Background:

260Z with a 2.8L engine, Maxima 2.4L head, ZX ignition, GM TBI fuel injection with SU carburetors converted to throttle bodies

The car ran fine last Saturday. I pulled it out of the garage and parked it back in the garage about an hour later. I don't recall anything strange happening. Yesterday, I took off the distributor cap to take some pictures of the coolant temperature sensor. I put the cap back on after I finished taking pictures.

Today:

I went to start the car. I primed the fuel pump (audible) and tried starting. When it didn't fire, I thought to check the coil wire to the cap. I tried again with the coil wire connected, but it still didn't start. I re-seated the cap, checked the coil wire again, and hooked up a meter to check voltage at the coil. I could smell some fuel coming out the exhaust, too. 

There was good voltage at the coil. I hooked up a battery charger and put it in Start mode to make sure the battery voltage wasn't dropping too much during cranking. I also tried starting fluid. Still nothing.

Wondering if I fried the ignition module, I hooked up the timing light to cylinder #6 so I could look for spark while cranking. The light indicated spark while cranking.

I left the car on the battery charger while I ran an errand. When I got back, I had the wife turn the key while monitoring the timing light on #1 against the timing mark. I also used starting fluid. Timing was right, but still no fire.

Wondering if the plugs might be too fouled, I changed them out, putting NGK 7131s (not 7133). The old plugs were somewhat fouled, but I've seen worse. No fire with the new plugs. I also checked spark with the timing light on #1 and an inline spark checker on #2. The glow on #2 looked good, and the timing light still lit up. Still no fire.

Bottom line:

I have fuel, spark, and timing. I will verify compression, but I'm not sure how it would fail suddenly. What am I missing here? I will also try NGK 7133 plugs as soon as I can get them.

11 hours ago, SteveJ said:

OBD-I does use the flashing lights after you put the paper clip in the right terminals of the ECU. There is software that allows a PC to read the codes, too, without having to count blinks.

From my Fiero days (88), I have a small amount of experience with the system a little older than what you're working with.  I don't know if they called it the same thing in the later cars, but back in 88, they used a system they called "ALDL", which is Assembly Line Diagnostic Link.

And the most common software used to talk to it was "WinALDL". Not sure if any of that is what you're dealing with in the later version you have, but that's what it was "way back then".

I (thankfully) know very little about the GM EFI, but I do remember there was a there was a clear flood mode. Thankfully mine mostly just worked fine and I didn't have to troubleshoot. I did jumper the ALDL pins once or twice to blink the stored codes out on the check engine light, but that's about it.

In any event, glad you made progress with the issue and things seem to be pretty much back to where you want them.

5 minutes ago, SteveJ said:

I don't have Windows 7 Pro on the two laptops with Windows 7. The software does run in compatibility mode. I probably just need to see if replacement batteries are still available for the laptops. They are Toshibas, so that improves the chances. When I make it a priority, it could happen.

You should be able to download, install and run the Microsoft Virtual Machine on any version of Windows 7.

As for laptop batteries, I long ago gave up on running laptops without an AC power cord. My newest laptop is well over 10 years old, and works great, and will even run for a short time without AC power.

Ye

1 minute ago, Captain Obvious said:

From my Fiero days (88), I have a small amount of experience with the system a little older than what you're working with.  I don't know if they called it the same thing in the later cars, but back in 88, they used a system they called "ALDL", which is Assembly Line Diagnostic Link.

And the most common software used to talk to it was "WinALDL". Not sure if any of that is what you're dealing with in the later version you have, but that's what it was "way back then".

I (thankfully) know very little about the GM EFI, but I do remember there was a there was a clear flood mode. Thankfully mine mostly just worked fine and I didn't have to troubleshoot. I did jumper the ALDL pins once or twice to blink the stored codes out on the check engine light, but that's about it.

In any event, glad you made progress with the issue and things seem to be pretty much back to where you want them.

Yep, it's still WinALDL. Now you have to have the right driver to do the USB to serial cable. 

Unplugging the TPS while the car was on did the clear flood mode. I'm not sure if WinALDL could have cleared it. The car really did flood, so I smelled the gas in the garage. That got me believing I was still getting fuel when I wasn't. It just made it where I also dug around and found the lurking issue with the distributor that would probably have caused me problems in the future.

It was a frustrating day, but it got me to learn more about the system I installed, so that is a good thing.

19 hours ago, SteveJ said:

GM TBI fuel injection with SU carburetors converted to throttle bodies

I know this is off topic, but it intrigued me. After a web search I am still left with questions. 

What throttle bodies, how are they adapted, and what are you using for electronic management?

 

23 minutes ago, Racer X said:

I know this is off topic, but it intrigued me. After a web search I am still left with questions. 

What throttle bodies, how are they adapted, and what are you using for electronic management?

 

The throttle bodies are SU carburetors. The domes and float bowls have been removed, and the nozzle is plugged. The injectors sit in adapter plates that replaced the domes.

The kit is from Patton Machine (http://www.pattonmachine.com/) using a GM ECU from Affordable Fuel Injection (https://affordable-fuel-injection.com/). I used -6AN fittings and hose in the engine bay and selected a Walbro fuel pump because it fit better on the fuel pump mounting bracket on the 260Z. I had to run a tap into the throttle linkage for the shaft that operates the TPS. The headers already had an O2 bung hole courtesy of the gentleman I purchased them from.

I was able to tuck the ECU on the firewall in the passenger footwell on the firewall. I utilized many factory connections in the wiring, so it ended up being fairly clean.

The GM TBI also runs at low pressure (<15PSI), so you don't have to swap everything over to high pressure hoses. Another benefit is that there are TONS of GM TBI parts available along with plenty of information online.

I believe you could also work with Rick Patton to integrate a MegaSquirt ECU into the system to give better flexibility in tuning.

I totaled up the cost of swapping in 280Z FI parts and MS. It was more than this kit. This kit is also different from what you'll typically see in Z cars. Only a handful of people have done this kit.

I am tempted to do this on the 240Z when I make it a priority to get it running again.

 

 

Edited November 15, 20204 yr by SteveJ

Steve, do you know if the original GM system was actually designed to utilize two throttle bodies (with two injectors), or just one?  In other words, was your system originally designed to run one TBI but is now running two smaller injectors in parallel instead and letting the O2 sensor provide the feedback to level everything out?

Back when I was current with my GM stuff, there was just one throttle body and they used that system on some of the in-line engines. I don't know if they ever did two of them on a V-engine or something like that.

Chevy V-8 suburbans running TBI have two injectors in a pod mounted near the top of he throttle body

11 minutes ago, Captain Obvious said:

Steve, do you know if the original GM system was actually designed to utilize two throttle bodies (with two injectors), or just one?  In other words, was your system originally designed to run one TBI but is now running two smaller injectors in parallel instead and letting the O2 sensor provide the feedback to level everything out?

Back when I was current with my GM stuff, there was just one throttle body and they used that system on some of the in-line engines. I don't know if they ever did two of them on a V-engine or something like that.

In the drawings of the system I downloaded, I found two injector signals.

Having said that, there are photos on the Patton Machine website showing triple TBI setups.

39 minutes ago, SteveJ said:

The throttle bodies are SU carburetors. The domes and float bowls have been removed, and the nozzle is plugged. The injectors sit in adapter plates that replaced the domes.

The kit is from Patton Machine (http://www.pattonmachine.com/) using a GM ECU from Affordable Fuel Injection (https://affordable-fuel-injection.com/). I used -6AN fittings and hose in the engine bay and selected a Walbro fuel pump because it fit better on the fuel pump mounting bracket on the 260Z. I had to run a tap into the throttle linkage for the shaft that operates the TPS. The headers already had an O2 bung hole courtesy of the gentleman I purchased them from.

I was able to tuck the ECU on the firewall in the passenger footwell on the firewall. I utilized many factory connections in the wiring, so it ended up being fairly clean.

The GM TBI also runs at low pressure (<15PSI), so you don't have to swap everything over to high pressure hoses. Another benefit is that there are TONS of GM TBI parts available along with plenty of information online.

I believe you could also work with Rick Patton to integrate a MegaSquirt ECU into the system to give better flexibility in tuning.

I totaled up the cost of swapping in 280Z FI parts and MS. It was more than this kit. This kit is also different from what you'll typically see in Z cars. Only a handful of people have done this kit.

I am tempted to do this on the 240Z when I make it a priority to get it running again.

 

 

Awesome!

Thanks so much for the information.

That's a cool setup!

It works well as long as I don't do something stupid like leave the coil wire off the distributor. The up-side is that I found some good diagnostic info on the GM TBI system to help me if I have problems in the future.

   

So going back through the issue... Problem started simply because you left the coil wire off the distributor. You're thinking that damaged the ignition module and then with all the cranking with a damaged module, it badly flooded the engine? Is that the basic progression of events?