenmike said:

Get a test lamp and see if power is being shut off on the + side of the coils first.  Don't forget this is a CAS crank angle sensor not a regular distributor. The ECU may shut off power to the coils OR it may just stop the ignition module from grounding the - side to produce a spark. There may be a good reason it doesn't want the engine to rev up.

 

I have a FSM for the '86 Hardbody and it doesn't have a diagram to show how the coils are powered or wired.

 

 

Thanks Mike. Good idea seeing if its a power or ground problem. Makes sense the little ignitors are controlling the grounding with the CAS instead of controlling power to +. i tried "hot wiring" the coils off the battery and that didn't fix anything so i bet its something on the neg side. You da man! Will report back soon