Real Fiero Tech

if you can start it with ether(carb cleaner) but wont run without it then its a fueling issue.

pump is shot.
injectors are clogged.
injectors arent' opening(no signal from computer)
Injector drivers in cpu no workie.(no signal from computer)

Or *just maybe* an intermittent ECM power/ground... since he's tried two different ECM's with similar results.

it's getting fuel, just not igniting it very well... I played around with the FPR, and for sure got more fuel when I turned pressure up. I don't suspect a fuel delivery issue, but it is possible. I'm thinking there's a loose connection, but it's gonna be hard to find...

also, carb cleaner and ether are two different things.

What ignition are you running?

Are the injectors pulsing? Have you noided one or more to make sure they're getting consistent signal? I @$$ume you've checked injector fuses.

The Dark Side of Will wrote:What ignition are you running?

Are the injectors pulsing? Have you noided one or more to make sure they're getting consistent signal? I @$$ume you've checked injector fuses.

stock 60v6 ignition. all fuses checked good, one of the first things I checked. I haven't noided any injectors yet, it's kinda a pain in the dick to do on this car b/c the injectors are under the intake.

this is going to sound absurd, but I'm starting to think the problem is somewhere in the chassis harness. years ago before I started this swap, I had some odd issues similar to what I'm having now, I have another harness I might try and put in, but that's a pretty massive endeavor, so for now I'm going to try and continue troubleshooting and see what I can come up with otherwise.

ericjon262 wrote:

The Dark Side of Will wrote:What ignition are you running?

Are the injectors pulsing? Have you noided one or more to make sure they're getting consistent signal? I @$$ume you've checked injector fuses.

stock 60v6 ignition. all fuses checked good, one of the first things I checked. I haven't noided any injectors yet, it's kinda a pain in the dick to do on this car b/c the injectors are under the intake.

You're reading injector pulse width, so the ECM is alive. BUT, haven't noided injectors.

Absent input from the ECM, the coil pack by itself can run the engine with starting fluid.

Noid the injectors to determine if they're getting signal or not.

pull the upper intake, pull the fuel rail but leave the lines hooked up. disconnect the ignition system, and crank the engine. stand and look to see if your injectors are spraying fuel.
its shadetree but it works.

also test the injector harness and verify there is a proper ground. This shouldn't be taking this long to fix.

Shaun41178(2) wrote:pull the upper intake, pull the fuel rail but leave the lines hooked up. disconnect the ignition system, and crank the engine. stand and look to see if your injectors are spraying fuel.
its shadetree but it works.

also test the injector harness and verify there is a proper ground. This shouldn't be taking this long to fix.

lol, come work my job for a week and tell me how long it should take. where's your 500 hp dyno sheet?

The Dark Side of Will wrote:

ericjon262 wrote:

The Dark Side of Will wrote:What ignition are you running?

Are the injectors pulsing? Have you noided one or more to make sure they're getting consistent signal? I @$$ume you've checked injector fuses.

stock 60v6 ignition. all fuses checked good, one of the first things I checked. I haven't noided any injectors yet, it's kinda a pain in the dick to do on this car b/c the injectors are under the intake.

You're reading injector pulse width, so the ECM is alive. BUT, haven't noided injectors.

Absent input from the ECM, the coil pack by itself can run the engine with starting fluid.

Noid the injectors to determine if they're getting signal or not.

picked up a noid light the other day, haven't had time to run the test yet, but I'm taking some time off soon, so i should be able to take another look at this old pos

this is a very odd scenario, so with the 3800 PCM, I can get it to run for up two about 3 minutes, if I spray ether in it for the initial start. there's no way it's running for minutes off of a burst of ether in the intake. on that same note, if I give it a little throttle, it give s puff of black smoke out of the exhaust, so it's definitely got fuel. with the 3400 PCM, I can't get it to run for more than a few seconds at a time, much more like a no-fuel scenario, spray a little ether in, it jumps to life for a sec, then stalls and dies. I put an inline ignition tester on it to see what the ignition was doing, and it looks like it might be dropping spark with the 3400 PCM hooked up, it's not consistent while cranking the engine. I haven't yet tried with the 3800 PCM, but I expect a similar result.

well, ignition is more consistent with the 3800 PCM then the 3400 PCM... odd. I started it with the 3800 PCM, ran for about 2 or 3 minutes, I disconnected the only fuel injector I can reach with the intake on and got an interesting result, no change. I was about to plug the noid light into it when it stalled and died, and of course, now doesn't want to restart...

Did it restart later? (ie, was it flooded when it died?)

How is your main body ground doing?

body ground looks good, it doesn't seem like it's flooding, and when I spray starter fluid in it, if briefly chirps to life, much like you would expect from a no fuel scenario. I'm gonna try and work on it later this week when I have some time off. it runs ok when it's cold, but as it warms up, it dies.

I didn't read too much on your thread, so I don't know much about your setup or anything, but I had a similar issue early on in my 3.4 DOHC swap. When cold the motor would fire right up, but if it was warm it would not restart. For example go out to the car, cold start is just fine, and I drive it around for a half hour. Get to the store, turn it off, come back out and it won't restart. I'd need to wait a good half hour or so before it'd restart, and even then it struggled.

Turns out when Darth did the tune for the 42# injectors he forgot to adjust the startup fueling, and so the ECU was basing its startup fueling on 24# injectors, and over-fueling the car. He burned me another chip and everything was good.

So, possibly could be a warm start fueling issue.

it's not in the tune, it's a hardware issue somewhere, hard part is where? the PCM appears to be working, so I'm guessing it's in the wiring somewhere. maybe a wire got hot? got pinched? not really sure, I did hook up a noid light, and it was flashing, but only intermittently, which hopefully means the fault is in the injector wiring, but it's tough to say without taking the whole thing apart. I'm going to work on it for a bit today and see what I can come up with.

there were lots of things about the obd2 computer I really didn't like, the biggest was that the tunable parameters only went to 6400 rpm, my cam and heads should make power above that. with a fault somewhere in the engine management or wiring, I decided it was time to make some changes. I ordered up a MS3x for it, and have started installation. I'm setting it up for coil per cylinder operation with LS2 style coils, SFI, and flexfuel.

install so far:



it's going to be soft mounted to the firewall behind the passenger seat, I've set it up as a standalone, just add power and a switched IGN+ which will be used only to run a relay of the B+ buss bar(lower right bar between the MS3x and relay/fuse center) it should look a little prettier when it's done, but I'm not going to add loom to it until all the wires are run.

Progress.

I replaced the Main harness, everything from the C100 back has been either replaced, thoroughly inspected, or currently being built. I mounted the MS3x behind the passenger seat, using MSD mounts. I have commenced wiring everything up, ATM, it's a very organized mess.

[img]http://i473.photobucket.com/albums/rr98 ... 212909.jpg[/img]

[img]http://i473.photobucket.com/albums/rr98 ... 133655.jpg[/img]

the setup is far from perfect, but it should perform well.

beyond that, the replacement of the main harness showed me I was missing a metric shitload of interior screws, I picked up some more screws, and now my interior plastics are way more solid than they were, which should make it much more pleasurable to drive, and I welded in a 2x3 crossmember to an 88 cradle I have here so I can get started on remounting the engine and transmission better using mount bushings from here:

https://liquidironindustrie...ve-with-Bushing.html

the main thing I don't like is that they use 9/16" bolts, not metric.
started the mounts for the LS2 coils, they need slight reinforcement, but should work ok until I find a better way to mount them. I'm thinking about modifying a set of valve covers to mount them similar to how they are done on a stock LS1/2, but this should get the car running for now.

[img]http://i473.photobucket.com/albums/rr98 ... 0218_n.jpg[/img]

Updates

wiring is pretty much done, need to wire up the boost control solenoid, and close out the fuse/relay center and it will be ready for loom. I came up with a much simpler, and more effective coil mounting bracket setup, and am way happier with it, I've also made several plumbing changes to account for the flexfuel sensor, boost control solenoid, and setup a more effective crankcase ventilation system. I took my FPR apart to install a new fitting, and the diaphragm looked a bit distorted, so I'm going to replace it as well, just to be on the safe side. in parallel with all of this, I've begun working on installing C5 vette 13 inch front brakes on all four corners. the fronts I'm using an adapter bracket made by sluppy123 from Old Europe, the rear are going to be a one-off setup.