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Tips and tricks for TPI troubleshooting/diagnostics?


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I am in the midst of refurbing my stored 240Z. I just refreshed the fuel tank and corrected some issues with the pump and filter. I am now looking at components under the hood, as I am not able to get combustion. I have fuel to the injectors, and spark to the plugs. The ECU is triggering the fuel pump priming cycle properly now. I am checking and cleaning contacts and connections as I go. I have not yet pulled the plugs (new plugs in hand to install) nor have I tested the injectors yet. I just re-read JTR's TPI and TBI swap guide, which is interesting but not really applicable. I have also browsed my 87 Camaro shop manual, which seems almost completely reliant on code reading. I ordered a cheap tool to force the check engine light to flash codes, but I am wondering if anyone has tools, scanners, tips, tricks etc to recommend. I may still have an intermittent short somewhere in the harness, and I am looking for an easy way to trigger injectors and test for proper flow, as well as test the fuel regulator. I am on the verge of buying a kit to do that, if necessary. Any input welcome!

 

tannji

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I'm assuming you have a 165 ECM and likely the $32 ID software? Though convenient, you don't really need a special tool to pull the codes - ignition off, jumper between the "A" (system ground) and "B" (ECU pin GE12 (I think, check your diagram), "Diagnostic Test Terminal") pins on the ALDL connector, ignition on - will give the codes at the SES light, which itself is pulled low (to ground) at the ECU. It will also put you in limp-home mode, super-rich, retarded timing, injectors clicking merrily away, so on.

 

Also get yourself a "noid light". Autozone carries them (intermittently). It's a little bulb that plugs into the injector connector and blinks when it gets a signal. Great for determining if you're getting a signal during cranking. There are different styles, be sure you get one for your GM injectors. Cost about $2.00.

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Yeah, I had to dig around to find noid lights, too. The clerk at Autozone didn't even know what they were, a customer that overheard me asking pointed them out to me as I was walking out.

 

The $32 ID I was talking about is the identification of the software running on your computer. The most common one for the '165 ecu is 32 (hex). That is the number the computer identifies itself as, on the ALDL datastream. However, other software can be run on the same box, pretty much just by swapping out the plug-in PROM board (the "Memcal"), or by reprogramming a replacement EPROM. Most of my experience is with the '7730, which is very similar to the '165.

 

If you start making significant changes to the engine, you'll have to learn to tune the software on the EPROM. You could try buying one of those "performance chips", but the guy setting up that chip won't know anything about your particular motor, ending up at best with a "best guess" setup. It's kind of like ordering a carburetor tune from somebody who has never seen your motor, doesn't make sense. It's fun, though, to learn to do it yourself. There's a forum about it over on thirdgen.org, the "DIY PROM" forum. The stickies at the top are an excellent intro into the whole subject.

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LOL, never occurred to me that that was a hexanomial reference... and I was scratching my head about what software that could be = )

I am actually pulling this engine out for a different swap... but I didn't like the idea of giving it to someone with the famous last words: "it worked when I parked it". I have a buyer, and it will be a building project for his running TPI Camaro... but I wanted to accomplish getting it running again and learn that little bit extra before I give it to him. I just recieved an Amazon purchase: "How to Tune and Modify Chevrolet Fuel Injection" in the mail... Looks to be just the ticket for getting me up to speed on these motors, even if I am just about to get out of them = ) It's a shame, this setup really did run well with the 700r4, but I don't want an Auto, and I am looking to prove to myself that I do not want a V-8, either... We will see how that one turns out though = )

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