North American 1992

[HPMotors]

Hey everyone. I'm in the USA and the car is also American, so please keep that in mind for any tips or advice you might have, I appreciate any thoughts.

I'm helping a friend try and get to the bottom of why their Elan will not start. He was driving the car and it shut off on him. Before bringing me into the situation he tried a new fuel filter, and verifying the fuel pump is working, verifying function of the inertial switch, checking for blown fuses, and a few other things. Since that time I have also re-verified those areas.

At the end of my testing, it appears that the ignition and mechanical aspects of the car are both as they should be. The car will crank up and run pretty much indefinitely when given an outside source of fuel (something like starting ether), and I've verified that the pump is working, and fuel pressure is making it to the fuel rail. However, when I checked with noid lights at the fuel injectors, they were not pulsing.

I've seen this behavior from malfunctioning immobilizer systems, except I'm not familiar with an immobilizer system that would allow a car to shut-off WHILE driving. So I'm currently unsure as to whether I'm looking at an immobilizer circuit issue or perhaps an injector driver issue failure in the ECU, or possibly a wiring continuity issue.

I'm looking for the following information on the immobilizer circuit; component location, testing methods if there are any, and a way to bypass it at least for testing. Also some better circuit information on the ECU system wiring diagram and component locations.

I'm looking for similar information for the ECU and it's wiring too. I'd like to verify continuity in the circuit for fuel injector 12v source and grounding/pulsing signals from the ECU as well.

Once again, this is for a North American version of the car. So I know components are located in different locations and wiring colors may be different. Thanks for any and all help.

[TorqueHorse]

Hi, sorry to hear you are having injector problems.

Now that you are a member of the forum, when logged in, you should be able to see a link to the Manuals section in the main navigation bar for the site.
There, you'll find the Service manual, Electrical manual, and Engine management manual (you'll want the "Closed Loop" version for the American/FED car) for starters, which have trouble shooting tips for the things you are describing.

Quick notes based on what you've observed so far. First, I don't think any FED versions were supplied with alarm immobilizers as stock, so if there is one, it would be an aftermarket thing for which wiring diagrams wouldn't be available here (but the fuel-shut off during crash/roll-over is included in those manuals). Second, being a fiberglass bodied car, folks complain about bad earths/grounding all the time. There are some ground points/rings for the electrical harness with the injectors that might be a place to start looking, if it is an intermittent issue that could arise while the person is driving and hits a bump, etc.

Others that have more experience with signals not getting to the injectors might chime in too. Welcome

[FunElan]

Maybe worth swapping in new injectors just to rule them out? Weird that it all shut off though...as those injectors fail in pairs.

[peteoddcar]

I think the loose plenum ground wires have given problems in the past.
Check the two inline connectors carefully between the body harness and engine dress harness.
By carefully I mean give them a tug test initially- they can make connection without being latched and then work out completely - this is especially likely if the car has had work done in that area above the transmission. It’s rare but terminals can snap inside the connector again a tug test on individual wires will find it
Also check there’s a 12v hot at the injectors when cranking.
Hope that helps

[HPMotors]

Thr me possibility that thr car doesn’t even have an immobilizer was considered. I’ll take a look at the section you recommended on the site here, and link the owner to this thread since he can look at those grounds and connectors mentioned. I honestly don’t recall what we saw when simply checking for 12v at rhr F.I. injector plugs. I know there’s some cars that are power switched, but that’s unusual. I’m assuming this have 12v at all times (with car in on or run) and are ground switched through the ECU. Thanks.